Monday 26 June
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08:00 - 18:00 #9915 - P001 Predictive factorsof unfavorable eventsafter gamma knife radiosurgeryfor vestibular schwannoma.
Predictive factorsof unfavorable eventsafter gamma knife radiosurgeryfor vestibular schwannoma.

OBJECTIVE

Gamma knife radiosurgery (GKS) for the treatment of vestibular schwannoma (VS) introduces risks to the facial nerve and auditory perception, and may involve post-treatment complications such as pseudoprogression, hydrocephalus, and other cranial neuropathies. This study of patients with VS who underwent GKSinvestigatedradiosurgical results, focusing on post-treatment complications and identifyingthe factors that predict such complications.

METHODS

We undertook a retrospective review of all VS patients treated with the PerfexionLeksellgamma knife between November 2007 and October 2010 at our institution. Patients who had a minimum of 12months of clinical and radiological assessments before and after GKS were included.

RESULTS

The 5-year serviceable hearing and facial nerve preservation values were 84.9% and 94.3%, respectively. Following GKS, 43 patients (18.30%) showed pseudoprogression, 15(6.38%) exhibited hydrocephalus, 22 (9.36%) showed trigeminal neuropathy, 14 (5.96%) showed vertigo or balance disturbances, and 25 (10.64%) showed facial myokymia. According to multivariate analysis, solid tumor nature was significantly associated with pseudoprogression and patient age was significantly associated with hydrocephalus. Patients receiving margin dose ≥ 13Gy or who underwent no prior surgical resection had a significantly higher probability of loss of serviceable hearing.Patients with smaller tumors had a trigeminal nerve preservation rate comparable to patients harboring larger tumors. Patients receiving margin dose < 13 Gy or older patients had a significantly higher probability of vestibular nerve dysfunction.

CONCLUSIONS

Further prospective studies should be designed to provide further insight into the exact relationship between the predictive factors we investigated and post-treatment complications.

Ji Hee KIM (Anyang-si, KOREA), Hyun Ho JUNG, Jin Woo CHANG, Won Seok CHANG
08:00 - 18:00 #10391 - P002 Deep brain stimulation as novel approach for Alzheimer disease: the emerging ethics of research rationale.
Deep brain stimulation as novel approach for Alzheimer disease: the emerging ethics of research rationale.

Question: Deep brain stimulation (DBS) has been investigated as potential intervention into the disease progression of Alzheimer’s disease (AD). There is an urgent need for improvement of existing dementia treatments. Any new investigational approach should adhere to high ethical requirements in order to protect participants’ safety with regard to uncertainties like unknown risk of side effects and adverse events. The assessment of such unknown risks is best conceived on a continuum from conservative protectionism to experimental adventurism (certainty-uncertainty continuum). Protectionism may impede scientific progress and can harm patients by hampering the development of new and better treatment possibilities. Because DBS involves (narrowly restricted) craniotomy, it belongs to “Class III” of medical devices implying “high risk” according to regulation by the European Parliament. This coarse classification into three classes (I, II and III) is unlikely to decompose the certainty-uncertainty continuum adequately into distinct categories. Other relevant features need also to be considered. Due to its reversibility and minimal-invasiveness, DBS paves the way for emerging new technologies and indications, although ethical justification of research rationale relying on conclusive evidence remains key. We recommend a linear relationship between risk and evidence: the riskier a novel approach, the higher the demands on quality criteria used to assess some research hypothesis.

Methods and results: We searched systematically (EMBASE and MEDLINE) for data on DBS for DBS (preclinically, case studies, investigational trials or feasibility studies and reviews), assessed the findings, and rated the published material according to established standards (AMSTAR-Checklist, Cochrane levels of evidence).

Conclusion: The first aim was to evaluate the research rationale for DBS of AD by examining the uncertainties associated with DBS’ mechanism of action, target selection and stimulation parameters specific to AD symptomatology and pathomechanism. The second aim was to classify the unknown risks and uncertainties on the basis of standardized criteria and the expert’s views held in the scientific community. Since the responsibility for novel investigational clinical trials is shared among ethics committees, researchers involved, and patients and caregivers affected, this classification will facilitate evidence-based decision-making and thus promote patients' informed consent.

Merlin BITTLINGER (Berlin, GERMANY)

Monday 26 June

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08:00 - 18:00 #9862 - P003 Shortening of battery-life of Activa-PC-generators in Deep Brain Stimulation under use of adaptors?
Shortening of battery-life of Activa-PC-generators in Deep Brain Stimulation under use of adaptors?

Objective The operative change of generators after DBS-surgery is necessary after several years, especially in patients with non-rechargeable generators. Since 2008 the new generation of Medtronic generators is available and the non-rechargeable Activa-PC replaced the Kinetra. The change from Kinetra to Activa-PC in patients who need new generators requires an adaptor when extension cables are not changed. From a clinical view the hypothesis was generated that the battery-life of Activa-PC generators is reduced under use of an adaptor. The aim of this study was to very this. 

Methods We retrospectively investigated patients suffering from Parkinson’s disease, dystonia and tremor who had an implantation of DBS electrodes and generators in our department. We investigated times from first-implantation to change or from change to change before and after change to Activa-PC with adaptor. The battery-lifes data were compared by Wilcoxon test.

In a second step the total electrical energy delivered was calculated for each patient before and after the change to Activa-PC with adaptor. Data were again compared by using Wilcoxon test.

Results

In our department up to now 20 patients who got an Activa-PC generator connected with an adaptor had a change of their new generator. One of these patients could not be included in further investigations.

From the 19 patients 16 were suffering from PD, one from tremor and two from dystonia. 

The mean durability of the Kinetra generator was 54,58 ± 13,77 months and 29,31 ± 5,84 months of the Activa-PC generator with adaptor.

Differences were significant using Wilcoxon test (p = 0,000276).

In order to reveal reasons for this shortening of battery-life, stimulation parameters were compared. In 16 patients stimulation parameters were documented. As the impedance was not available for all patients the total electricity delivered per impedance was calculated. For the Kinetra generator TEED/impedance was 290,5834 ± 96,6859 mW * Ω and for the Activa-PC 293,7803 ± 95,0821 mW * Ω. Differences were not significant using Wilcoxon test (p = 1).

Conclusion A shorter durability of Activa-PC generators under use of adaptors was seen in this study. This could not be reasoned by higher stimulation parameters.  

Patients have to be informed that durability of generators is shortened under use of adaptors. This might lead in some cases to a recommendation of rechargeable systems or to a change of the extension cables during the exchange of the generator.

Ann-Kristin HELMERS (Kiel, GERMANY), Isabell LÜBBING, Karsten WITT, Hubertus Maximilian MEHDORN, Michael SYNOWITZ, Daniela FALK
08:00 - 18:00 #10100 - P004 Usefulness of segmented leads in anatomical variants of the brain.
Usefulness of segmented leads in anatomical variants of the brain.

Introduction: Deep Brain Stimulation is an established treatment modality in various movement disorders including
dystonia. Due to the close proximity of the most common target point (GPi) to critical functional structures as the optic
tract and the internal capsule, therapeutic yield might be limited by side effects.
Recently, segmented DBS leads have been made available. This technique comes with the promise of increased
efficacy and side effect reduction. We hereby report on the first case of dystonia treated with directional lead deep
brain stimulation.
Materials/Methods: A 31 year old female presented with a 20 year history of generalized dystonia. The severe
additional
ataxic component left her wheelchair bound and she suffered from severe dysarthria.
The neurological complex was thought to be caused by a proven isolated Vitamin E deficiency
syndrome. MRI revealed structural changes of the basal ganglia anatomy with anatomical
distortions pronounced on the left (Image 1). Standard coordinates did not match the individual
anatomy of the patient. She therefore underwent bilateral GPi DBS surgery using direct
targeting of the left GPI. Directional leads were implanted in both hemispheres.
Results: After calculation of standard AC-PC coordinates (3.5 mm anterior, 22.0 mm lateral and 4.0 mm below MCP)
the trajectory was adapted guided by MRI anatomy to the lateral border of the optic tract. The posterior
communicating artery took a atypical course above the optical tract further limiting the approach. Targeting was
guided by three micro electrode recording tracts and a directional lead system (Vercise DBS, Boston Scientific) was
implanted in an all-in-one GA setting. Conventional stimulation caused a fast worsening of the dysarthria and painful
stimulation induced side effects. The segmented contacts were intensively tested at 90μs and 130 Hz in the
postoperative course. Distinct effect/side-effect patterns for each contact were observed.

Conclusions: Segmented leads allowing current steering offer new perspectives for DBS and will likely result in
increased treatment efficacy while reducing side effect at the same time. While this is true for well known disorders
and their targets (PD, generalized dystonia) this technique also yields the potential to treat disorders currently not
amendable to DBS as no good benefit/side-effect ratio could be achieved with conventional DBS.

Philipp SLOTTY (Düsseldorf, GERMANY), Youssef ABUSHABA, Jarek MACIACZYK, Jan VESPER
08:00 - 18:00 #10170 - P005 Dissociation between effect of STN-DBS and dopaminergic responsiveness 10 yerrs after STN-DBS surgery.
Dissociation between effect of STN-DBS and dopaminergic responsiveness 10 yerrs after STN-DBS surgery.

Objectives

Subthalamic deep brain stimulation (STN-DBS) has been presumed closely related to dopamine system.  Levodopa responsiveness has been discussed as an important predictor for success of STN-DBS for Parkinson disease (PD).  However, the long-term outcome of the relationship between STN-DBS and levodopa responsiveness are still unclear.  It is well known that lebodopa responsiveness for PD will fall year by year, but it is unclear whether STN-DBS responsiveness also falls in accordance with the fall of levodopa responsiveness.  We tried to clarify whether STN-DBS responsiveness for PD also falls as levodopa responsiveness more than 10 years after surgery.

Methods

We compared UPDRS part III scores in four different conditions with or without medication or DBS in seven PD patients who received bilateral STN-DBS and followed up more than 10 years.  Levodopa infusion test was also carried out in six of these patients. 

Results

STN-DBS showed statistically better improvement (17.2±7.5 points) in UPDRS part III score compared to medication (4.2±4.0 points). 

STN-DBS also showed better improvement (18.0±8.1 points) in UPDRS part III score compared to levodopa intravenous infusion (6.4±4.3 points).  Two patients developed hallucination and one patient developed facial dystonia after levodopa infusion. 

Conclusions

             It showed dissociation between STN-DBS responsiveness and levodopa responsiveness more than 10 years after surgery.  It also suggested that mechanisms of STN-DBS may isolated from dopamine system.

Kenji SUGIYAMA (Hamamatsu, JAPAN), Takao NOZAKI, Tetsuya ASAKAWA, Hiroki NAMBA
08:00 - 18:00 #10212 - P006 Deep Brain Stimulation in Parkinson’s disease : short pulse width increases the therapeutic window and the total energy delivered.
Deep Brain Stimulation in Parkinson’s disease : short pulse width increases the therapeutic window and the total energy delivered.

OBJECTIVES : We investigated the effect of short pulse width on the therapeutic window in Parkinson’s disease patients with deep brain stimulation in the subthalamic nucleus (STN).

METHODS : Five pulse width values ranging from 10 to 60 microseconds were applied randomly, in a double blinded fashion, during a single programming session. Ten patients with Vercise DBS leads, Boston Scientific, were included at least 3 months after surgery. The principal outcome was the therapeutic window, i.e. the difference between the amplitude threshold for pyramidal side effects (tolerance threshold) and the amplitude threshold for rigidity suppression (efficacy threshold). The secondary outcome was the total electrical energy delivered (TEED) by the neurostimulator on different pulse width values. 

RESULTS : The therapeutic window widened when pulse width decreased, with increasing tolerance and efficacy thresholds. The widest therapeutic window was obtained at 20 microseconds. In order to achieve the same clinical efficacy at 20 microseconds as at 60 microseconds, the total electrical energy delivered (TEED) was increased.

CONCLUSION : This double-blinded study confirms that low pulse width widens the therapeutic window. Nonetheless, TEED is increased to reach clinical efficacy when pulse width is shortened. Therefore, in routine post-operative management, we advocate for lowering the pulse width only if the therapeutic window is narrow, but not systematically.

Walid BOUTHOUR (Geneva, SWITZERLAND), Jennifer WEGRZYK, Shahan MOMJIAN, Vanessa FLEURY, Emilie TOMKOVA CHAOUI, Pierre BURKHARD, Paul KRACK, André ZACHARIA
08:00 - 18:00 #10224 - P007 Comparison of battery-life of non-rechargeable Generators in Deep Brain Stimulation- Kinetra versus Activa-PC.
Comparison of battery-life of non-rechargeable Generators in Deep Brain Stimulation- Kinetra versus Activa-PC.

Objective The operative change of non-rechargable generators after DBS-surgery is necessary after several years. Since 2008 a new generation of Medtronic generators is available and the non-rechargeable Activa-PC replaced the Kinetra. From a clinical view the hypothesis was generated that Kinetra has a longer battery-life than Activa-PC. The aim of this study was to verify these findings.

Methods We retrospectively captured the battery-life of every single patient after implantation of DBS electrodes and generators between 2005 and 2012 in our department due to Parkinson´s disease and compared the battery-life of the Kinetra- and the Activa PC groups. To calculate the current usage, the total energy delivered (TEED) was estimated for each patient using stimulation parameters one year after electrode implantation and compared the TEED in both groups.

Results 192 patients could be included in the study, among those 105 with Kinetra generators and 86 with Activa-PC generators. The mean battery-life of the Kinetra was significant longer (5,439 ± 0,199 y) than of the Activa PC (4,438 ± 0,165 y) (p = 0,023).

The mean TEED without impedance for the Kinetra group was 219,9031 ± 121,5310 mW * Ω and for the Activa-PC group 145,1321 ± 72,6729 mW * Ω, which implied significant lower stimulation parameters in the Activa PC group (p = 0,00038).

Conclusion A significant shorter battery-life of the new generator Activa-PC in comparison to the older model Kinetra was shown. Since higher battery consuming stimulation parameters as a reason could be excluded, a shorter battery-capacity is probable. Reasons for this e.g. the smaller size of the new implant, new functions or other causes could not be revealed by this study. 

Ann-Kristin HELMERS (Kiel, GERMANY), Isabell LÜBBING, Karsten WITT, Michael SYNOWITZ, Hubertus Maximilian MEHDORN, Daniela FALK
08:00 - 18:00 #10276 - P008 Usefulness of intraoperative neurophysiological monitoring in pallidal deep brain stimulation surgery in paediatric patients.
Usefulness of intraoperative neurophysiological monitoring in pallidal deep brain stimulation surgery in paediatric patients.

OBJECTIVES

Internal pallidal nucleus stimulation surgery for the treatment of dystonia is performed under general anesthesia in paediatric patients. The recording of evoked activity in the visual and motor cortex by intraoperative stimulation of the therapeutic electrodes could be useful to optimize their localization.

METHODS

We perform intraoperative electrical stimulation through the cerebral electrodes according to the usual therapeutic parameters while recording motor cortical and visual evoked activity. We collect the intensity in wich capsular and visual responses appear. We search for a possible correlation between the intraoperative findings and the response after the activation of the system.

RESULTS

Five patients aged between 7 and 16 years old have been operated. Visual evoked response was obtained in all of them at an intensity between 1 and 6 volts.Involvement of the internal capsule has been recorded in four of them between 4 and 6 volts. We did not change te location of the electrodes despite these findings. Postoperative CT monitoring showed the placement of the electrodes according to preoperative planning. In the patients that intraoperative motor stimulation was obtained, a lower threshold of adverse effects due to internal capsule involvement was observed in the postoperative period. In all cases we solved this using higher contacts for therapeutic stimulation.

CONCLUSIONS

Intraoperative neurophysiological monitoring may be useful to optimize the location of the internal pallidal electrodes and to predict the stimulation window due to its proximity to the internal capsule.

Santiago CANDELA (Esplugues de Llobregat-Barcelona, SPAIN), Alejandra CLIMENT, Vanesa THONON, Belén PÉREZ, Maria VANEGAS, Darío ORTIGOZA, Alejandra DARLING, Mariana ALAMAR, Jordi RUMIÀ, Enrique FERRER
08:00 - 18:00 #10278 - P009 Neuromate®(Renishaw®) robot assisted pallidal stimulation surgery in paediatric patients: accuracy and clinical results. Initial experience.
Neuromate®(Renishaw®) robot assisted pallidal stimulation surgery in paediatric patients: accuracy and clinical results. Initial experience.

OBJETIVES

We have initiated a pallidal stimulation program for the treatment of paediatric patients with dystonia. For the implantation of the cerebral electrodes we use the Neuromate® (Renishaw®) robot without associating a stereotactic frame. We intend to verify the accuracy of the robot for this technique and the effectiveness of it.

METHODS

We prospectively collect the distances between the electrodes and their respective planned trajectories merging the postoperative CT with the preoperative plan. We record the clinical results comparing preopeative and postoperative BFM (Burke-Fahn-Marsden) and UMRS (Unified Motor Rating Scale) scales and the complications derived from "hardware" and from stimulation.

RESULTS

We have operated five patients with ages ranging from 7 to 16 years, three with primary dystonia and two with myoclonus-dystonia (SGCE), with a follow up from 0 to 10 months. The average precision in the placement of the electrodes has been 1mm at the target level. In all cases there has been a clear clinical improvement as well as a significant reduction in the motor (62-73%) and functional (53%) BFM scale in the dystonic patients, and in the UMRS scale for action myoclonias (90 %). Also functional tests (62.5%-72%) in the patients with myoclonus due to SGCE mutation.There have been no hardware-related complications. In the first operated patient with primary dystonia dysartria limits intensity of stimulation in lower contacts of right electrode. This is the only complication derived from stimulation, probably due to medility of the electrode.

CONCLUSIONS

The Neuromate®(Renishaw®) stereotactic robot is an accurate tool for the placement of internal pallid electrodes in children with movement disorders. This is an effective and safe technique for the treatment of these entities.

Santiago CANDELA (Esplugues de Llobregat-Barcelona, SPAIN), Belén PÉREZ, Jordi MUCHART, Maria VANEGAS, Alejandra DARLING, Darío ORTIGOZA, Monica REBOLLO, Mariana ALAMAR, Jordi RUMIÀ, Enrique FERRER
08:00 - 18:00 #10289 - P010 Use of Multiple Trajectories in Deep Brain Stimulation (DBS) of the Nucleus ventralis intermedius (VIM).
Use of Multiple Trajectories in Deep Brain Stimulation (DBS) of the Nucleus ventralis intermedius (VIM).

Objective: Meanwhile the DBS targeting the VIM region is a standard procedure for the treatment of medical refractory tremor. In difference to other target points a direct visualization of the VIM in standard MRI´s is not possible. Therefore the intraoperative testing of symptoms is essential. For essential tremor data for clinical outcome in larger series exist, for other indications only case reports or small series were published. Indications, intraoperative methods and the optimal target are under discussion. The aim of this study was, to control our advancement for this target point.

Methods: We retrospectively analyzed data of all patients, who have undergone DBS-surgery with targeting the VIM, in our department from 2008 until 2016. We recorded age, gender, indications for surgery, number of microelectrodes, trajectory for the permanent electrode, intraoperative reduction of symptoms, reasons for avoiding the central trajectory, the coordinates of the active contacts of the permanent electrode and compared these data with the clinical outcome. Surgeries were all performed under local anesthesia with MRI-planning and intraoperative micro recording and testing of symptoms.

Results: In the 9 years period 89 DBS-surgeries targeting the VIM were performed, indications for surgery were Essential Tremor 68.5%, MS-Tremor 15.7%, PD-Tremor 4.5%, Orthostatic Tremor 3.4%, Holmes Tremor 2.2%, and other Tremor minorities 5.6%. Mean age of the patients was 61 years ± 14.7 years (range 15 years to 81years). Bilateral stimulation was performed in 83 patients (93.2%), unilateral in 6 patients.

Within the 172 implantations of VIM-electrodes we were able to use 3 or more microelectrodes for a three-dimensional view in 76.2%, 2 in 14.5%, 1 in 4.1% and no microelectrodes in 5.2%, regarding an individual risk evaluation.  For the permanent electrode the central trajectory was chosen in 60.5% 39.5% were implanted over periphery trajectories. Reasons were a better effect (14.7 %), less side effects (27% left and 14.6%) or sometimes a combination of both (23.6%) with sometimes just slight differences.

A good reduction of the symptoms was mainly shown intraoperatively (range from 20% effect up to 100% tremor reduction) and was compared to the symptoms reduction under permanent stimulation.

Conclusion: For the optimal outcome of the patients the intraoperative testing of the tremor symptoms over multiple trajectories is an essential addition to the MRI-based target planning.

Larissa PENNER (Kiel, GERMANY), Ann-Kristin HELMERS, Isabel LÜBBING, Steffen PASCHEN, Michael SYNOWITZ, Hubertus Maximilian MEHDORN, Daniela FALK
08:00 - 18:00 #10315 - P011 Brain shifts during deep brain stimulation found on immediate post-operative magnetic resonance image.
Brain shifts during deep brain stimulation found on immediate post-operative magnetic resonance image.

Introduction : Brain shift during deep brain stimulation (DBS) surgery result in mistargeting of electrode especially at second electrode insertion. Leakage of cerebrospinal fluid (CSF) is thought to be a cause of brain shifting.

Methods : Fourty five patients who took immediate magnetic resonance image (MRI) after DBS were retrospectively reviewed. Their air volume which represent leakage of CSF were segmented and calculated by 3D-slicer. Stereotactic coordinates of anatomical structures of anterior commissure, posterior commissure and structures that visualize better in MRI which represents location of common DBS targets (anterior thalamic nucleus (ATN), globus pallidus interna (GPi and subthalamic nucleus (STN)) are measured by Surgiplan software.

Results : Mean air volume measured was 14.7 cc. Brain shifting was most prominent in y axis (every structure, <0.01) and shift of more than 1mm in vector were seen in AC, ATN and both STN. Air volume was most contributing factor for brain shifts. Other factors such as sex, age, diagnosis for DBS, and operation time did not show significant relation in most targets. However, age seems to be related with air volume (p=0.086) and operation time showed trend toward increasing air volume (p=0.082). No significant difference was seen related to diagnosis of patients for DBS (p=0.104).

Conclusion : Though we failed to show operation time nor air volume result in brain shifting, brain seems moving toward direction of gravity. If operating elderly patients and taking long operation time, more posterior the actual target would be located.

Kyung Rae CHO (Seoul, KOREA), Jung-Il LEE
08:00 - 18:00 #10323 - P012 Does deep brain stimulation impair swimming performance: A randomized crossover study.
Does deep brain stimulation impair swimming performance: A randomized crossover study.

Objective: A stimulation-induced drowning hazard has recently been described in a patient with Parkinson’s disease, who developed a profound inability to swim following treatment with deep brain stimulation (DBS) at the posterior subthalamic area. The impairment was present despite normal neurological examination, and was reversible with withdrawal of stimulation. This study aimed to systematically determine whether DBS impairs swimming ability in a larger patient cohort.

Methods: 18 participants (including index case) with Parkinson’s disease (n=13), essential tremor (n=3), Tourette’s syndrome (n=1) or post-traumatic brain injury proximal tremor (n=1), treated with posterior subthalamic area (n=15) or globus pallidus interna (n=3) DBS, were assessed in a randomized, double-blind crossover study. Ability to swim with DBS ON versus OFF was compared within each participant, during three trials of freestyle and breaststroke, in a standardized pool environment. Outcome measures were distance covered, lap time, and Aquatic Skills Proficiency Assessment (ASPA) score.

Results: Paired-sample t-tests showed no statistically significant effect of stimulation status on measures of swimming ability for freestyle or breaststroke. However, clinically observable changes were seen in three participants. The index case displayed severe persisting impairment in all measures of swimming ability with DBS ON, which normalized with DBS OFF. With stimulation ON, the index case’s freestyle trial time increased by 54% (±2.0), distance covered reduced by 40% (±10.0), and ASPA score reduced by 69% (±0.0). The impairment predominantly involved difficulty with limb coordination and postural control, rendering him unable to swim effectively. Two participants showed clinically observable improvements in trial time and ASPA scores with DBS ON during freestyle and breaststroke.

Conclusion: The index case demonstrated that DBS can induce a serious and persisting swimming impairment that is not evident during routine neurological assessment. However, systematic analysis revealed no significant swimming impairment in other participants with DBS (n=17). There were no discernable features unique to the index case regarding pathology or stimulation site. Patients should be informed that DBS may rarely worsen swimming ability to a level affecting safety, and that DBS is unlikely to improve swimming above pre-DBS baseline.

Sarah MORGAN (Perth, AUSTRALIA), Omar BANGASH, Nataphoom BENJANUVATRA, Megan THORBURN, Irne DU PLESSIS, Christopher LIND
08:00 - 18:00 #10331 - P013 Learning more about the optimal anatomical position for deep brain stimulation in essential tremor patients: 3D visualisation of intraoperative stimulation test results.
Learning more about the optimal anatomical position for deep brain stimulation in essential tremor patients: 3D visualisation of intraoperative stimulation test results.

INTRODUCTION

The outcome of deep brain stimulation (DBS) depends heavily on the position of the implanted lead. After a preoperative anatomical planning, most groups collect numerous intraoperative data such as therapeutic effects induced by stimulation tests. To choose the final implant position, physicians “mentally” visualise all available data. The aim of the present work was to develop a method visualising intraoperative stimulation test results, patient’s images, electric field (EF) simulations for the patient-specific stimulation conditions and the corresponding therapeutic effects quantitatively evaluated by accelerometry. The application to five essential tremor (ET) patients should give a first idea about the optimal target position. 

METHODS

In Clermont-Ferrand University Hospital the anatomic target structure and the neighbouring structures were manually outlined, a target and a trajectory defined and two parallel trajectories per hemisphere intraoperatively evaluated. Stimulation tests were performed at 7 to 8 positions per trajectory and several stimulation current amplitudes. The therapeutic effect was evaluated using a previously published method based on accelerometry. Finite element models and simulations were performed for up to three stimulation amplitudes per position and EF isosurfaces (0.2V/mm) were extracted. For the 3D visualization of the numerous overlapping isosurfaces, we generated “improvement maps” by assigning to each voxel within the isosurfaces the highest tremor improvement. Those maps were visualized together with anatomical images, delineated structures and trajectories (Paraview, Kitware Inc). The method was applied to 5 ET patients implanted in the ventro-intermediate nucleus of the thalamus (VIM). Results were analysed by the neurosurgeon regarding the optimal implant position.  

RESULTS

The clinical teams were able to identify the optimal implant position for all patients with more ease and in less time compared to the routine discussion using pen and paper. Additionally, for 7 of the 9 improvement maps, the highest improvement region was found to be in the posterior subthalamic area, inferior and posterior to the VIM.

CONCLUSION

Improvement maps assist the clinicians in determining the optimal implant location of the chronic DBS lead. Results support findings of other studies that the fibre tracts in the posterior subthalamic area like prelemniscal radiations may be responsible for alleviating tremor in ET patients.

Ashesh SHAH, Fabiola ALONSO, Jean-Jacques LEMAIRE, Daniela PISON, Jérôme COSTE, Karin WÅRDELL (Linköping, SWEDEN), Erik SCHKOMMODAU , Simone HEMM-ODE
08:00 - 18:00 #10349 - P014 Combining tractography-based cortico-subthalamic connectivity and electrode position to inform post-operative management of stimulation settings.
Combining tractography-based cortico-subthalamic connectivity and electrode position to inform post-operative management of stimulation settings.

Diffusion-Weighted Imaging (DWI) and tractography allow noninvasive mapping of the structural connections of the brain, and may provide important information for optimizing Deep Brain Stimulation (DBS) treatment. The hyperdirect pathway (HDP), connecting the subthalamic nucleus (STN) with motor cortex, is assumed to play a key role in mediating the beneficial effects of DBS. Less is known about the HDP, connecting the STN to prefrontal regions, and whether this might play a role in adverse effects of DBS on cognitive function.

This study aims to apply recent methodological advances in DWI acquisition and analysis to generate a connectivity-based map of the STN. This can be combined with postoperative electrode position localization with the aim of guiding postoperative stimulation management.

By combining high spatial and angular resolution DWI data with state-of-the-art tractography frameworks (Constrained Spherical Deconvolution based probabilistic tractography) we delineated connections to the STN from motor cortex (MC) and prefrontal (PF) regions. Analyzing these connections, we identified regions of the STN that were dominated by MC or PF connectivity. Post-operative electrode positions were identified and correlated to manual STN segmentations and cortico-subthalamic motor connectivity using in-house Matlab tools.

Our method can delineate a motor connectivity gradient going from high in the dorsolateral aspect of the STN to low towards the antero-medial aspect. We also examined the motor connectivity gradient at each electrode contact point in seven patients with Parkinson’s Disease at 3 month follow up. We found no clear relationship between the ‘active’ (therapeutic) electrode contact and degree of STN-motor connectivity. However, when analyzing the electrode position with the manually delineated STN outline, we find that in 12/14 DBS leads the active contact is the one with the largest or second to largest STN volume coverage. Further analysis will be carried out to model the volume and connectivity of STN tissue stimulated with patient-specific stimulation parameters.

These preliminary results are promising and in line with the previously established anatomy of the STN. This framework could potentially help both neurosurgeons during pre-operative STN targeting and clinicians in optimizing the post-operative testing and management of stimulation settings.

Mikkel V. PETERSEN (Cleveland, USA), Torben E. LUND, Niels SUNDE, Karen ØSTERGAARD
08:00 - 18:00 #10409 - P015 Prepulse Inhibition is Modulated by Electric Stimulation of the Nucleus Subthalamicus in Parkinson´s Disease.
Prepulse Inhibition is Modulated by Electric Stimulation of the Nucleus Subthalamicus in Parkinson´s Disease.

Objective: Deep Brain Stimulation (DBS) of the subthalamic nucleus (STN) improves motor symptoms and quality of life in patients suffering from idiopathic Parkinson's disease (PD). How DBS of the STN affects neuronal network activity is not completely understood. Prepulse inhibition (PPI) of acoustic startle response (ASR) is an operational method to measure the pre-attentive filtering process known as sensorimotor gating. Changes in PPI indicate alteration in network activity as found in neuropsychiatric disorders like Parkinson’s disease. Thus in the present clinical study we investigated how STN-DBS affects sensorimotor gating in patients with idiopathic Parkinson's disease.

Methods: Nine patients with PD and treated with STN-DBS were investigated three months after implantation of the DBS-system (Medtronic, ACTIVA). The medication was stopped 12h before testing. After UPDRS measurement PPI was assessed under two conditions: without stimulation (STN-OFF) and STN high frequency stimulation (STN-ON) with the best UPDRS-III-improvement . PPI was tested with an Interval of 30, 60 and 100ms between prepulse and pulse.

Results: DBS of the STN (STN-ON) compared to no stimulation (STN-OFF) significantly increased PPI (F(1,8)=16,4; p<.01) in patients with Parkinson´s disease.

Conclusion: STN-DBS improves PPI in patients with Parkinson’s disease. Conceivably. PPI could be used as a surrogate marker to indicate how DBS modulates network activity. Our results render PPI measurement as a potential marker for disease- and target specific optimization of DBS settings independent of the examiner or the patient. Further studies integrating also results from functional imaging are warranted.

Jared SCHUSTER (Magdeburg, GERMANY), Imke GALAZKY, Maria KÜHNE, Silke SPECHT, Sven NULLMEIER, Hans-Jochen HEINZE, Tino ZAEHLE, Andreas KUPSCH, Jürgen VOGES, Patricia PANTHER
08:00 - 18:00 #10428 - P016 Postoperative lead movement after deep brain stimulation surgery and changes of stimulation area.
Postoperative lead movement after deep brain stimulation surgery and changes of stimulation area.

Introduction

Lead movement after deep brain stimulation (DBS) may occur and influence the area of stimulation. The cause of the displacement is not fully understood. The aim of the study was to investigate differences in lead position between the day after surgery and approximately one month postoperatively and also simulate the electric field (EF) around the active contacts.

Methods

23 patients with movement disorders underwent DBS surgery (37 leads). CT at the two time points were co-fused respectively with the stereotactic images in Surgiplan. The coordinates (x, y, z) of the lead tips were compared between the two dates (paired t-test). 8 of these patients were selected for the EF simulation in Comsol Multiphysics.

Results

There was a significant discrepancy (mean ± s.d.) on the left lead: x (0.44 ± 0.72, p < 0.01), y (0.64 ± 0.54, p < 0.001), z (0.62 ± 0.71, p < 0.001).  On the right lead, corresponding values were: x (-0.11 ± 0.61, n.s.), y (0.71 ± 0.54, p < 0.001), z (0.49 ± 0.81, p < 0.05).  No correlation was found between bilateral (n =14) vs. unilateral DBS, gender (n = 17 male) and age < 60 years (n = 8).  The lead movement affected the EF spread (Fig. 1).

Conclusion

The left lead tip displayed a tendency to move lateral, anterior and inferior and the right a tendency to move anterior and inferior. Lead movement after DBS can be a factor to consider before starting the stimulation. The differences in the area of stimulation might affect clinical outcome.

Nathanael GÖRANSSON (Linköping, SWEDEN), Johannes JOHANSSON, Fabiola ALONSO, Karin WÅRDELL, Peter ZSIGMOND
08:00 - 18:00 #10433 - P017 Comparison between intraopereative and chronic deep brain stimulation.
Comparison between intraopereative and chronic deep brain stimulation.

INTRODUCTION

The success of the deep brain stimulation (DBS) therapy relies primarily in the localization of the implanted electrode, implying the need of utmost accuracy in the targeting process. Intraoperative microelectrode recording and stimulation tests are a common procedure before implanting the permanent DBS lead to determine the optimal position with a large therapeutic window where side effects are avoided and the best improvement of the symptoms is achieved. Differences in dimensions and operating modes exist between the exploration and the permanent DBS electrode which might lead to different stimulation fields, even when ideal placement is achieved. The aim of this investigation is to compare the electric field (EF) distribution around the intraoperative and the chronic electrode, assuming that both have exactly the same position.

METHODS

3D models of the intraoperative exploration electrode and the chronically implanted DBS lead 3389 (Medtronic Inc., USA) were developed using COMSOL 5.2 (COMSOL AB, Sweden). Patient-specific MR images were used to determine the conductive medium around the electrode. The exploration electrode and the first DBS contact were set to current and voltage respectively (0.2mA(V) - 3 mA(V) in 0.1 mA(V) steps). The intraoperative model included the grounded guide tube used to introduce the exploration electrode; for the chronic DBS model, the outer boundaries were grounded and the inactive contacts were set to floating potential considering a monopolar configuration. The localization of the exploration and the chronic electrode was set according to the planned trajectory. The EF was visualized and compared in terms of volume and extension using a fixed isocontour of 0.2 V/mm.

RESULTS

The EF distribution simulated for the exploration electrode showed the influence of the parallel trajectory and the grounded guide tube. For an amplitude of e.g. 2 mA/2 V, the EF extension of the intraoperative was 0.6 mm larger than the chronic electrode at the target level; the corresponding difference in volume was 76.1 mm3.

CONCLUSION

Differences in the EF shape between the exploration and the chronic DBS electrode have been observed using patient-specific models. The larger EF extension obtained for the exploration electrode responds to its higher impedance and the use of current controlled stimulation. The presence of EF around the guide tube and the influence of the parallel trajectory require further experimental and clinical evaluation.

Fabiola ALONSO (Linköping, SWEDEN), Dorian VOGEL, Karin WÅRDELL, Simone HEMM
08:00 - 18:00 #10444 - P018 Identification and surgical management in suboptimal DBS lead placement.
Identification and surgical management in suboptimal DBS lead placement.

Objective: If outcome of DBS treatment does not meet expectations, identification of suboptimal lead placement needs to be placed on objective grounds, as a tool for planning lead revision and for deciding on details of the surgical procedure.

Patients and Methods: Electrode positions are routinely controlled by fusion of post-surgical CCT to pre-surgical stereotaxy CT and to the on-fused T2 and contrast enhanced T1 weighted MRI. Additional post-surgical MRI may be used for confirmation. Electrode tip and electrode catheter are compared to the the pre-surgical planning of tip and trajectory and intra-operative decision on final trajectory. Depending on clinical development, early or late lead revision is indicated in case of insufficient (unilateral) response, persistent fluctuations or walking disturbance. If a trajectory different to the first chosen is feasible, a one-step-procedure is considered whereas a serious conflict between existing site and new plan are found, a two-step procedure with explantation and new implantation is chosen. Standardized control of clinical status before and thereafter by UPDRS-III at Med-On/ Med-Off and Stim-On/ Stim-Off conditions are included in the protocol.

Results: Within a series of 130 consecutive DBS procedures for PD, indication for lead revision was set in 4 patients (3%) and in 10 further transferred after DBS elsewhere. In two patients two-step-procedures were chosen and in 12 patients single step operations were possible by fluoroscopy control of stepwise insertion of new microelectrodes and removal of old electrodes. Distance of electrode sites to planned ideal site ranged from 2mm to 8.4 mm. Except for two patients who were lately identified as suffering from multi system atrophy MSA, all the other 12 patients showed marked improvement in overall mobility and satisfaction with decision for lead revision and outcome.

Conclusion: Suboptimal outcome in DBS deserves precise investigation of lead location and may be successfully treated by lead-re-positioning. In view of severe lead artefacts on post-surgical MRI especially in the STN region, the use of the pre-surgical MRI is essential.

Cordula MATTHIES (Wuerzburg, GERMANY), Robert NICKL, Patrick FRICKE, Martin REICH, Ralf-Ingo ERNESTUS, Jens VOLKMANN, Frank STEIGERWALD
08:00 - 18:00 #10446 - P019 Neurosurgical experience with segmented lead implantation for directional deep brain stimulation.
Neurosurgical experience with segmented lead implantation for directional deep brain stimulation.

Objective:

The feasibility of applying new directional leads (D-leads) in standard DBS procedures, possible difficulties or complications were the focus of this study.

Background:

Deep brain stimulation is mainly used for treatment of movement disorders. Despite high precision in electrode placement, side effects can occur by stimulating adjacent fibers or nuclei by the volume of tissue activated (VTA). Leads with smaller electrode contacts by horizontal segmentation into three contacts instead of one ring contact are designed to apply and to direct smaller stimulation volumes.

Material and methods:

31 patients (23 male, Ø age 59,9, 27 PD, 1 dystonia, 3 tremor, 3 unilateral) underwent a DBS procedure with 59 segmented leads. Stereotactic planning, micro-electrode recording and testing were identical to the previous procedure. The decision for directional leads was made intraoperatively, if test stimulation through the microelectrodes indicated a narrow therapeutic window. Lateral fluoroscopy was used to control implantation of the definite DBS lead. In contrast to standard electrodes not only the depth and possible sagittal deviation from the planned trajectory was important, but also the rotation of the electrode, which was controlled by alignment of a X-ray marker above the electrode level. For placing the two middle contacts with D-lead components at the spot of best response, the lowest tip was planned to be placed about 3 mm deeper than usual.

Results:

In three cases complications occurred (1 subcutaneous hematoma, 1 electrode dislocation, 1 brain edema) not different from conventional lead implantation. Slightly longer fluoroscopy time was needed for D-leadplacement compared to conventional leads (415.53 vs. 32896 Gycm²; p=0.09). Mean operation duration did not differ between either lead type (08:59 vs. 08:55 h:min). ). In early follow-up, in most patients at least unilateral D-lead segment has been activated for chronic stimulation. 

Conclusion:

From a surgeon’s point of view, the exact implantation of the directional leads in a correct horizontal mode is slightly more challenging than a conventional DBS lead, but feasible. The higher x-ray-dose is minimal and surely acceptable in view of the estimated long-term advantage. Prospective studies to compare ring-mode-stimulation with directional-stimulation are needed and are already in process.

 

Patrick FRICKE, Robert NICKL (Würzburg, GERMANY), Frank STEIGERWALD, Martin REICH, Ralf-Ingo ERNESTUS, Jens VOLKMANN, Cordula MATTHIES
08:00 - 18:00 #10447 - P020 Comparison of lead localization in postoperative CT versus MRI.
Comparison of lead localization in postoperative CT versus MRI.

Evaluation of lead position accuracy may be accomplished by postoperative CT or MRI. Image distortion induced by the lead contacts in MRI question the accuracy and usefulness of this technique. Here, we compare the electrode position in postoperative CT and MRI by direct fusion of both modalities in DBS for Parkinson's Disease (PD).  Therefore, visual electrode selection and related determination of stimulation parameters in post-OP MRI or CT-MRI fusion is of rising importance

Method:

After DBS 9 subjects (2 dystonia, Ø age 57.7, 8 male)were investigated by postoperative imaging including MRI T1-MPRAGE (3Tesla, Trio, Siemens Inc, 1mm slices) and CT-scan (64-channel, Philips, 1mm axial slices) at a minimum of 4 weeks post-operatively to avoid pneumocephalus artefacts. Image analysis was performed in three steps, first direct image fusion of postoperative MRI T1-MPRAGE and postoperative CT was performed, second anterior and posterior commissure distance (AC_PC) and its midpoint were identified and third coordinates of the most distal electrode contact tip relative to AC_PC-midpoint were registered. These coordinates were compared in either modality and the average difference of the electrode position was measured taking modality induced MRI or CT artefacts into account as previously described.1,2

Results:

18 electrodes were analyzed. Average vector distances of the distal electrode tip in post-op MRI versus CT fused images was 1.04mm (range 0.1- 2.74mm). Further statistical analysis showed special differences in z coordinates, with significant deeper electrode position in CT versus MRI by a mean of 0.61mm (SD 0.9 mm, p = 0.03*), but no statistically significant differences in other planes by either technique.

Discussion:

Comparison of electrode localization showed on average differences below pixel resolution, although, in few individuals discrepancies above 2 mm were detected. In most patients a systematic deeper localization of the most inferior electrode contact was identified by CT compared to MRI. These findings could be of clinical relevance in attempts of prediction of neurostimulation effects by VTA models. For optimal implementation of postoperative MRI into the control and programming planning work flow, these cases need further systematic analysis in order to identify a gold standard for lead localization.

Robert NICKL (Würzburg, GERMANY), Martin REICH, Patrick FRICKE, Frank STEIGERWALD, Jens VOLKMANN, Ralf-Ingo ERNESTUS
08:00 - 18:00 #10450 - P021 A device-based quantification and assessment of tremor in deep brain stimulation patients.
A device-based quantification and assessment of tremor in deep brain stimulation patients.

Background:

Deep brain stimulation (DBS) is an established method for the treatment of movement disorders, such as in Parkinson’s disease or essential tremor. The involuntary tremor movements occur primarily in the upper limb. In clinical practice, the physician’s visual observations provide the basis for intraoperative test stimulations and stimulator reprogramming. However, this approach is highly subjective. Objective measurements may improve clinical practice by quantifying the severity of tremor and other relevant scores.

Objectives:

Sensor-based information can help physicians to fine-tune DBS parameters to suppress tremors while minimizing the energy delivered to the brain. In this context, we developed a wearable sensor with a software tool to capture, filter and analyze sensor data online.

Methods:

Our initial focus is to quantify and classify pathological hand tremor, using both commercially-available and our custom-built device. We measured kinematic and bioelectrical activity on the patient’s forearm. To assess tremor in real-time, we developed a semi-automated software tool (based on custom-written MATLAB™ software). Bandpass-filtered tremor-dominant acceleration waveforms of the respective hand tremor can be recorded and analysed online for progressive status tracking during either the intraoperative test stimulations or reprogramming sessions of the implanted pulse generator. To this end, we analyse signal components of relevant movement events in the power spectrum and statistical metrics in the time domain.

Results:

Our study focuses on the principal dynamics of DBS input–output relationships. In practical terms, we can reliably identify relations between clinical outcomes capturing tremor dynamics and changes in electrical stimulation amplitude. Our preliminary results demonstrate that the developed techniques could be utilized to help clinicians to find optimal stimulation parameter settings. In addition, multiple observations during reprogramming sessions of deep brain stimulators have shown that features extracted from the wearable sensor data correlate with clinical rating scores.

Conclusion:

This work presents a first step toward the optimization of clinical outcomes for tremor patients based on systematic data capture and analysis. The future work will focus on pathological tremor modelling and on the long run to check, if the proposed signals may be usable for self-steering feedback controlled stimulators.

 

 

Rene Peter BREMM (Belvaux, LUXEMBOURG), Jorge GONÇALVES, Klaus Peter KOCH, Frank HERTEL
08:00 - 18:00 #10477 - P022 Accuracy of stereotactic electrode placement in deep brain stimulation by intraoperative computed tomography.
Accuracy of stereotactic electrode placement in deep brain stimulation by intraoperative computed tomography.

Introduction: The purpose of this study was to evaluate the accuracy of stereotactic electrode placement in patients undergoing deep brain stimulation by using pre- and post-operative stereotactic computed tomography (CT).

Material & Methodes: 23 patients with movement disorders (Parkinson disease (n = 7), tremor (n = 9), dystonia (n = 7)) treated with bilateral deep brain stimulation (DBS) (overall 46 target points) were investigated. The target point of the electrode was planned stereotactically in combination with a pre-operative stereotactic helical computed tomography (CT). A post-operative CT, which was carried out still in the operating room while the patient had the stereotactic frame on the head, was performed in order to control the position of the electrodes in relation to the previously planned target point. The position of the four electrode contacts was measured according to the Talairach space (AC-PC line) and compared with the coordinates of the planned target point. Image fusion by anatomical landmarks or the next day and other electrode positions than the calculated center electrode position in the 5 electrode carrier Ben’s Gun were an exclusion criterion.

Results: The mean spatial distance of planned target perpendicular to the electrode was 1.32 ± 0.75 mm.

Discussion: These results show the high accuracy of stereotactic implantation of DBS electrodes assisted by pre-and postoperative image fusion with computed tomography (CT).

Wilhelm EISNER (Innsbruck, AUSTRIA), Florian SOHM, Sebastian QUIRBACH, Thomas FIEGELE
08:00 - 18:00 #10505 - P023 Rescue DBS leads for persistent symptomatology following Subthalamic deep brain stimulation for Parkinson's disease.
Rescue DBS leads for persistent symptomatology following Subthalamic deep brain stimulation for Parkinson's disease.

While DBS of the STN is highly effective in treating PD motor symptomatology, a subset of patients may continue to be troubled by refractory DBS-responsive symptoms, despite appropriate lead placement and clinical optimization. Out of approximately 600 deep brain stimulation surgeries performed at our center over 10 years, 6 STN DBS patients (5 bilateral, 1 unilateral, 1 of whom underwent initial surgery at a different institution) received “rescue” DBS targeting a second brain area for additional control of their Parkinson’s symptoms. All patients had reasonable lead placement and tolerability, and experienced clinical improvement with STN stimulation. Unilateral globus pallidus interna (GPI) electrodes were placed in three patients for persistent dyskinesias, and three patients underwent unilateral ventral intermediate (VIM) thalamic electrode placement for breakthrough tremor.  All patients suffered from relatively young onset PD (median age of onset 34 years old, range 17- 43). The median age at surgery was 45 years old (range 36-53 yo). The median interval from PD onset to the first DBS surgery was 9 years (7-27 years), and between the first and second surgeries was 3 years (0.5-12 years).

In the three patients who received GPI leads, the symptoms that led to the first STN surgery were painful dystonia, dyskinesia and fluctuations. Although both improved with STN stimulation, they continued to experience troublesome dyskinesias despite reasonable lead placement, extensive programming and medication adjustments. All three reported significant improvement of dyskinesia following addition of the GPI rescue lead.

In three patients requiring addition of a VIM lead, all had severe tremor and one also had dyskinesia. All experienced moderate degree of tremor improvement with STN DBS but required high settings and continued to experience tremor breakthrough. All three subsequently experienced further tremor improvement, although two patients continued to have some residual positional tremors that impacted certain activities.

These cases, along with similar reports from other centers (Cook et al. 2015; Matias et al. 2016) demonstrate the potential for a second “rescue” lead – GPI for dyskinesias and VIM for tremor - to provide additional benefit in select cases.

Arash FAZL, Michael POURFAR, Alon MOGILNER (New York, USA)
08:00 - 18:00 #10521 - P024 Dual-target Deep Brain Stimulation for Co-morbid Tourette’s syndrome and Tardive Dyskinesia.
Dual-target Deep Brain Stimulation for Co-morbid Tourette’s syndrome and Tardive Dyskinesia.

Emerging evidence has demonstrated DBS to be efficacious in the treatment of refractory Tourette’s syndrome (TS), although the optimal target remains a matter of debate. Pallidal DBS has been reported as effective in treating both TS as well as Tardive Dyskinesia (TD). We present a case of a patient with co-morbid TS and TD referred for surgical intervention.
A 59 YO female with TS since childhood was referred to our center. Her condition was complicated by haloperidol-induced TD, characterized by facial movements and teeth grinding. Multiple medication trials were attempted, limited by side effects including worsening of tardive movements. The frequent neck tics caused radicular symptoms of severe neck and left shoulder pain. Initial exam demonstrated recurrent bruxism with tongue movements, brow lifting and frequent neck jerking movements. YGTSS: 18+0+30=48, YBOCS: 5+4=9.
The decision made to implant both CM thalamic and pallidal leads bilaterally. She underwent staged dual-lead DBS, with the left hemispheric leads followed by the right three weeks later. The GPI leads were initially programmed alone with improvement in teeth grinding but not tics leading to introduction of thalamic stimulation one month later with subsequent improvement in tics.
Postoperatively, her tics significantly diminished and her neck and shoulder pain completely resolved. Her teeth grinding transiently improved then returned despite several programming adjustments. She experienced continued OCD behaviors. 10 months post-DBS, her YGTSS: 8+0+10=18, YBOCS: 0+8=8.

Conclusions:

  1. Simultaneous GPI and CM thalamic stimulation has proven well tolerated with no apparent stimulation-related side effects beyond those typically encountered with higher stimulation parameters with either target.
  2. Thalamic stimulation led to a significant and sustained improvement in tics with less impact on OCD behaviors.
  3. Meige-like tardive movements initially improved when only GPI DBS was initiated but recurred without significant lasting improvement to date.
  4. Determining whether GPI or CM stimulation alone or in combination is most responsible for tic improvement is challenging but it appeared that tic improvement became more apparent following introduction of CM stimulation.

 

Michael POURFAR, Alon MOGILNER (New York, USA)
08:00 - 18:00 #10533 - P025 Limiting brain penetrations during DBS surgery using an interventional-MRI guided DBS placement platform.
Limiting brain penetrations during DBS surgery using an interventional-MRI guided DBS placement platform.

Abstract title:

Limiting brain penetrations during DBS surgery using an interventional-MRI guided DBS placement platform

Background:

Deep brain stimulation (DBS) has become a well-accepted surgical treatment option for medically refractory Parkinson’s disease.  The surgery traditionally has involved stereotactic techniques refined with microelectrode (MER) mapping and stimulation of the target.  These techniques may require multiple trajectory passes through the brain prior to final implantation of the leads.  There is evidence that the number of trajectories may increase the risk of hemorrhage.    Interventional-mri guided (iMRI) DBS is a new technique that allows real-time image guided implantation of the electrodes without MER or stimulation, limiting the number of passes through the brain.

Material/Methods

50 patients underwent iMRI guided implantation of DBS electrodes for Parkinson’s disease since September of 2011.   There were 23 female and 27 male patients.  Mean age was 67.8.  (SD 7.14)  Mean years with PD prior to surgery was 9.77 years (SD 5.73).  All patients underwent DBS implantation with the ClearPoint technique using a diagnostic MR scanner.  11 were implanted using a Siemens Symphony 1.5 T scanner, and 39 were implanted using a Siemens AERA 1.5T scanner. All had bilateral implants with 47 having had the STN as the target and 3 the GPi.

Results

100 leads were implanted via MRI guided technique.  For six leads, a second trajectory was performed for improved accuracy.  Our overall mean error in accuracy was 0.56 mm on the left and 0.63 mm on the right without the corrective trajectory.  With the correction our overall error was 0.56 mm on the left and 0.53 mm on the right.  We had an average of 1.06 passes for 100 DBS implants.  This compared to an average of 1.69 brain passes in our cohort of MER guided patients. (P<.005)

Conclusions

iMRI guided DBS implantation allows implantation of leads with reduced number of brain penetrations.  This may reduce the risk of surgical related hemorrhages compared to traditional MER guided surgery.

Azmi HOOMAN (Oradell, USA)
08:00 - 18:00 #10560 - P026 Combination of CT angiography and MRI in surgical planning of Deep Brain Stimulation.
Combination of CT angiography and MRI in surgical planning of Deep Brain Stimulation.

Background: For safe DBS planning an accurate visualization and localization of vessels is mandatory. Contrast enhanced (ce) MRI depicts both arteries and veins. Computed tomography angiography (CTA) detects arteries with high geometric accuracy. We routinely combine both modalities for DBS planning. In this study we analyzed the number and location of vessels visible in ceMRI and CTA in each trajectory.

Materials and Methods: A total of 222 trajectories in a consecutive series of 113 patients who underwent DBS operations from March 2014 to February 2017 were included. In all patients a preoperative T1-weighted 3D ceMRI sequence, a CTA and a postoperative native CT scan were available. In all 222 trajectories the number of veins and arteries in a 5 mm diameter around the planned trajectory was counted in both modalities (T1w-3D-ceMRI and CTA). If a vessel was visible in both modalities the distance was measured.

Results: A total of 371 vessels were counted in a total of 222 trajectories. 240 vessels (65%) were visible in both modalities. In 134 vessels we detected a difference of the vessel’s location with an average distance of 1.24 mm (SD 0.58). 81 vessels (22%) were visible only in ceMRI, 50 vessels (13%) only in CTA. We had a total of 4 bleedings in 3 patients (1.8% per lead) of which 1 was symptomatic (0.45%). All of them were implants into the subthalamic nucleus, one with a posterior approach. In all but one we performed microelectrode recording.

Conclusion: The majority of vessels were visible in both modalities. However, in more than half of these cases the location was not identical. Here, the location in CTA can be regarded as ground truth. Moreover, both CTA and ceMRI depicted vessels not seen in the other imaging modality. We therefore assume that the combination of both imaging modalities for DBS planning increases the chance to detect vessels along the planned trajectories, thus reducing the risk of intracranial bleeding. This assumption is supported by our low bleeding rate of 1.8%.

Marie Therese KRÜGER (Freiburg, GERMANY), Volker Arnd COENEN, Karl EGGER, Peter REINACHER
08:00 - 18:00 #10587 - P027 Rechargeable pacemaker technology in deep brain stimulation: a step forward, but not for everyone.
Rechargeable pacemaker technology in deep brain stimulation: a step forward, but not for everyone.

Objective:

Since a few years rechargeable pacemaker technology is available in deep brain stimulation. This technical innovation becomes more and more important in clinical practice, particularly for patients with a need for high energy delivery. Unforeseen handling issues, however, may compromise its use in certain patients.

Methods:

Over a period of ten years, 360 patients underwent deep brain stimulation for various indications. Rechargeable pacemakers are increasingly used upon replacement after battery depletion. Despite meticulous screening for suitability, we had to switch battery to non-rechargeable technology because of unforeseen technical difficulties in two patients.

Results:

A 73-year-old man with a high cognitive performance with Parkinson's disease, underwent bilateral deep brain stimulation in the internal globus pallidus. Pulse generators were replaced because of battery depletion in 2-year intervals. At the time of third replacement, it was decided to use rechargeable technology because of the relatively frequent need of pacemaker replacements. Two years later the patient requested to remove the pacemaker and reimplant a non-rechargeable once more because of increasing problems with handling of the recharger and inconvenience with the daily monitoring of the battery level.

A 62-year-old woman underwent bilateral deep brain stimulation in the nucleus accumbens for alcohol addiction. She needed biennial pacemaker replacements, the pacemaker was replaced against a rechargeable device at the time of the second replacement. Two years later system malfunction was detected with fracture of the extension cable secondary to twiddler's syndrome. The patient for the main part had had increased difficulties recharging the battery.

Conclusions:

Rechargeable pacemakers undoubtedly are a step forward in providing standard of care medical treatment. Many patients stand to benefit from rechargeable technology, smaller devices and fewer replacement operations. However, with new technology we also have new requirements concerning technical capabilities and compliance. Although removal of a rechargeable device before end of service of the battery and replacement with a non-rechargeable pacemaker poses an undue economic burden, it may be the only solution under certain circumstances to guarantee the benefit of chronic stimulation.

Joachim RUNGE (Hannover, GERMANY), Mahmoud ABDALLAT, Assel SARYYEVA, Andreas WLOCH, Joachim K. KRAUSS
08:00 - 18:00 #10589 - P028 Improvement of dystonic storm after relocation of pallidal electrodes in dyt-6 positive generalized dystonia.
Improvement of dystonic storm after relocation of pallidal electrodes in dyt-6 positive generalized dystonia.

Objective:

Dystonic storm is a rare but life threatening condition. DBS or radiofrequency lesioning have been used in severe cases, however, there is no agreement on the optimal target. Patients who had already previous basal ganglia surgery pose a particular challenge with limited treatment options available.

Methods:

An 11-year-old boy with pallidal DBS for treatment of DYT-6 positive generalized dystonia since 2 years developed severe dystonic storm. After implantation of DBS electrodes at age 9 his condition had improved for more than 2 years. Upon the occurrence of dystonic storm, re-programing of DBS could not ameliorate the severe status dystonicus. Only sedation with high dose benzodiazepines, baclofen, gabapentin and trihexyphenidyl resulted in transient improvement.

Results:

The BMFDR motor score on admission was 138. MRI imaging showed positioning of the DBS electrodes in the globus pallidus internus (GPi), however, more lateral and posterior than at the usual target. It was decided to reimplant the GPi electrodes and to implant thalamic Vim electrodes in addition. Early postoperatively this resulted in marked and immediate improvement of dystonic storm (BMFDRS 100,5). At 12-month follow-up, there was remarkable benefit and the patient could walk and attend school without medication.

Conclusion:

Dystonic storm may develop despite periods of beneficial response to pallidal DBS for several years. If electrodes are no optimally placed in the posteroventral lateral GPi, repositioning should be considered, which might not only abate status dystonicus, but also provide lasting benefits.

Luisa CASSINI ASCENCAO (Hannover, GERMANY), Martje E. VAN EGMOND, Marinus OTERDOOM, Assel SARYYEVA, Joachim RUNGE, Mahmoud ABDALLAT, Marina A.J. TIJSSEN , Joachim K. KRAUSS
08:00 - 18:00 #10635 - P029 Frame mounting and stereotactic accuracy: a phantom study.
Frame mounting and stereotactic accuracy: a phantom study.

Mounting the stereotactic frame is one of the most crucial steps in deep brain stimulation surgeries. In the routine clinical practice, we aim to mount the frame as symmetrical as possible parallel to the Reid’s line. However, in several cases the frame is mounted asymmetrical, often due to patient-related reasons. In this study, we addressed the question whether this influences the accuracy of stereotactic electrode implantation, and if yes, to which extent. A citrullus lanatus was used for this study. Symmetric and asymmetric mounting of the frame was performed and CT and MR images were obtained. Three different stereotactic software packages were used to analyze the results. In addition, manual calculations were performed. We have found that an asymmetrically mounted frame (deviated, tilted or rotated) does not affect the accuracy in the medio-lateral axis (X coordinate) or the antero-posterior axis (Y coordinate). However, it can lead to a clinically relevant error in the supero-inferior axis (Z coordinate). These results suggest that asymmetrical frame mounting can lead to stereotactic inaccuracy.  

Onur ALPTEKIN (Istanbul, TURKEY), Felix S GUBLER, Linda ACKERMANS, Pieter L. KUBBEN, Mark L. KUIJF, Ersoy KOCABICAK, Yasin TEMEL
08:00 - 18:00 #10650 - P030 Complications in Deep Brain Stimulation – Surgical Revision Approaches.
Complications in Deep Brain Stimulation – Surgical Revision Approaches.

Background: The non-elective surgical revision of deep brain stimulation (DBS) patients is a growing concern amongst neurosurgeons. Scarce literature is available concerning the surgical management of DBS complications, particularly the non-infectious kind and there are no globally accepted guidelines on how to handle these complications. Furthermore, both the epidemiology and surgical management provided in each case vary greatly and are therefore worthy of study.

Methods: Retrospective cohort study of patients submitted to DBS surgery between 2006 and 2016 at our centre. The demographics - gender, age - and clinical variables - disease, the reason for non-elective re-intervention, and the performed surgical technique - were analysed.

Results: 195 patients were included (119 males; 76 females). The majority suffered from Parkinson’s disease (PD)–166 (85.1%) versus 25(12.8%) with Dystonia (DYST) and 2 (1%) with Essential Tremor (ET) and 2 (1%) with Tourette Syndrome. 18 non-elective surgical interventions were performed– 9% of treated patients (88.9% DP–16 patients and 11.1% DYST–2 patients). In this subgroup, 8 patients had an infection (44.4%), 1 had a central nervous system infection, 5 presented with hardware exposure and 4 displayed a foreign body reaction. An initial system-preserving technique (non-removal of the entire system) was used for every patient as a first line treatment. Only 3 patients (16.7%) required a second surgery for removal of the entire system, of which 2 presented with an infection of the subclavian IPG pouch and 1 with hardware exposure. Neither PD, nor DYST were related with an increased risk for non-programmed surgical intervention (p-value=0.596).

Conclusions: Even though entire system removal has been the consensual approach to DBS-related complications, this data supports that a system-preserving technique is of high-value and should be taken into consideration whilst planning for a surgical revision of patients presenting with these complications.

Diogo BELO, José Pedro LAVRADOR (Mem-Martins, PORTUGAL), Maria Begoña CATTONI, Herculano CARVALHO
08:00 - 18:00 #10653 - P031 Effect of frontal angle of approach on microelectrode recording and clinical parameters in STN-DBS surgery.
Effect of frontal angle of approach on microelectrode recording and clinical parameters in STN-DBS surgery.

Objective: Subthalamic nucleus (STN) is a widely used anatomical target in deep brain stimulation (DBS) surgery. Highly precise targeting the STN in Parkinson’s disease is vital. Furthermore, the length of the STN passed by the final electrode is desired to be as possible as long to achieve more stimulation combinations and flexibility in further programming. For these reasons, we questioned the relation between different stereotactic approach angles and clinical parameters in our series of STN DBS surgeries.

Methods: The DBS database of Maastricht University Medical Center Neurosurgery Department between 2005 and 2015 was retrospectively analyzed. Patient demographics, preoperative and postoperative UPDRS-III (Unified Parkinson Disease Rating Scale) scores, levodopa equivalent doses (LED), intraoperative microelectrode recording (MER) data and sagittal and coronal stereotactic angles were documented. 94 STNs of 51 patients met the criteria and were included into study. Effects of stereotactic angles were analyzed statistically.

Results: Twenty-two patients were females and 29 were males. Mean electrophysiological STN length was calculated 4.7 mm ±1.5SD (0.5-7.5). The mean sagittal angle of approach was 57.2° ±10.3SD (34.2-83.9) and the coronal angle was 24.8° ±5.7SD (11.6-52.0). A mean 44.3% decrease was found between preoperative and postoperative med-off UPDRS-III scores. Postoperative analysis for levodopa doses showed a mean 50.9% decrease in postoperative LED. Two tailed correlation analysis between groups showed a positive correlation between the length of electrophysiological motor STN and postoperative percentage of the LED decrease. Correlation analyses performed between groups also showed a negative correlation between sagittal angle and percentage of UPDRS-III decrease. Another significant negative correlation was also found between the sagittal angle and STN length.

Conclusion: Our study showed that a lower sagittal trajectory angle (around 50°) is correlated with a longer electrophysiological STN and better improvement in postoperative UPDRS score. However, the coronal angle did not affect the clinical and electrophysiological parameters. Another interesting finding was that a longer intraoperative STN recording was related to a lower postoperative LED. Thus, we may speculate that a patient with longer STN recording may require less dopaminergic medication postoperatively.    

Mehmet TONGE (Istanbul, TURKEY), Josephine LINDHOUT, Ersoy KOCABICAK, Umit Akin DERE, Yasin TEMEL
08:00 - 18:00 #10660 - P032 Bilateral deep brain stimulation of the subthalamic nuclei in Parkinson’s disease patients with camptocormic posture.
Bilateral deep brain stimulation of the subthalamic nuclei in Parkinson’s disease patients with camptocormic posture.

Objective: Camptocormia is a disabling syndrome characterized by forward flexion that can be an idiopathic or associated with numerous diseases like movement disorders, especially Parkinson's disease (PD). Treatment options are usually futile and L-dopa shows little or no effect. Posture improvement could be expected in bilateral deep brain stimulation (DBS) of the globus pallidus internus (GPi) or subthalamic nucleus (STN) in PD patients with camptocormia. Outcome results are inconsistent, especially for STN. The aim of this study was to determine the efficacy of bilateral STN DBS in alleviating the degree of camptocormia in two PD patients.

Patients and methods: Two patients (67 year old female and a 66 year old male) suffering from PD in the last ten years and more were subjected to bilateral STN DBS procedure. The positions of electrodes were verified with a postoperative magnetic resonance imaging. The results were objectivized by measuring thoracolumbar flexion angle before and after operation and using all recommended scales for the international survey of DBS.

Results: The degree of forward flexion of the spine has substantially decreased and the quality of life, motor symptoms and functioning improved in both patients. 

Conclusion: STN DBS should be considered as a potential treatment option for PD patients with camptocormia. Further analysis is needed to conclude what PD patients are candidates for bilateral STN or GPi stimulation in the treatment of camptocormia.

Fadi ALMAHARIQ (Zagreb, CROATIA)
08:00 - 18:00 #10670 - P033 Psychosis immediately after the subthalamic nucleus lesion effect.
Psychosis immediately after the subthalamic nucleus lesion effect.

Introduction
Deep brain stimulation (DBS) is used for the treatment of movement disorders in Parkinson’s disease (PD) and the standard targets are globus Pallidus interna (GPi) and subthalamic nucleus (STN)[1]. DBS can improve the psychiatric symptoms by altering the tonic activity of subcortical circuits but the exact mechanism is still remains unclear[2]. In STN stimulation some transient manias, or hallucinations complications reported, but these complications usually occurred after onset of STN stimulation. We want to share our two patient’s experiences who developed agitated psychosis and hallucinations complications, immediately after bilateral STN DBS implantation but before stimulation on.
Material & Method
The patient’s ages were 48 and 51 years old they had no prior psychiatric history. They were underwent to operations without prior medication interruption. Three guide cannulas were passed first on left and later on right. On each side and microelectrode recording (MER) was recorded from 5.0 mm above to 2.0 mm below the target. In two patients during the right side MER, hallucinations and meaningless speech developed. The patients were took quickly to the computerized tomography (CT) after the macrostimulation and skin closure. CT scans did not reveal any abnormality. The first patient underwent to operation theatre again for implantable pulse generator implantation and after the operation he was taken to intensive care unit (ICU). The pulse generator implantation of the second patient was made after 7 days. The second patients’ agitation and hallucination complications was ceased only 3 or 4 hours after and he didn't remember anything. However, complications of the first patient prolonged approximately 6 or 7 days.
Discussion
Both patients DBS leads were placed within STN and substantia nigra (SN). Injury of SN (esp. in young patients) may lead to excess dopamine release (Particularly when medication is on). The injury on ventral STN and SN especially in young patients may associated with limbic side effects.
Conclusion
There are a lot of report about psychosis as a consequence of electrical STN stimulation, but the report about to arise directly from injury of STN and surrounding structures by a DBS lead is limited. Immediately anesthesia after the delirium symptoms may be questioned therefore the second part of the surgery may be postponed.

Atilla YILMAZ (Hatay, TURKEY), Bircan YUCEKAYA, Esra HUZMELI, Gulsah OZTURK, Esra OKUYUCU
08:00 - 18:00 #10672 - P034 The Effect of Vancomycin Powder on Surgical Site Infections in Deep Brain Stimulation Surgery.
The Effect of Vancomycin Powder on Surgical Site Infections in Deep Brain Stimulation Surgery.

Introduction

Surgical site infections are a problematic complication in deep brain stimulation, with estimates ranging as high as 10%.  Application of vancomycin powder to the surgical bed prior to closure has shown positive results in instrumented spine surgery.  To assess its impact in reducing infections in deep brain stimulation (DBS) surgery, we compared a prospective cohort of patients undergoing DBS lead and generator placements using vancomycin powder with a retrospective cohort off patients that did not receive vancomycin powder. 

 Methods

A total of 450 DBS cases were included between April 2015 and December 2016 (215 cases without vancomycin powder, analyzed retrospectively and 235 cases, analyzed prospectively with vancomycin powder) with a minimum of three month follow-up. Operations included all DBS lead insertions, extension wire and pulse generator implantations and generator exchanges. A surgical site infection was defined as culture positive evidence of infection that necessitated antibiotic therapy and/or removal of hardware, including superficial wound infections. Infection rates were recorded and compared.

Results

Infections were noted in 5/215 (2.3%) of the pre-vancomycin powder group compared to only 1/235 (0.4%) in the vancomycin powder group. The sole infection in the vancomycin powder group consisted of a patient who presented with gross infection of the left chest generator necessitating removal of the entire system.  Culture data tested positive for methicillin-sensitive S. aureus and was successfully treated with a prolonged course of intravenous antibiotics.

Conclusion

The use of vancomycin powder in DBS surgery appears to be a safe and feasible protocol to decrease surgical site infections without increasing the risk of antibiotic resistant organisms.  Larger prospective randomized trials are necessary to determine vancomycin powders ability to significantly reduced the infection rate in DBS surgery.

Ryan KOCHANSKI, Nunna RAVI, Nazari POUYA, Sepehr SANI (Chicago, USA)
08:00 - 18:00 #10678 - P035 Cardiovascular effects of deep brain electrical stimulation in human: the nurogenic heart systematic review.
Cardiovascular effects of deep brain electrical stimulation in human: the nurogenic heart systematic review.

Abstract:

Introduction: Deep brain stimulation (DBS) has been applied to treat various neurological disorders and to record from different brain regions. The effects of electrical stimulation of different brain parts on cardiovascular physiology have been investigated in several reports. Here in, we review brain stimulation effects on cardiovascular function.

Methods: A systematic review of the English literature using PubMed search. Brain targets resulted in clinical cardiovascular effects with DBS were included. Cortical stimulation was excluded. The stimulated targets were classified based on anatomical location and type of cardiovascular effect.

Results: Intraoperative electrical stimulation of Subthalamic nucleus (STN) showed heart rate (HR) increment in several studies, particularly dorsal stimulation of STN in contrast to ventral. Globus pallidus internus (GPi) stimulation evoked a paradoxical arousal reaction resulted in transient increase in blood pressure (BP). Moreover, amygdaloid nucleus and nucleus accumbens (NAc) DBS showed an increase in both HR and BP. Hypothalamic stimulation varied with the site of stimulation. Posterior hypothalamic area showed no change in HR or BP, whereas Ventroposterior Hypothalamus and Posteriomedial hypothalamus showed an increase in both.  In regards to periaqueductal gray matter/periventricular gray matter (PAG/PVG) DBS, decrement in BP was noted with stimulation of the ventral part and an increment with dorsal stimulation.

Conclusion: STN is the most studied target. Other targets that showed positive cardiovascular effect include amygdala, NAc, hypothalamus and PVG/PAG. Stimulating the GPi, per se, does not appear to have any positive effects. In addition to various neurological disorders, DBS could be used in the future to treat disorders related to the cardiovascular system.

Arif ABDULBAKI (Magdeburg, GERMANY), Faisal AL-OTAIBI
08:00 - 18:00 #10688 - P036 Deep brain stimulation: software for patient-specific electric field simulations.
Deep brain stimulation: software for patient-specific electric field simulations.

Introduction

The electric field (EF) around the active deep brain stimulation (DBS) contact is of interest for optimizing the therapeutic effect. We have previously developed a method for simulation and visualization of the EF. The aim of the project is to improve the software for quick and user friendly simulations.  

Methods

The ELMA software for brain model creation has been improved by adding quick ROI selection and transformation to an electrical conductivity map based on tissue classification through multiple slices of the preoperative MRI. These data are used as input for Comsol Multiphysics simulations of the EF. Two points along the position of the lead, as seen in the postoperative images, are used for correct placement in the brain model. Multiple DBS lead models are pre-programmed. The active contact and amplitude are user-selected.

Results

After a simulation the result is visualized with a user defined isolevel or isosurface superimposed on the patients preoperative MRI. An example is shown in Fig. 1. The 3389 lead is places in zona inserta (Zi) and contact 1 activated with 2 and 4 V respectively. An isolevel of 0.2 V/mm is used corresponding to a ~ 3-4 µm axon diameter when using a pulse length of 60 µs. More examples will be presented at the meeting.

Conclusion

The software for patient-specific simulations of EF around DBS electrodes has been improved for quicker simulations and more DBS leads. As a next step user friendly Apps will be implemented.

Karin WÅRDELL (Linköping, SWEDEN), Fabiola ALONSO, Johannes JOHANSSON
08:00 - 18:00 #10690 - P037 Factors influencing patients’ choice of fixed life or rechargeable implantable pulse generators for deep brain stimulation.
Factors influencing patients’ choice of fixed life or rechargeable implantable pulse generators for deep brain stimulation.

Factors influencing patients’ choice of fixed life or rechargeable implantable pulse generators for deep brain stimulation

 

Tahir Khaleeq, Harutomo Hasegawa, Keyoumars Ashkan

King’s College Hospital, London, UK.

 

Abstract

Background: Deep brain stimulation is increasingly used for movement disorders. Recently, an increasing variety of implantable pulse generators (IPGs) have been available, including rechargeable types which are associated with a longer battery life and high satisfaction. However, patients’ views on which factors are important when deciding whether to use a fixed life or rechargeable IPG have not been well studied. Methods: We surveyed 12 consecutive adult patients attending a pre-DBS neurosurgery clinic (11 males, 1 female). They were asked which type of battery they would prefer and the main reasons for their choice. Results: 10 patients opted for a fixed-life battery and 2 opted for the rechargeable. For those who chose the fixed-life battery, the main reasons were they will forget to recharge the battery (8 patients) , that a fixed-life battery would require less responsibility (6 patients), be more convenient (5 patients) and will offer a better lifestyle (4 patients). For the 2 patients who chose the rechargeable battery, the main reason was the avoidance of further surgery. The size of the battery was a concern in 8 patients (2 neutral, 2 not concerned). The need to have surgery to replace the battery was a concern in 3 patients (9 not concerned). The need to recharge the battery was a concern in 8 patients (4 not concerned). Acceptable charging frequency for a rechargeable battery was reported to be yearly (5 patients), monthly (6 patients) and fortnightly (1 patient). Acceptable duration of charging was reported to be less than 15 minutes (2 patients), 15-30 minutes (5 patients), 30 to 45 minutes (2 patients) and 45mins to 1 hour (3 patients). Conclusion: In our sample of patients most chose the fixed-life battery. Many factors affect a patient’s choice of type of battery. The charging frequency, the possibility of forgetting to charge the battery and the convenience and lifestyle of not having to recharge the battery were important factors.

Tahir KHALEEQ (london, UK), Harutomo HASEGAWA, Keyoumars ASHKAN
08:00 - 18:00 #10723 - P038 Trajectory angle revisions in subthalamic deep brain stimulations for Parkinson’s disease.
Trajectory angle revisions in subthalamic deep brain stimulations for Parkinson’s disease.

Purpose: Previously deep brain stimulation revision due to misplaced leads from targets were reported previously. However, the importance of trajectory angle is not well known. Anteriorly slanted low ring angled trajectories may be farther from sensory-motor subthalamic nucleus and closer to corticospinal tracts with lower outcomes and side-effects.

Materials and methods: Among 200 patients treated by deep brain stimulation from March 2013 to Dec 2016 in the Asan Medical Center by one neurosurgeon and one neurologist (J.K. Lee and C.S. Lee), subthalamic lead reposition cases were collected. Patients with ring angles < 55° were defined as having low ring angle trajectory. We defined trajectory revision as the ring angle change ≥ 15°. Patient’s global impression (PGI) were scored postoperatively. For a subgroup of four referred patients with six leads we could collect ring angles of all operated cohort by a surgeon. The ring angles of these patients were compared to patients indicated for revisions.

Results: Leads were repositioned in nine patients of 15 electrodes. Intervals between the initial lead insertions and revisions ranged from 1 to 157 months (median: 38 months). Before revision, patients improved by 24±19 % (0 – 55 %) in UPDRS part III motor scores. All patients indicated for revision showed various side effects and suboptimal outcomes.

Five of fifteen leads (33 %) indicated for revisions had low ring angles, < 55°. In seven of fifteen leads (47 %), ring angles were increased ≥ 15°. Patients improved in PGI (patients’ global impression of improvement) scores by 1.2±1.5. Patients with either target or trajectory revisions showed improvements in PGI scores except one patient with PGI score -1.

For all subthalamic 40 leads operated by surgeon A, mean ring angles were 55±8°. Revised leads previously operated by surgeon A had 47±7°, significantly lower than the all surgery patients by the surgeon A (p = 0.02) in Mann-Whitney U test.

Conclusion: We show that low ring angled trajectory may be associated with suboptimal outcome which are indicated for revisions. A subgroup of patients who had suboptimal outcomes had low ring angles. Previously, only target revisions were reported for DBS. Low ring angled trajectory which can be closer to corticospinal tracts and farther from sensory-motor STN may be a potential target of DBS revision.

Park SEONG-CHEOL (Seoul, KOREA), Jung Kyo LEE, Chong Sik LEE
08:00 - 18:00 #10730 - P039 Deep Brain Stimulation Leads with Segmented Contacts Enable Directional Control of Neural Activation in the Subthalamic Nucleus.
Deep Brain Stimulation Leads with Segmented Contacts Enable Directional Control of Neural Activation in the Subthalamic Nucleus.

Objectives: Conventional deep brain stimulation (DBS) leads stimulate brain targets in a nondirectional fashion, whereas directional DBS leads with segmented electrodes allow for more flexibility in shaping the stimulation field. The latter may be used to optimize therapeutic efficacy and reduce stimulation-related side-effects. A computational model was used to evaluate directional neural activation in the subthalamic nucleus (STN) resulting from stimulation with the InfinityTM DBS lead (Abbott, Plano, TX).

Methods: A two-stage computational model of STN-DBS was used to analyze neural activation generated with the Infinity directional lead (1.5 mm spacing, 1-3-3-1 configuration). The first stage involved using a finite element analysis (FEA) model to calculate electrical potentials generated in the brain with cathodic monopolar DBS (1.5 mA, 90 µs). The FEA model incorporated a multimodal, imaging-based detailed anatomical (MIDA) model of the human head, and the DBS lead was placed with contact 1 at the ventral STN boundary and surrounded by a 0.5mm thick encapsulation layer. In the second stage, electrical potentials from the FEA model were coupled to biophysical cellular models of 1,000 STN projection neurons with realistic morphological and electrophysiological characteristics. Volume of tissue activation (VTA) was compared between nondirectional (segments 2A-C) and unidirectional (segment 2A) DBS. The extent of directionality was calculated as the percentage of VTA volume on the side of the lead with segment 2A.

Results: VTAs were distinct for nondirectional and unidirectional DBS (Figure). At 1.5 mA amplitude, the VTA volume was larger with unidirectional stimulation (4.29 mm3) than nondirectional stimulation (3.85 mm3). Additionally, the extent of directionality was greater for unidirectional stimulation (93%) compared to nondirectional stimulation (56%).

Conclusion: An anatomically-precise computational model of STN-DBS demonstrated that unidirectional stimulation increases directionality in the region of neural activation and produces a larger VTA volume at a given stimulation amplitude, compared to nondirectional stimulation. Clinically, these results indicate that directional DBS leads may be used to increase the therapeutic window by providing a customized stimulation field focused only on targeted brain regions, and may increase battery life by reducing the stimulation amplitude required to activate a given volume of tissue [Rebelo NANS 2017].

Binith CHEERAN (London, UK), Lalit VENKATESAN, Alexander KENT
08:00 - 18:00 #10733 - P040 Involvement of the subthalamic nucleus in the maintenance of cognitive flexibility: Evidence from local field potential recordings.
Involvement of the subthalamic nucleus in the maintenance of cognitive flexibility: Evidence from local field potential recordings.

Imaging techniques have revealed that several cortical brain regions like the prefrontal cortex, the anterior cingulate cortex, and the posterior parietal cortex are involved in the maintenance of cognitive flexibility. However, the role of basal ganglia in the ability to switch between several concepts remains unknown. To address this issue we recorded local field potentials from the nucleus subthalamicus (STN) while participants performed a task that required executive processes like planning and set shifting. Seven patients with Parkinson disease that underwent STN deep brain stimulation have been included in the study. The patients performed a computerized version of the Wisconsin Card Sorting Test. The participants were required to match the cards according to three possible matching rules (color, shape and number). After the sorting choice was made, a feedback ‘switch’ or ‘repeat’ indicated that the rule had to be changed or repeated respectively. Integration cue is the first repeat cue following a shift cue. The results show that the amplitudes of the integration cue are larger than those of the repeat cue. Integration condition induced oscillatory changes with the highest power in the theta band in comparison to the repeat condition. Moreover, there is a significant late higher activation of beta band for the integration trials. In conclusion, there are broadband oscillatory changes in the STN during executive processes. STN appears to be involved in shifting cognitive sets and modulating responses.

Lejla PARACKA, Marcus HELDMANN, Mahmoud ABDALLAT, Dirk DRESSLER, Thomas MÜNTE, Bruno KOPP, Florian WEGNER, Joachim K KRAUSS (HANNOVER, GERMANY)
08:00 - 18:00 #10752 - P041 Establishing Deep Brain Stimulation Surgery Program in developing countries; Shiraz (Southern Iran) Experience.
Establishing Deep Brain Stimulation Surgery Program in developing countries; Shiraz (Southern Iran) Experience.

Deep brain stimulation (DBS) is an effective therapy for Parkinson's disease and dystonia, as well as some other evolving indications. This therapy has been utilized since 1990 in many centers across the world, and in many countries and cities more than one center is providing this therapy. Yet, many large parts of the developing world still miss such therapy due to numerous strategic and economic issues. Establishing a new center in a developing country faces unique challenges and dilemmas for the responsible team.

We established the DBS surgery program in Shiraz in 2014, as the second center in Iran with a population of over 80 million people countrywide. Shiraz is one of the major cities located in the Southeast of the country, and is the major referral medical center for most of the Southern provinces, covering one fourth of the whole population.

We started DBS surgery in Shiraz with the support of the new national health reform program since 2014. Loyalty to the team work principles and provision of enough international exposure and training to the whole team were essential considerations in our experience. Major changes have occurred in the team, technique, hardware, programming, and financial supply since the beginning, which are thoroughly discussed in this presentation. 

Ali RAZMKON (SHIRAZ, IRAN, ISLAMIC REPUBLIC), Sina SALEHI, Peyman PETRAMFAR
08:00 - 18:00 #10753 - P042 Oh Dear, the neurostimulator battery has depleted: Lund experience of the consequences of depleted neurostimulators.
Oh Dear, the neurostimulator battery has depleted: Lund experience of the consequences of depleted neurostimulators.

Background

Even though the clinicians as well as the patients have an idea of when it is time to exchange the neuro-stimulator (NS) due to reduced battery capacity, it is not always the exchange is done before depletion due to various reasons. Due to changes in the management of scheduled NS exchange 16% of the patients had total DBS treatment arrest due to battery depletion before exchange. 

Aim 

Investigate consequences of DBS treatment arrest due to depleted NS batteries in terms of reoccurrence of symptoms and time to recovery after exchange and which actions that were  taken while waiting for surgery. 

Method  

The patient records for the 23 out of the 25 whom during the years 2015 and 2016 had battery depletion before the exchange of NS were reviewed.  Diagnosis, target(s) consequences (hospital care, increased home care, symptoms etc.), reason (hospital or patient delay) time between decreased battery capacity and battery depletion, DBS settings and time until recovery.  

Result 

In most patients the hospital delay were the major reason for depletion. The majority (n=13) had Parkinson’s disease (PD), followed by essential tremor (n=7) and dystonia (n=3). All patents had bilateral electrodes, 11 of them had bilateral NS. DBS targets were Thalamus VIM, STN and GPi. The time between battery depletion and exchange 0 to 57 days and during this time 3 patients were hospitalized (or nursing home). In PD the medication was increased especially in those with one dual channel NS. All patients’ their movement disorder symptoms were perceived as worsened. Family members or care givers needed to help/support in everyday activities.  

None of the patients had a life-threatening condition and all perceived good DBS effects (may be not as good as before depletion) after the DBS has been optimally programmed (1-6 mth postop).

 

Conclusion 

Battery depletion had severe impact on the patients and their families’ everyday life due to severe movement disorder symptoms, furthermore it also increased the healthcare needed especially in patients with PD pre- as well as postoperative. Thus, it is really worthwhile minimizing time without DBS treatment due to battery depletion and it is better to exchange NS sooner than later and create routines for calling nursing care homes for report of residual battery capacity.  

 

 

Anna-Lena TÖRNQVIST JENSEN, Martina NILSSON (Höör, SWEDEN), Hjalmar BJARTMARZ
08:00 - 18:00 #10772 - P043 Beyond Staph: A single center's experience with infectious complications in Deep Brain Stimulation.
Beyond Staph: A single center's experience with infectious complications in Deep Brain Stimulation.

Introduction: Infection is estimated to affect 5-15% of DBS implantation cases. IPG infections are more common than intracerebral infections, but likely these figures have been underreported. Device-related infections are most often associated with Staph aureus, but other pathogens may be encountered. Especially as the volume of DBS procedures increases, we anticipate unusual infectious complications. We review a single center's experience with DBS-related infections.

Methods: A retrospective review of all DBS-related procedures performed by a single surgeon was performed. Both new system implantations, generator exchanges and other procedures were cataloged, and not was made of any infection that required further surgical treatment for infections. A survey of the pathogen involved was performed and antibiotic susceptibilities noted. Patient outcomes are summarized.

Results: IPG site infections occurred more often than extension site or intracranial infections. While Staphylococcus aureus was the most common pathogen in this series, other notable pathogens included other Staphylococcus species, Enterebacter cloacae, Klebsiella pneumoniae, and Candida parapsilosis. These unusual cases are discussed in detail.

Conclusion:While infectious complications of DBS are uncommon, the incidence of infection and the range of pathogens should be appreciated.

Erika PETERSEN (Little Rock, USA)
08:00 - 18:00 #10788 - P044 Concordance of MR-imaging based automatic segmentation of the Subthalamic Nucleus and intraoperatively recorded electrophysiology.
Concordance of MR-imaging based automatic segmentation of the Subthalamic Nucleus and intraoperatively recorded electrophysiology.

Background and Purpose: Automatic segmentation methods are gaining relevancy in image-based targeting of neural structures. In order to evaluate the feasibility of such approaches we retrospectively analyzed the concordance of MR-imaging based automatic segmentation of the Subthalamic Nucleus (STN) and intraoperatively recorded mircoelectrode recordings (MER).

 Methods: The data of ten patients STN-implanted with 20 DBS electrodes for the treatment of PD (9) and dystonia (1) were processed using Brainlab Elements Anatomical Mapping segmentation of the STN – with two volumetric T1 (with and without contrast) and volumetric T2 images as input. The stereotactic CT was co-registered with that imaging and the stereotactic coordinates for these cases originally planned using ELEKTA Surgiplan were imported, so that the actually surgically executed trajectories could be overlaid onto the segmentation. Records of the electrophysiology (MER, measured in 0.5 mm steps) along the central trajectory were analyzed with respect to distance of noted STN entry and STN exit to the segmented STN boundary (40 distances).

 Results: In none of the patients did the independently pre-planned trajectory miss the subsequently segmented STN - indicating a good overlap of the trajectory planning concept employed in our center and the automatic segmentations. Along those trajectories the electrophysiological STN entry deviated (median) 1,6 mm (n=20, min=0, max=4,5) and the STN exit deviated 0,7 mm (n=20, min=0, max=3,9) from the segmented STN boundary. In 8 instances the STN entry showed electrophysiologicaly deeper (closer to target) than the segmented boundary (12 instances STN entry was recorded higher than the boundary), in 2 instances the STN exit showed electrophysiologicaly higher (still within than the STN boundary) and in 18 instances deeper, respectively.

 Conclusions: In the trajectories analyzed with intraoperative MER, the electrophysiological borders of the STN and the borders of the automatically segmented STN in the MRIs had a high level of concordance. To further characterize this observation, we are currently analyzing a larger patient cohort and factoring in recordings from alternate tracks. If this trend is confirmed, automatic three-dimensional segmentation of the STN is an exciting method to visualize patient anatomy for neurosurgeons and neurologists.

Peter C. REINACHER (Freiburg, GERMANY), Bálint VÁRKUTI, Marie T. KRÜGER, Tobias PIROTH, Karl EGGER, Volker Arnd COENEN
08:00 - 18:00 #10790 - P045 The Wake Up Time Evaluation After Subthalamic Nucleus Deep Brain Stimulation Surgery – Pilot Study.
The Wake Up Time Evaluation After Subthalamic Nucleus Deep Brain Stimulation Surgery – Pilot Study.

The Wake Up Time Evaluation After Subthalamic Nucleus Deep Brain Stimulation Surgery – Pilot Study

Introduction

Deep brain stimulation surgery (DBSS) is the treatment modality for medical refractory movement disorders especially Parkinson's disease (PD), essential tremor and dystonia. The Subthalamic Nucleus (STN) and the Globus Pallidus Internus are accepted effective areas for PD.

DBSS could be separate in two parts. The first part is the placement of the electrode(s) and the second part is the implantation of impulse generator.

Several reports suggested that the first part of the operation should be make awake because to verify that the test stimulation of the electrode improves the patient's symptoms with minimal side-effects. The second part of the surgery could be made by cervical regional anesthesia or under general anesthesia.

The management of the patients after the general anesthesia is important and it continues until the patient has returned to their physiological preoperative state. Especially in PD the postoperative management is important because the PD patients are more sensitive to sedatives and are prone to hypoventilation. The Aldrete scoring system (ASS) is the most widely used scoring system to clinically assess the status of the patients about recovering from anesthesia. The maximum score of the ASS is 10 and the minimum is 2 and when the ASS reached up to nine the patients assume as returned to their physiological preoperative state and could be sent from postoperative care unit.

Material Method

6 patients were presented with PD that were undergone STN DBSS reviewed. The first part of the surgery was made under local anesthesia and the second part of the surgery was made under general anesthesia. The time interval from the extubating time to reach up score 9 according to ASS has been calculated (Wake up time).

Results

The minimum and maximum wake up time has been found 13 minutes and 15 minutes respectively and the mean wake up time has been found 14,2 minutes.

Discussion and Conclusion

There are a few reports in the literature about the recovering time from anesthesia after DBSS. Our aim to evaluate and compare the recovering time of DBSS with other surgeries. The number of patients are insufficient because our study is a pilot study and it is still continue.

Atilla YILMAZ (Hatay, TURKEY), Onur KOYUNCU, Hulya YILMAZ, Akin AKAKIN, Esra OKUYUCU
08:00 - 18:00 #10794 - P046 Comparison of direct MRI guided versus atlas based targeting for subthalamic nucleus and globus pallidus deep brain stimulation.
Comparison of direct MRI guided versus atlas based targeting for subthalamic nucleus and globus pallidus deep brain stimulation.

Introduction: Subthalamic nucleus (STN) and globus pallidus (GPi) targets for deep brain stimulation (DBS) can be defined by reference to atlas coordinates or direct visualisation of the target on MRI. The aim of this study was to evaluate the difference between atlas-based targeting and direct MRI guided targeting. Methods: We reviewed prospectively collected records of adult patients who underwent DBS surgery from 2007 to 2016. MRI guided targeting was used to implant 206 STN electrodes and 62 GPi electrodes in 139 patients with Parkinson disease or dystonia. Surgery was performed using a Leksell G frame and targeting performed on 2mm thick T2 weighted MRI (for STN) and proton density (for GPi) scans acquired preoperatively. The Cartesian STN and GPi coordinates were normalised to the AC-PC plane and compared with atlas coordinates. Atlas STN coordinates were 12mm lateral (x), 2mm posterior (y) and 4 mm ventral (z); atlas GPi coordinates were 22mm lateral (x), 2 mm anterior (y), and 4 mm ventral (z) in relation to the AC– PC plane (y=distance from midpoint of AC-PC line). Results: The directly targeted coordinates (mean, SD, range) for STN were: x (9.9 ± 1.1 (7.1 – 13.2)), y (-0.8 ± 1.1 (-4.2 – 2)), z (-4.7 ± 0.59 (-5.9 - -1.5)) and for GPi were: x (22.3 ± 2.0 (17.8 – 26.1)), y (-0.2 ± 2.1 (-4.5 – 3.4)), z (-4.3 ± 0.8 (-6.1 – -2.3)). The mean of the directly visualised STN was 2.1mm more medial (4.9 to -1.2, p < 0.0001), 0.2mm more anterior (-2.2 to -6, p < 0.0001) and 0.7mm more ventral (-1.9 to 2.5, p < 0.0001) than the atlas target. The mean of the directly visualised GPi target was 0.3mm (-4.2 to 4.1) more medial (not significant) 2.2mm (-6.5 to 1.4, p < 0.001) more posterior and 0.3mm (-2.1 to 1.7, p=0.009) more ventral than atlas coordinates. Conclusions: MRI guided direct targeting may be more accurate than atlas based targeting due to individual variations in anatomy. 

Mariane MELO (Belo Horizonte, BRAZIL), Harutomo HASEGAWA, Nilesh MUNDIL, Keyoumars ASHKAN
08:00 - 18:00 #10801 - P047 Electric current changes iron metabolism in patients with deep brain stimulation.
Electric current changes iron metabolism in patients with deep brain stimulation.

Background:Alterations in iron homeostasis can participate in development of Parkinson disease (PD) due to accumulation of iron in the substantia nigra. Blood serum concentration of labile iron, transferrin and ferritin play important role in transfer of peripheral iron into the brain. Deep brain stimulation (DBS) is an established and effective method of treatment of motor symptoms in PD. DBS delivers a constant low, electrical current to a small region of the brain through implanted electrodes.  The aim of this study was to evaluate changes in iron metabolism in PD patients after DBS. Methods:Examined group consisted of 18 patients with PD: 13 patients who underwent unilateral implantation of electrode in subthalamic nucleus (STN), 4 patients who underwent bilateral implantation of electrodes into the STN , and 1 who underwent unilateral thalamotomy, 3 patients with dystonia : 1 with unilateral GPi electrode implantation , 1 with bilateral GPi electrode implantation and 1 with pallidotomy, Another 1 patient with essential tremor who underwent thalamotomy.Iron, ferritin and transferrin blood levels were assessed before and at least 12 hours after the commencement of DBS or the day after surgery.Results: The reduction of iron concentration after the electric stimulation was significant from 13,8 umol/l before to 7,7 umol/l on stimulation. After stimulation a significant rise of ferritin (from 146 ng/ml before to 181,3 ng/ml after)(p=0,023), significant reduction of transferrin concentration from 2,4 to 2,1 g/l (p=0,001) and reduction of transferrin saturation from 24,6% to 13,3% (p=0,001) were observed.In group of patients who underwent thalamotomy or pallidotomy there were no statistically significant differences in iron concentrations (17,4umol/l  and 13,3umol/l; p=0,46 ), ferritin levels ( 168ng/l and 197ng/l p=0,7), transferrin levels before and after surgery (2,41g/l and 2,41g/l  p=1,0) and transferrin saturation (29,8% and 22,7% p=0,54).Conclusions:Alterations in iron metabolism can be seen after surgeries with implantation of neurostimulators and further with electric DBS, but are not observed after lesion surgeries without postoperative electric stimulation. Findings of this study indicate that DBS by delivering electric current, alternates the iron metabolism in PD patients. It could suggest that DBS not only improves motor symptoms, but may also influence on pathogenesis of this disease, which is associated with proper iron homeostasis.

 

Paweł SOKAL (Bydgoszcz, POLAND), Marek HARAT, Marcin RUDAŚ, Marcin RUSINEK
08:00 - 18:00 #10802 - P048 Stimulation on the boundary of anterodorsal STN and the area above the STN in a patient with Parkinson’s disease and levodopa-induced peak-dose dyskinesia.
Stimulation on the boundary of anterodorsal STN and the area above the STN in a patient with Parkinson’s disease and levodopa-induced peak-dose dyskinesia.

The direct antidyskinetic effect of deep brain stimulation of the subthalamic nucleus (STN-DBS) in Parkinson’s disease (PD) patients with levodopa-induced dyskinesia (LID) is provided by involvement of the white matter above the STN into the stimulation. For this purpose bipolar stimulation or monopolar two-contact stimulation with active contacts within the aforementioned structures is performed.

We observed the direct relief of LID as well as appropriate antiparkinsonian effect by monopolar stimulation by one contact located on the boundary of anterodorsal STN and the area above the STN.

Materials and Methods: A 60-year-old woman with 6-year history of akinetic-rigid PD with on-of motor fluctuations and severe peak-dose dyskinesia (levodopa equivalent dose = 1580 mg/day) underwent bilateral STN-DBS procedure according to the standard stereotactic coordinates. Postoperative CT-MRI fusion demonstrated mild proximal dislocation of both electrodes in such a way that the most distal contacts were located on the boundary of anterodorsal STN and the white matter above the STN. The patient underwent monopolar stimulation using both most distal contacts (130 Hz, 60 msec, 2,5V). There was no adverse effects.  The levodopa dosage was unchanged perioperatively.

Results: During the follow up pre-existing choreiform LID transformed into akathisia and after the first month of stimulation the complete control of LID was observed. Almost complete control of OFF-state motor symptoms and motor fluctuations was achieved. The patient’s quality of life improved significantly. After two months of follow up the daily levodopa equivalent dose was gradually reduced to 300 mg/day.

Conclusions: Monopolar one-contact stimulation on the boundary of anterodorsal STN and the area above the STN was observed to induce direct relief of LID as well as appropriate antiparkinsonian effect.

Andrii POPOV, Valeriy CHEBURAKHIN (Kyiv, UKRAINE), Kostiantyn KOSTIUK
08:00 - 18:00 #10810 - P049 Electrode–Brain Interface in Globus Pallidus Internus Deep Brain Stimulation.
Electrode–Brain Interface in Globus Pallidus Internus Deep Brain Stimulation.

Introduction: In this study we analyze the electrode–brain interface (EBI) in the globus pallidus internus (GPI) and the estimated electrical field density geometry and radial extension required to induce an internal capsule and optic tract clinical response.

Methods: A total of 184 electrode contacts implanted in the GPI were analyzed. The anatomical distance between the center of each contact and the optic tract and internal capsule was measured on the magnetic resonance image (MRI). Monopolar electrical stimulation was applied to elicit a clinical response from the internal capsule and optic tract. The threshold-distance data for the estimated electrical field ET (V/mm).

Results: Five contacts were excluded due to relatively high impedance. The mean distance between the distal contact and optic tract was 1.84 mm, and the mean distance from the electrodes’ nearest contacts to the internal capsule was 3.4 mm. DBS stimulation parameters were at 60 us, 130 Hz, and monopolar mode. The clinical response threshold was 0.8 V/mm for optic tract and 1.2 V/mm for the internal capsule. The overall estimated isolevel of the electrical field that activated a clinical response around each contact was 2.4 mm at 1 volt stimulation.

Conclusion: This study revealed the extent of electrical field delivered from a cylindrical electrode contact. Utilizing an electrode with multiple small contacts to steer the electrical field toward the target can minimize the unintended stimulation side effects.

Faisal AL-OTAIBI (Riyadh, SAUDI ARABIA), Amal MOKEEM
08:00 - 18:00 #10812 - P050 Long term follow up of subthalamic deep brain stimulation for Parkinson’s Disease confirms stability of Levodopa equivalent dose drug reduction .
Long term follow up of subthalamic deep brain stimulation for Parkinson’s Disease confirms stability of Levodopa equivalent dose drug reduction .

Study’s Objectives:

To determine the long-term levodopa equivalent dose (LED) drug reduction following deep brain stimulation (DBS) of subthalamic nucleus (STN) in Parkinson’s patients.

Methods Used:

Retrospective observational study of 106 Parkinson’s disease (PD) patients who underwent bilateral STN stimulation between October 2002 and December 2014.

Variables recorded included age, sex, first symptom, date of diagnosis of PD, duration of diagnosis at operation date, last clinical follow up. Also, the voltage, rate and pulse width of DBS in last clinical follow up were recorded.

Medications at both preoperative and last clinical follow up were recorded and total LED dose in milligrams were calculated using Parkinson’s disease measurement calculator.

 

 Results:

Of the 106 patients, 70 were male and 36 were female.

The average preoperative total LED  was 1352.13 mg and the post operative total LED was 618.86mg.

The average percentage of drug reduction post DBS was 48.25 % at the last clinic follow up .The median period of follow up post DBS was 45.5 months ( 3.7 years, Range = 9.8 months (0.8 years ) -154 months ( 12.7 years).

Using Spearman’s Correlation coefficients, there was a negligible correlation between the percentage reduction in LED and the duration of follow up (rho=-0.01, p=0.93) and also between the post-operative LED and duration of follow-up (rho=0.004, p=0.97). This implies that both the percentage reduction in LED and post-operative LED are maintained over time.

Also, noted was a weak , but non-significant positive correlation between the duration of diagnosis and the percentage of drug reduction (rho=0.17,p=0.139) implying that patients with longstanding disease had a greater percentage reduction in LED at the final follow up but statistically not significant.

Conclusion:

Our study confirms that LED reduction does not change significantly in the long term for patient with STN DBS which suggests that DBS may have a protective neuro-modulatory effect.

 

Murugan SITARAMAN (Birmingham, UK), Jamilla KAUSAR, Hayley GARRATT, Benjamin WRIGHT, Hardev PALL, Anwen WHITE, Rosalind MITCHELL, Ismail UGHRATDAR
08:00 - 18:00 #10818 - P051 Widening possibilities in DBS for essential tremor: 8-contact-lead for cZI and vin aligned in the same trajectory.
Widening possibilities in DBS for essential tremor: 8-contact-lead for cZI and vin aligned in the same trajectory.

Bilateral deep brain stimulation (DBS) of the thalamic Vim nucleus has been accepted as the standard treatment for essential tremor (ET), but results are limited by side effects such as speech impairment, ataxia and stimulation tolerance in long term1; in extreme cases reoperation may be required2. More recently, stimulation of the caudal Zona Incerta (cZI)3 emerged as a promising target for tremor control, aiming the ascending cerebello-rubro-thalamic fibers with encouraging results. We proposed bilateral implantation of 8-contact-electrodes aligning the VIM and the cZI in the same trajectory, offering multiple stimulation targets with no additional risk for the patient. The index case of refractory ET treated with bilateral double target DBS is presented here. A 65-year-old man diagnosed with ET for 49 years referred progressive functional impairment especially in the last 5 years. Action tremor was quite disabling, particularly when trying to perform simple daily tasks, such as grabbing a cup, using a fork or shaving. Stigmatizing tremor also compromised his professional activity as salesman. He scored 37/144 in Fahn-Tolosa-Marin Tremor Rating Scale (FTMRS) even receiving propranolol 40mg/day and primidone 700 mg/day limited by side effects. Bilateral DBS was proposed as a treatment option for the tremor, which was performed using 8-contact leads. The stereotactic planning included the Vim and the cZI in one straight trajectory in each side according to the anatomy of the region. As a single trajectory was performed in each side, no additional risk for the patient was taken. In the first 6 weeks, the therapeutic window (130Hz and 60µs) was tested in each of the contacts. Satisfactory tremor control was achieved with monopolar stimulation in upper contacts (Vim) and also in lower ones (cZI), with different profiles of adverse effects. Since the tremor control was outstanding and no significant side effects were observed at the level of cZi (monopolar stimulation in contact 3 as the cathode), we kept this as therapeutic stimulation for 10 months. The patient experienced close to full tremor control most of the time and we observed 86% improvement in global scores in FTMRS (5/144). Tremor amplitude in the dominant hand was also assessed by accelerometry (Lift Pulse Software - Lift Labs, USA) with 92,3% improvement when compared to no stimulation. Studies comprising more cases can determine which level of this complex region is best for tremor control.

Dos Santos Ghilardi MARIA GABRIELA, Melisa IBARRA, Paul Rodrigo REIS, William Omar LOPEZ CONTRERAS, Armando ALANINOS, Clement HAMANI, Erich FONOFF (São Paulo, BRAZIL)
08:00 - 18:00 #10820 - P052 87 Deep Brain Stimulation patients with rechargeable battery. Selection criteria, follow up and satisfaction survey.
87 Deep Brain Stimulation patients with rechargeable battery. Selection criteria, follow up and satisfaction survey.

Background: Deep Brain Stimulation(DBS) has been traditionaly implanted with non rechargeable battery.Some groups argue that the implantation of the rechargeable battery is associated wiht difficulty to learn to handle it,pain in the moment of recharghing it and the much greater cost of the system.Nevertheless,the implantation of rechargeable battery since the electrodes are implanted for the first time,or in the replacement of the previous non rechargeable battery is increasing in some centers like ours.

Objective:To report clinical follow-up in 87 patients who underwent DBS with rechargeable battery.Criteria inclusion,follow up and satisfaction survey.

Methods:  87 patients between 13 and 77 years old,56% female,in a period of time between December 2012-February 2017 and follow up between 1-50 months,underwent DBS mainly for movements disorders,but also for psychiatric,epilepsy and pain illness. Based on diagnosis and calculating duration of the battery, relation between chest wall thickness and battery size and cost of the device to long term, patients received rechargeable battery most of them since the electrodes were implanted for the first time, but also as a second stage changing previous non rechargable battery.  Surgeries were performed with Leksell frame,Surgiplan software,3TMRI,microrecording,macrostimulation,all of it with awake patient in most of the cases.Sedation or general anesthesia was used for the battery implantation,all in one stage procedure.Satisfaction survey was applied focusing on the learning process to handle the battery,efficiency in the use of the battery,damages presented in the recharging device and side effect such as pain. 

Results:All patients are adequately recharching the battery,55% by themselves,and the others by close relatives or caregivers. 87% learned to handle it within the first week,11% within the first month and 2% within the 3 first months after surgery.4% has had the battery at 0 charge one time.72% has full communication expressed in 8 cubes in black.5% have damaged part of the rechargeable system that was repaired in a timely manner. 15% have had minor pain or discomfort any time after surgery and 6% when they were charged.  The most frequent areas of pain were:subclavicular area,right neck and shoulder.

Conclusions: DBS with rechargeable battery is easy to handle with minor damages in the system per se and manegeable pain. Long term it is less expensive. More cases and longer follow up should be carried out.   

Adriana Lucia LOPEZ RIOS (TORONTO, CANADA), Francisco Aureliano GARCIA JIMENEZ, Omar BURITICA, Katherine Johanna NARANJO PEREZ, William Duncan HUTCHISON
08:00 - 18:00 #10821 - P053 Altered Brain White Matter Integrity in Patients with Parkinson Disease Treated by Deep Brain Stimulation: A Tract Based Spatial Statistics Study.
Altered Brain White Matter Integrity in Patients with Parkinson Disease Treated by Deep Brain Stimulation: A Tract Based Spatial Statistics Study.

Introduction:

Diffusion tensor imaging (DTI) is widely used in neurological and neuropsychiatric diseases, such as Parkinson’s disease (PD). We intended to evaluate the effectiveness of white matter tract based spatial statistics (TBSS) generated from DTI in patients with PD in detecting differences in patient motor response to deep brain stimulation (DBS).

Methods:

Six subjects with advanced PD from 55-66 years old were scanned for DTI protocol under anesthesia in a 3.0T Philips Achieva MR scanner before surgery. Motor scores (UPDRS-III) were collected before and after DBS (mean follow-up 5.9 months). The group was divided into two cohorts: patients with improvement in UPDRS-III after DBS; and patients without improvement in UPDRs-III after DBS. 

The diffusion volumes were first corrected for eddy current distortions and motion artifacts. Diffusion tensor maps were computed from the pre-processed DTI volumes for each subject on a voxel-by-voxel basis using FSL FDT diffusion toolbox. Various DTI indices such as fractional anisotropy (FA), mean diffusivity (MD), and diffusion traces along main Cartesian axes (L1, L2, L3) were generated. To generate TBSS, all FA maps were aligned MNI space and FA skeletonisation was then applied to all FA images with a threshold of 0.2 set to only constrain analysis to highly anisotropic white matter tissue. Also, TBSS were applied to the none FA images (MD, L1, L2 and L3).  

Results:

Significant differences were identified between ‘responders’ and ‘nonresponders’. In summary, FA shows high number of white matter skeleton voxels (4.23%) altered significantly between two groups of PD patients compared to the other DTI maps. Compared to the patients with low UPDRS-III score, FA shows significant increase in patients with higher UPDRS-III score or responders and diffusion trace along z direction shows significant decreases in patients with lower UPDRS-III score or nonresponders.

Conclusion:

The results suggest that many regions of white matter pathology were altered differently and show the variability of DTI parameters related to the neuropathology of the PD patients. While the focus has generally been on the motor component of the cortico-basal ganglia-thalamo-cortical circuit, diffuse changes affecting the associative and limbic components may also play a role in DBS response. While studying all brain networks is not feasible, TBSS has potential to serve as an screening tool to identify regions of interest.  

Mahdi ALIZADEH, Jennifer MULLER, Jonathan RILEY, Feroze MOHAMED, Ashwini SHARAN, Chengyuan WU (Philadelphia, USA)
08:00 - 18:00 #10346 - P053b The use of rechargeable or non-rechargeable deep brain stimulation devices in parkinson’s disease (PD) and dystonia: A cost analysis.
P053b The use of rechargeable or non-rechargeable deep brain stimulation devices in parkinson’s disease (PD) and dystonia: A cost analysis.

Objectives: Deep brain stimulation (DBS) is a recommended option for the treatment of movement disorders in well-selected patients. Both rechargeable and non-rechargeable devices are available; one of the advantages of a rechargeable DBS device may lie in the avoidance of costs for battery replacements and associated risks and hospitalisations. The objective of this study was to evaluate the economic impact of using a rechargeable DBS device over a non-rechargeable device in patients treated for either Parkinson’s Disease (PD) or Dystonia.

Methods: An economic model (Markov Model) was built to follow a group of dystonia and PD DBS patients over time comparing two scenarios, one assuming a rechargeable and one assuming a non-rechargeable device, for first implant and replacements. The model captures patients’ replacement surgeries, hospitalisations, adverse events and deaths. Data for the model were sourced from the Medtronic product surveillance registry (PSR; patient characteristics, adverse events and consequences associated with implant and replacement surgeries) and non-rechargeable device longevity data from Medtronic performance registry based modelling analyses. For the rechargeable device longevity, current longevity (9 years) and a hypothetical longevity scenario (15 years) were tested. Clinical expert advice was used to inform model assumptions. Costs were estimated from a UK health care perspective. Sensitivity analyses were undertaken to test for parameter uncertainty, including time horizon. 

Results: Results of the base case analysis (16 year time horizon) show:For PD,an average of 3.68 battery replacements in the non-rechargeable vs 0.62 in the rechargeable group; for Dystonia, 5.08 and 0.74 replacements in the non-rechargeable vs the rechargeable group(15-year hypothetical device longevity). Over 16 years,the model suggests cost savings of £15,564 (PD) and £27,954 (Dystonia) using the 9 year device longevity, and £20,418 and £32,060, respectively, for a 15-year hypothetical device longevity. Sensitivity analyses showed that over a patient’s life time, cost savings were £28,450(PD) and £65,413(dystonia)(15-year hypothetical device longevity).

Conclusion: The use of a rechargeable DBS device in this model is cost saving in the long-term compared to a non-rechargeable device. Prolonging rechargeable device life to 15 years is predicted to reduce DBS treatment costs and would thus improve DBS therapy cost-effectiveness, for both PD and dystonia. 

Simon EGGINGTON , Katherine STROMBERG , Silke WALLESER AUTIERO, Todd WEAVER, Paul R. PROF. ELDRIDGE (LIVERPOOL, UK)

Monday 26 June

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08:00 - 18:00 #10139 - P054 Deep Brain Stimulation for Depression: using an individual patient-level registry to explore patient characteristics and clinical outcomes.
Deep Brain Stimulation for Depression: using an individual patient-level registry to explore patient characteristics and clinical outcomes.

Objectives

There is now a significant body of published literature reporting the outcomes from Deep Brain Stimulation (DBS) for major depression (MDD). To explore patient characteristics, we constructed a patient-level registry based on reported studies between 2005 and 2017.

Method

Studies published reporting outcomes from DBS for MDD between 2005 and 2017 were included. All study types were included if patient outcomes were reported. Duplicate reporting was flagged so that reports of outcomes from the same patients could be excluded.

Results

The registry currently contains data for 234 patients from 25 studies. Of these, 171 patients from 17 published studies were unique. Patients who received DBS for indications other than MDD were excluded (N=11).

The median number of participants in included studies was 7 (range 1 – 30). The mean ± SD duration of follow-up was 12.8 ± 5.4 months; and 41.1% of studies reported follow-up of less than one year. Countries with the most DBS electrode implantations were: USA (40.4%); Canada (29.3%); and Netherlands (14.6%).

Gender breakdown was: males (41.5%); females (58.5%); unreported (19.5%). The mean age of onset was 27.2 ± 7.1 years and the average age of surgery was 48.8 ± 4.9 years. The average duration of the current depressive episode was 8.7 ± 2.2 years.

The most common targets for DBS were: CG25 (43.9%); VC/VS (25.7%); and ALIC (14.6%). Other targets made up 15.8% of cases.

The mean baseline HRSD-17 score was 24.4 ± 3.5, indicating symptoms in the severe range. However, 32.1% of patients had baseline scores in the ‘moderate’ range. The no. of failed antidepressant trials was unreported in 56.1% of cases. Most (67.3%) had previously had ECT, but 6.4% had not. This was unreported for 26.3%.

Comorbidity was poorly reported. Axis I comorbidity is not reported in 84.2% of cases. Although personality disorder is reported in 5.9%, it is unreported in 70.2% of cases.

The overall response rate was 40.4%, but 53.2% did not respond. The response status was not known in 6.4% of patients.

Conclusion

Inconsistent reporting of baseline patient characteristics means that there is uncertainty about comparability of DBS patients to ablative neurosurgical patients in terms of severity.

It is still unclear what the optimum target is and further work is required to determine this. Patient characteristics remain poorly reported and this limits generalisability to patients for whom neurosurgery may be considered.

David CHRISTMAS (Dundee, Scotland, UK), Keith MATTHEWS
08:00 - 18:00 #10141 - P055 Changes in Interpersonal Functioning following Bilateral Anterior Cingulotomy (ACING) or psychological therapy for chronic, treatment-refractory Depression.
Changes in Interpersonal Functioning following Bilateral Anterior Cingulotomy (ACING) or psychological therapy for chronic, treatment-refractory Depression.

Objectives Interpersonal dysfunction is a core component of depressive illness but is poorly studied or understood. Here, we report profiles of interpersonal functioning in 16 patients undergoing anterior cingulotomy (ACING) for chronic depression and compare them with 42 patients undergoing a specific psychological therapy developed for chronic depression.

Method The 64-item Inventory of Interpersonal Problems (IIP-64) is a self-report measure of difficulties that people encounter in their interpersonal relationships. The IIP-64 assesses interpersonal problems in eight specific domains of interpersonal functioning. The Total T-score reflects the overall burden of difficulties. Sixteen patients undergoing ACING completed the IIP-64 at baseline and 12-months following surgery. This group was compared to 42 patients with chronic depression who underwent a course of psychological therapy (CBASP). The outcome measure in both groups was change on the 17-item Hamilton Rating Scale for Depression (HRSD-17). Response was defined as ≥50% improvement from baseline score.  We compared changes in scores on the IIP-64 in relation to changes in symptom burden and response to both treatments. Total T-scores post-treatment were compared between responders and non-responders for both groups. Finally, we attempted to relate change in depressive symptoms to changes in interpersonal functioning.

Results Sixteen individuals (M:F - 1:15) underwent ACING. The mean ± SD age was 48.9 ± 8.3 years. The mean ± SD baseline HRSD-17 score was 28.6 ± 4.9.

Forty-two patients (M:F ratio 9:33) received CBASP. The mean ± age was 51.0 ± 9.8 years. The mean ± SD baseline HRSD-17 score was 20.5 ± 4.7.

In the ACING group, 7 (43.8%) were responders. In the CBASP treated group, 13 (31.0%) were responders.

In all responders, there was a statistically-significant correlation between change in HRSD-17 score and change in IIP-64 total score: ACING (Pearson’s r=0.896, P=0.006); CBASP (Pearson’s r=0.599, P=0.03).

Conclusion

Following both neurosurgery and psychological therapy, responders showed changes in interpersonal functioning that were not seen in non-responders. In responders, there was a relationship between change in symptoms and change in interpersonal functioning.

There was no evidence of deterioration in interpersonal functioning following ACING; even in non-responders.

It is likely that improvements in interpersonal functioning are mediated by a common factor – improvement in depressive symptoms.

Anne MATHER (Dundee, UK), Keith MATTHEWS, David CHRISTMAS
08:00 - 18:00 #10142 - P056 Prospective Care Planning for Patients Receiving Neurosurgical Treatments for Depression: Essential For Optimised Outcomes.
Prospective Care Planning for Patients Receiving Neurosurgical Treatments for Depression: Essential For Optimised Outcomes.

Objectives

Care planning is an important component of the pathway for individuals undergoing neurosurgical treatment for depression. All patients have prolonged histories of ill health and are typically embedded within complex networks of care and support. We developed audit criteria to assess whether our care planning was consistent with WSSFN Consensus Guidance (Nuttin et al, 2014). Here we describe the operationalisation of this process.

Method

We designed a care-planning audit tool focusing on eight key domains: multi-disciplinary involvement; immediate post-op period; focus of treatment; engagement with patient; collaboration between neurosurgical service and local services; consistency of follow-up; adherence to care plan; and frequency of contact. These domains reflect the care planning of both our service and the patient’s locality mental health services.

Pre-operative care plans and adherence at 12-month follow-up were rated for 27 anterior cingulotomy patients and 5 Vagus Nerve Stimulation patients. We compared two time periods: 1999-2008 (21 procedures); 2010-2015 (15 procedures) to examine changes over time. We also compared scores between procedures.

Results

Highest scores were seen in the ‘consistency of follow-up’ domain, which reflected consistency in key healthcare personnel. Next highest scores were in the ‘frequency’ domain, indicating that patients were seen regularly in the 12-months following surgery. Lowest scores were seen in the ‘adherence to care plan’ and ‘immediate post-op period’.

Scores on ‘adherence to care plan’ reduced a little over time, whilst the domains that showed improvement were: ‘immediate post-op period; and ‘focus of treatment’. Scores for ACING patients were higher than scores for VNS.

These findings suggest that there are consistent challenges relating to care planning but that more structured approaches by neurosurgical services may help to overcome these difficulties.

Conclusion

Care planning is vital and has the potential to impact upon patient outcomes. Whilst neurosurgical services may not be able to control all aspects of care provided by other services, we clearly have a role in establishing explicit, realistic, and collaborative care plans for patients undergoing neurosurgery. We are now developing standards for care planning that we can use in discussions with local services when planning care for patients undergoing psychiatric neurosurgery. We will audit against these new standards in the future.

Anne MATHER (Dundee, UK), David CHRISTMAS, Keith MATTHEWS
08:00 - 18:00 #10225 - P057 Oculomotor side effects due to deep brain stimulation of the medial forebrain bundle: tractography analysis.
Oculomotor side effects due to deep brain stimulation of the medial forebrain bundle: tractography analysis.

Background: Deep brain stimulation (DBS) to the superolateral branch of the medial forebrain bundle (MFB) has been reported to incur rapid anti-depressant effects (Schlaepfer et al., 2013, Fenoy et al., 2016). Diplopia is a side effect often experienced when programming. We sought to identify modulated fiber tracts associated with diplopia so they can be avoided and targeting improved.

Methods: 6 patients were implanted with electrodes targeting their individually mapped MFB. Optimal parameters resulting in anti-depressant effect were 1+2-3-, 130 Hz, 60 µs, 3-4V; stimulation of electrode contact 0 resulted in diplopia in every patient at 1V. The volume of tissue activated (VTA) was estimated using cathodal contact parameters; this was used as the seed region in deterministic fiber tracking to identify modulated fiber tracts.

Results: Use of contact 0 as a seed region revealed modulated tracts that were in proximity to atlas-defined oculomotor fibers. These tracts were consistently ventral and dissociable from those correlated with anti-depressant effect. Both sets of modulated fibers traversed the targeted MFB region. Mean coordinate of contact 0 was (5, -2.5, -9); contact 2 was (5.2, -0.5, -5).

Conclusion: Modulated fibers that incurred diplopia were consistently ventral to those producing anti-depressant effect. More rostral targeting within the MFB region is preferable. It is unlikely that current steering would improve side effect avoidance with Z as the critical dimension.

Albert FENOY (Houston, USA), Sudhakar SELVARAJ, Joao QUEVEDO, Jair SOARES
08:00 - 18:00 #10311 - P058 Matabolic Brain Networks in Parkinson’s Disease Patients with Depression Symptom Based on 18F-FDG PET Imaging.
Matabolic Brain Networks in Parkinson’s Disease Patients with Depression Symptom Based on 18F-FDG PET Imaging.

                              Matabolic Brain Networks in Parkinson’s Disease Patients with Depression Symptom Based on 18F-FDG PET Imaging

Objectives: Parkinson’s disease (PD), characterized by loss of dopamine neurons in the substantia nigra (SN) and the subsequent deficiency in striatal dopaminergic system, is the second most common  neurodegenerative disorder with a frequent comorbid symptom of depression. Drawing the brain metabolic pattern of PD may help to target the core biological and psychological features of the psychiatric comorbidity and to the diagnosis and recovery criteria. In this study, we use 18F-FDG PET to show brain metabolic network for Parkinson’s Disease-associated depression.

Methods: Glucose metabolism in 21patients and 17 age-matched healthy controls were studied using 18F-FDG PET. SPM was used to compare brain metabolism in PD patients with depression with that in healthy controls.

Results: The SPM (statistical parametric mapping ) analysis showed hypermetabolism in the putamen (bilateral), the globus pallidus (bilateral), lentiform nucleus (bilateral) and striatum compared with the controls ( P<0.01 ). PD patients with depression had bilateral area of hypometabolism in the frontal lobe, temperal lobe and parahippocampal gyrus compared with healthy controls. (P<0.01).  

Conclusion: The changes in brain glucose metabolism illustrated the brain metabolic pattern in PD patients with depression. Furthermore, the pattern went accordance with the severity of depression. The regions with altered metabolism could interconnected to form a network and integrate information related to depression in PD patients. Our study may provide information for targeting the potential candidate brain regions for understanding the pathophysiology of depression in PD patients and assessing the severity of the illness.

Keywords: PET , Parkinson’s Disease, depression, functional imaging , glucose metabolism    

Xiaoxiao ZHANG, Bomin SUN (shanghai, CHINA)
08:00 - 18:00 #10686 - P059 Temporal dynamics of local field potential activity recorded in the ventral tegmental area and the nucleus accumbens in the flinders sensitive line rodent model of depression.
Temporal dynamics of local field potential activity recorded in the ventral tegmental area and the nucleus accumbens in the flinders sensitive line rodent model of depression.

Depression is a common disorder and comprises the leading cause of disability worldwide. Within the limbic circuitry passing through the medial forebrain bundle (MFB), the mesolimbic pathway is particularly implicated in the pathophysiology of depression, since it is associated with reward, aversive learning, social behavior, and addictive behavior. It is known that, in rodents, specific dopaminergic cells from the ventral tegmental area (VTA) project to the medial shell of the nucleus accumbens (NAc). Furthermore, appetitive motivation for rewards and fearful motivation toward threats are organized in circuits arranged in an environment-dependent keyboard fashion in the NAc medial shell. However, if and how this circuitry is altered in depression is not yet understood.

In order to detect electrophysiological signatures associated with a depressive phenotype, we recorded local field potentials (LFP) in the VTA and NAc medial shell of control (Sprague-Dawley) and Flinders Sensitive Line (FSL) rats using stereotactically inserted bipolar concentric electrodes. Recordings were performed at several time points in vivo, during free behavior, both while the rats were in their usual home environment and in a stressful environment. Correct electrode placement was evaluated through histological analysis.

The data is currently being analyzed using time-frequency domain and connectivity analysis techniques in MATLAB and will be presented at the meeting. Between-group and within-group comparisons are being performed for both home environment and stressful environment conditions. Early assessment suggests differences across the groups in the VTA and NAc power spectra and connectivity measurements, differences which are accentuated in the stressful environment.

The data point towards altered electrophysiological activity in a rodent model of depression in neural structures associated with major depressive disorder and provides guidance to future studies that will integrate LFP recordings with electrical and optogenetic stimulation of the MFB in the FSL rat.

Felipe BRANCO DE PAIVA (Freiburg, GERMANY), Wilf GARDNER, Sebastián CASTAÑO, Volker Arnd COENEN, Máté DÖBRÖSSY
08:00 - 18:00 #10748 - P060 Optogenetic stimulation of the MFB in the Flinders Sensitive Line rat model of Depression with an Intact vs. a Depleted Dopamine-System.
Optogenetic stimulation of the MFB in the Flinders Sensitive Line rat model of Depression with an Intact vs. a Depleted Dopamine-System.

Major Depression is a common, multifactorial psychiatric disease with heterogeneous symptoms, including anhedonia and reduced motivation. These symptoms are associated with the dysfunction of the limbic circuitry in the brain. The dopaminergic neurons of this circuitry are involved in reward and motivation, and targeted for the treatment of depression. Modulation of these neurons by antidepressant medication or the pathways with Deep Brain Stimulation can reverse a depression-like phenotype in rodents. Nevertheless, mechanisms of the disease and the therapeutic effects of stimulation are not understood.

In this study, we used optogenetic stimulation of the medial forebrain bundle (MFB) as a treatment attempt in a rodent model of depression, the Flinder’s Sensitive Line (FSL) rat. The FSL rat has been bred selectively for more than 25 years and shows a depressive-like phenotype due to decreased BDNF levels, decreased 5-HT synthesis, hyperactive HPA-axis and more.

FSL rats with an intact dopamine system (DA+) were compared with rats that received a bilateral 6-OHDA lesion of the Nucleus accumbens (DA-), depleting the reward circuitry. The effect of the stimulation in depleted vs. intact animals was investigated in freely moving rats in a number of behavioral tests. Animals of the stimulation groups received 30 min of light stimulation directly prior to each behavior test. The behavior was tested using the sucrose preference test, forced swim test, social interaction test, open field test, ultrasonic vocalization and activity measurements, induced by amphetamine or stimulation.

 

Results show an increase in amphetamine-induced activity in both groups, but the effect is much less prominent in the DA- groups, confirming the partial lesion. Activity is also enhanced by stimulation of the MFB. Stimulation increased the track length in the open field in all groups, but the track length in the center zone was only increased in the DA+ group. Besides, stimulation of the MFB enhanced social interactions in the DA+ group.

The increased activity due to stimulation of the MFB and the observed exploratory behavior of the rats indicate a robust SEEKING (enhanced drive) response, thus an activation of the brain reward circuitry. Extended track length in the center zone of the open field and increased social interactions only in the stimulated DA+ group point towards an important role of the dopaminergic part of the limbic system in possible treatments for Major Depression.

Lisa-Marie PFEIFFER, Stephanie THIELE, Volker Arnd COENEN, Máté DÖBRÖSSY (Freiburg, GERMANY)

Monday 26 June

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08:00 - 18:00

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08:00 - 18:00 #10124 - P061 Deep Brain Stimulation for Dystonia - Pallidal stimulation and thalamic stimulation -.
Deep Brain Stimulation for Dystonia - Pallidal stimulation and thalamic stimulation -.

Background: Deep brain stimulation of globus pallidus internus (GPi-DBS) has proved efficient in primary dystonia and some secondary dystonias. However, 15% to 20% of dystonia patients underwent GPi-DBS respond to this therapy insufficiently. Exploration of alternative DBS target is important to provide further treatment. We have performed stimulation or ablation of thalamic Vo nucleus for focal hand dystonia and some generalized dystonia, in addition to GPi-DBS. Here, we report the clinical featrures of patient with dystonia underwent GPi-DBS and Vo-DBS/ablation.

Subject and Method: A total of 46 patients with dystonia underwent DBS from 2003 to 2014 at Tokushima University Hospital. All patients were assessed every one to three months after surgery. Motor symptoms of dystonia were assessed by the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS).

Results: Forty-four patients underwent only GPi-DBS (GPi group) and six patients underwent GPi-DBS followed by thalamic Vo surgery (GPi+Vo group). The improvement ratio of BFMDRS after surgery was 54% in the GPi group, and 67% in the GPi+Vo group. In the GPi+Vo group, four of six were focal hand dystonia (FHD), and two of six were primary generalized dystonia (DYT-6 and sporadic dystonia).

Discussion: In 2005 and 2006, two multicenter randomized controlled trial proved GPi-DBS has the efficacy in primary generalized/segmental dystonia. However, recent reports revealed the presence of the poor responders to GPi-DBS by limitation of therapy due to the stimulation related side effect, and by a pathogenetic reason such as DYT-6 positive. Although it is known that thalamic Vo-DBS is effective for FHD, in our case, DYT-6 dystonia also well responded to Vo-DBS. Recently, the genesis of dystonia has been suggested to be associated with altered activities, not only of the basal ganglia, but also of the cerebellum. In the Vo-complex nucleus, the Voa is largely associated with the pallido-thalamic pathway while the Vop is with the cerebello-thalamic pathway.16 This indicates that unlike GPi-DBS, Vo-complex stimulation has the potential to modulate the activities of not only the pallidal pathway but also the cerebellar pathway at the thalamus level. We suggest that the thalamic Vo-complex nucleus could serve as an alternative target for some generalized dystonia with a relation to the cerebello-thalamic pathway as well as FHD.

Hideo MURE (Tokushima, JAPAN), Ryoma MORIGAKI, Shinya OKITA, Ryosuke MIYAMOTO, Shinji NAGAHIRO, Satoshi GOTO
08:00 - 18:00 #10295 - P062 Experience on surgical treatment of dystonia in Nepal.
Experience on surgical treatment of dystonia in Nepal.

Introduction:

Medical treatment of dystonia is very complex and sometimes unsuccessful. Surgical treatment like thalamotomy, pallidotomy and Deep brain stimulation (DBS) can be beneficial for the patients.

Methods

Two cases of dystonia have been treated surgically in Annapurna Neurological Institute and Allied Sciences in last two years. First case is a case of 47 years old lady with tardive dystonia who underwent bilateral GPi(Globus Pallidus Interna) pallidotomy under local anesthesia. Her preoperative Burke-Fahn-Marsden Dystonia rating score(BFMDRS) was 36/123. There was no postoperative complications and her postoperative BFMDRS was 1/123. There was no recurrence in two years follow up period.

Second case is a 48 years old male with primary dystonia involving the neck and trunk muscles. His preoperative BFMDRS score was 42/123. He neither responded to medical treatment nor to botulism toxins. He also underwent bilateral GPi Pallidotomy under local anesthesia. His postoperative BFMDRS score was 2/123. This patient developed mild dysarthia after surgery and it is improving with time. There is no recurrence of symptoms in nine months follow up period.

The standard functional targets were used. Then fusion of MRI( 3 Tesla Philips) and CT (1 slice Siemens) stereotaxy( with ZD Fisher frame) was used and it was reconfirmed with the inbuilt Schaltenbrant Atlas. Total eight lesions were made in each side with 70 degree centigrade for 40 second each using Cosman Radiofrequency (RF) generator  and the lesioning probe was 1 mm in diameter with 2 mm exposed tip. Continuous monitoring of motor symptoms and visual symptoms were done during the surgery

Result

The patients’ dystonia improved in terms of BFMDRS score and there were no major postoperative complications.

Conclusion

Patients with dystonia can benefit from bilateral GPi pallidotomy but GPi DBS is also an alternate option for affordable patients.

 

 

 

Resha SHRESTHA (Kathmandu, NEPAL)
08:00 - 18:00 #10322 - P063 Botulinum Toxin Injection for the Treatment of Hemifacial Spasm-Technical Note.
Botulinum Toxin Injection for the Treatment of Hemifacial Spasm-Technical Note.

Objective: To introduce the botulinum toxin injecton technique on the periocular area for the treatment of hemifacial spasm and report the treatment results.

Materials and Methods : Thirteen sessions with five patients were performed with botulinum toxin therapy injected to the periocular area. Botulinum toxin was injected at four sites on the affected side at a dose of 2.5 unit botulinum toxin per site.
Results: All treated patients had symjptom improvement. The degree of improvement measured on the visual analogue scale was 89.3%, and the average duration of the effect was 6.3 months. One patient had ptosis after his third session.

Conclusion: Botulinum toxin therapy is effective for the treatment of hemifacial spasm. Our patients were satisfied with the treatment results. Ptosis is the most common complication reported in the literature, but it can be avoided by preventing the spread of neurotoxin after the injection and avoiding inadvertent injections.

Eunyoung KIM (Incheon, KOREA), Myeongjin KIM, Gitaek YEE, Chanjong YOO, Uhn LEE
08:00 - 18:00 #10327 - P064 Clinical outcomes after pallidal Surgery for Secondary dystonia.
Clinical outcomes after pallidal Surgery for Secondary dystonia.

Secondary dystonia is  extremely disabling affecting the quality of life of the individual as well as the caretaker. Multiple treatment options  are aimed at improving physical ability. Treatment options for generalised, hemi-dystonia or segmental dystonia are limited. Lesioning and /or Deep Brain Stimulation have become the treatment of choice for primary dystonia. The results in secondary dystonia are  variable. We share our experience  of patients with secondary dystonia including,  clinical details, technical difficulties, complications and outcomes.

Materials

Nineteen patients with secondary dystonia were analysed.

The clinical picture varied from inability to swallow, breathing difficulties, inabilty to sit, oromandibular dystonia, truncal dystonia and deformities.  

 The patients were evaluated with standardised rating scales and treatment planned in consultation with the team. 

Patients underwent either lesioning or Deep Brain stimulation. The targets were either in the globus pallidus interna and thalamus, decided after team discussion.  

Quality of life and outcomes were analysed.

Results

The clinical improvement in secondary dystonia is not as good as in primary dystonia. The quality of life improved in segmental dystonia  and in some cases of generalised dystonia. Generalised dystonia secondary to hypoxic ischemic damage  did not show any significant improvement.

Conclusion

Clinical outcomes  are variable in secondary dystonia  though not as rewarding as in primary dystonia. 

Milind SANKHE (MUMBAI, INDIA)
08:00 - 18:00 #10432 - P065 Long-term follow-up after Deep brain stimulation of the VOA (Nucleus oralis anterior thalami) for Dystonic-jerky-unsteady-hand-syndrome.
Long-term follow-up after Deep brain stimulation of the VOA (Nucleus oralis anterior thalami) for Dystonic-jerky-unsteady-hand-syndrome.

Objective: In the literature data of deep brain stimulation for post stroke dystonia are rare, particularly for long-term outcome. Due to disappointing benefits after single target stimulation multiple targets are discussed.

Methods: We report one patient with a dystonic-jerky-unsteady-hand-syndrome, who presented with hyperkinetic movements of the right arm. MRI showed small explaining lesion in the left ventroposterior thalamus and additional small lesions in the cerebellum. Due to failure of noninvasive therapies we have planned the unilateral stimulation of the left VOA and supplementary the GPI in standby. The surgery was performed using stereotactic MRI and multiple trajectories for micro recording and macro stimulation under local anaesthesia in 2008.

Results: Intraoperative we found good thalamic activity on the trajectory of the VOA. A good reduction of the symptoms was shown under macro stimulation without relevant side effects. Owing to the impressive effect the GPI-stimulation wasn’t performed. Under permanent stimulation improvement with complete reduction of tremor and dystonic movements was achieved from first day of stimulation and meanwhile in the nine year follow-up. No adapting of stimulation parameters was necessary. Patient is absolute independent in every day´s life and ongoing on work.

Conclusion: We conclude that the deep brain stimulation of the VOA could be an effective method for the long-term treatment of post stroke tremor and dystonia with outstanding economic importance. 

Daniela FALK (Kiel, GERMANY), Nils WARNEKE, Jens VOLKMANN, H. Maximilian MEHDORN
08:00 - 18:00 #10443 - P066 Complications of deep brain stimulation for secondary dystonia in the early postoperative period (30-day morbidity): experience in 49 patients.
Complications of deep brain stimulation for secondary dystonia in the early postoperative period (30-day morbidity): experience in 49 patients.

Objective: Deep brain stimulation (DBS) has been shown to be efficacious in the treatment of primary dystonia (idiopathic and inherited dystonia). There is less experience in, however, secondary dystonia (acquired dystonia). Since patients with secondary dystonia, who are often more disabled, may be more vulnerable to postoperative complications we aimed to investigate the 30-day morbidity in a large cohort of patients with secondary dystonia operated over a period of 19 years.

Methods: From 1997 until 2016, a total of 49 patients (27 women and 22 men; mean age 43,5 years (range 13-77)) with secondary dystonia underwent DBS with electrodes implanted either in the thalamic Nucl. ventralis intermedius (Vim) or the posteroventral lateral globus pallidus internus (GPi). Most frequent cause of for dystonia was cerebral palsy in 17 patients.

 

Results: There were no intraoperative complications or complications in the early postoperative period related to surgery. The electrode location was corrected in 2 instances. Two patients developed a wound infection, one patient had a subdural hematoma and subcutaneous collection of cerebrospinal fluid (CSF). Three weeks after DBS the subdural hematoma and CSF resolved.

 

Conclusion: The 30-day morbidity rate in DBS for secondary dystonia is comparable to that in primary dystonia. DBS surgery may be offered to patients with secondary dystonia without concerns about higher morbidity.

Andreas WLOCH (HANNOVER, GERMANY), Abdallat MAHMOUD, Assel SARYYEVA, Christoph BLAHAK, Marc WOLF, Christoph SCHRADER, Joachim RUNGE, Joachim K. KRAUSS
08:00 - 18:00 #10445 - P067 Long term follow-up in Mohr-Tranebjaerg syndrome after pallidal stimulation.
Long term follow-up in Mohr-Tranebjaerg syndrome after pallidal stimulation.

Objective: Pallidal deep brain stimulation (DBS) has been established as a treatment option in patients with medically refractory dystonia. Mohr-Tranebjaerg syndrome (MTS) or Dystonia-Deafness-Syndrome is a rare genetic disorder characterized by deafness, dystonia and neurological abnormalities like impaired vision, dementia and cortical blindness. So far little is known about the efficacy of DBS in MTS.

 

Methods: A 44-year- old man with a history of generalized dystonia, deafness, visual blindness, ataxia and tremor was diagnosed with MTS which was confirmed by genetic analysis. He underwent bilateral stereotactic implantation of DBS electrodes in the posteroventral lateral globus pallidus internus (GPi). Electrode location was confirmed by postoperative stereotactic CT.

 

Results: Bilateral pallidal stimulation yielded modest improvement of dystonia at 6-months follow-up. During the next four months there was an increase of tremor and ataxia. The initial benefit was lost within the next two years. Extensive reprogramming did not yield additional improvement. After three years of chronic stimulation it was decided to switch off the pacemaker because of loss of efficacy.

 

Conclusions: It is important to check for the genetic background in patients with unusual clinical symptoms. As opposed to inherited isolated dystonia, patients with MTS may achieve little benefit from pallidal DBS.

Andreas WLOCH (HANNOVER, GERMANY), Christoph BLAHAK, Hansjörg BÄZNER, Joachim K. KRAUSS
08:00 - 18:00 #10460 - P068 Case series of deep brain stimulation of globus pallidus internus as therapy for dystonic storm in a single center in colombia.
Case series of deep brain stimulation of globus pallidus internus as therapy for dystonic storm in a single center in colombia.

Introduction: Dystonic Storm (DS) is a life-threatening complication of dystonia characterized by sudden and persistent episodes of dystonic movements that become increasingly frequent and severe, requiring urgent hospital admission, leading to respiratory, metabolic and bulbar complications1,2. Pharmacologic treatment has been the mainstay management, however, many refractory patients will still require further treatments. Deep brain stimulation (DBS) of bilateral globus pallidus internus (GPi) is an interesting therapeutic strategy that has been used for dystonia and now it has been proposed to be used for DS.Case series: We describe 5 cases (Two pediatric and three adults) with DS, admitted to our institution, that required emergent placement of a bilateral GPi DBS to control their symptoms (Table 1.). Dystonia etiology was identified as secondary in two of them (cerebral palsy with dyskinetic predominance), other case with a genetic syndrome, and two cases continue in studies for primary genetic causes. All five patients coursed with dystonic movements of different body regions including neck, extremities and trunk that interfered with ambulation. Severity was measured with the UDRS scale. Precipitating factors were identified in two cases (superior airway infection and electrode dislocation). Pharmacologic therapy wasn’t effective in any of the cases and ICU admission was necessary before surgery. Before discharge, symptomatic relief (diminution of dystonic movements and resolution of abnormal postures) was achieved in all five patients in a mean period of 6,6 days (1,6 days adults, 14 days pediatric).Discussion: DS treatment is challenging. As reported by Fassano et al. in 89 cases of DS, pharmacological therapy was used as first line treatment in 82.4% of cases, ceasing DS only in 9 cases (10.1%), while surgery [either DBS (13 cases) or ablations] was used in the 30.2% of cases being effective in the 33.7% of these events1. In our case series, pharmacologic therapy wasn’t sufficient to abort DS and DBS placement in bilateral GPi was effective for symptoms control.Conclusions: GPi DBS can be a suitable, versatile, reversible and adequate therapy of DS. Further research is needed to establish adequate criteria in respect of the proper moment of implantation, initial and follow-up parameters configuration changes as well as concomitant pharmacological therapy.

Daniel OSPINA-DELGADO, Alejandro ENRÍQUEZ-MARULANDA, Eduardo ORREGO-GONZÁLEZ, Jorge OROZCO, Juan GÓMEZ-CASTRO, Javier LOBATO-POLO (CALI, COLOMBIA)
08:00 - 18:00 #10461 - P069 Dystonic status in a 10-year-old patient with dystonic cerebral palsy and a previously implanted deep brain stimulation: case report.
Dystonic status in a 10-year-old patient with dystonic cerebral palsy and a previously implanted deep brain stimulation: case report.

Introduction:Deep brain stimulation (DBS) devices may be used for refractory dystonia, which do not respond to medical management4.Despite it is not widely used, this surgery is becoming a more common practice because it can be safely performed as a last resort. This is one of the few reported cases of SD in a child with a DBS previously implanted.Case Presentation:A 10-year-old boy with a previous history of perinatal kernicterus and mixed cerebral palsy, developed progressive dystonic symptoms over the course of a year.He began to have markedly cervical and trunk spasms; extension of upper right limb appeared, which lead to dystonic posture.Furthermore, he was developmentally disabled and progressed to becoming wheelchair bound. At age 5, bilateral DBS electrodes were placed into the Globus Pallidus Internus (GPi). The patient was admitted to our pediatric emergency department with feeding problems and worsening of dystonic movements in the upper limbs and a painful opisthotonic posture. UDRS scale was 42. CT-scan-findings revealed bilateral electrode displacement of 2.5mm from both GPi.Three days following admission, he underwent bilateral replacement of GPi DBS, with a new system. Targeting the nucleus was made using direct technique, because of important discrepancy between coordinates, functional brain atlas and kid's brain.   Subsequently, stimulation was titrated to an amplitude of 2.0mAmp, a pulse width of 100mcseg and a frequency of 130Hz, afterwards he was transferred to the ICU.The patient improved completely on POD-7 and was discharged home on POD-21.Discussion:SD is a life-threatening-condition usually related to metabolic disturbances, surgery, infections or changes in medication3.In our case, we believe that migration of the electrodes triggered a SD. A European cohort reported 2,3 % cases of electrodes displacement, with 4,6% of the cases associated to dystonic status2. Several causes have been theorized to explain electrodes upward migration. Brain shift, steady growth of the patient, dystonic movements of the head and neck and surgical errors are the most common causes involved1. Dislocation of the device causes gradual loss of stimulation efficacy.Conclusion: DBS electrodes displacement is a rare condition which neurosurgeons seldom see.Despite its infrequency, it must be considered in cases of worsening dystonic movements, with prior successful DBS implantation, especially in the pediatric population.

Eduardo ORREGO-GONZÁLEZ, Alejandro ENRÍQUEZ-MARULANDA, Daniel OSPINA-DELGADO, Jorge OROZCO, Juan GÓMEZ-CASTRO, Javier LOBATO-POLO (CALI, COLOMBIA)
08:00 - 18:00 #10580 - P070 Comparative Study Between The Outcomes of Neuroablative And Neuromodulation Techniques In The Treatment Of Secondary Dystonia.
Comparative Study Between The Outcomes of Neuroablative And Neuromodulation Techniques In The Treatment Of Secondary Dystonia.

Background:

Secondary dystonia are the syndromes that have dystonic symptoms due to brain insult which can be associated with neonatal encephalopathy syndromes, trauma, vascular injury, infections, demyelinations, or hereditary disorders associated with neurodegenerative process. The disability inflected by dystonia encouraged the development of many neurosurgical procedures in order to improve the quality of life of these patients.

The aim of this study was to compare the outcomes of different Neuroablative and modulation techniques in treatment of secondary dystonia.

Patients and methods

This is a prospective study included 80 patients suffering from intractable secondary dystonia. Ablative techniques included the brain lesioning procedure and combined anterior and posterior lumbar rhizotomy (CAPR). Modulation techniques were deep brain stimulation (DBS). Patients with generalized dystonia were included in either of the brain lesioning or the deep brain stimulation, and patients with predominant affection of both lower limbs were included in the (CAPR) group.

Assessment measures included the evaluation of the muscle tone, range of motion, and the Burke-Fahn-Marsden dystonia rating scale through a follow up period of one year.

Results

Muscle tone was significantly reduced in the ablative techniques, but the changes in the DBS group were not significant. The range of motion improved in all groups; the changes were significant in the ablative techniques but were not significant in the DBS group. The BFMDRS showed improvement in all groups, the changes were significant in all groups except the DBS group.

Conclusion

Both neuroablative and neuromodulation techniques have the beneficial impact on secondary dystonias especially with stationary neurological pathologies with no significant statistical difference between both techniques.

While the neuromodulation techniques had the advantages of being adjustable, titratable, reversible, and can be performed bilaterally.

Mohamed NADA (Cairo, EGYPT), Walid ABDEL GHANY, Zeiad FAYED, Khaled ELBAHY, Emad GHANEM
08:00 - 18:00 #10662 - P071 Deep brain stimulation of the internal globus pallidus in dystonia- predominant paroxysmal nonkinesigenic dyskinesia.
Deep brain stimulation of the internal globus pallidus in dystonia- predominant paroxysmal nonkinesigenic dyskinesia.

Paroxysmal nonkinesigenic dyskinesia  (PNKD) is a rare inherited movement disorder characterized by sudden episodes of dystonia, chorea, ballism or a combination of these, precipitated by several stimuli but not by movements or physical effort. We report a 19 year-old man with treatment-refractory PNKD since the age of 4 with daily severe episodes of generalized dystonia who displayed a successful outcome 6 months after bilateral globus pallidus internus (GPi) deep brain stimulation (DBS). Baseline severity and improvement in motor function was evaluated using the UDRS for his constant dystonic features and during the paroxysmal events. Two 3387- Medtronic electrodes were implanted under microrecording and semi-macrostimulation with patient awake, and connected to an ACTIVA RC pulse generator.  The stimulation was turned ON three weeks after the implant. At 6-months follow-up with stimulation On, fixed dystonia severity reduced 43% in the UDRS score from preoperatory baseline (50 vs. 28). The total UDRS score during the paroxysmal generalized dystonic events at baseline was 86, with severe compromise of larynx muscles as the main medical concern due to choking and aphonia. These events disappeared during the immediate weeks after the implant of the electrodes; they came back at the end of week 3. After 2 weeks of turning the stimulation On, the severity of the paroxysmal dystonic episodes reduced 46.5% (86 vs 53.5%) with a progressive reduction in their frequency until the total disappearance of the paroxysmal events after 4 months On- stimulation. No major adverse effects were recorded. Bilateral GPi- DBS resulted in a complete control of the paroxysmal dystonia events, including the severe axial features, with no neurological complications. 

Rodrigo MERCADO (Guadalajara, MEXICO), Carlos ZUNIGA- RAMIREZ, Octavio GARCIA-GOMEZ
08:00 - 18:00 #10663 - P072 Significant functional improvement in a patient with Myoclonus Dystonia after unilateral and simultaneous Vim thalamotomy and posteroventral pallidotomy.
Significant functional improvement in a patient with Myoclonus Dystonia after unilateral and simultaneous Vim thalamotomy and posteroventral pallidotomy.

Myoclonus- dystonia (MD) is a severe movement disorder with a negative functional impact due to its severity and poor pharmacological response. Bilateral deep brain stimulation (DBS) has been used to treat MD patients, targeting the GPi, the Vim or both targets simultaneously. No reports of radiofrequency lesions have been described in recent literature due to the limitations of a unilateral approach. We present a case of a right-handed 19 year-old girl, with severe hereditary myoclonus dystonia who had simultaneous left-side Vim thalamotomy (VimTh) and posteroventral pallidotomy (PVP), who showed a significant benefit in postoperatory functional scores. Motor improvements were evaluated with rest/action and total subscores of the Unified Myoclonus Rating Scale (UMRS), functional improvements with the patient questionnaire and functional test subscores of the UMRS, Dystonia severity was evaluated with the Unified Dystonia Rating Scale (UDRS), preoperatively and 6 months after surgery.  At 6-months follow-up, myoclonus improved 60% in the total UMRS score. The motor improvement in the right limbs using rest and action subscores was 98%, with no benefit observed in the left side limbs. Functional improvement was highlighted by the right side benefit obtained, with a 74% improvement in the overall functional tests, and a 94% improvement if the left hand spiral score was drawn out of the sum. The patient perception of improvement was 92% according to the patient questionnaire subscore of the UMRS. The severity of dystonia reduced 38% according to the total UDRS; the subscore for right shoulders, hip and limbs displayed a more significant improvement with a 79% severity reduction, with no benefits observed in left side hemi-body.  No major adverse effects were recorded. Improvements are consistent with those reported in DBS cases. We did not find any limitations in functional benefits with this unilateral procedure, since the largest improvement was directed towards the dominant side of the patient. The combined approach of VimTh and PVP allowed us to reach a better control not only in the dystonic features but also in the severity of the myoclonus with no neurological complications. Unilateral and simultaneous radiofrequency Vim thalamotomy and posteroventral pallidotomy are safe and highly effective in patients with MD, with a profound positive impact in motor severity and functional scores when aimed at the dominant side.

Rodrigo MERCADO (Guadalajara, MEXICO), Carlos ZUNIGA- RAMIREZ, Ilse FUENTES-VIRGEN
08:00 - 18:00 #10689 - P073 Pallidal oscillation in a patient with posttraumatic secondary dystonia.
Pallidal oscillation in a patient with posttraumatic secondary dystonia.

Objective: To evaluate pallidal oscillation in secondary dystonia following a head injury. Methods: The patient was an 18-year-old male. At the age of 15, he suffered a left brain contusion due to a traffic accident.  At the age of 17, he experienced forced opening of the mouth while sitting (upright position), chewing, and speaking. He was able to drink with a straw, but was unable to chew or speak. We diagnosed him with secondary dystonia induced by movement. Bilateral pallidal deep brain stimulation (DBS) was performed under general anesthesia. Bilateral local field potentials (LFPs) and EEG over the sensorimotor areas in the resting state were recorded from four bilateral contacts of the DBS electrodes 1week after the operation. Contacts 0 and 1were located in the internal pallidum (GPi), and Contacts 2 and 3 were in the external pallidum (GPe). LFPs were calculated for the three bipolar contact pairs of DBS electrodes. Power spectra of 2-35Hz were identified as sub-frequency bands and defined as follows: 2-4Hz (delta), 5-7Hz (theta), 8-13Hz (alpha), and 14-35Hz (beta). Results: (1) Oscillatory activities: Spectral peaks of the delta band in the GPi, GPe, and motor cortex (MCx) were more prominent than those of the theta, alpha, and beta bands. The delta power was increased more on the right than on the left. (2) Functional coupling between the GPe and GPi: The coherences between the GPe and GPi in the delta and theta bands were stronger on the right than on the left. (3) Functional coupling between the ipsilateral MCx and GPe or GPi: On the left, no prominent coherence in the four bands was observed between the MCx and GPi or GPe. However, on the right, the delta band in the GPi was strongly coherent with the MCx, and the theta band in the GPe was also coherent with the MCx. Conclusion: The left brain was affected, but the right brain was not. The left and right oscillatory activities were quite different. The delta power increased in the right GPi and GPe, and was functionally coupled with the MCx. DBS treatment using monopolar stimulation with contact 0 bilaterally was very effective. The phenomenon of oscillatory activities in the non-affected GP may be similar to the functional compensation that occurs in patients with chronic stroke.

Fusako YOKOCHI (Tokyo, JAPAN)
08:00 - 18:00 #10732 - P074 Subtle sensory abnormalities in patients with isolated idiopathic and hereditary dystonia.
Subtle sensory abnormalities in patients with isolated idiopathic and hereditary dystonia.

Sensory abnormalities are increasingly being recognized as an accompanying symptom in patients with dystonia. The aim of this study was to investigate whether sensory abnormalities could be related to age or the distribution of motor symptoms in patients with idiopathic and hereditary dystonia. For this purpose we recruited 20 dystonic patients from which 8 had generalized dystonia, 7 cervical dystonia and 5 segmental dystonia with arm/hand involvement. The patients with arm/hand involvement were divided into two subgroups: younger than 40 years (6 patients) and older than 40 years (7 patients). All patients with cervical dystonia were older than 40 years. We used Quantitative Sensory Testing (QST) at the back of the hand in all patients and at the shoulder in patients with cervical dystonia. The main finding on the hand QST was impaired dynamic mechanical allodynia (DMA) and thermal sensory limen (TSL). The other impairments were characteristic of the subgroups. The alterations were present on the clinically more and less affected side, but more pronounced on the side more affected with dystonia. Patients with cervical dystonia showed a reduced hot detection threshold (HDT) and CDT, enhanced TSL and DMA at the back of the hand, whereas the shoulder QST only revealed increased CPT and DMA. In summary, QST clearly shows distinct sensory abnormalities in patients with idiopathic and hereditary dystonia, which partly varied with age and which may also manifest in body regions without evident dystonia.

Lejla PARACKA, Florian WEGNER, Christian BLAHAK, Mahmoud ABDALLAT, Dirk DRESSLER, Matthias KARST, Joachim K KRAUSS (HANNOVER, GERMANY)
08:00 - 18:00 #10773 - P075 Subthalamic Nucleus Deep Brain Stimulation in primary dystonia: An over 10-years fellow-up study.
Subthalamic Nucleus Deep Brain Stimulation in primary dystonia: An over 10-years fellow-up study.

Objective  To investigate over 10-years efficacy of the subthalamic nucleus-deep brain stimulation(STN-DBS) on primary dystonia.Methods All patients are selected from the group consisting of 13 primary dystonia patients receiving bilateral STN-DBS implantation treatment from May 2002 to November 2006.All patients were evaluated with the Burke–Fahn–Marsden dystonia rating scale (BFMDRS) and 36-item short form (SF-36) before surgery and at 1 month, 1 year and then over 10 years later postoperatively,follow-up time ranged from 10 to 15 years (mean: 12.7±1.8 years).Results All patients with bilateral STN DBS experienced a remarkable long-term and stability improvement after STN-DBS stimulation. The mean increase in movement score of the BFMDRS was 60%, 82%, and 84% after 1 month, 1 year and at least 10 years later stimulation. The quality of life (SF-36 questionnaire) significantly improved with 1 month stimulation (P<0.001), the improvement progressed within 1 year (P<0.05), and then kept stable . Adverse events included misplacement of the electrode,wire breakage and exclusive reaction. Conclusion  This over 10-years follow-up study confirms the benificial effect of STN DBS in primary dystonia,significantly improving motor symptoms and quality of life,long-term efficacy and stability. 

Yixin PAN, Dianyou LI, Chunyan CAO, Shikun ZHAN, Peng HUANG, Xiaoxiao ZHANG, Wei LIU, Bomin SUN (shanghai, CHINA)
08:00 - 18:00 #10775 - P076 Evaluation of DBS GPi treatment in dystonia – 2 year follow-up.
Evaluation of DBS GPi treatment in dystonia – 2 year follow-up.

Background and purpose: Dystonia, with variety of its clinical forms is a multidisciplinary challenge for physicians. Author presents a group of patients with various dystonia types treated with subthalamic (STN) or pallidal (GPi) deep brain stimulation (DBS).

Materials and methods:  42 patients (20 male, 22 female) age from 6 to 64  (mean 31,4) affected by dystonia were treated with DBS. 16 patients diagnosed with idiopathic general dystonia, 14 NBIA- related general dystonia, 5 hemidystonia, 3 torcicollis, 2 DYT-1- related general dystonia,  1 myoclonic dystonia and 1 oromandibular dystonia. The patients were evaluated with the Fahn-Marsden Scale (FMS), Unified Dystonia Rating Scale (UDRS), Global Dystonia Scale (GDS) and torticollis patients were evaluated with Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) before treatment and 6, 12 and 24 moths after the procedure. The permanent electrodes were implanted  to GPi in 31 cases or to STN in 9 patients or GPi and STN in 2 patients. The target was identified with direct and indirect method. Intrasurgical macrostimulation and microrecording were used for neurophysiological evaluation of the target.

Results: No serious morbidity or mortality were noticed in the group.  Local chest hematoma was reported at the region, where internal pulse generator was implanted. Best results were achieved among patients with with DYT-1 related general dystonia (mean 91%) and oromandibular dystonia (84%). The poorest results were noted at the PKAN group (mean 41%).  Mean improvement of 72% was achieved in all groups.

Krzysztof SZALECKI (warszawa, POLAND), Henryk KOZIARA, Rafal ROLA, Pawel NAUMAN, Tomasz MANDAT
08:00 - 18:00 #10789 - P077 Bilateral posteroventral Pallidotomy in the management of post-anoxic generalized dystonia.
Bilateral posteroventral Pallidotomy in the management of post-anoxic generalized dystonia.

Bilateral posteroventral Pallidotomy in the management of post-anoxic generalized dystonia

 

Dystonia is the third most common movement disorder after tremors and Parkinson’s disease, that significantly renders the functionality of an individual and hence the society. Secondary post-anoxic generalized dystonia isn’t uncommon in developing countries with lack of effective perinatal care and facilities. Our aim is to clinically assess the role of bilateral pallidotomy on seven patients with post-anoxic generalized dystonia.    

 

Method:

This study is done on a retrospective manner on seven patients (3 males- 4 females), with age range from (8- 29) diagnosed with post-anoxic generalized dystonia, who received Bilateral posteroventral Pallidotomy, aiming to lessen the severity of the dystonia.  Guided by a peri-operative clinical assessment and scaling with Burke–Fahn–Marsden dystonia rating scale. All patients had a post operative MRI to confirm pallidotomy lesion site.

 

Results:

The seven patients had a noticeable improvement on BFM score and the severity of the dystonia after one month follow up, but for one patient who had an associated contracture and scoliosis that rendered his clinical improvement.

 where the BFM score mean pre-operative 53.57, with a standard deviation 20.13, while post operative BFM score mean was 42.5 with standard deviation 20.31 ( p value= 0.007) , thus there is a 20.75% reduction in the mean BFM score.

 

Conclusion:

Bilateral posteroventral Pallidotomy is considered a safe and effective line of management in generalized dystonia especially secondary dystonia. None the less it doesn’t carry the drawbacks of other alternative managements as in DBS, like hardware hazards, from infection or dislocation, or its long term maintenance and high costs. By highlighting the efficacy of pallidotomy and studying more patients and with applying our data to more comparative studies, that will lead us to more understanding to the most suitable option for each patient.

 

 

 

 

Heba M. AZOUZ, Zeiad Y. FAYED, Mohammed A. NADA (Cairo, EGYPT), Walid A. ABDEL GHANY, Mohammed EID
08:00 - 18:00 #10808 - P078 Unilateral Stereotactic RF Lesion of Posterior Zona Incerta as a Treatment Hemidystonia: Comparative Study.
Unilateral Stereotactic RF Lesion of Posterior Zona Incerta as a Treatment Hemidystonia: Comparative Study.

Introduction: Hemidystonia is a neurological condition caused by plastic changes developed after an injury to cortical-thalamic-spinal pathways, usually secondary to different causes. In the past various cases series have shown encouraging results of lesions in various targets for the treatment secondary dystonia. More recently reports applied DBS showing no better results. Currently, there no standardized treatment for this condition. 

Objectives: We present preliminary results of an open trial comparing best medical treatment (oral medication and botulin toxin) with unilateral single lesion of the posterior zona incerta.

Material and Methods: Fourteen patients entered the study. All patients had baseline evaluation (BL) with dystonia (FMDS) and quality of life rating scales (SF-36) at 1, 3 and 6 months after BL evaluation. Patients had the choice either surgery or best medical treatment. Six patients accepted the surgical procedure while 7 were followed under medical treatment for at least 180 days. 

Results: Patients under medical treatment presented FMDS average score of 30.4±8 and 6.3%, 18% and 18% improvement at 1, 3 and 6 months respectively. Patients operated had FMDS average score of 33.6±7.6 and 34.5%, 43.8%, 37% in in 1, 3 and 6 months respectively in FMDS (ANOVA + Bonferroni post-test p< 0.05). The operated patients revealed average of 75,6% improvement in the subscore of functional capacity of SF-36, while the medically treated patients revealed average 8,5%. The operated group had 65,6% improvement in pain subscore while the medically treated patients had 17,3%. 

Conclusion: Despite the limited number of patients and relatively short follow up, the preliminary results revealed that surgical treatment was significantly better than best medical treatment for patients with hemidystonia. Further trials should be performed to confirm the results in long term.

Angelo AZEVEDO, Carolina SOUZA, Rubens CURY, Jessie NAVARRO, Eduardo ALHO, Fabio FERNANDES, Erich FONOFF (São Paulo, BRAZIL)

Monday 26 June

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08:00 - 18:00 #9878 - P079 sEEG is a safe procedure for a comprehensive anatomical exploration of the insula in drug resistant epilepsy: A retrospective study of 108 procedures representing 254 transopercular insular electrodes.
sEEG is a safe procedure for a comprehensive anatomical exploration of the insula in drug resistant epilepsy: A retrospective study of 108 procedures representing 254 transopercular insular electrodes.

BACKGROUND                                      

The exploration of the insula in pre-surgical evaluation of epilepsy is considered to be associated with a high vascular risk resulting in an incomplete exploration of the insular cortex.

OBJECTIVE

We report a retrospective observational study of insular exploration using stereoelectroencephalography (sEEG) with transopercular and parasagittal oblique intracerebral electrodes from January 2008 to January 2015. The first purpose of this study was to evaluate the surgical risks of insular cortex sEEG exploration. The second purpose was to define the ability of placing intracerebral contacts in the whole insular cortex.

METHODS

Ninety-nine patients underwent 108 magnetic resonance imaging (MRI)-guided stereotactic implantations of intracerebral electrodes in the context of pre-operative assessment of drug-resistant epilepsy, including at least one electrode placed in the insular cortex. On post-operative computed tomography (CT) images co-registered with MRI, followed by MRI segmentation and application of a transformation matrix, intracerebral contact coordinates of the insular electrodes’ contacts were anatomically localized in the Talairach space. Finally, dispersion and clustering analysis was performed.

RESULTS

There was no morbidity, in particular hemorrhagic complications, or mortality related to insular electrodes. Statistical comparison of intracerebral contact positions demonstrated that whole insula exploration is possible on the left and right sides. In addition, the clustering analysis showed the homogeneous distribution of the electrodes within the insular cortex.

CONCLUSION

In the pre-surgical evaluation of drug-resistant epilepsy, the insular cortex can be explored safely and comprehensively using transopercular sEEG electrodes. Parasagittal oblique trajectories may also be associated to achieve an optimal exploration.

Sophie COLNAT-COULBOIS (NANCY), Anne Laure SALADO, Laurent KOESSLER, Gabriel DE MIJOLLA, Emmanuelle SCHMITT, Jean Pierre VIGNAL, Jacques JONAS, Thierry CIVIT, Louise TYVAERT, Louis MAILLARD
08:00 - 18:00 #10107 - P080 MRI-Guided Stereotactic Bilateral Anterior Capsulotomy improves the clinical treatment of psychiatric comorbidity in epilepsy.
MRI-Guided Stereotactic Bilateral Anterior Capsulotomy improves the clinical treatment of psychiatric comorbidity in epilepsy.

Aim: Investigation of the long-term efficiency in clinical treatment and social function improvements of the MRI-guided stereotactic bilateral anterior capsulotomy in chronic epileptic patients with psychiatric comorbidity .

Methods: 15 patients with psychiatric comorbidity in epilepsy who underwent the capsulotomy were included . The treatment effects were evaluated with Positive and Negative syndrome scale (PANSS), Barratt impulsiveness scale (BIS-11-C), Buss-Perry scale (BPS) and Social Disability Screening Scale.

Results: Evaluations were performed at baseline,1 week , 6 months and 1 year after surgery . There was an improvement based on the statistical analysis for Positive Symptom(21.07±7.17vs11.40±3.43vs9.20±2.14vs8.29±1.86);Negative Symptom(26.60±5.79vs17.00±3.51vs13.07±4.40vs11.67±4.82);Barratt no-planning impulsiveness Scale(29.00±5.96vs10.67±4.95vs9.17±3.86vs8.50±3.64);Barratt Cognitive impulsiveness Scale(32.33±6.97vs11.33±3.76vs7.67±3.59vs7.14±4.14 );Barratt Motor impulsiveness Scale(51.50±9.81vs27.83±4.71vs6.16±4.99vs5.18±4.75);Buss-Perry Scale(78.07±7.96vs61.40±6.13vs51.47±8.69vs48.73±10.03);Scocial disability screening Scale(12.53±3.67vs7.80±2.98vs5.60±3.48vs5.14±3.61).

Conclusion: MRI-Guided Stereotactic Bilateral Anterior Capsulotomy could improve the positive symptom such as aggressive behavior disorder(ABD) and impulsive behavior disorder(IBD) ,the negative symptom such as depression, and the compliance of other treatments, also further reconstitute their social function for the epilepitic patients with psychiatric comorbidity. 

Peng HUANG, Zhengdao DENG, Bomin SUN (shanghai, CHINA)
08:00 - 18:00 #10160 - P081 Neuroprotective Effects of Anterior Thalamic Nuclei Stimulation on Epileptic Monkeys.
Neuroprotective Effects of Anterior Thalamic Nuclei Stimulation on Epileptic Monkeys.

Background Anterior thalamic Nuclei (ANT) stimulation has been proven effective in controlling epilepsy in many studies, but its mechanisms remain unclear. Objective To study the neuroprotective effects of ANT stimulation on epileptic monkeys. Methods Eight male rhesus monkeys were randomly assigned to a stimulation group (n=3), a sham-stimulation group (n=3) and a control group (n=2). DBS devices were implanted into the left ANT of monkeys from the stimulation and sham-stimulation groups. Kainic acid was injected into the left hippocampi of monkeys from the stimulation and sham-stimulation groups, and saline of the same amount was injected in the control monkeys. Chronic ANT stimulation was administered in the stimulation monkeys. All animals were continuously video-monitored for epileptic seizures in the following 6 months. Immunohistochemical stainings were performed to determine the pathological alterations. Results The monthly seizure frequency was 45.7% lower in the stimulation group than in the sham-stimulation group. The amount of survival neurons of the stimulation group was significantly higher than that of the sham-stimulation group. The gliosis was also lower in the stimulation group. Conclusions Chronic ANT stimulation can reduce the hippocampal injury and gliosis, which may be an important mechanism of ANT stimulation on the temporal epilepsy.

Zhang JIAN-GUO, Shi LIN (Beijing, CHINA)
08:00 - 18:00 #10194 - P082 Early stereotactic radio frequency ablation of hypothalamic hamartoma using robotic guidance is safe: A case report and review of literature.
Early stereotactic radio frequency ablation of hypothalamic hamartoma using robotic guidance is safe: A case report and review of literature.

Management of hypothalamic hamartoma (HH) with intractable gelastic epilepsy remains challenging. We performed robotic (ROSA) guided radiofrequency ablation for the treatment of HH with intractable gelastic epilepsy in a child of 6 months age. During the surgery, intracranial depth electrode implanted to the hamartoma to identify the ictal onset. Planning for surgery was performed under ROSA assistance with MRI guided targeting and radiofrequency ablation of the hypothalamic hamartoma was performed to achieve disconnection effects. No intraoperative complications occurred. The present study was primarily aimed at verifying the feasibility of using robotic guided radiofrequency disconnection technique in terms of safety, short surgical duration in younger patients to prevent further secondary epileptogenesis from hypothalamic hamartomas.

Heri SUBIANTO (Surabaya, INDONESIA), Vivek TANDON, Ramesh DODDAMANI, Bhargavi RAMANUJAM, Poodipedi Sarat CHANDRA, Manjari TRIPATHI
08:00 - 18:00 #10229 - P083 Surgical treatment for super-refractory status epilepticus.
Surgical treatment for super-refractory status epilepticus.

Introduction: The super-refractory status epilepticus (SRSE), defined as a seizure that persist for more than 24 hours after the intravenous anesthetic pharmacological treatment, is associated with high morbidity and mortality.  The maximum medical treatment fails in >30% of cases, in which discharge control can be achieved by neurosurgical procedures.


Objective: To report the application of neurosurgical treatment in patients with SRSE, both in pediatric and adults patients.


Methods: We present 5 cases of SRSE with hemispheric syndromes, without focal expansive lesions. All of them received maximum pharmacological treatment that included continuous infusion of propofol and / or midazolam, without seizure control. They were undergone surgically through disconnection or resection techniques.
- Patient 1: Female, 21 years old; left fronto-temporal dysplasia and maturational delay. EEG: left frontal acute seizure evolved to status epilepticus. Left hemispherotomy was performed. Seizure-free since surgery (07/07/13).
- Patient 2: Female, 18 years old;  Parry-Romberg Syndrome. Left hemispherotomy was performed 36 days after admission. She developed hydrocephalus; requiring ventriculoperitoneal shunt. Seizure-free since surgery (05/21/14).
- Patient 3: Female, 8 years old; focal refractory epilepsy. EEG: refractory status epilepticus. Right temporal lobectomy is performed, improvement of epileptic seizure was obtained. She persisted with complex partial seizures every 2 months, controlled with pharmacological treatment.
- Patient 4: Female, 21 year old; Rasmussen encephalitis. EEG: refractory status epilepticus. Right hemispherotomy was performed. Seizure-free since surgery (03/06/15).
- Patient 5: Male, 4 months old; right hemimegalencephaly, associated with predominantly fronto-parietal pachygyria. EEG compatible with right hemi-hypsarrhythmia preceding refractory status epilepticus. Left hemispherotomy was performed (08/02/17). Seizure-free since the 9th postoperative day.


Outcomes: 4 of the 5 patients undergoing surgery were completely free of seizures and one persisted with medically managed seizures.


Conclusion: Management of SRSE is a challenge in clinical practice. The literature on therapeutic options after the maximum medical treatment is scarce. This encouraging experience proposes surgery as an effective measure in SRSE with non-expansive focal lesions in which pharmacological treatment has failed.

Gustavo GARATEGUI, Jorge RASMUSSEN, Carlos CALVIMONTES, Walter SILVA, María Del Carmen GARCÍA, Carlos CIRAOLO (Buenos Aires, ARGENTINA)
08:00 - 18:00 #10230 - P084 Deep brain stimulation in refractory epilepsy: experience in a Latin American center.
Deep brain stimulation in refractory epilepsy: experience in a Latin American center.

Introduction: Epilepsy surgery is a valid option for patients with refractory epilepsy, which constitute approximately 30% of the total of cases. Epileptic syndromes without structural lesions or bilateral or multiple foci are candidates for non-resective techniques, among which Neuromodulation as one of the most modern forms of emerging treatment.

Methods: In our experience in palliative surgery of epilepsy through neuromodulation, two patients have been implanted. The electrodes was bilaterally placed in orthogonal transventricular direction towards the anterosuperior portion of the anterior thalamic nucleus. The first case was a 45-year-old man with a history of monoxide poisoning who evolved at 3 years with refractory generalized seizures. MRI showed bilateral temporomesial sclerosis. VEEG showed bitemporal discharges without lateralization. 8 bilateral deep electrodes were implanted with stereotactic guidance in wich a bitemporal origin was observed. Resective surgery was contraindicated and DBS was implanted. The second patient was a 21-year-old man, with a history of 8 years of epilepsy with falls and tonic clonic seizure several times per day. Pharmacological treatment obtained just only an initial improvement, without sustained control of seizures. It was studied by MRI, VEEG and PET, without being able to determine indications of laterality of the epileptogenic focus. Finally, SEEG was performed using 15 deep electrodes, which showed bifronto-temporal foci. Based on the results obtained DBS was indicated.

Outcomes: Both DBS system implanted has been switched on, achieving a significant reduction of the seizures in the medium and short term, respectively. Longer follow-up time is necessary to give definitive results. The patients tolerated very well the procedure without intraprocedural neither post-surgical complications.

Conclusion: In view of the results obtained and the perspectives of our center, we plan to continue developing this type of treatment in an interdisciplinary way. In our experience, DBS of the anterior thalamus nucleus for refractory epilepsy is a safe form of treatment for the patient. The international literature demonstrated its effectiveness in the control of the amount of crisis and duration of the same, which projects us to develop this technique at the level of the worldwide reference groups.

Carlos CALVIMONTES, Gustavo GARATEGUI, Jorge RASMUSSEN, Uriel NOVICK, Walter SILVA, María Del Carmen GARCÍA, Carlos CIRAOLO (Buenos Aires, ARGENTINA)
08:00 - 18:00 #10242 - P085 Relationship between postoperative EEG recruiting response and lead location in deep brain stimulation of the anterior nucleus of the thalamus for refractory epilepsy.
Relationship between postoperative EEG recruiting response and lead location in deep brain stimulation of the anterior nucleus of the thalamus for refractory epilepsy.

Objectives: A controversy exist in interpretating the postoperative EEG driving response (DR) an indicator of electrode placement within the thalamic nucleus in the deep brain stimulation (DBS) of the anterior nucleus of the thalamus (ANT) for refractory epilepsy.

Materials and Methods: We retrospectively investigated the relation between postoperative EEG DR and the location of electrodes (n=11) in 6 patients who underwent ANT DBS for refractory epilepsy. (Table 1)

Results: A cerebral synchronizing, EEG DR (Fig.1) was observed in 10 electrodes, however, 9 of 11 electrodes were found to be located within ANT. Among the 2 electrodes missed ANT, DR was observed in one, misplaced electrode facing the anterior surface of ANT within the third ventricle (Fig. 2a). The other misplaced electrode without DR elicitation showed a DR after repositioning of the electrode (Fig. 2b).

Conclusions: A diagnostic significance of DR as an indirect evidence of electrode within thalamic nuclei is limited. If DR is not elicicited, it should be regarded as a misplacement. Even if DR is elicited, it should not be interpreted as a sound indicator of proper electrode placement within the thalamus. Therefore, a sophisticated, postoperative imaging study is warranted in every case of ANT DBS.

Hak-Cheol KO , Hak-Cheol KO (Seoul, KOREA), Byung-Chul SON, Young-Min SHON, Jin-Gyu CHOI, Sang-Woo HA
08:00 - 18:00 #10258 - P086 Optogenetic retrogression of epileptogenesis.
Optogenetic retrogression of epileptogenesis.

Introduction Optogenetics is a combination of optical and genetic methods used to control the activity of specific populations of cells using light with high temporal and spatial resolution. Our aim was to reproduce kindling phenomenon using optogenetics.

Method Transgenic rats expressing light-sensitive protein, channelrhodopsin-2 (ChR2), on neuronal membrane were used. ChR2 is activated with blue light and has permeability of cations. We developed an observation facility where EEG and behaviors could be monitored 24hr/day for days with plastic optical fibers implanted into the hippocampus in freely moving animals. Short burst of optical stimuli was given once per hour, 12 times a day, for 4 days.

Results Short burst of optical stimuli activated the neurons and oscillatory hyperexcitation wave  sustained for a short period, which presented afterdischarges on EEG with minimal behavioral changes. The duration of afterdischarges progressively increased with each trial, and behavioral seizures also aggravated. Finally, generalized seizures were frequently induced, which meant that kindling phenomenon occurred. Surprisingly, when additional neuronal stimulation were added, the hyperexcitation began to be suppressed and simultaneous activation of astrocytes were observed. This suppressive effect was revealed to be the result of homeostatic increase in adenosine.

Conclusion We proved that kindling phenomenon could occur evenby selective activation of neurons using optogenetics. Futhermore, we succeeded to identify the innate suppression mechanism towards neuronal excitation.

Yoshiteru SHIMODA (Sendai, JAPAN), Masaki IWASAKI, Nobukazu NAKASATO, Teiji TOMINAGA, Ko MATSUI
08:00 - 18:00 #10319 - P087 Epilepsy surgery using three-dimensional cortico-vascular and SEEG reconstructions.
Epilepsy surgery using three-dimensional cortico-vascular and SEEG reconstructions.

Introduction

The orientation in the intracranial space remains a neurosurgical challenge and transition from slices to three-dimensional (3D) imaging makes surgeon closer to the reality. New developments in magnetic resonance imaging (MRI) and the release of free softwares as 3DSlicer, Freesurfer and FSL improved dramatically the quality of 3D reconstruction. Our aim to present the possibilities of 3D cortico-vascular and stereotactic electroencephalography (SEEG) reconstructions using common MRI sequences and free softwares.

Material and Methods

This study has included fifty-five consecutive epilepsy patients operated on during the period between January 2015 and December 2016. All patients underwent 1.5 T preoperative MRI and DICOM data postprocessing using FSL, Freesurfer and 3DSlicer. Intraoperative neuronavigation was performed in 40 patients and SEEG was performed in 15 patients using postprocessed images and raw data.

Results

Three-dimensional  reconstruction improve preoperative planning and intraoperative orientation especially in extratemporal epilepsy patients where the sulcal pattern is more complex and tailored SEEG implantations and cortical resctions are needed.

 Conclusions

Postprocessing of raw MRI and CT DICOM sets could provide useful preoperative and intraoperative information.

Krasimir MINKIN (Sofia, BULGARIA), Kaloyan GABROVSKI, Marin PENKOV, Petya DIMOVA
08:00 - 18:00 #10321 - P088 Background and purpose: Previously, automatic detectors for electrocorticography pathologic low (LFAs) and high-frequency activities (HFAs) were trained based on expert’s manual classification results. We introduce a new optimization method, reinforcement.
Background and purpose: Previously, automatic detectors for electrocorticography pathologic low (LFAs) and high-frequency activities (HFAs) were trained based on expert’s manual classification results. We introduce a new optimization method, reinforcement.

Background and purpose: Previously, automatic detectors for electrocorticography pathologic low (LFAs) and high-frequency activities (HFAs) were trained based on expert’s manual classification results. We introduce a new optimization method, reinforcement machine learning based on the resective epilepsy surgery seizure outcome, to improve the automatic detector for interictal pathologic activities in neocortical epilepsy (NE).
Methods: We analyzed electrocorticographies from 39 patients with medically intractable NE. We separately analyzed 38 frequency-bins from 0.9 to 600 Hz to sort out bands related with seizure outcome. An automatic detector using four kinds of thresholds of low and high amplitude, duration and number was used. The two different interictal electrocorticography dataset was selected containing epileptiform activities. In the first, training dataset, the automatic detector was trained to best differentiate the seizure-free group from the not-seizure-group based on ranks of resection percentages of detected activities using genetic algorithm. This fitness function is identical to the one-tailed U of the Mann-Whitney U test on the premise that resection percentages of the detected activities should be higher in the seizure-free group. We tested 70,000 threshold combinations in the training and found 6,000 optimized automatic detectors which can significantly differentiate seizure outcome groups (p < 0.05). These optimized automatic detectors were retested in the second validation dataset. Then, we also measured resection percentage differences of detected activities between seizure outcome groups (Dif-R) to evaluate detector performances and compare with literature.
Results: There were 16 seizure-free (41%) patients. The mean follow-up duration was 21 ± 11 months (13 to 44 months). Automatic detectors found significantly seizure outcome related activities in 2.3 – 30 Hz, 75 and 90 Hz and 155 – 555 Hz in the validation dataset. Dif-R of LFAs were median 16.5 % and the maximum 81 % in 4 Hz and median 32 % and the maximum 63 % in 5.8 Hz in the validation dataset. Dif-R of HFAs were median 53 % and the maximum 57 % in 223 Hz.
Conclusion: Using the reinforcement machine learning from seizure outcome, we could achieve Dif-Rs much higher than the best manual and automatic detections of HFAs in literature (17 to 27 %). Thus, we suggest this method would be useful for improving detector performance with minimal human intervention.

Park SEONG-CHEOL (Seoul, KOREA)
08:00 - 18:00 #10502 - P089 Ictal pattern of temporal lobe epilepsy based on high frequency oscillations of stereotactic electroencephalography.
Ictal pattern of temporal lobe epilepsy based on high frequency oscillations of stereotactic electroencephalography.

Background  In this study, we attempted to establish the ictal HFOs network to figure out how focal HFOs generated from an epileptogenic cortex spread out and synchronize across large areas of cortex.

Methods We applied the network topology measures to 20 seizures observed in 5 patients from their SEEG signals. We measured inter-electrode cross-coefficient between all pairs of electrodes for each 1 second window. By constructing the HFOs network, the topology was analyzed by network measures such as the density and the components.

Results By using the SEEG to explore the dynamic topologies of cortical and subcortical HFOs networks, we found the HFOs network synchronization and ripple energy increase during seizure progression.

Conclusion The improvement of spatiotemporal resolution established by SEEG and HFOs’ network helped us to recognize and analyze the epileptic seizures. Consistent topologies changes implied the common epileptogenic pattern in temporal lobe epilepsy.

Cheng-Chia LEE (Taipei, TAIWAN)
08:00 - 18:00 #10522 - P090 Epilepsy Surgery for Focal Cortical dysplasia.
Epilepsy Surgery for Focal Cortical dysplasia.

Purpose:

Epilepsy surgery for focal cortical dysplasia (FCD) often requires multiple non-invasive as well as invasive pre-surgical evaluations and innovative surgical strategies. There is limited data regarding surgical management of people with chronic drug resistant epilepsy (DRE) & FCD among the low and middle-income countries (LAMIC) including India.

Method:

Presurgical evaluation, surgical strategy and outcome of 53 people who underwent resective surgery for DRE with FCD between January 2008 and November 2016 were analyzed. Blumcke et.al 2011 classification was used for histo-pathological categorization. Engel classification was used for defining seizure outcome. The surgical outcome was correlated with preoperative clinical, VEEG, MRI, invasive monitoring, surgical findings as well as histopathology and QOLIE- 89 scores.

 

Results:

This cohort consists of 19 cases evaluated retrospectively and 34 cases prospectively. Age of onset ranged from 1 to 43 years (mean 9.28yrs; SD 7.25). Duration of epilepsy ranged from 1-39 years (mean 11.68; SD 8.99). The following regional distribution was found; Temporal-31 (Language-13), Frontal-9 (Motor Cortex- 5), Parietal-5 (Sensory Cortex-4), Occipital-3 and multilobar-5. Forty seven percent of the cases had FCD in the right hemisphere and 53% had FCD in the left hemisphere. Invasive monitoring was performed for identification of the epileptogenic zone (EZ) as well as eloquent cortex in 7 and intra-operative electro-corticography (ECoG) was used in 32 cases. Histopathology revealed the following distribution; FCD Ia-5, Ib- 2, Ic-4, IIa-6, IIb-10, IIIa-20, IIIb -3, IIId-3. Overall outcome of Engel’s class Ia was 61.3 %. Pre- operative QOLIE-89 score was 26.33-40.17 (mean 33.69, SD 4.35) and post-operative score was 59.21-89.79(mean 73.81; SD 8.29; p=0.04).

Conclusions:

Surgical management of people with DRE and FCD is possible in countries with limited resources. Meticulous pre-surgical evaluation to localize epileptogenic zone and complete resection of the focus and lesion can lead to cure or control of epilepsy and improvement in QOL was observed along with seizure-free outcome. The  author will present several illustrative  cases with videos of the surgical strategy. The resected tissue is a gold-mine and can be subjected to proteomic, genomic and metabolomic evaluation through international research collaboration. 

Bhaskara Rao MALLA (Bangalore, INDIA), A ARIVAZHAGAN, Jitender CHATURVEDI
08:00 - 18:00 #10548 - P091 Restricted resection of unilateral polymicrogyria for refractory epilepsy.
Restricted resection of unilateral polymicrogyria for refractory epilepsy.

Polymicrogyria(PMG)is a highly heterogeneous malformation of cortical development. 60% to 85% of patients with PMG have epilepsy which could be partially or generalized and even catastrophic. We present two cases of unilateral PMG with partial seizure pattern refractory to medication treated by resective surgery with/without intracranial electroencephalogram (IEEG) at our center.

The presurgical evaluation methods included medical history assessment, neurological examination, magnetic resonance imaging (MRI), video- electroencephalogram (VEEG) monitoring with surface electrodes and stereotactic intracranial electrodes, and neuropsychological assessments. The surgical results, pathological diagnosis and follow-up data are analyzed.

The first patient (27 years old male, seizure begin at 4) has seizure onset with aura of dizziness and without functional deficit. MRI showed right hemisphere PMG mainly on frontal and parietal lobe. Ictal VEEG revealed right hemisphere epileptiform activity mainly on the posterior part. Stereotactic IEEG and functional mapping was performed followed with restricted resection of the part of the parietal PMG. (Fig.1)  There was no neurological deficit and neuropsychological deterioration after surgery. And after 2 years of follow-up only 2 seizures was reported. The second patient(16 years old female, seizure begin at 2) has seizure onset with aura of right hand paresthesia and she has right hand paralysis. MRI showed small left hemisphere with PMG. Ictal VEEG revealed left hemisphere epileptiform activity. Because of her poor family, direct resection of the parietal PMG posterior to the central sulcus was performed. (Fig.2) There wasn't new neurological deficit and neuropsychological deterioration after surgery. She is seizure free till now which is 2.5 years after surgery. The pathological diagnosis revealed heterotopia and fusion of the molecular layer and deep underlying complex sulcal branching in both patients.

Schizencephaly(SZ) and PMG are malformations arising due to defects in postmigrational development of neurons. They are in the same pathological spectrum. This two cases showed that epileptogenic zone are mainly around the cleft in the area of PMG though the cleft are not connect with ventricle. And the pathological results showed the heterotopia in both patients. PMG may have different epileptogenic potential and our two cases showed that cortical cleft with heterotopia may highly facilitate to epileptogenesis. 

Jie REN (Beijing, CHINA), Guoming LUAN
08:00 - 18:00 #10578 - P092 The changing landscape in epilepsy surgery: pathological substrate.
The changing landscape in epilepsy surgery: pathological substrate.

Introduction: The number of procedures for treatment of refractory epilepsy boomed after the introduction of MRI in clinical practice. MRI was able to identify new brain pathology and adequately document the traditional ones. We studied the pathological findings over time of 982 patients submitted to surgery over the last 10 years.

 

Methods: 982 patients submitted to resective surgery for refractory epilepsy from 2006 to 2015 were studied. Their type of resection and the more frequent pathological findings were plotted over time.

 

Results: At the first year of the studied series (10 years ago), there were 43 mesial temporal sclerosis patients (MTS), 16 with cortical dysplasia, 25 with brain tumors, 8 with vascular pathology, 4 with Rasmussen syndrome, 2 with Sturge-Weber, 6 with HHE and 10 patients with no detectable lesion. During the last studied year (2015), there were 12 patients with MTS, 20 with cortical dysplasia, 27 with tumors, 10 with vascular pathology, 1 with Sturge-Weber, 5 with HHE, and 25 had no detectable lesion; there was no patient with Rasmussen syndrome. Overall, there was a progressive decrease in the number of patients with MTS, and in increment of patients with no detectable pathology. The number of procedures per year remained stable (ranging from 82 to 110). Rasmussen patients are now seen only sporadically.

 

Discussion: It appears that the pathological spectrum found in epilepsy surgery patients has been changing over the last decade. We are doing more non-lesional cases (in whom we could expect a worse outcome compared to lesional cases), and less MTS patients. The number of patients with brain tumors, vascular pathology and cortical dysplasia remained stable. Rasmussen syndrome patients are now rare; on the other hand, we have seen a significant increase in auto-immune encephalitis. Contrary to Rasmussen patients, patients with auto-immune encephalitis usually have bilateral lesions and are not surgical candidates.

Arthur CUKIERT, Cristine CUKIERT (São Paulo, BRAZIL), Pedro MARIANI, Jose BURATTINI
08:00 - 18:00 #10654 - P093 Best responders” (>80% seizure reduction) to Vagal nerve stimulation in a paediatric drug-resistant epileptic population .
Best responders” (>80% seizure reduction) to Vagal nerve stimulation in a paediatric drug-resistant epileptic population .

 

Introduction. Although different Authors report the efficacy of VNS in paediatric population, only few papers focused on the so-called “best responders” (patients showing > 80% seizure reduction).

Materials and methods. Among all the paediatric cases operated upon in our centre, we focused on best responders, i. e. the children showing a decrease >80% in seizure rate.

Results. Between 2007 and 2015, 32 patients were implanted during paediatric age for drug-resistant epilepsies. 17 patients (58.6%) presented a decrease of the seizure rate > 80%. 3/17 patients became seizures free.The prevalence of the best responders did not differ significantly at 6 (50%), 12 (50%) and 24 months (55%). 12/32 patients underwent the scale PedsQl 4.0 to assess the health-related quality of life (HRQOL). Comparing the best-responders to all the other patients, we obtained a significant correlation in the following sub-items: alertness (p-values 0,010), concentration (p-value 0.032), memory (p-value 0.046), communication skills (p-value 0.005) and adaptive behaviour (p-value 0.010). Comparing various clinical features to the outcome, we found that only the etiology of epilepsy correlated with best outcome: the patients suffering from structural-metabolic epilepsies showed a p-value = 0.022; 4 patients presented with Tuberous Sclerosis Complex, becoming in 2/4 seizures free. Finally, comparing the age at the implant and the outcomes, youngests (<7 years) correlate with best results (Spearman i. + 0.425): 84.6% presented with decrease of the seizure rate >80% and 3 patients (23%) are currently seizure free.

Conclusions. In our experience, 58.6% of our patients presented a reduction > 80% of the seizures rate and at present 3/32 are seizures free. We suggest that the earlier the implant the better the outcome and that structural epilepsies, like TSC or large cortical dysplasias, obtained a best response when conpared to genetic or unknown aethiology epilepsies.

Andrea LANDI, David PIRILLO (Milano, ITALY), Clarissa CAVANDOLI, Andrea TREZZA, Daniele GRIONI
08:00 - 18:00 #10726 - P094 Targeting perisylvian structures with depth electrodes in SEEG studies.
Targeting perisylvian structures with depth electrodes in SEEG studies.

Objectives: We aim at describing the surgical approaches for the implantation of perisylvian depth electrodes in patients with drug-resistant epilepsy. Based on a retrospective analysis of functional mapping using electrical stimulation in a population of patients, we aim at providing guidelines for targeting specific functional areas.

Methods: In a population of 8 patients undergoing presurgical evaluation for drug-resistant epilepsy, we have implanted depth electrodes that are targeting the insular-opercular areas using three main approaches: a) orthogonal trans-opercular; b) parasagittal oblique anterior; c) parasagittal oblique posterior. Functional mapping using 50 Hz electrical stimulation is performed, and the results are co-registered across patients using FreeSurfer and Matlab scripts to provide combined insular-opercular functional maps.

Results: Perisylvian implantations (Fig 1a, patient 8) have been performed without complications, including parasagittal oblique trajectories (Fig. 1b). A number of 142 clinical symptoms evoked by electrical stimulation were co-registered across patients to create functional maps. Some symptoms showed a spatial segregation, as illustrated in the cortical surface reconstruction (Fig. 1c) and the inflated version (Fig. 1d).

Conclusions: Targeting perisylvian structures using approaches guided by the functional maps contributes to the success of the SEEG investigations.

Jean CIUREA (Bucharest, ROMANIA), Rasina ALIN , Ioana MANDRUTZA, Andrei BARBORICA, Maliia MIHAI DRAGOS, Irina POPA, Ana GHEORGHIU, Arbune ARBUNE
08:00 - 18:00 #10742 - P095 Cost-effectiveness of stereotactic laser amygdalohippocampotomy compared with open epilepsy surgery.
Cost-effectiveness of stereotactic laser amygdalohippocampotomy compared with open epilepsy surgery.

Introduction: Stereotactic laser amygdalohippocampotomy (SLAH), performed with laser interstitial thermal therapy, is a recent addition to the minimally invasive alternatives to open epilepsy surgery. Several studies have demonstrated that stereotactic ablative procedures are capable of achieving short term outcomes in the range of traditional surgical resections. Despite the considerable advantages minimally invasive approaches offer to patients, they may be associated with additional costs related to disposable charges, but which may be counter-balanced by decreased length of stay and case acuity. We therefore undertook a short-term economic evaluation of SLAH in comparison to open epilepsy surgery.

Methods: 45 encounters were reviewed including the 15 most recent of 3 groups: SLAH cases using the ClearPoint® intraoperative-MRI system, SLAH cases using the CRW® stereotactic frame, and open surgery cases. One-way MANOVA determined differences for Total Cost among groups and between open surgery and combined SLAH procedures. Costs were stratified by category. Significant multivariate effects were defined at alpha=0.05. Bonferroni alpha correction defined significant univariate effects(p<0.0038).

Results: Significant differences were found for Total Costs (F[2,38]=10.48, p=0.0002), OR/Anesthesia Time (F[2,38]=54.90, p<0.0001), Hospitalization, Medication and Test Costs (all p<0.0001). On average, open surgery cost $15,488 (95% Bonferroni CI: $3,996 , $26,980) more than minimally invasive methods, which were not significantly different from each other. Open surgery costs associated with OR/Anesthesia Time and Hospitalization costs were also significantly different from comparators, with average excess costs of $8,672 ($5,387 , $11,956) and $11,189 ($7,338 , $15,041) respectively. There was no significant difference in procedure-related costs (p=0.04), or patient payment estimates (p=0.23).

Conclusion: Relative to open surgery, minimally invasive approaches offer measurable reductions in cost. Hospitalization costs account for the majority of the difference in cost, related to a mean 7-day increase in length of stay among open surgery patients. With no difference in payment estimates, it is unlikely that these findings are attributable to variations in billing or healthcare payer practices. In addition to other advantages such as decreased discomfort, stereotactic laser amygdalohippocampotomy (SLAH) is an economically sound alternative to open epilepsy surgery.

Lucas PHILIPP, Joel EGGEBEEN, John WILLIE, Robert GROSS (Atlanta, USA)
08:00 - 18:00 #10744 - P096 Disconnection or Resection.
Disconnection or Resection.

Newer techniques are evolving to perform surgeries for refractory epilepsy.

Focus is being laid on the making the surgery less invasive  with good outcomes and reduced rate of complications.

Disconnection procedures are  popular  with it’s aim at tissue preservation and lesser long term complications.

Disconnection procedures need better understanding of the ventricular and  white matter anatomy.

Tissue viability and eloquent area preservation when feasible  are the main aims of disconnection procedures.Though hemispheric disconnection is now established form of surgical treatment for epilepsy of hemispheric origin, the decision making in lobar epilepsy, scar epilepsy and epilepsy of deeper origin is pathology dependent.

Motor preservation is one of the main concerns in lobar disconnections. The decision making is largely dependent on surgeon’s comfort and pathology.

Available data does not provide the guidelines to make the decision between resection and disconnection procedures for lobar epilepsy. 

We  analyse long-term seizure freedom, complication rates of the reported disconnection procedures.

An attempt is also made to provide some guidelines for use of resection or disconnection procedures.

Milind SANKHE (MUMBAI, INDIA)
08:00 - 18:00 #10785 - P097 Intracranial EEG-guided radiofrequency thermocoagulation for refractory focal epilepsy.
Intracranial EEG-guided radiofrequency thermocoagulation for refractory focal epilepsy.

BACKGROUND

Destructive surgery offers the chance of cure in refractory epilepsy patients. Radiofrequency thermocoagulation (RF-TC) is a minimally invasive technique that allows for the creation of small lesions through stereotactic intracranial EEG (sEEG) electrodes, potentially allowing patients to avoid open epilepsy surgery.

METHODS

From 2014-2016, 7 patients with refractory focal epilepsy underwent sEEG and were treated with RF-TC after localization of seizures and related eloquent cortices. Electrode contacts involved in seizure onset and early spread were ablated using a radiofrequency lesion-generator system (Cosman Medical Inc., Burlington, MA, USA). In patients with seizure foci in eloquent cortex, neurologic function was tested after each increase in power. EEG was recorded before and after ablation. Brain MRI was performed within 24h to determine lesion extent. Postoperative seizure outcomes and neurologic deficits were assessed.

RESULTS

Seven patients between 32-63 years (4 female, 3 male) were treated. Six patients were lesional (3 cortical dysplasias; 1 stroke; 1 cystic lesion; 1 encephalomalacia); one was non-lesional. All underwent sEEG using a median of 9 (range 6-19) 10-contact depth electrodes; one patient also had 4 subdural strip electrodes. Onsets were left frontal (3), right frontal (1), left parietal (1), left temporal (1), and posterior cingulate (1). All patients underwent RF-TC during awake sEEG monitoring, either at the bedside (3) or in the operating theatre (4). Current was delivered stepwise from 1.5 to 6 Watt for up to 60 seconds. A median of 16 (range 5-28) contacts were ablated. Cortices underlying two strip electrode contacts were also ablated in 1 patient. Re-ablation was performed in 2 patients in subsequent hours or days that had continued epileptiform discharges post-ablation. Lesion size was inadequate on MRI in 1 patient, who then immediately underwent stereotactic laser interstitial thermal ablation under anesthesia along two existing electrode trajectories. Five of 7 pts were free of disabling seizures at a median of 12 (range 4-30) months postop. There were no permanent neurologic deficits.

CONCLUSIONS

RF-TC is a safe, minimally invasive treatment option for patients with refractory focal epilepsy. Though 71% of our patients were free from disabling seizures and avoided craniotomies with sEEG-guided RF-TC alone, longer follow-up and larger series are needed to confirm the efficacy of the procedure. 

Rebecca FASANO (Atlanta, USA), Jennifer CHENG, Jon WILLIE, Robert GROSS
08:00 - 18:00 #10813 - P098 Minimally invasive stereotactic laser ablation of the corpus callosum in adults with intractable epilepsy.
Minimally invasive stereotactic laser ablation of the corpus callosum in adults with intractable epilepsy.

RATIONALE

Corpus callosotomy (CC) is a surgical disconnection to treat generalized and atonic seizures in refractory epilepsy patients. While minimally invasive MRI-guided stereotactic laser ablation is a safe, effective alternative for refractory focal epilepsy, stereotactic laser corpus callosotomy (SLCC) is less defined. We compare outcomes of 4 patients who underwent SLCC to 4 patients who underwent open CC.

METHODS

At surgery, patients in the SLCC and CC groups were a median 32.5 (range 20-47) and 32 (range 26-39) y old, respectively.  All but 1 SLCC patient had vagus nerve stimulators, 1 in each group had prior temporal lobe surgery, and all but 1 were male. All 4 SLCC patients had atonic seizures and diagnoses of Lennox Gastaut syndrome (LGS); 3 underwent anterior 2/3 SLCC; of which 1 had additional ablation (posterior 1/3 SLCC) 1 m later for continued seizures. A 4th SLCC patient that had prior incomplete CC had worse atonic seizures after mesial temporal lobe ablation for mesial temporal sclerosis and had completion SLCC (genu and splenium) 8 m later.  Two CC patients had focal seizures with frequent generalization; 2 had LGS with atonic seizures; all underwent anterior 2/3 CC.

RESULTS

Acute hospital stays in the SLCC and CC groups were median 3.5(range 2-9) and 13 (range 3-21) d, respectively. Total hospitalization stays in SLCC and CC groups were median 11(range 2-31) and 21(range 10-35)d, respectively, including subsequent inpatient rehab stays and a readmission in 1 CC patient for seizures. One patient in each group had an intracranial hemorrhage; 1 in each group had supplementary motor area syndrome. Two SLCC patients had persistent deficits (mild hemiparesis; incontinence); 1 CC patient had persistent abulia. With median postop follow-up of 9 m(range 6-16 m) and 5 y(range 9 m–9 y), atonic seizures ceased in all SLCC, but only 1 CC patient, respectively. Generalized seizures decreased by >50% in all patients except 1 SLCC patient. All SLCC patients had  >50% decrease in absence seizures. Absence and focal seizures were unchanged in 3 of 4 CC patients. Two SLCC patients were seizure free; no open CC patients were seizure free.

CONCLUSIONS

Minimally invasive MRI guided SLCC is a safe, effective alternative to open CC. Patients undergoing SLCC had comparable rates of postop complications but shorter hospital and rehab stays. Seizure outcomes appear favorable after SLCC, but larger groups, longer follow up, and improved patient matching are required.

 

Rebecca FASANO (Atlanta, USA), Robert GROSS, Amit SAINDANE, Deqiang QIU, Jon WILLIE
08:00 - 18:00 #10823 - P099 Vagus nerve stimulation - Adapting the surgical technique to individual anatomical variations.
Vagus nerve stimulation - Adapting the surgical technique to individual anatomical variations.

Introduction

Vagus nerve stimulation (VNS) is one of the main surgical options for refractory epilepsy both in adult and pediatric population. The authors present here their surgical experience on the first series of patients with drug-resistant epilepsy operated for VNS in Romania and discuss how to adapt the surgical technique to individual anatomical variations of the vagus nerve and its relationship with common carotid artery and internal jugular vein.

Patients and methods

We included in this series 300 patients with refractory epilepsy operated for VNS in Neurosurgery Clinic, "Bagdasar-Arseni" Clinical Hospital, between October 2012 and February 2017. In all cases we used the latest VNS generator model (103). For all patients we used a left latero-cervical approach. The medium follow-up period was 11 months and the minimum follow-up period was one month.

Results and Discussions

There were 63 children and 237 adults in our series. The gender distribution was 147 females and 153 males. The average period of hospitalization was 4,8 days. There were no deaths in our series. There was a single case of left vocal cord paresis which remitted at two months follow-up. Postoperative hoarseness was noticed in 26 patients (8,6%) and disphagia in 19 patients (6,3%). The anatomical variations observed by the authors include: a vertical orientation of the great vessels with the internal jugular vein located superiorly, common carotid artery located inferiorly and the vagus nerve in intermediate position (compared with normal "horizontal" orientation with jugular vein located laterally and common carotid artery located medially), and a greater size of the internal jugular vein. When we met both anatomical variants in the same individual (observed in 29 patients - 9,6%), the vagus nerve dissection became more difficult and the risk of the vascular injury increased, because the vagus nerve was practically covered by a voluminous internal jugular vein. Surgical technique should be addapted in this situation and includes a carefully dissection of the internal jugular vein with the mobilization and rotation of the vein in order to gain a proper access to the vagus nerve.

Conclusions

VNS is a safe and efficient surgical procedure with a short hospitalization period and minimum postoperative complications. Adapting the surgical technique to individual anatomical variants makes the intraoperative and postoperative complications related to VNS procedure to become very rare events.

Felix BREHAR (Bucharest, ROMANIA), Mircea GORGAN

Monday 26 June

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08:00 - 18:00 #10491 - P100 Gamma Knife Radiosurgery for Idiopathic Glossopharyngeal Neuralgia: Experience with Five Cases.
Gamma Knife Radiosurgery for Idiopathic Glossopharyngeal Neuralgia: Experience with Five Cases.

Purpose: Gamma Knife radiosurgery (GKS) has been proposed as an alternative therapeutic option for patients with intractable glossopharyngeal neuralgia (GPN) who are poor candidates for microvascular decompression surgery. The role of GKS for GPN remains controversial, and only a few cases have been reported.

Materials and METHODS: Forty-three patients with intractable idiopathic GPN have been surgically treated. Among them, five patients (3 males, 2 females; mean age 75 [range 50–80] years) were treated with Gamma Knife radiosurgery (Model C, Elekta Instruments AB, Sweden) because of serious medical problems or advanced age. The maximum target dose ranged from 50 to 85 Gray (Gy) was delivered using a single 4-mm collimator. The target for GPN was either the cisternal segment of the glossopharyngeal nerve (n=3) or the glossopharyngeal meatus (GPM) (n=2). The three patients with primary GPN treated with a dose ≥80 Gy, regardless of the target. The other two patients were treated with prescribed doses of 50–75 Gy, because both the trigeminal nerve and GPM were needed to be targeted to treat trigeminal neuralgia simultaneously. The pre- and post-GKS pain outcomes were evaluated using the visual analog scale with the Barrow Neurological Institute pain intensity scoring system.

RESULTS: The mean follow-up was 40.8 (range 2–75) months. The three patients with primary GPN treated with a dose ≥80 Gy had good pain relief (Class II-III), regardless of the target. Despite some improvement, pain relief was unsatisfactory in the other two patients (class IV). No GKS-associated complications were observed in any patient.

CONCLUSIONS: GKS appears to be a safe therapeutic modality for medically refractory GPN in selected patients.

Young Hwan AHN (Suwon, KOREA), Sang Ryul LEE
08:00 - 18:00 #10664 - P101 Comparison of Surgical Outcomes of Idiopathic Glossopharyngeal Neuralgia between Microvascular Decompression and Gamma Knife Radiosurgery.
Comparison of Surgical Outcomes of Idiopathic Glossopharyngeal Neuralgia between Microvascular Decompression and Gamma Knife Radiosurgery.

Microvascular decompression (MVD) is considered as the first line therapeutic option for glossopharyngeal neuralgia (GPN). Gamma Knife radiosurgery (GKS) has been proposed as an alternative therapeutic option for the selected patients with intractable GPN. The objective of this study was to compare surgical outcomes of GPN between MVD and GKS.

Forty-three patients (24 males, 19 females; mean age 55.8 [range 32–80] years) with intractable idiopathic GPN were surgically treated from 1996 to 2016. MVD was chosen as the first line therapeutic option in 38 patients and was performed with the transposition technique (26 cases, 68.4%) and the interposition technique (12 cases, 31.6%).

Five patients (3 males, 2 females; mean age 75 [range 50–80] years) were treated by GKS because of serious medical problems or advanced age. The maximum target dose was 50-85 Gray (Gy), delivered using a single 4-mm collimator. The target for GPN was either the cisternal segment of the glossopharyngeal nerve (n=3) or the glossopharyngeal meatus (GPM) (n=2). Three patients were treated with ≥80 Gy. The other two patients were treated with reduced doses of 50–75 Gy, as the trigeminal nerve was targeted to treat concurrent trigeminal neuralgia. The pre- and post-GKS pain outcomes were evaluated using the Barrow Neurological Institute (BNI) pain intensity scoring system.

The average follow-up durations in patients treated with MVD and GKS were 55.97 months (range 3-251 months) and 41.5 months (range 3-75 months). Among 38 patients treated with MVD, 30 patients became pain free immediate post-operatively and maintained in BNI grade I state (78.9%). Among the 32 patients treated with MVD who were followed up for ≥ 1 year, 31 good pain relief (BNI grade I-II, 96.8%). Neuralgic pain recurred in one patient; however, the pain was less frequent and less severe than that observed preoperatively. Cranial nerve impairments developed in 4 cases, but resolved in the following months. A permanent decrease in hearing occurred in one patient.

Among the five patients treated by GKS, the three patients with a dose ≥80 Gy had good pain relief (Class II- III). Despite some improvement, pain relief was unsatisfactory in the other two patients (class III-IV). No GKS-associated complications were observed in any patient.

The results suggest that MVD is the treatment of choice for medically intractable GPN. GKS appears to be a safe therapeutic modality for medically refractory GPN in selected patients.

Kyung Mo KIM (Suwon, KOREA), Mi Kyung KIM, Sang Ryul LEE, Young Hwan AHN
08:00 - 18:00 #10698 - P102 Improvement of facial sensory loss by motor cortex stimulation in trigeminal neuropathic pain.
Improvement of facial sensory loss by motor cortex stimulation in trigeminal neuropathic pain.

INTRODUCTION

Motor cortical stimulation (MCS) is a tool to   treat intractable chronic neuropathic central pain mainly in patients operated for trigeminal pain. If the MCS can ameliorates dysesthesias and/or allodynia very few cases of sensory loss improvement have been reported. We describe two patients with partial recovery  of painful trigeminal second branch sensory loss.

CLINICAL CASES

These two females 38 and 52 years-old underwent percutaneous trigeminal thermocoagulation respectively 2 and 5 years before the admission to our Department for  typical trigeminal neuralgia. After these procedures a neuropathic pain in trigeminal second branch developed. Medical therapies were ineffective to treat the pain so a Motor Cortex Stimulation  was carried out using a 16 poles paddle connected to a  implantable multiple source generator. The surgical technique used to implant the device consisted in the use of neuronavigation and of  intraoperative neurophysiological registration to find the somatotopic motor cortex  area  of  the face.

RESULTS

The pain one month after surgey decreases of 40%. Two month after MCS implant, the patients reported improvement of  tactile sensitivity of second branch  trigeminal sensory loss.

DISCUSSION

The mechanisms leading to sensory restoration is unclear. One hypothesis could report  that the sensory impairment, maintained by central mechanisms has been reversed by MCS, leading to the sensory restoration.

Alessandro DARIO (VARESE, ITALY), Gianluca AGRESTA, Davide LOCATELLI
08:00 - 18:00 #10731 - P103 Sensory changes and prognostic factors of microvascular decompression (MVD) in patients with primary trigeminal neuralgia. Experience of the General Hospital of Mexico.
Sensory changes and prognostic factors of microvascular decompression (MVD) in patients with primary trigeminal neuralgia. Experience of the General Hospital of Mexico.

Objective: To determine the postoperative outcome, recurrence and prognostic factors of MVD in patients with primary trigeminal neuralgia (TGN) operated at the General Hospital of Mexico.

Material and Methods. The study included 70 patients with diagnosis of primary trigeminal neuralgia with a follow-up of 10 years. A Kaplan-Meier survival analysis was generated at 1 and 10 years of follow-up for the study of recurrence. We assessed pain using the Visual Analog Pain Scale (VAPS) before and after MVD. The results were analyzed using a Mann-Whitney test with a significant p <0.05.
Prognostic variables were patient age, sex, affected segments of the trigeminal nerve, and conflicting blood vessel in relation to recurrence.

Results. The mean age of the patients was 35 years. 49 patients (70%) were female and 21 patients (30%) were male. The involvement of the ophthalmic branch (V1) was diagnosed in 17 patients (24.28%), mandibular branch (V3) in 17 patients (24.28%) and maxillary branch (V2) and mandibular branch (V3) in 36 patients (51.42%). 72% of the patients had affection on the right side of the face (n=50). All patients had an arterial neurovascular conflict. The conflicting artery was the Superior Cerebellar Artery (SUCA) in 97.14% (n = 68) and later the Anteroinferior Cerebellar Artery (AICA) in 2.85% (n = 2). According to Kaplan-Meier analysis, the success rate (defined as pain-free patients without any medication) was 96% at 1 year and estimated to be 84.24% after 10 years of follow-up. Immediate relief from pain occurred in all patients. None of the following patient-related factors played any significant role in prognosis: sex, patient age, affected segments of the trigeminal nerve, and conflicting blood vessel in relation to recurrence. Permanent hypoesthesia and motor function of the trigeminal nerve was intact in all patients. No other complication was found.

Conclusion. MVD offers patients affected by TGN due to vascular compression a long-lasting cure in 96% of the cases at 1 year and estimated to be 84.24% after 10 years of follow-up. MVD is a safe and effective management option for TGN with neurovascular conflict.

José D. CARRILLO-RUÍZ (Ciudad de México, MEXICO), Ana Isabel GARCÍA-JERÓNIMO, Juan Manuel ALTAMIRANO, Carlos VILLANUEVA-FLORES, Oscar PÉREZ- SÁNCHEZ, Gustavo AGUADO- CARRILLO, José L. NAVARRO-OLVERA, Julián E. SOTO- ABRAHAM, Francisco VELASCO-CAMPOS, Erick ARIÑEZ-BARAHONA, Mauricio A. ESQUEDA-LIQUIDANO

Monday 26 June

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08:00 - 18:00 #10114 - P104 Fixing Fragmented Minds – The Role of International Law for the Freedom of Scientific Research – Using the example of psychiatric and functional neurosurgery.
Fixing Fragmented Minds – The Role of International Law for the Freedom of Scientific Research – Using the example of psychiatric and functional neurosurgery.

In an era of ongoing internationalization of medical research, the question of how medical science is guided by regulatory framework becomes increasingly important. This starts at a constitutional level with the freedom of scientific research and translates into national laws specific to certain research topics. However, there is a growing need for international rules, that apply to the medical research community as a whole. This becomes all the more apparent in highly specialized fields of medical research like functional and psychiatric neurosurgery, where the number of patients is small and research cooperations are indispensable to produce statistically relevant results.

I analyze sources of international law (e.g. the declaration of Helsinki or the International Covenant on Economic, Social and Cultural Rights) addressing the issue of freedom of scientific research. I centrally discuss the problem of whether and to what extend these documents impact on and are binding in national law. Specifically, I raise the question if international sources of law can become part of the constitutional framework of freedom of scientific research by shaping and developing its meaning according to time and social reality.

The freedom of scientific research has its origins at the beginning of the 20th century, when empirical approaches had gained enough public respect to be instrumentalized for state interests.
Nowadays, many European constitutions have specific provisions protecting the freedom of scientific research, e.g. article 5 para. 3 of the German Basic Law. Other states, like the US or Canada, do not have explicit constitutional law for the freedom of scientific research and its protection falls under the provision of the freedom of thought and expression (in the US the First Amendment to the Bill of Rights).

The legal definition of content and scope of freedom of scientific research is not self-evident and needs to be readjusted as new challenges arise in the scientific community. I argue that in an era of increasing globalization of medial sience the international body of rules regulating scientific conduct needs to be more precise and binding. These rules should be primarily on an abstract and general level, applying to the entirety of medical research. However, each subspeciality encounters its particular challenges. My goal is to foster a discussion about the necessity of binding international guidelines in the field of psychiatric and functional neurosurgery

Lucia REUTER, Lucia REUTER (Berlin, GERMANY)
08:00 - 18:00 #10238 - P105 Postoperative localization of intracranial electrodes for epilepsy surgery using open-source imaging programs: clinician’s perspective.
Postoperative localization of intracranial electrodes for epilepsy surgery using open-source imaging programs: clinician’s perspective.

Visualization of implanted intracranial electrodes in three-dimensional space provides valuable information for surgeons in planning resection in epilepsy surgery. Many studies published various coregistration methods for accurately visualizing intracranial electrodes. From a clinician’s point of view, coregesitration method should be easy to learn and fast to apply, especially in hospitals with limited human resources. We introduce simple coregistration method using two open source imaging programs (Freesurfer and Slicer) with acceptable accuracy and beautiful three-dimensional visualization. Seven consecutive patients with intractable drug-resistant epilepsy were included in this study. Subdural grids, strips and depth electrodes were inserted as needed.  All patients underwent thin sliced preoperative MRI (3T, 0.9 mm thin-sliced T1 MPRAGE) and postoperative 2 mm thin-sliced CT scan. Freesurfer program was used for three-dimensional cortical reconstruction. Because this process generally takes several hours, it was prepared before the day before surgery. Reconstructed three dimensional images could be used as a reference for planning subdural electrode placement as well. Slicer program was used for coregistratimg postoperative CT and preoperative MRI or reconstructed cortical images by Freesurfer. A built-in registration module(BRAINS) with Rigid and Affine registration phases were used. In case of subdural or strip electrodes, electrode localization of postoperative CT over reconstructed cortical surfaces using markers. Linear transformation was needed when there was a brain shifting. Coregistration of depth electrodes were easier because of the minimal brain shifting. Required time for each coregistration process was less than 10 minutes. The accuracy of results was verified during the second surgery, which was satisfactory. We concluded that this method is easy and fast with acceptable accuracy for usual epilepsy surgery with intracranial electrode placement. 

Jang Hoon KIM (Seoul, KOREA), Jong Hyun KIM, Haewon ROH
08:00 - 18:00 #10545 - P106 Salvaging DBS Hardware Erosions without Explantation: Hydrogen Peroxide to the Rescue!
Salvaging DBS Hardware Erosions without Explantation: Hydrogen Peroxide to the Rescue!

Objectives: Following a non-infectious DBS hardware erosion, the standard practice is to explant the device and re-implant after sufficient healing. This leads to significant hospital costs and a temporary cessation of therapeutic stimulation. In the published literature, erosion complications are typically lumped together within the category of infectious complications. In this study, we investigated if we can differentiate non-infectious erosions from infectious wound dehiscence and determine if erosions could be managed without explantation.

Methods: n=3 patients presented to our clinic with implantable neural stimulator (INS) erosions in their chest. Standard microbiology tests ruled out erosions of infectious etiology. Figure 1 is a typical presentation of a non-infectious INS erosion. Wound debridement was performed with hydrogen peroxide (HP) and the wounds were primarily revised without hardware explantation. Patients were followed-up a minimum of six months post-operatively. Clinical images were documented to demonstrate progress of wound healing.

Results: n=2 subjects were able to keep their DBS hardware and there was no cessation of therapeutic stimulation. The third patient presented two months later with an onbvious infection requiring explantation. Figure 1 demonstrates the erosion preoperatively and six months post-operatively of one of the successful cases. An analysis of hardware and hospital associated costs saved per case was approximately $50,000 USD. We present a detailed algorithm to manage hardware-related complications in DBS.

Conclusion: The application of HP during wound debridement and revision for non-infectious INS and scalp erosions can be used as a hardware-saving procedure. Details of the procedure are provided for practical purposes. We expect this hardware-saving procedure is applicable to not only DBS practitioners, but also those using Spinal Cord Stimulation, Motor Cortex Stimulation, and experimental neurostimulator devices.

Adi SULISTYANTO (Vancouver, CANADA), Anujan POOLOGAINDRAN, Zurab IVANISHVILI, Christopher HONEY
08:00 - 18:00 #10643 - P107 Brindley device results in the treatment in patients with spinal cord injury.
Brindley device results in the treatment in patients with spinal cord injury.

AIM: to analyze the clinical and urodynamic results as well as the complications from SARS (sacral anterior root stimulator) extradural implantation in the treatment of patients with spinal cord injury (SCI) associated with neurogenic detrusor overactivity (NDO). Materials and methods: Descriptive study of the results obtained in a single center from 6 patients diagnosed SCI with NDO and implanted since 2012. RESULTS: All patients were male, aged 38 ±10 years, and suffered a traumatic complete spinal cord lesion. The average time of evolution was 84 months (48-108). 83% of the patients showed ASIA A classification, 83% located at dorsal level. Symptomatic recurrent urinary infection (more than three per year) rate before SARS was 100%, and 0% after the procedure (p<0,69). Before SARS all patients suffered urinary incontinence due to overactive detrusor, and after SARS 100% of the patients gained control and achieved a bladder capacity greater than 300 ml. Preoperative autonomic dysreflexia rate was 66% and afterwards only 5% (p<0,07). All patients achieved an effective voiding, with residual post-voiding volume lower than 50ml and stopped using catheters. 66% of the patients used the device for erectile function and 88% of the cases use for bowel function. Infection rate has been 0%. Failure of the device was seen in three patients but only in the external controller, all of them where solved without surgery. Conclusion Since 2012, our group has been carrying out SARS implants in selected patients using the extradural technique with good clinical and urodynamic results, in terms of improvement of urinary incontinence, infection rate, erectile and bowel function in patients with NDO due to SCI. It proves to be a safe procedure when carried out in an interdisciplinary team.

J CASTAÑO , M ESPINOZA (Bogotà, COLOMBIA)
08:00 - 18:00 #10727 - P108 Transcranial magnetic stimulation in brain language functional areas surgery.
Transcranial magnetic stimulation in brain language functional areas surgery.

Introduction
Transcranial magnetic stimulation (TMS) can induce speech arrest at 25 Hz repetitive TMS used  for brain mapping in a population of epileptic patients scheduled for epilepsy surgery (Pascual-Leone1991) . It is based on reversible temporal brain tissue lesion principle. There are date suggesting that speech arrest could offer information not only on dominant hemisphere but on spatial Brocca area localization in the brain (Jennum).  
Method
A total of 72 patients were evaluated for epilepsy surgery. An innovative Neuro MSD device was used for TMS studies. The maximum TMS output of this device is in the range of 0 to 4 Tesla (for iron core). The figure eight shaped stimulation coil and an iron   cone shaped core were used for focalization. Motor threshold is the intensity of stimulation needed to induce contraction in thumb. This intensity was used to block Brocca area activity in digit span. Different word picture association tasks were used.
Results
None of our patients presented postoperative permanent language deficits.  
We found that TMS not even block speech but elicit misjudgment of word picture association. It was categorized as wrong, late, slow or absent. Wernike area was more difficult to localize, but we found that there are different patterns depending on stimulus timing before, during and short after naming tasks which are presented.   
Discussions
Temporary lesions is comparable to current stimulation or Wada test and is obtained by TMS noninvasively. This is helpful during dominant hemisphere resection for epilepsy or other lesions. TMS blocks speech in most of subjects but not in all. Head motor primary area is mainly involved in speech arrest but real motor aphasia is rear and bilateral speech control is found mostly in reeducated left handed subjects.
Conclusion
TMS is a noninvasive method of modulating cortex and is proper for study of language in humans. It can give information on hemispheric dominance a motor area localization. Standardized study could provide important insights on the organization of this function not explained by evolution theory.

Jean CIUREA (Bucharest, ROMANIA), Rasina ALIN , Ioana MANDRUTZA, Andrei BARBORICA
08:00 - 18:00 #10756 - P109 ”Functional” trephinations in Ancient Egypt.
”Functional” trephinations in Ancient Egypt.

It does not seem possible to past the text here. I am attaching it as a separate file.

Patric BLOMSTEDT (Umeå, SWEDEN)
08:00 - 18:00 #10763 - P110 Comparison of efficacy, safety, duration and advantages between a frameless fiducial-less brain biopsy method and the standard frame-based stereotactic biopsy.
Comparison of efficacy, safety, duration and advantages between a frameless fiducial-less brain biopsy method and the standard frame-based stereotactic biopsy.

Background and Study Aims: The purpose of the present study is to compare the characteristics, i.e. efficacy, duration and hospital stay, of a frameless fiducial-less brain biopsy method with those of the standard frame-based stereotactic technique. Material and Methods: In the present prospective cohort study were enrolled 56 adult patients: 1) for whom no conclusive diagnosis could be settled in a noninvasive manner; and 2a) who also had lesions involving deeply seated and eloquent areas, or multifocal lesions, or lesions for which the probable diagnosis is a contraindication for craniotomy, or 2b) were poor candidates for open craniotomy (over 80 years old or serious comorbidities that were considered contraindications for open craniotomy). 28 patients were operated on with each method. Regarding the frameless biopsy technique, we used a navigation system (StealthStation® S7™) without fiducials in combination with the Navigus trajectory guide. Concerning the frame-based stereotactic method we used the Cosman-Roberts-Wells (CRW) frame and a planning software (FrameLink™ Stereotactic Planning Software). Results:  Failure of diagnosis was recorded in 4 cases (14.3%) of the frame-based method group and 3 cases (10.7%) of the frameless fiducial-less method group, in spite of the accurate targeting, without a statistically significant difference (p= 1.0). The mean duration of the overall procedure was 111.3min for the frame-based method and 79.1min for the frameless method, a statistically significant difference (p= 0.001). Concerning neurologic morbidity, new abnormal findings in the postoperative head CT scan (p= 1.0) and postoperative hospital stay (p= 0.66) the two methods did not differ significantly. The smallest maximal diameter of a lesion successfully targeted, acquiring samples which led to a diagnosis, was 15mm for both groups. Conclusions: The above frameless fiducial-less brain biopsy method was shown to be equally efficacious and safe, compared with the standard stereotactic frame-based technique, in terms of diagnostic yield, neurologic complications, and new findings in the postoperative head CT scan. Moreover, the frameless method was associated with a shorter duration of the overall procedure and of the respective preparatory steps; however with similar duration of the operation only and similar time spent inside the operating room overall. Finally, the length of postoperative hospitalization did not differ significantly too.

Constantine CONSTANTOYANNIS, Miltiadis GEORGIOPOULOS (Patras, GREECE)

Monday 26 June

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08:00 - 18:00 #10098 - P111 Occipital nerve stimulation (ONS) with body compliant leads for chronic migraine treatment.
Occipital nerve stimulation (ONS) with body compliant leads for chronic migraine treatment.

Introduction: Migraine is a highly prevalent disease and often refractory to medical therapy. ONS has been shown to
provide pain relief in patients with refractory primary headache disorders. It is also less invasive than other surgical
approaches; however, drawbacks have been reported, including technical issues with implantable components and
lack of efficacy of the treatment. The mobility of the head-neck region causes patient discomfort at the implantation
sites, when conventional straight wire SCS leads are used in ONS. We therefore investigated a new flexible, body
compliant SCS lead and system for its suitability in ONS in a series of patients for efficacy, complications and overall
outcome.
Materials/Methods: We hereby present a series of 27 patients suffering from chronic migraine (CM) (ICH criteria),
who underwent ONS lead implantation (12 contact leads bilaterally, Algovita, Algostim). Prior to implantation, all
patients received unsuccessfully conservative and surgical therapies, including antidepressants, occipital nerve
blocks, opioids and botulinum toxin injections. Using a midline incision at C1-2, two 12 contact leads were placed
subcutaneously and positioned under fluoroscopy bilaterally at the level of C1, respectively. Leads were tunneled and
the generator was placed in an all-in-one procedure under general anesthesia.
Results: At three months follow-up, a reduction in headache days in 16 out of 27 patients (26.5 to 20.4 days) was
observed, corresponding to a pain relief (9.9/7.0 on the VAS). Ten (10) patients reported a pain reduction of more than
30%, one (1) patient did not benefit so far (3 months postop). Decrease in pain led to an improvement in functional
capacity of the patient during the 3 months follow-up post implantation. (6-months results will be included at the time
of presentation). One failure occurred due to skin erosion of the lead tip during initial placement with concomitant
dislocation; a successful revision was performed. Frequent problems with stimulator rechargement could be solved in
all cases. No other complications, side effects or reports on patients discomfort were noted.
Discussion: There is an ongoing debate about optimal implant technique, indications and outcome measurement of
ONS. By using a new 20% stretchable implantable lead, mechanical complications can be reduced. Due to delayed
effect of the treatment we used an all-in-one approach with an outcome follow-up of 3-6 months.

Jan VESPER (DUSSELDORF, GERMANY), Youssef ABUSHABA, Jarek MACIACZYK, Stefan SCHU, Philipp SLOTTY
08:00 - 18:00 #10133 - P112 Accuracy of MR-guided focused ultrasound therapy - comparison with radiofrequency lesioning -.
Accuracy of MR-guided focused ultrasound therapy - comparison with radiofrequency lesioning -.

[OBJECTIVE] MR-guided focused ultrasound therapy (MRgFUS) for medication-refractory essential tremor (ET) was introduced as a clinical trial in Japan in 2013. Accuracy is certainly important in the stereotactic neurosurgery, and even in MRgFUS, it is important that a lesion is created accurately in the target. Therefore, we examined the positional error and the volume of the lesion created with MRgFUS comparing with radiofrequency lesioning (RF).
[SUBJECT and METHOD] We compared 10 cases treated with MRgFUS for refractory medication-refractory ET after June 2014 (group A) with 7 cases treated by RF for dystonia (Group B), regarding the positional error between the target and the center of the lesion, and the volume. Exablate Neuro® was used for MRgFUS. Elekta Stereotactic System® was used for RF to create a lesion at 70℃ for 60 seconds after the test coagulation at 60℃ for 30 seconds with 2 * 2 mm an uninsulated tip. We measured the positional error by measuring it between the target and the center of the lesion, and the volume of the lesion by vertical * horizontal * height / 2, and we compared them statistically.
[RESULTS] The positional error of the lesion was 1.06 ± 0.44mm in group A and 3.47 ± 1.73 mm in group B, which was significantly smaller in group A (p = 0.007). The volume of the lesion was 62.1 ± 26.1mm³ in group A and 126.2 ± 66.4mm³ in group B, which was significantly smaller in group A (p = 0.018).
[CONCLUSION] MRgFUS has a smaller positional error than RF, and it is possible to create a lesion with higher accuracy.

Kenji FUKUTOME (Osaka, JAPAN), Ryota KIMURA, Yoshinari OKUMURA, Hidehiro HIRABAYASHI, Ohnishi HIDEYUKI

Monday 26 June

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08:00 - 18:00 #8933 - P113 Intrathecal baclofen therapy for Lesch-Nyhan disease: a case report.
Intrathecal baclofen therapy for Lesch-Nyhan disease: a case report.

Background and Objectives: Lesch-Nyhan Disease (LND) is extremely rare inherited disorder of purine salvage metabolism, clinically manifesting hyperuricaemia, compulsive self-injurious behavior, and extrapyramidal motor disorder. Various symptoms of LND is treated with pharmacological treatment such as antispastic drugs, antipsychoics, anti-parkinsonian drugs and dietary supplements, whereas their abnormal posturing or involuntary movement is difficult to control. Here we report a case of LND treated by intrathecal baclofen therapy (ITB), and discuss its role on their symptoms. Case report: A 22 year-old male genetically diagnosed as LND was referred to our clinic for his intermittent dyskinesia and hypertonic posturing. His abnormal posturing has been treated with oral haloperidol, diazepam and dantrolene as well as botulinum toxin A injection, but their efficacy was not satisfactory. The patient’s family wished to undergo  ITB. After the confirmation of the effect of intrathecal administration of baclofen on relief of his abnormal posturing, permanent implantation of infusion system was conducted under general anesthesia. Soon after operation, baclofen was administered with the dose of 28 ug/day, which sufficiently improved the score of Unified Dystonia Rating Scale from 40 to 19. Surface EMG study suggested his abnormal posture might be caused by dystonia, which improved after ITB. No adverse effects of ITB occurred so far. Conclusion: Intrathecal administration of baclofen with relatively low dose is effective for relief of motor symptoms in LND, at least for a short-term follow-up period. Abnormal posturing seen in LND seems to be dystonia, in which ITB could be of therapeutic value.

Takeshi SATOW (Nagahama city, JAPAN), Ogawa MASAFUMI, Komuro TARO, Tsujimoto TORU, Kobayashi AKIRA
08:00 - 18:00 #10577 - P114 Intradural Fibrin for Repair of Cerebrospinal Fluid Leaks.
Intradural Fibrin for Repair of Cerebrospinal Fluid Leaks.

Cerebrospinal fluid (CSF) leaks are common in patients undergoing new intrathecal pump catheter implantations.  The incidence of CSF leaks has increased significantly with the advent of non-occluding intrathecal catheters.  In general, CSF leaks following intrathecal catheterization are first treated with epidural blood patches.  When patients do not respond to epidural blood patches, surgical repair is attempted through a laminectomy and direct sewing of the dural defect.  While direct visualization and repair of the dural defect is often successful, it is also invasive and puts the patient at risk for future spinal instability.  These procedures do not guarantee that the open laminectomy repair will fix the CSF leak either.

 

Rather than performing an invasive procedure, we have recently begun using a fibrin glue plug with intra- and extra-dural placement of fibrin glue.  Initially, this procedure was performed intraoperatively after reopening the prior catheter incision and placing the needle close to the dural defect.  We are now are transitioning to a percutaneous approach to sealing the csf leak that can be performed outside of the OR.  In this report, we will provide two case studies in which intraoperative placement of tisseal was used to refractory CSF leaks following intrathecal catheterization.

Weyhenmeyer JONATHAN, Albert LEE (indianapolis, USA)

Monday 26 June

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08:00 - 18:00 #10414 - P115 Predictive Factors of Early Distant Brain Failure after Gamma Knife Radiosurgery Alone in Patients with Brain Metastases of Non-Small-Cell Lung Cancer.
Predictive Factors of Early Distant Brain Failure after Gamma Knife Radiosurgery Alone in Patients with Brain Metastases of Non-Small-Cell Lung Cancer.

Background: The objective of this study was to elucidate the predictive factors for early distant brain failure in
patients with brain metastases of non-small-cell lung cancer (NSCLC) who were treated with gamma knife
radiosurgery (GKRS) without previous whole-brain radiotherapy (WBRT) or surgery.


Materials and Methods: We retrospectively reviewed clinical and imaging data of 459 patients with brain
metastases of NSCLC who underwent GKRS from June 2008 to December 2013. The primary end-point was
early distant brain failure, defined as the detection of newly developed metastatic lesions on magnetic resonance
imaging (MRI) 3 months after GKRS. Factors such as tumor pathology subtype, concurrent systemic
chemotherapy, epidermal growth factor receptor (EGFR) mutation status, use of EGFR tyrosine kinase
inhibitors (TKIs), systemic disease status, presence of a metastatic lesion only in delayed MRI, and volume and
number of metastases were analyzed.


Results: There were no statistically significant differences with respect to pathologic subtype, concurrent
systemic chemotherapy, EGFR mutation, and early distant brain failure. Patients treated with EGFR-TKIs (p =
0.004), with a stable systemic disease status (p = 0.028) and 3 or fewer brain lesions (p = 0.000) experienced a
significantly lower incidence of early distant brain failure.


Conclusion: This study suggests that GKRS alone could be considered for patients treated with EGFR-TKIs
who have a stable systemic disease status and 3 or fewer brain lesions. WBRT should be considered for other
patients.

Na YOUNG CHUL, Chang WON SEOK (Seoul, KOREA), Jung HYUN HO, Hye Ryun KIM, Cho BYUNG CHUL, Jin Woo CHANG, Park YONG GOU
08:00 - 18:00 #10735 - P116 The Stony Brook awake craniotomy protocol: a technical note.
The Stony Brook awake craniotomy protocol: a technical note.

Background: Awake craniotomy allows for intraoperative cortical mapping and functional testing during the resection of brain tumors that involve an eloquent region of the brain. However, most current awake craniotomy techniques require a rigid fixation of the skull that can cause discomfort to the patient during the awake phase of the surgery. Furthermore, airway management during different stages of surgery is complicated, and can cause unnecessary stress on both the surgeon and staff. We have developed a simple protocol for craniotomy under general anesthesia, with subsequent "wake-up" testing, which maximizes both patient and operative team comfort, leading to optimal outcomes.

 

Objective: To discuss the protocol that we have developed at the Stony Brook University Hospital. Neurosurgical and anesthetic techniques along with two example cases involving motor and language mapping will be discussed in detail.

 

Methods: Patients were positioned in a supine (for frontal craniotomy) or a lateral position (for temporal craniotomy). We used the frameless Brainlab™ skull-mounted array for stereotactic navigation. Rigid fixation of the skull was avoided. General anesthesia was used during the “asleep” phase of the surgery, with airways established by a laryngeal mask airway (LMA) or endotracheal (ET) tube. Following removal of the bone flap and opening of the dura, patients were woken up, and the LMA or ET tube was removed. Cortical mapping was performed to establish a safe entry zone for tumor removal. While the tumors were being removed, we continued motor examination and casual conversation with the patient to ensure safety. Completion of resection was confirmed with intraoperative ultrasound and microscope examination. Patients were lightly sedated during the remaining phase of the surgery until skin closure.

 

Results: No patient exhibited any neurological deficits or adverse anesthesia outcomes during the postoperative period. Gross total excision was achieved in the patient that underwent language mapping. In the patient that underwent motor mapping, resection was halted as a result of the patient developing hand weakness intraoperatively, which resolved immediately.


Conclusion: The protocol developed at Stony Brook University avoids rigid skull fixation and simplifies airway management, helping to maximize patient and physician comfort while allowing for successful tumor resection.

Erica SHEN, Colleen CALANDRA, Christopher PAGE, Sofia GERALEMOU, Wesam ANDRAOUS, Charles MIKELL (Stony Brook, USA)

Monday 26 June

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08:00 - 18:00 #10249 - P117 Robotized stereotactic assistant system assisted stereotactic surgery for the treatment of hypertensive brainstem hemorrhage.
Robotized stereotactic assistant system assisted stereotactic surgery for the treatment of hypertensive brainstem hemorrhage.

Objective: To analyze robotized stereotactic assistant (ROSA) system assisted stereotactic surgery for the treatment of hypertensive brainstem hemorrhage. Methods: The clinical data of 33 patients with hypertensive brainstem hemorrhage undergoing minimally invasive surgery were analyzed retrospectively. According to the time node, the patients were divided into frame group (n=17, stereotactic frame assisted, January 2014 to March 2016) and ROSA group (n=16, the ROSA robot assisted, May to October 2016). Results: The hematoma evacuation rate was higher in ROSA group than in frame group (χ2= 5.28, P<0.05). The operation time and postoperative extubation time were shorter in ROSA group than in frame group (t=1.762, P<0.05; t=2.493, P<0.05 respectively). The postoperative hemorrhage occurred in 3 cases and intracranial infection in 2 in frame group, while did not occur in ROSA group, and the difference was not statistically significant between the two groups (P=0.125, P=0.258 respectively). Conclusions The hematoma evacuation rate, operation time and postoperative extubation time is superior in ROSA system assisted to stereotactic frame assisted minimally invasive surgical treatment for hypertensive brainstem hemorrhage. ROSA system is suitable for ultra-early treatment of hypertensive brainstem hemorrhage. 

Yingqun TAO (Shenyang, CHINA), Hai JIN, Feng XU
08:00 - 18:00 #10235 - P118 The feasibility of intraoperative local field potential recording from microelectrode during deep brain stimulation for Parkinson’s disease.
The feasibility of intraoperative local field potential recording from microelectrode during deep brain stimulation for Parkinson’s disease.

Evidences from many studies suggest the increased beta-band oscillatory activity of the local field potential (LFP) is a characteristic finding of the STN in the Parkinsonian off-medication state. Most LFPs were recorded postoperatively using the inserted macroelectrode. This method has the advantage of obtaining stable recordings but generally requires two-staged operations. We tested the feasibility of recording LFP from microelectrode simultaneously with neuronal spikes during the surgery. Data from 10 PD patients who underwent DBS surgery were included in this study.

Signals from microelectrodes were amplified and differently filtered to display both activities during the surgery. LFP recordings were also recorded postoperatively from implanted macroelectrodes and compared to intraoperative recordings in available cases. Intraoperative signals were sampled with the sampling rate of 50,000 Hz for spike activities and 1,000 Hz for LFPs. Postoperative LFP recordings were performed 3 or 4 days after the surgery before implanting subcutaneous pulse generators. The externalized temporary cables were connected to a signal amplifier and high pass filtered at 1 Hz with notch filtering at 60 Hz, and digitalized by A/D converter with a sampling rate of 1,000 Hz. Stable LFPs with prominent beta band activity were only noted in 5 out of 10 patients during the surgery. In contrast, all postoperative LFP recordings were stably recorded and prominent beta band activity was noted in all cases. Intraoperative LFPs showed lower signal-to-noise ratio and higher rate of unstable recording due to various artifacts. Postoperative LFPs showed smaller amplitude of waveforms and more prominent dual peaks at low- and high beta band.

We concluded that intraoperative LFPs from the microelectrode was not suitable for clinical purpose. Prominent beta band LFP activities were observed in all patients recorded from macroelectrodes postoperatively, but only in half of patients in intraoperative microelectrode recordings.

Haewon ROH, Jong Hyun KIM (Seoul, KOREA), Kyuha CHONG
08:00 - 18:00 #10420 - P119 Multiple single unit activity in ventral intermediate thalamus of essential tremor patients during intention tremor.
Multiple single unit activity in ventral intermediate thalamus of essential tremor patients during intention tremor.

Essential Tremor is the most common movement disorder; however its pathophysiology is still unclear. Severe cases have been treated successfully with Deep Brain Stimulation of the Ventral Intermediate nucleus of the Thalamus (Vim).

To further elucidate the involvement of the Vim in the pathophysiology of this condition we recorded single unit and local field potential (LFP) activity in the bilateral Vim.  Microelctrode recordings were made from 4 patients as part of the intra-surgical exploration during the implantation of deep brain stimulation electrodes. Accelerometric signal of the contralateral hand was also acquired, during intention tremor and rest state. All patients were awake during recording.

Spike sorting yielded 66 units (27 single cell activity and 39 multi cell activity) recorded during rest (n= 54) and tremor (n= 32). We characterised the firing rate, action potential duration, burst index, mean spikes per burst, burst rate and proportion of spikes in bursts between tremor and rest.  No significant difference were found (non-corrected Wilcoxon rank sum test p>0.05), and recorded units could not be separated into distinct populations. Four out of 23 units tested during tremor were phase locked at tremor frequency (4-5Hz), one of which also displayed phase locking at double the tremor frequency. Two out of 28 units were phase locked at 15-20 Hz during baseline.

The LFP showed increased power at tremor frequency during tremor, coherent with tremor activity. In some cases, LFP power at tremor frequency showed a strong correlation with tremor intensity at sub-second time scale. This correlated activity occurred with a variable delay (~250-650 ms) with the accelerometer leading the LFP.  LFP and tremor also showed frequency coupling at sub-second time scale, furthermore the tremor frequency appeared to oscillate at ~0.5 Hz.

This study revealed that although Vim neurons showed a different phase locking tendency between tremor and baseline, no difference could be detected by testing classical firing indexes. LFP and accelerometer signal of hand tremor were coupled both in amplitude and frequency, with a tendency of the tremor to lead the LFP.   We find a periodical fluctuation of the tremor frequency at ~0.5 Hz both in LFP as well as the accelerometer signal,  which to our knowledge is a new pathological feature of intention tremor.

Andrea GIORNI (Brisbane, AUSTRALIA), Franҫois WINDELS, Peter STRATTON, Terry COYNE, Peter SILBURN, Pankaj SAH
08:00 - 18:00 #10439 - P120 Microelectrode Recordings of the Globus Pallidus internus (GPi) in Cerebral Palsy Patients.
Microelectrode Recordings of the Globus Pallidus internus (GPi) in Cerebral Palsy Patients.

Objectives: Individuals with cerebral palsy often develop secondary dystonic symptoms, for which deep brain stimulation (DBS) of the Globus Pallidus internus (GPi) can be indicated. However, DBS of the GPi has had mixed outcomes in these patients, and data on the neurophysiology of the GPi in dystonic CP is lacking. Previous models of dystonia suggest that low firing rates in GPi might be related to dystonic symptoms, but debate remains whether anesthetics are involved. We took microelectrode recordings (MER’s) to measure the firing rates and patterns of GPi single-units in CP patients in awake and anesthetized states. Furthermore, subcortical lesions in CP patients are the principal reason for symptom generation, and could play a role in de-afferenting cells. To test this hypothesis, we employed a new macro-stimulation technique.

Methods: 6 CP patients underwent Bi-lateral DBS surgery targeting the GPi. 4 out of the 6 patients were sedated under general anesthesia. Depth of anesthesia was monitored using the Bispectral index. MER’s were taken prior to the implantation of DBS electrodes and GPi cells were identified from MER data. Firing rates, firing patterns and burst index values were measured. Comparisons were made between single units from anesthetized patients, and those from the awake patients. For the macro-stimulations, a stimulating electrode was used to excite afferent connections by placing it 5mm away from the recording electrodes.

Results: The firing rate of CP GPi cells in patients under GA was found to be lower (mean ± standard deviation; 22.8 ± 11.3 Hz; n=56) than cells in the awake patient (52 ± 22.2 Hz; n=18; P<0.0001). CP GPi cells under general anesthesia displayed a more bursty firing pattern and had a higher median burst index value compared to the awake patient (2.2 ± 1.8 vs 1.5 ± 0.3 respectively; P<0.01).  Furthermore, GPi firing rate was positively correlated with Bispectral index (Pearson's r=0.99). Finally, using our stimulation technique, we found complete lack of inhibitory response localized to the damaged side of a patient’s brain.

Conclusion: To our knowledge, this is the first evaluation of the neuronal properties of the GPi in cerebral palsy.  Our results suggest that GA is responsible for the lower firing rate of GPi neurons, and hence not directly correlated with the dystonic symptoms of CP. Additionally, macro-stimulations seem to be a valid technique for the assessment of neuronal de-afferentiation in humans

Majid GASIM, Botero Posada LUIS FERNANDO, Ricardo PLATA AGUILAR, Adriana Lucia LOPEZ-RIOS, William Duncan HUTCHISON (Toronto, CANADA)
08:00 - 18:00 #10475 - P121 Technical Reasons for Differences in Intraoperative Findings in Semi - Macrostimulation and Postoperative Neurological State in Respect to Dysarthria or other Side Effects?
Technical Reasons for Differences in Intraoperative Findings in Semi - Macrostimulation and Postoperative Neurological State in Respect to Dysarthria or other Side Effects?

OBJECTIVE: Deep brain stimulation in parkinsons disease, essential tremor and various forms of dystonia is well established and in its effectiveness proven. To identify side effects like dysarthria or motor symptoms as early as possible surgery is performed under local anesthesia in combination with intraoperative semi macro stimulation. But despite of that, seldom patients show side effects postoperative.

METHODS: We examined the recording microelectrodes and stimulating semi-macro-electrodes by magnifying glasses during surgery.

RESULTS: We never discovered a problem in the tungsten electrodes for micro-recording but some of the stimulation probes exhibited an inappropriate removal of the isolation on the tip of the electrodes. The insulation was still covering the tip of the probe resulting in no stimulation side effects during surgery. It was leading the surgeon and the neurophysiologist to the wrong estimation that the electrode placement will be perfect being proven wrong in postoperative side effects.

CONCLUSION: Surgeons have to be aware that mal-production of electrodes may occure being not detectable by threshold measurement of the electrodes because of bridging liquids in the surgical site. The surgeon has to check every electrode before inserting into the guide tubes especially when electrodes are delivered in sterile trays by manufacturers.

Wilhelm EISNER (Innsbruck, AUSTRIA), Sebastian QUIRBACH

Monday 26 June

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POSTERS14
08:00 - 18:00

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08:00 - 18:00 #10091 - P122 Establishing an MRI-guided and MRI-verified deep brain stimulation service in Malta through cross border collaboration: Audit of the first five years.
Establishing an MRI-guided and MRI-verified deep brain stimulation service in Malta through cross border collaboration: Audit of the first five years.

Objectives: A specialist multidisciplinary approach and lifelong follow-up is required for patients undergoing Deep Brain Stimulation (DBS). Access can be a challenge for remote communities or small nation states where the population cannot support such specialised services for the relatively small numbers of patients. Malta has a population of just under 450 000. The number of patients likely to benefit from DBS was envisaged to be around 5 to 10 per year. The purpose of this study was to determine the outcome of a cross border collaboration between specialist services in London and a tertiary centre in Malta.

Methods: Between 2011 and 2015, the total number of patients undergoing deep brain stimulation was 35. Of these, 29 patients received bilateral subthalamic nucleus (STN) DBS for Parkinson’s Disease. Surgery was performed using a Leksell G-frame under general anaesthesia using an MRI-guided and MRI-verified approach. Pre-operative motor function was compared with one year post-operative motor function assessments in 26 patients. Pre-operative and post-operative quality of life assessment was also completed in 24 patients.

Results: The demographics of the 26 patients were: 16 M; age 60 ± 9, range 32-70; disease duration 8.8 ± 2.7. There was a statistically significant improvement in off-medication Unified Parkinson’s Disease Rating Scale (UPDRS) III motor function (41.7%), reduction in Levodopa Equivalent Dose (LED) (30.6%) and improvement in quality of life as measured by the Parkinson’s Disease Questionnaire (PDQ-39) (52.3%). Sub analysis of the PDQ-39 dimensions showed significant improvement in all dimensions except communication, with greatest benefit for activities of daily living (ADLs) (72.4%) and stigma (66.3%). Surgical adverse events were transient with no permanent sequelae. Patients receiving DBS to targets other than the STN and for different indications also benefitted from the procedure.

Conclusion: This audit demonstrates the successful delivery of specialist services through cross border collaboration with achievement of expected results in terms of therapeutic benefit to patients. This positive outcome was contingent on the political desire to introduce and support the service and the close collaboration between specialists in both centres.

Ludvic ZRINZO (London, UK), Charmaine CHIRCOP, Nicola DINGLI, Annelise AQUILINA, Josanne AQUILINA
08:00 - 18:00 #10152 - P123 DBS lead fractures in movement disorder patients.
DBS lead fractures in movement disorder patients.

Objectives : DBS is effective for movement disorder, pain, psychiatric disorders, etc. Sometimes, in Dystonia patient and parkinsonian-dystonia patient developed DBS lead fracture.

 

Material and methods : We operated over 500 DBS and SCS, MCS operations during last 15 years. Among 6 patients developed DBS lead fractures. Disease entity consisted with 5 parkinsonism patients, 1 dystonia patient. 1)Among 1 parkinsonian 43-year-male patient devloped Rt DBS lead extension line fracture after 4 DBS operation. IPG showed battery was gone. We changed into new IPG and extension line. 2) 56-year-male patient operated STN DBS surgery in other hospital. 2 year later, Rt DBS impetance was bad, we checked radiography of skull and lead extension line fracture was suspected. In operation view, we checked lead extension line fracture and changed into new one. 3) 61-year-female patient operated Gpi- DBS surgery in other hospital. 3 years later, IPG connecting extension line fracture was developed and changed into new extension line.

 

Results : 4) 65-year-male patient operated STN- DBS surgery in other hospital. 3 years later, IPG connecting extension line fracture was developed and changed into new extension line 5) 27-year-male dystonia patient operated Gpi- DBS surgery . 5years later, DBS lead connecting proximal extension line fracture was developed and changed into new extension line 6) 58-year-male Parkinsonism patient operated STN- DBS surgery . 5years later, DBS lead connecting proximal extension line fracture was developed and changed into new extension line . DBS lead fracture site is 4 IPG connecting extension line , 2 DBS lead connecting proximal extension line.

Conclusion  : DBS is safe and effective treatment for intractable movement disorder patients. If patient's symptom is aggravated after DBS surgery and should check radiography of skull and, chest but rarely developed lead fracture in dystonia or parkinsonism patients.

 

 

 

 

Mooseong KIM (Busan, KOREA), Won Hee LEE, Keunsoo LEE, Paeng SEUNG HWA, Seyoung PYO, Younggyun JEONG, Yongtae JUNG
08:00 - 18:00 #10159 - P124 Delayed Responses to STN Deep Brain Stimulation in Patients with Parkinson’s Disease.
Delayed Responses to STN Deep Brain Stimulation in Patients with Parkinson’s Disease.

Subthalamic nuclei (STN) deep brain stimulation (DBS) has become a widely accepted treatment modality in relieving tremor and rigidity for Parkinson’s disease. Usually, if the DBS lead is accurately and properly placed in the STN, tremor and rigidity will attenuate almost instantly after DBS is turned on. Recently, we began to notice a “delayed response” phenomenon in STN DBS surgeries, in which case the intraoperative STN test stimulation failed to show its expected effects whereas the stimulation in the ward did. We identified 6 patients who demonstrated definite delayed responses to STN DBS in a 3-year period. The clinical data of these patients were collected and analyzed. Our findings remind us that if the MER is perfect but test stimulation fails, we should consider the possibility of the STN delayed response phenomenon, which may help us out from missing a good target and changing targets aimlessly.

Shi LIN (Beijing, CHINA), Zhang JIAN-GUO
08:00 - 18:00 #10180 - P125 Clinical Outcome and Location of Active Contacts in Caudal Zona Incerta (cZI) Deep Brain Stimulation (DBS) for Tremor-Dominant Movement Disorders.
Clinical Outcome and Location of Active Contacts in Caudal Zona Incerta (cZI) Deep Brain Stimulation (DBS) for Tremor-Dominant Movement Disorders.

Objective : We investigated the clinical outcome and location of active contacts in chronic caudal zona incerta (cZI) deep brain stimulation (DBS) in the treatment of tremor-dominant movement disorders.

Methods : To evaluate the efficacy of cZI DBS on tremor in patients with essential tremor (ET) and Parkinson’s  disease (PD), assessment using the subscores of essential tremor rating scale (ETRS) and part III (motor) subscores of the unified Parkinson’s disease rating scale (UPDRS) was performed at 12 month postoperatively. The changes in the severity of tremor was measured as percent (%) tremor reduction. To determine the location of active contacts, 10 leads in 9 patients with cZI DBS were inevestigated.

Results : The scores of item 5 and 6 (contralateral tremor) of the ETRS decreased by 76.5 % (8.38 ± 2.26 to 2.13 ± 1.89, p<0.01, paired t test) and those of items 11-15 (contralateral hand function) improved by 72.6 % at postoperative 12 month (14.50 ± 4.21 to 4.38 ± 3.25, p<0.01, paired t test). The degree of improvement in PD was 81.9 % in items 20-21 (contralateral tremor), 50% in item 22 (contralateral rigidity), and 81.5 % in items 23-26 (contralateral bradykinesia). The head tremor improved by 83.3% in item 4 (from 6 to 1) with bilateral cZI stimulation. Three patient experience dysphasia. However, no permanent speech disturbance was observed. The mean intensity of stimulation at postoperative 12 month did not differ from that in early postoperative period, indicating stimulation tolerance was not significant during chronic cZI stimulation.

Conclusion : Chronic cZI stimulation is a safe and effective means in the treatment of tremor-dominant movement disorders. 

Son BYUNG-CHUL (Seoul, KOREA), Choi JIN-GYU, Ha SANG-WOO
08:00 - 18:00 #10191 - P126 Freezing of gait after pallidal stimulation for Parkinson disease.
Freezing of gait after pallidal stimulation for Parkinson disease.

Background and objectives: Established targets of deep brain stimulation (DBS) in Parkinson disease (PD) are the subthalamic nucleus (STN) or globus pallidus internus (GPi). An early comparative study revealed the superiority of STN DBS in improvement of motor score in the medication-off period and reduction of dopaminergic medication. Consequently, the STN has been the most common target of DBS for PD for a long time. However, a current randomized comparative study reevaluated the potential of GPi DBS, and revealed that GPi DBS improved motor functions similarly to STN DBS with less psychiatric or cognitive deficit after surgery. Therefore, we selected the target in each patient based on the characteristics of these targets and the number of cases with GPi DBS was increasing. However, we had some patients who suffered from freezing of gait despite improvement of cardinal PD symptoms and dyskinesia/dystonia after GPi DBS. We report cases with freezing of gait after GPi DBS.

Methods: We retrospectively reviewed 77 patients who underwent bilateral DBS for PD between 2012 and 2015. Among them, twelve patients (16%) underwent GPi DBS. The reason for selecting GPi was severe dyskinesia or dystonia with low dose medications (8 cases) and/or a high risk of neuropsychological or psychiatric complications such as high aged patients or patients with mild cognitive decline (7 cases).

Results: GPi DBS significantly improved motor function, fluctuation, and dyskinesia/dystonia as well as STN DBS. On the other hand, 5 patients (42%) showed apparent deterioration of freezing of gait after GPi DBS. We tried increasing of dopaminergic medication or readjustment of stimulation parameters using interleaving mode for these patients. However, sufficient improvement of gait problem was not obtained.

Conclusions: GPi DBS is effective in improving cardinal motor symptoms and dyskinesia/dystonia in PD. However, vigilance is needed, because significant incidence of freezing of gait occurs after GPi DBS. We discuss about the mechanism and treatments for this problem.

Atsushi UMEMURA (Tokyo, JAPAN), Genko OYAMA, Yasushi SHIMO, Madoka NAKAJIMA, Asuka NAKAJIMA, Takayuki JO, Satoko SEKIMOTO, Ryota NAKAMURA, Fuyuko SASAKI, Hirokazu IWAMURO, Masanobu ITO, Hajime ARAI, Nobutaka HATTORI
08:00 - 18:00 #10266 - P127 Deep brain stimulation for Holmes tremor, a case series.
Deep brain stimulation for Holmes tremor, a case series.

a.          Objective

Deep brain stimulation is an established treatment in movement disorders. Holmes tremor following unilateral cerebellar brain lesions is rare and deep brain stimulation in these cases is always an individual decision. To reassess results of our surgical indications we compiled our cases related to the published literature for this special indication.

b.          Methods

We report on our five patient case series with post lesion Holmes tremor, their indications, lesion positions, target points, stimulation parameters and overall outcome after deep brain stimulation between the years 2002 - 2014. In all patients conservative medical treatment failed or showed no significant improvement in the patients’ overall quality of life. In addition we reviewed the published literature showing numerous case series but no randomized studies yet.

c.              Results

Unilateral deep brain surgery was initiated in all five patients. We targeted the contralateral Nucleus ventralis intermedius (VIM). Intraoperative four out of five patients had significant symptom improvement, but one patient tremor was tested intraoperative and showed no significant effect with testing over 10 trajectories, therefore no electrode was implanted. From the beginning of stimulation a significant reduction of target symptoms appeared with up to complete disappearance and improvement of quality of life. This effect was ongoing until now with a medium follow up of 36 months.

d.              Conclusion

In consent with published data deep brain stimulation for Holmes tremor can reduce the symptoms up to complete disappearance and improve the overall quality of life of patients. Since therapy may fail individual diagnosis should be strictly analyzed and maybe MRI-techniques like fibertracking could help to clarify the individual anatomy.

Isabel LUEBBING (Kiel, GERMANY), Ann-Kristin HELMERS, Daniela FALK, Carsten WITT, Hubertus Maximilian MEHDORN, Michael SYNOWITZ, Ulf KRAUSE-TITZ
08:00 - 18:00 #10280 - P128 128 Intrathecal baclofen therapy for GAD(+) Stiff-Person Syndrome: A Case Series of 4 patients.
128 Intrathecal baclofen therapy for GAD(+) Stiff-Person Syndrome: A Case Series of 4 patients.

OBJECTIVE

To report four cases of a rare disorder, GAD (+) Stiff Person Syndrome (SPS), treated with Intrathecal baclofen therapy.

 

BACKGROUND

Stiff person syndrome is a rare disorder of unclear etiology characterized by progressive rigidity and stiffness resulting in postural deformities. Stiff-Person syndrome is an autoimmune disorder and highly correlates with the presence of anti–glutamic acid decarboxylase (GAD) antibodies.  Baclofen, Benzodiazepines and autoimmune suppressive treatments as steroids, Rituximab, and plasma exchange have been used in SPS patients. However, when the above treatments are inadequate, intrathecal baclofen may be used.

 

RESULTS

We report 4 patients with GAD(+) SPS which presented with severe refractory neurological manifestations of the disease,  and greatly benefited from intrathecal baclofen (ITB) therapy. A 34 year old man diagnosed with SPS presented with refractory progressive spasms of the lower trunk. Unresponsive to oral baclofen, diazepam, steroids and eventually IVIG, the patient has lost his ability to walk. Treated with implantation of ITB, the patient's spasm had decreased dramatically, and he had regained his ability to walk. The second and the third patients were a 33 year old woman and a 17 years old girl diagnosed with acute SPS developed to a life threatening disease. Starting with increased muscular tonus, the two patients had developed progressive diaphragmatic spasm leading to respiratory failure. The patient underwent an implantation of ITB pump and the diaphragm contractility was regained. Soon after, the patient had withdrawal from mechanical ventilation. The two patients had been discharged from the hospital fully functional, with a substantial reduction in their symptoms. The fourth patient was a 31 year old woman with painful spasms of the legs and trunk. Despite IV immunoglobulin and plasma exchange therapy treatments, spasms progressed to the muscles of the neck and shoulders.  An ITB pump was implanted and considerable clinical improvement was demonstrated.

 

CONCLUSION

We describe four cases of GAD(+) SPS patients, presented with severe debilitating and even life threatening manifestations of their condition. After poor response to conventional SPS therapy, including oral baclofen, benzodiazepines, steroids and plasma exchange, all the 4 patients described here highly benefited from intrathecal baclofen (ITB) therapy. 

Lior UNGAR (Rehovot, ISRAEL), Takaomi TAIRA, Zion ZIBLY
08:00 - 18:00 #10293 - P129 Long-term (10 to 14 years) follow-up of bilateral pallidal stimulation for patients with primary generalized dystonia.
Long-term (10 to 14 years) follow-up of bilateral pallidal stimulation for patients with primary generalized dystonia.

Objectives

Bilateral pallidal stimulation is an established surgical management of patients with primary generalized dystonia (PGD). The aim of this study is to present our long-term results (with at least 10 years follow-up) of bilateral pallidal stimulation in patients with PGD.

Methods

The study population is composed of 9 patients with the diagnosis of PGD (5 patients with DYT-1 positive PGD and 4 patients with DYT-1 negative PGD with at least 10 years postoperative follow-up period). The patients were operated on in general anesthesia. The stereotactic target - posteroventrolateral pallidum was calculated according to the midcommissural point derived from fusion of stereotactic computer tomography images with magnetic resonance images. The formal objective assessment included the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS). The BFMDRS assessment was performed usually before and after it annually up to 10 years when bilateral pallidal stimulation was switched on. The postoperative scores in stimulation on condition were compared to baseline scores. The internal pulse generators (IPGs) were not switched of in postoperative period for assessment. All the patients were primary implanted with single channel and reimplanted over follow-up period with non-rechargeable IPGs.

Results

At the last follow-up visit (ranging from 10 to 14 years after surgery) the functional and motor parts of the BFMDRS for patients with DYT-1 positive PGD were improved by 68 % and 65 % respectively when compared to baseline scores. The functional and motor parts of the BFMDRS for patients with DYT-1 negative PGD were improved by 65 % and 58 % when compared to baseline scores. The hardware-related complications were quiet common affecting 5 patients and included 2 breakages of DBS leads, 2 erosions located over the connector, 2 rapid depletions of IPG. 1 rapid IPG depletion resulted in severe life-threatening status dystonicus.  

Conclusions

Bilateral pallidal stimulation is an effective treatment in patients with PGD with long-lasting antidystonic effect validated by objective BFMDRS. The incidence of hardware-related complications is relatively high. Most of these complications can be managed successfully by repeated procedures and reduced by appropriate surgical technique. The patients often needed the single channel IPG replacement surgeries due to frequent IPG depletions. There is a need to implant rechargeable IPGs in dystonic patients. 

Michał SOBSTYL (Warsaw, POLAND), Mirosław ZĄBEK, Artur ZACZYŃSKI, Tomasz PASTERSKI
08:00 - 18:00 #10294 - P130 Pallidal deep brain stimulation in the treatment of meige syndrome.
Pallidal deep brain stimulation in the treatment of meige syndrome.

Objectives

Meige syndrome (MS) is characterized by blepharospasm, facial, oromandibular, and cervical dystonia. The medical treatment of this condition is challenging and unsuccessful over long time. Recent case reports and small clinical series showed that bilateral deep brain stimulation (DBS) of globus pallidus pars interna (GPi) improves dystonic features of MS validated by Burk-Fahn-Marsden Dystonia Rating Scale (BFMDRS). 

 

Methods

We report on our experience in using bilateral GPi DBS in 5 cases of MS. We present short-term (3 months) follow-up as well long-term (from 24 months to 48 months) results. Preoperative and postoperative BFMDRS assessments were performed on each patient. The postoperative BFMDRS scores was done when both stimulators were switched on and compared to baseline scores.

Results

Bilateral GPi DBS reduced the BFMDRS total movement score by 75 % at short-term follow-up, and by 87 % at long-term follow-up when compared to baseline scores.  The BFMDRS total disability score was reduced by 46 % at short-term follow-up, and by 56 % at long-term follow-up when compared to baseline scores.   

Conclusions

Our results showed that bilateral GPi DBS in MS is effective and safe, if conservative treatment options failed. The benefit is not only observed at short and at long-term follow-up ranging from 24 to 48 months.

Michał SOBSTYL (Warsaw, POLAND), Mirosław ZĄBEK, Artur ZACZYŃSKI, Tomasz PASTERSKI
08:00 - 18:00 #10304 - P131 Use of 80 HZ stimulation in subthalamic deep brain stimulation parkinson’s disase patients may improve axial symptoms and speech with longstanding effect.
Use of 80 HZ stimulation in subthalamic deep brain stimulation parkinson’s disase patients may improve axial symptoms and speech with longstanding effect.

Objectives

Bilateral subthalamic nucleus deep brain stimulation (STN DBS) remains an effective and long-lasting therapy for patients with advanced Parkinson’s disease (PD). Some patients develop stimulation resistant symptoms like freezing of gait and gait disturbances in on condition. These axial symptoms in contrary to limb tremor, rigidity and bradykinesia are not well controlled by high frequency STN DBS over longer follow-up periods.

Interestingly, we observed that unilateral single-channel internal pulse generator (IPG) depletion may improve paradoxically axial symptoms and gait. After replacement of IPG and changing the stimulation frequency from high (130m Hz) to low (80 Hz) the axial and limb PD symptoms were well controlled. The aim of the study was to evaluate 80 Hz stimulation in advanced PD patients after unilateral IPG depletion.

Methods

We report on our experience in using low frequency 80 Hz bilateral STN DBS in 7 patients with longstanding PD. All patients experienced depletion of one IPG which paradoxically improved some axial symptoms. After replacement  surgery and reinstitution of 130 Hz stimulation axial symptoms deteriorated.  Subsequent lowering stimulation frequency to 80 Hz improved axial symptoms. The objective assessments included the UPDRS part II and III, Stand-Walk-Sit (SWS) test during 130 Hz and 80 Hz stimulation in medication off and on condition.  

Results

We observed significant improvement of axial scores and gait after switching from 130 Hz to 80 Hz stimulation frequency. The gait (SWS) test and gait disorder scores of UPDRS part III improvements were clearly demonstrated in stimulation on 80 Hz condition. Interestingly, speech also improved under bilateral 80 Hz stimulation. In some patients the voltage had to be increased to better control segmental PD symptoms.  

Conclusions

Rapid depletion of single channel IPG programmed with high frequency stimulation 130 Hz results in simultaneous improvement of axial symptoms like freezing of gait in on condition reported by the patients themselves . It  can be concluded that bilateral 130 Hz in STN DBS may not be the preferred frequency for continuous stimulation and may impair some gait and balance problem seen in PD patients. Lowering the frequency to 80 Hz solved these problems in reported patients.

 

Michał SOBSTYL (Warsaw, POLAND), Artur ZACZYŃSKI, Tomasz PASTERSKI , Mirosław ZĄBEK
08:00 - 18:00 #10305 - P132 A middle term results in surgery of Parkinson disease. Series of 58 cases, department of neurosurgery-Zemirli hospital, Algers, Algeria.
A middle term results in surgery of Parkinson disease. Series of 58 cases, department of neurosurgery-Zemirli hospital, Algers, Algeria.

introduction: Parkinson's disease(PD)remains a major cause of neurological disability affecting millions of patients around the world.While pharmacotherapy remains the primary treatment of PD symptoms,surgical therapies have showed a resurgence of succeful appropriate selection of patients,deep brain stimulation(DBS)is now considered one of the most important advances in PDtherapiy

Material and methods: Since july 2004 to 2016 fifty-eight (58) patients suffering from PD were operated in our department.This study included 36men and 22 women eanging between 34 complete form,14 trembling and 10 rigid form ;the age range from 37 to 70 years (mean age :52 years and  age onset 40 years.Lesionotomy of the GPI in 2 cases,of the VIM in 17 cases ,2 cases of unilateral lesionotomy with DBS and bilateral deep brain stimulation (DBS) in 39 patients.The coordinates X Y Z of STN and GPI are calculated on work station after realising a fusion between a stereotactic CTScan  and an MRI.Usually the stimulation of the GPI,STN and thalamotomy were performed without anesthesia.Electrophysiological microrecordings and clinical per operative assessment were realized for the accuracy of the location of the electrode in the STN

Results:Satisfactory to excellent results were precocous in surgery of PD .The comperative study of pre and post operative scores including the UPDRS III (motor score) has noted a significant reduction of 65% in the UPDRS OFF and 63% in the UPDRS ON .Thermolesion of the VIM  has demonstreted efficacy on tremor in 70% the major post operativ complication observed wase the stimulator infection in two cases .we deplored no mortality or morbidity

Conclusion: Parkinson disease surgery using both ablative and deep brain stimulation seems to be a reasonable option for medically intractable patients the appropriate selection of patients provide a good outcome

Guenane LAKHDAR (Algeria, ALGERIA)
08:00 - 18:00 #10306 - P133 Tremulous spasmodic torticollis treated by bilateral pallidal stimulation. Case report.
Tremulous spasmodic torticollis treated by bilateral pallidal stimulation. Case report.

Objective

The aim of the report is to present a case of a 72 year-old-woman with diagnosis of longstanding debilitating dystonic tremulous spasmodic torticollis. The patient had been suffering from dystonic condition for 23 years. Pharmacological treatment including benzodiazepines as well botulinum toxin injections failed to adequately control dystonic jerking movements of the head, neck as well action dystonic upper limb tremor. The patient was referred for deep brain stimulation (DBS) surgery.

Methods: The patient underwent bilateral implantation of DBS leads into the posterolateral segment of the globus pallidus internus. The surgery was uneventful. The right sided internal pulse generator due to development of seroma required reimplantation from chest wall to abdominal wall 1 month after surgery. The formal preoperative objective assessment included Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS). The postoperative TWSTRS assessments were done every 6 months up to 2 years after surgery.

Results: At the last follow-up visit, the severity, disability and pain scores of TWSTRS were improved by 54 %, 64 % and 58 % respectively. There were no hardware-related complications over follow-up period. Increase of the voltage 1 year postoperatively produced bradykinetic gait which was reversible after lowering the stimulation voltage.   

Conclusion: Our preliminary experience indicates that bilateral GPi DBS can be an effective treatment for disabling tremulous spasmodic torticollis. Bilateral GPi DBS in dystonic patients may produce bradykinetic symptoms which are reversible. 

 

Michał SOBSTYL (Warsaw, POLAND), Tomasz PASTERSKI , Mirosław ZĄBEK
08:00 - 18:00 #10465 - P134 STN Deep Brain Stimulation for Parkinsons disease, analysis of 27 cases in our setup.
STN Deep Brain Stimulation for Parkinsons disease, analysis of 27 cases in our setup.

Objective:

 

To underscore the effectiveness of Deep brain stimulation for Parkinsonian patients with impaired quality of life in our setup with limited resources.

 

Background:

 

Presently deep brain stimulation along with medical treatment stays the most effective treatment modality for patients with medically intolerant Parkinson's disease.

We present the results of STN DBS surgery for a series of 27 patients at our setup.

 

Materials & Methods:

 

It’s a prospective case series conducted at Neurosurgery Unit II ,Lahore General Hospital. Total 27 patients were enrolled with 26 cases of Parkinson's disease and a case of Dopa responsive dystonia. Study duration was 2 years commencing Oct 2014- Sep 2016. STN was the target for electrode implantation in all cases. Clinical diagnosis and the merit to undergo Deep brain stimulation was done by Neurology department. Patients were assessed using UPDRS score preop and postop at 6 weeks, 3 months, 6 months ,12 months and 6 monthly thereafter.

 

Results :

 

Of 27, 20 patients were male and 7 female. Age group ranged from 22-75 years. These patients had varying severity of symptoms ranging from 5-30 years. Scoring on UPDRS showed significant improvement in its various domains. In on-stimulation & on-medication state, UPDRS part II was reduced by 50% , part III(motor score) was reduced by 68% and part IV reduced by 70%. Daily dosage of antiparkinsonian medications was reduced by 60% and therefore was able to achieve adequate control of dyskinesias & motor fluctuations. Daily off-time was reduced by 67%. Complications encountered

were a case of small ICH, 1 case of seroma in IPG pocket, pneumonia (1) and 2 stimulation related ( reversible).

 

Conclusion:

Results of bilateral STN stimulation in carefully selected advanced parkinson's disease patients yield favourable outcome and these results are maintained at 2 years followup. These results are very encouraging for us in extending this procedure to other variety of movement disorders.

 

 

Khalid MAHMOOD, Khalid MAHMOOD (Lahore, PAKISTAN)
08:00 - 18:00 #10514 - P135 Resting-state fMRI reveals tremor network alterations in Parkinson’s disease versus essential tremor.
Resting-state fMRI reveals tremor network alterations in Parkinson’s disease versus essential tremor.

Background: Tremor is a main feature of two different movement disorders, Parkinson’s disease (PD) and essential tremor (ET), for which previously published data suggested functionally different underlying brain circuitry.

Objectives: We analyzed resting-state fMRI data of 16 patients: 8 with tremor-dominant PD, and 8 with ET (mean age 74 years). Tremor was predominant in the right upper limb in all patients. In PD, 7 out of 8 were under Levodopa medication at the time of scanning, with a mean dose of 525 mg (range 0-800).

Methods: The functional connectivity of the tremor network has been probed using a seed-to-voxel (further referred to as seed connectivity analysis) and ROI-wise (further referred to as network analysis) approach. Four seeds (dentate nucleus, red nucleus, thalamus, precentral gyrus) in both hemispheres were investigated.

Results: We report exclusive negative functional connectivity (FC) during resting-state in ET between the right dentate and left red nucleus towards the left precentral gyrus. Furthermore, the same connectivity is consistently positive in PD (independent of the medication levels).

Conclusions: The major differences in FC between two groups suggest an altered tremor network in PD and ET and further point toward the involvement of the putamen and globus pallidus (both internal and external) on one side, as well as the right ventral anterior thalamic nuclei, on the other side. In summary, our findings suggest that rs-fMRI could be used as an additional confirmation test, beside the clinical history and examination and the eventual adding of a DAT scan, in the differential diagnosis between PD and ET. 

Constantin TULEASCA (Lausanne, SWITZERLAND), Elena NAJDENOVSKA, Alessandra GRIFFA, Nadine GIRARD, Jerome CHAMPOUDRY, Tatiana WITJAS, Jean RÉGIS, Jean-Philippe THIRAN, Meritxell BACH CUADRA, Marc LEVIVIER, Dimitri VAN DE VILLE
08:00 - 18:00 #10537 - P136 The prognostic value of early relapsed lateral spread response after microvascular decompression in patients with hemifacial spasm.
The prognostic value of early relapsed lateral spread response after microvascular decompression in patients with hemifacial spasm.

Objective: The lateral spread response (LSR) is a useful intraoperative tool to guide an adequate microvascular decompression (MVD). However, there has been controversy to consider it as a reliable prognostic indicator for MVD outcome. The purpose of this study was to evaluate the meaning of relapsed LSR after MVD, in terms of prognostic value of clinical outcome.

 

Methods : The authors performed MVD for 48 patients with hemifacial spasm from July 2016 to October 2016 in our institute. All patients were serially investigated with electromyographic test to detect LSR before surgery, 4 day and 2 weeks after MVD. A total of 42 patients were involved who showed complete disappearance of LSR during MVD. They were divided into 2 groups according to the LSR changes at 4 days after MVD; group 1) patients with relapsed LSR group 2) patients without LSR. The authors tried to correlate the postoperative LSR changes with clinical outcome after MVD for hemifacial spasm, over 3 months follow-up.

 

Results : A total of 14 patients (33.3%) demonstrated relapsed LSR 4 days after surgery (group 1). 12 of 14 patients (85.7%) showed residual spasm, more frequent than that of patients in group 2 (16 of 28 patients, 51.9%) at 1 week after MVD with statistical meaning (p<0.001). Similar results were found on the follow-up results of 1 month (57.1% vs 14.3%) and 3 months (28.6% vs 0%) after surgery.

 

Conclusions : The authors found that patients with positive LSR early after MVD required longer time to achieve spasm free, thus postoperative LSR findings could provide prognostic value of clinical outcome of MVD. The LSR can be used as a useful tool for intraoperative and postoperative monitoring.    

Na Young JUNG (Seoul, KOREA), Chang Kyu PARK, Eun Jeong KWEON, Sang Keum PAK, Won Seok CHANG, Hyun Ho JUNG, Jin Woo CHANG
08:00 - 18:00 #10551 - P137 Surgical interventions for task specific dystonia (writer’s dystonia).
Surgical interventions for task specific dystonia (writer’s dystonia).

Objectives:

Writer’s cramp is a focal dystonia producing abnormal postures during selective motor activities. Thalamotomy or globus pallidus internus deep brain stimulation (GPi DBS) have been used as surgical treatment in patients not responding to medical treatment.

Methods:

Four patients (all men, age 16-47 years) with refractory focal hand dystonia underwent either Ventrooralis (Vo) thalamotomy (three patients) or GPi DBS (one patient) using stereotactic techniques. Preoperative video recordings, writer’s cramp rating scale for dystonic posture and latency of dystonia (WMS) and symptom severity scores (SSS) were evaluated at baseline and at latest follow up ranging from 1-4 years.

Results:

All patients had difficulty in performing their most common tasks. The duration of symptoms ranged from 2-12 years. All patients obtained immediate postoperative relief from the dystonic symptoms and the effect was sustained during the follow up period. The WMS (range 0-28) improved from a mean of 17.5 before surgery to 2.5 after six months whereas the SSS (maximum 43 and minimum 10) improved from a mean of 30.75 before surgery to 11 after six months. There were no surgical complications, morbidity or mortality.

Conclusion: Vo thalamotomy or GPi DBS offer successful symptom relief in patients of task specific dystonia.

Paresh DOSHI, Bharati KARKERA (mumbai, INDIA)
08:00 - 18:00 #10564 - P138 Ipsilateral effects of unilateral Deep Brain Stimulation for Essential Tremor.
Ipsilateral effects of unilateral Deep Brain Stimulation for Essential Tremor.

Background: In Essential Tremor (ET), Deep Brain Stimulation (DBS) targets the thalamic and/or subthalamic areas contralateral to the side of the body that’s aimed to treat. But some reports have indicated that there also are some ipsilateral effects of unilateral DBS for ET.

Objectives: To investigate the degree of ipsilateral effects from unilateral DBS in patients with ET.

Methods: A retrospective cohort of 49 patients (29 males) with unilateral Vim or cZi DBS for ET were evaluated using the Essential Tremor Rating Scale (ETRS) preop, at short term (≈ 1 year) and at long term follow up (≥ 2 years).

Results: Total ETRS was reduced from 50.2 at baseline to 21.9 at short term and 30.1 at long term follow up. Contralateral tremor (item 5/6) was improved from 6.2 to 0.6 and 1.3, respectively. Hand function (items 11 – 14) was improved with 11.1, 2.7 and 4.9, respectively. No significant improvement was seen regarding ipsilateral tremor or hand function at short or long term follow up.

Conclusions: Ipsilateral improvement on hand tremor or hand functions was not significant in our material. Some individuals displayed a pronounced improvement, but this does not seem to be consistent over time.

Anders FYTAGORIDIS (Stockholm, SWEDEN), Patric BLOMSTEDT
08:00 - 18:00 #10590 - P139 Cribrous subthalamic nucleus as a target for deep brain stimulation in Parkinson`s disease.
Cribrous subthalamic nucleus as a target for deep brain stimulation in Parkinson`s disease.

Background: Perivascular spaces (Virchow-Robin, PVS) are pial-lined slit-like spaces that surround perforating cerebral vessels. Small PVS (<2mm) can be detected in MRI in all ages. Enlarged PVS are considered a sign of normal brain aging and mostly asymptomatic. In patients with Parkinson's disease (PD), expanded PVS are often. Relationship between dilated PVS and PD is unclear; both alleviation and worsening of parkinsonian symptoms in contralateral extremities are described.

Objective: To report a case of successful DBS in patient with cribrous STN.

Methods: A 57-year-old woman had an 11-year history of PD. Motor symptoms manifested on the right side. Disabling pharmacoresistant motor fluctuations and dyskinesia appeared after 9 years and she was assigned for evaluation for PD-surgery. On admission, patient had bilateral akinetic-rigid syndrome with significant predominance in the right extremities, moderate postural instability, slight cranial and cervical dystonia. Levodopa-intake induced significant amelioration in hypokinesia and rigidity, improvement in balance and walking. Moderate dyskinesia was observed mainly in the right arm and leg. We used standard scales for clinical evaluation (UPDRS, PDQ-39, Schwab&England).  Standard MRI revealed pronounced lacunar cysts in the left brain peduncle and striatum limiting stereotactic placement of DBS-electrode.

Results: In order to assess DBS-suitability, comprehensive neuroimaging evaluation was performed. Direct visualization of basal ganglia was performed using 3T MRI and MR-tractography. Overextended PVS were detected in the left subthalamic nucleus and posterior subthalamic area. However, shape and size of cribrous STN were within normal range and internal capsule was not dislocated. Subsequently, DBS-electrodes were implanted in STN bilaterally using standard procedure. Position of the left STN-electrode was calculated by the anterolateral margin of PVS. Microelectrode recording performed during surgery showed no differences in neuronal electrical activity of the cribrous and normal STN. At three-month follow-up, UPDRS-III in off-medication state reduced by 79%, levodopa equivalent daily dose by 61%, PDQ39 by 35%. Motor fluctuations and dyskinesia improved significantly. Daily activity in off-state increased by 30%.

Conclusion: Expanded PVS in midbrain and basal ganglia region may affect clinical manifestation of PD. Although, presence of cribrous changes do not hinder DBS or predict unfavorable outcome.

Anna GAMALEYA (Moscow, RUSSIA), Alexey TOMSKIY, Alexey SEDOV, Valentin POPOV, Artem BATALOV, Igor PRONIN
08:00 - 18:00 #10617 - P140 Preliminary experience with SCS in primary freezing of gait and postural instability.
Preliminary experience with SCS in primary freezing of gait and postural instability.

Objective:

Primary freezing of gait (PFOG) is difficult to manage and often not responsive to medical treatment. Spinal cord stimulation (SCS) has been introduced recently as a possible treatment for gait disorders in Parkinson disease. There is no experience with SCS treatment in PFOG. Here we report our preliminary experience of a prospective study in a patient with PFOG treated by SCS.

Methods:

A 78-year-old woman with a 6-year history of PFOG and postural instability was referred for further treatment. Initially pedunculopontine nucleus DBS was considered. However, with regard to age it was decided to offer SCS. She underwent implantation of a paddle 5-6-5 electrode (Specify, Medtronic) into the epidural space between T8 and T9 under local anesthesia. Electrodes were placed in the midline where test stimulation induced paresthesias in both legs. A variety of different stimulation settings was tested. Finally, the following stimulation parameters were used: amplitude range 4-6 V, pulse width 300 µs, in cycle mode, frequency 130 Hz, 0.2 s/2 s

Results:

At 2-month follow-up, there was mild improvement in freezing of gait.  Improvement of postural instability was not observed. Objective measurements (pre- vs. postoperative) were as follows: Time-up-and-go test (50s/35 s), Timed 10 meter test (109s/80s), Tinnetti scale score (12/22), UPDRS III motor score on (26/23), UPDRS III item 29, gait (3/2), UPDRS item 14, freezing (3/2), UPDRS item 30, postural instability (2/2).

Conclusions:

Our preliminary studies indicate that SCS might be a possible treatment option in PFOG. Experience with long-term follow-up in a larger number of patients is needed.

Assel SARYYEVA (Germany, GERMANY), Luisa CASSINI ASCENCAO, Joachim RUNGE, Christoph SCHRADER, Joachim K. KRAUSS
08:00 - 18:00 #10644 - P141 Holmes tremor: Algorithm to choose the surgical target.
Holmes tremor: Algorithm to choose the surgical target.

Holmes tremor is a disabling condition characterized by moderate to severe rest, action, and postural tremor. Treatment failure is frequent. Based in our previous casuistic with patients showing a major distortion of the thalamus or unsatisfactory Vim intraoperative tremor control, we developed an algorithm in which presurgical target planning included two nuclei: Vim and posteroventral Globus pallidus internus (GPi). The definitive target was decided after single-cell microelectrode recording, intraoperative test stimulation, thresholds for stimulation-induced adverse effects and best clinical response compared to baseline status. The electrode was implanted in the nucleus with the best tremor suppression. GPi DBS was initially decided if one of the following conditions was present: *When intraoperative tremor control was unsatisfactory despite Vim high-intensity stimulation or tremor worsening occurred. *If the Vim area appeared in neuroimaging studies (includ tractogeaphy) absent or grossly altered. *When the therapeutic range between clinical improvement and side effects was narrow. Seven patients received definitive Gpi DBS implantation, while three patients received Vim DBS; all 10 cases achieved adequate tremor control. Presurgical planning of two targets allowed choosing best optimal response. Gpi stimulation could be considered in cases in which thalamic anatomy is considerably altered or Vim intraoperative stimulation does not produce satisfactory results.

M ESPINOZA (Bogotà, COLOMBIA), G ARANGO, X GARCIA
08:00 - 18:00 #10645 - P142 Globus Pallidus pars interns (Gpi) deep brain stimulation for tardive syndrome: long term follow up of 12 cases.
Globus Pallidus pars interns (Gpi) deep brain stimulation for tardive syndrome: long term follow up of 12 cases.

Tardive syndrome is a group of movement disorders secondary to prolonged exposure to dopamine receptor blocking agents or to other medications. The clinical expression include dystonic, dyskinetic, choreiform, athetoid, tremolous, or myoclonic patterns and tics isolated or frequently in combination. For some patients, withdrawal of the offending medication will be the main treatment, while for others a chronic course is the outcome. The nature of the disorder is functional, i.e, there is an intact brain anatomy. The results of GPi stimulation in 12 consecutive patients with tardive syndromes refractory to adequate medical treatment. Eight patients had dystonia and four dyskinesia as the dominant clinical feature. All received bilateral GPi stimulation. The mean improvement at the last examination was 75% (70-95%) using the BFMDRS. No longlasting or residual neurological deficit were observed. Conclusions: Gpi DBS for tardive syndromes is an effective and a safe approach for individuals whose symptoms do not respond to medical treatment.

Jairo ESPINOZA (Bogotà, COLOMBIA), G ARANGO, X GARCIA, J ORJUELA
08:00 - 18:00 #10701 - P143 Parietooccipital metabolic state in 18F-FDG PET reflects the reserve capacity of motor improvement after GPi DBS in Parkinson’s disease patients.
Parietooccipital metabolic state in 18F-FDG PET reflects the reserve capacity of motor improvement after GPi DBS in Parkinson’s disease patients.

Introduction: Although deep brain stimulation (DBS) considerably restores motor function of patients with advanced Parkinson’s disease (PD), it only partially compensates for manifestations of dopaminergic neuronal cell death in the midbrain and there is a difference in the degree of motor improvement (MI) for each patient. Hence, we hypothesized that each patient has own reserve capacity for improvement in parkinsonian motor symptoms after DBS, and that 18F-fluorodeoxyglucose (FDG) PET would reveal the individual intrinsic capacity of recovery because it measures a local synaptic activity and regional cerebral metabolism. The aim of this study is to evaluate the utility of 18F-FDG PET in predicting the motor outcome of DBS for treatment of advanced PD.

Methods: Twenty-seven PD patients (M: F = 14: 13, age 28–64 years) undergoing DBS of globus pallidus interna were assessed pre- and post-operatively with Unified Parkinson’s disease rating scale part III measured on and off levodopa. All patients performed 18F-FDG PET before surgery and we measured the regional resting cerebral metabolic rate of glucose based on the automated anatomical labeling template and estimated the standardized uptake value ratio (SUVR) as the reference regions of the cerebellum. The areas that are significantly different in metabolic rates between the MI groups (≥ 60% vs. < 60%) after GPi DBS were determined by voxel-based analysis using 2-sample t-test.

Results: There were no difference in age, sex, disease severity, response to levodopa challenge test, and electrode location between two MI groups of ≥ 60% and < 60%. However, 18F-FDG PET of subjects with MI < 60% revealed significant SUVR decrease in the calcarine, cuneus, lingual, occipital superior, parietal superior, and parietal inferior gyri of the both hemispheres. The mean weighted SUVR of these areas were 1.05±0.066 and 1.12±0.78 in the groups of MI < 60% and ≥ 60 %, respectively, and the difference was statistically significant on multivariate logistic regression analysis (P = 0.041).

Conclusion: These data show a significant relationship between preoperative 18F-FDG PET activity of parieatooccipital lobe and MI following GPi DBS in advanced PD patients. Preoperative 18F-FDG PET may be helpful in predicting the motor outcomes of DBS and selecting optimal candidates for surgery. 

Lee EUN JUNG (Gyeonggi-do, KOREA), Shin IL YOUNG, Hyo Jeong MOON, Oh JUNGSU S, Kim JAE SEUNG, Chung SUN JU, Jeon SANG RYONG
08:00 - 18:00 #10706 - P144 Three cases report of deep brain stimulation therapy for post-stroke movement disorders.
Three cases report of deep brain stimulation therapy for post-stroke movement disorders.

It is reported that involuntary movements develop after 1-4 % of strokes. Poststroke movement disorders can manifest in Parkinsonism or a wide range of hyperkinetic movement disorders including chorea, ballism, athetosis, dystonia, tremor, myoclonus, stereotypies, and akathisia.

As we have performed deep brain stimulation therapy for three patients with post-stroke involuntary movement disorder, so we will report them with literature considerations

Case one was 75 years old male who has developed the left putaminal hemorrhage at 44 years old. He has gradually developed the athetosis in the right hand since several month before. Although the patient was administrated various agents including anti dopaminergic agent, clonazepam, sodium valproate and topiramate etc. as pharmacological therapy, his athetosis was not improved at all.

Therefore he underwent deep brain stimulation.  There is discussion about the target of post-stroke involuntary movements and either the Vop nuclei, Vim nuclei or GPi nuclei are considered as the target. Three patterns of deep brain stimulation by GPi alone, CZi-Vim-Vop alone and both were compared and examined. The GPi alone stimulation resulted in improvement of the abnormal posture and the patient was able to use the chopsticks well.

Case two was 72 years old man who developed the right putaminal hemorrhage in 58 years old and has suffered from left hemiparesis with spasticity since then. He underwent various medication, botulinus toxin and intrathecal baclofen therapy for spasticity. His spasticity was not improved with treatment and he has gradually developed painful athetotsis in the left hand. We performed GPi-DBS for his athetosis and he has been well since then.

Case three was 81 years old woman who underwent extirpation of the cavernous angioma in the left temporal lobe. She has suddenly developed the hemiballism two months before. The magnetic resonance image showed the small hemorrhage near the left subthalamic nucleus. The Vop-Vim-cZi DBS was carried out because the hemiballism was getting worse. The stimulation of Vop resulted in effectiveness for hemiballism

Hidehiro HIRABAYASHI (Tokyo, JAPAN), Kaido TAKANOBU, Shimogawara TATSUO, Hoshida TOHRU, Murase EIKO
08:00 - 18:00 #10719 - P145 Correlating sensor data for essential tremor with tremor ratings and quality of life using machine learning techniques.
Correlating sensor data for essential tremor with tremor ratings and quality of life using machine learning techniques.

Background: Tremor related diseases affect millions of people around the world, hindering various everyday life tasks, such as holding a glass of water. Tremor severity assessment is an important element for the diagnosis and treatment decision making process. For decades, subjective clinical rating scales were mostly performed. Recently, remarkable attention around computerized tremor analysis has grown. While dedicated devices are expensive and not practical for the everyday use, smartphone applications are promising. Previous studies on Parkinson’s disease or Essential Tremor mostly classified the Fahn score rating scale. Objective: Using machine learning techniques to regress tremor severity observed by clinicians (ETRS) and patients (QUEST), and give the research accessibility and new insights that would later lead to decision making process improvements. Methods: Five wrist-worn different tests were performed on 20 Essential Tremor patients from the open-source TREMOR12 iPhone/iWatch compatible application. Linear displacements and joint rotations are measured from in-device accelerometer and gyroscope. From these signals, time, frequency and time-frequency domain tools are used to extract the following features: dominant frequency, dominant magnitude, signal RMS, signal period and the power growth during the test. Results: While the study demonstrates good predictive power, its feature extraction shows to bring improvements when compared to previous close setting studies. Conclusion: This study gives the research new directions and tools in order to perform further investigations around tremor severity evaluation. Smartphone sensors improvement in the following years, research on the best predicted variable to use and larger data collection may lead to very robust models, measuring rapidly, accurately and more objectively tremor severity than clinical rating scales.

Guillaume ZAMORA, Pieter KUBBEN (Maastricht, THE NETHERLANDS), Aurelie DEGENEFFE, Uzay KAYMAK
08:00 - 18:00 #10736 - P146 Better than better: Multimodality-assistant microvascular decompression for hemifacial spasm.
Better than better: Multimodality-assistant microvascular decompression for hemifacial spasm.

Objective

Microvascular decompression (MVD) has become the standard treatment for hemifacial spasm(HFS). However, as a functional operation in the cerebellopontine angle (CPA), this process can be risky and the postoperative outcomes might not be good enough sometimes. In order to obtain a better result with less complication, how to perform this surgery better is worth to be further addressed.

Method

Between January 2009 and December 2016, we retrospectively analyzed 731 HFS patients who underwent MVD with at least 1-year follow up. Patients were divided into two groups on the basis of application of intraoperative neurophysiological monitoring(IONM) with facial electromyography(EMG) of lateral spreading response(LSR) and brainstem auditory evoked potential(BAEP) (group A, 2013-2016, n= 409) or not (group B, 2009-2012, n=322). The use of endoscopes is indicated for patients who had difficulty in identifying the nerve-vessel conflicts or unfavorable IONM signal. With regard to endoscopic assistance, patients were subdivided into two subgroup for the use of endoscopes such as redo, multiple offending vessels(group B-E,n=28) , or the same indication plus persistent LSR after offending vessel separation (group A-E, n=49).

Result

After MVD surgery with one year follow up, 395(98.5%) patients achieved excellent resolution of spasm in group A, and 288(89.4%) patients in group B. In subgroups, 41(83.7%) patients were completed relieved from spasm, and 7(14.3%) patients partial relieved in group A-E. On the other hand, 19(67.9%) patients were completed relieved from spasm,  with 7(25.0%) patients partial relieved in group B-E. There were postoperative complications with hearing impairment(0.2% in group A, 1.2% in group B), CSF leakage(2.2% in group A, 2.5% in group B), and partial facial palsy(0.5% in group A, 0.9% in group B). In the post-operative follow-up visits over more than one year, there were significant differences between the clinical outcomes of the two groups (p<0.05).

Conclusion

Intraoperative electrophysiological mentoring is helpful to distinguish the offending vessels and useful in guiding neurosurgeons to obtain sufficient decompression without complication. For difficult and complicated HFS, combined IONM and endoscopic assistance may raise up the success rate. Routine implementation of neurophysiological monitoring and meticulous attention to the microsurgical anatomy of the CPA under endoscopic assistance have made the satisfied outcome.

Szu-Yen PAN (Taichung, TAIWAN), Wen-Yu CHENG, Shinh-Dung LEE, Chiung-Chyi SHEN
08:00 - 18:00 #10750 - P147 Awake versus asleep DBS in the caudal zona incerta for essential tremor – an analysis of 60 patients.
Awake versus asleep DBS in the caudal zona incerta for essential tremor – an analysis of 60 patients.

I am sorry, but it does not seem possible to paste the abstract here. I am therefor attaching it as a word file

Patric BLOMSTEDT (Umeå, SWEDEN), Rasmus STENMARK
08:00 - 18:00 #10754 - P148 Neuroanatomical distribution of adverse speech effects due to deep brain stimulation.
Neuroanatomical distribution of adverse speech effects due to deep brain stimulation.

It is not posible to paste the abstract here. I am therefor attaching it as a separate file

Sandström LINDA, Patric BLOMSTEDT (Umeå, SWEDEN), Fredrik KARLSSON
08:00 - 18:00 #10765 - P149 Is the era of peroperative teststimulation outdated when implanting DBS leads for tremor?
Is the era of peroperative teststimulation outdated when implanting DBS leads for tremor?

Introduction

The development of the imaging technique has increased the possibility for direct targeting when implanting DBS leads, improving the possibility of direct targeting. This together with per-operative imaging (with the stereotactic frame on) for confirmation of lead placement may make peroperative teststimulation less useful in relation to its costs (time, possible liquor leakage). Furthermore, tremor is most often abolished/substantially reduced within minutes after positioning of the leads which makes it impossible to assess the tremorreduction/contact.

Aim

The aim with this study was to investigate if teststimulation induced/not induced side effects when implanting leads aiming PSA1 and VIM/VOA/VOP2 also occurred at test-stimulation >3 months postoperative. 

Method

Data from per- and postoperative (>3 mth) test-stimulation of 15 patients with Essential tremor (ET) implanted with leads ((Medtronic Inc. lead 3387) aiming PSA and VIM/VOA/VOP were reviewed.  Targeting was based on MRI, no MER3 was used, but peroperative confirmation images of lead placement was done with the frame on. The settings at teststimulation settings were: 60 µs, 130 Hz and 1V-3V. Comparisons of the presence or absence of the predefined side effects (speech and voice, vision and eye movements, paraesthesia and dystonia) was done.

Result

Fourteen out of the 15 patients were in local anaesthesia implanted bilaterally. Thus 116 contacts were compared pairwise. There were no similarities between per- and postoperative teststimulation in terms of presence/absence of side effects, except from paraesthesia and that the side effects were sparse on the proximal contacts at both assessments. All patients had significant (ETRS = p<0.001) tremor reduction >6 months after surgery, 19 leads had monopolar setting with one cathode, 3 monopolar with two cathodes, and 7 had bipolar setting, 2.23V ±9; 62µs ±6; 145 Hz ±25.

Conclusion,

Peroperative teststimulation may not be useful for target confirmation when targeting PSA and VIM/VOA/VOP since the result for the side effects not are reproducible. However, abandon peroperative teststimulation might only be possible in centres having good preoperative imaging as well as peroperative imaging with the frame on for confirmation of the lead placement.

Anna-Lena TÖRNQVIST JENSEN (LUND, SWEDEN), Martina NILSSON, Hjalmar BJARTMARZ
08:00 - 18:00 #10767 - P150 Clinical effects of posterior subthalamic area/globus pallidus interna deep brain stimulation for dystonic head tremor.
Clinical effects of posterior subthalamic area/globus pallidus interna deep brain stimulation for dystonic head tremor.

Objectives

Dystonic head tremor (DHT) is predominant head tremor accompanied by dystonic involuntary movement in the craniocervical muscles. As so far, globus pallidus interna (GPi) and ventrooralis (Vo) is established as prospective surgical targets for dystonia, while ventral intermediate nucleus (Vim) and posterior subthalamic area (PSA) for tremulous symptom respectively. We report a patient with DHT successfully alleviated by simultaneous PSA and GPi deep brain stimulation (DBS).

Methods

A 70-year-old male had suffered from tremor in his bilateral upper limb since his 30s, then DHT for 15 years to date. Neither pharmaco- nor physiotherapy had relieved the symptoms, and he was referred to our department for neurosurgical treatment. In brain MR imaging, enormous dilatation of lateral ventricle presumably related to former intracranial surgery in his infancy period was noted, which made the stereotactic insertion of electrodes through the frontal cortex to thalamic area too hard to plan. In addition, the lateral border of thalamus was hardly contoured in MR imaging so that direct targeting of thalamic area was definitely impossible. From these morphologic factors, bilateral PSA and GPi instead of thalamus were chosen as DBS targets for the case.

Results & conclusions

At first, stimulation of PSA alone was applied, which was effective only on rhythmic tremulous movement but not on dystonic component. Then additional GPi stimulation succeeded in ameliorating the residual dystonia satisfactorily. Recent blind trial reported in 2014 underlined that thalamic/subthalamic area DBS was promising for DHT (Pauls KA et al). Besides those findings, the present case suggested that simultaneous PSA/GPi DBS is also powerful therapeutic option for DHT.

Takeshi NAKAJIMA (Japan, JAPAN), Takehiko KONNO, Makoto SATO, Keisuke OTANI, Masayuki TETSUKA, Kensuke KAWAI
08:00 - 18:00 #10776 - P151 Co-axial stimulation of the ventral tier of the thalamus and subthlamus for tremors.
Co-axial stimulation of the ventral tier of the thalamus and subthlamus for tremors.

Objectives: Deep brain stimulation (DBS) is effective treatment of choice for various types of tremors. The targets are the ventral tier of the thalamus (Vo and Vim) and the subthalamus. For some tremors, these targets are simultaneously stimulated to have optimum outcomes. We have examined the effects of co-axial stimulation of the ventral tier of the thalamus and the subthalamus. 

Patients and methods: We have retrospectively analysed the preoperative imaging and postoperative clinical results of 10 patients with tremors who underwent deep brain stimulation. The age range of the patients were from 17 to 72 years old. Nine men and a woman were involved. The causes of the tremors were essential tremors in 6 patients, Parkinson’s disease in 2 patients, atypical Parkinsonism in a patients and Holmes’ tremor in a patient. Five patients had Vim-DBS and other 5 patients had coaxial Vo or Vim and SA-DBS. Severity of tremors in each patient was assessed using tremor rating scale. Preoperative imaging included diffusion weighted, T1, and T2 weighted imaging. Stereotactic coordinates for Vim were 13-15 mm lateral to the midline and 5-6 mm anterior to the posterior commissure  on the plane of anterior and posterior commissures (AC-PC). Vo was located 2-3 mm anterior to the Vim. The SA was located at 11-13mm lateral to the midline, 5-8 mm posterior to the mid-commissural point, and 3.5-5mm below the AC-PC plane. 

Results: The postoperative TRS was improved by 55-95% (mean 76%) after DBS. In patients Vim and SA DBS, two patients used Vim DBS only. Three patients utilised coaxial Vo/Vim and SA DBS. These patients were with Holmes tremor, atypical Parkinsonism, and essential tremors. The patients did not experience severe complications. 

Conclusion: In patients with tremors, some patients have excellent outcome with coaxial stimulation of Vo/Vim and SA. 

Hiroki TODA (Osaka, JAPAN)
08:00 - 18:00 #10803 - P152 GPi DBS treatment in Postural instability in Parkinson's disease with 8 contact lead experience.
GPi DBS treatment in Postural instability in Parkinson's disease with 8 contact lead experience.

Deep brain stimulation (DBS) has been a widely accepted treatment modality for advanced Parkinson's disease (PD) . Postural instability in PD have been a great challenge in the clinical practice.In the PD patients with postural instability, the selection of DBS targets is still challenging. GPi target for deep brain stimulation (DBS) in the treatment of postural instability is more  preferred. In this article we want to share our experience with GPi target in PD . We present  5 patients who underwent to Gpi DBS for PD and we compare preoperative condition with  6th month follow up. we used a variety of different scales to measure the severity of the patient's symptoms, including the Unified Parkinson's Disease Rating Scale (UPDRS), the freezing of gait questionnaire (FOG-Q) and the gait and falls questionnaire (GF-Q).GPi DBS  have positive effects to postural instability as well as freezing of gait and falling after PD.

Gulsah OZTURK (ISTANBUL, TURKEY), Atilla YILMAZ
08:00 - 18:00 #10815 - P154 Unilateral raprl DBS in the treatment of parkinson´s disease symptoms. Results until 48 months follow-up.
Unilateral raprl DBS in the treatment of parkinson´s disease symptoms. Results until 48 months follow-up.

OBJETIVE:  Prelemniscal radiations (Raprl) is an effective target to treat the symptoms of Parkinson´s disease (PD). The objective of this study is evaluate the effectiveness of unilateral Raprl DBS through UPDRS-III scale, with a long term follow-up until 48 months.

METHODS: PD patients with surgical criteria of Hoehn-Yahr stages II-III were unilateral implanted with a tetrapolar DBS electrodes in Raprl contralateral to the extremities with more prominent symptoms. Anatomical ubication was assisted by MRI/CT/atlas fusion, microelectrode recording, and included micro- and macro-stimulation. Motor symptoms was evaluated in an open label protocol through punctual items of the UPDRS-III score, and were applied pre-operatively and 6, 12, 24, and 48 months after the onset of stimulation in an OFF-medication/ON-stimulation condition. The scores were recorded focus to pre-operative condition and were obtained for each symptom in both sides and statistical significance determined through double-tail Wilcoxon test. Also the influence of demographic outcome variables was analyzed using Pearson test. Alpha was <0.05 and beta of 0.20.

RESULTS: Nineteen patients were implanted.  The most important symptoms that were decreased were tremor (p<0.001) and rigidity (p<0.001) from the beginning of the study and were sustained inclusive to the 48 months Bradykinesia was not reported with an important level of change. A greater than 80% decrease in UPDRS score for contralateral symptoms (classified as excellent results) occurred in 14 patients (73.7%), while in the other 5 it decreased from 33 to 79% (considered suboptimal results). These changes remained statistically significant up to 48 months (p < 0.01), while ipsilateral symptoms progressively increased. Suboptimal results were associated with selective improvement of only one symptom

CONCLUSIONS: Unilateral Raprl DBS Stimulation were effecive to treat contralateral symptoms including tremor and rigidity. This effect was sustained in a long term follow-up inclusive of 48 months

José D. CARRILLO-RUÍZ (Ciudad de México, MEXICO), Francisco VELASCO-CAMPOS, V SALCIDO , G. CASTRO, Julián E. SOTO- ABRAHAM, Mauricio A. ESQUEDA-LIQUIDANO

Monday 26 June

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08:00 - 18:00 #10265 - P155 Ventriculoperitoneal shunt for normal pressure hydrocephalus accompanied by degenerative brain disease: Correlation between metabolic neuroimages, pathological findings and surgical results.
Ventriculoperitoneal shunt for normal pressure hydrocephalus accompanied by degenerative brain disease: Correlation between metabolic neuroimages, pathological findings and surgical results.

Objective: Normal pressure hydrocephalus (NPH), which was occurred in elderly patients, has characteristic symptoms of cognitive disorder, gait disturbance disorder, and urinary incontinence. In these patients, ventricular peritoneal shunt surgery is known to be the most effective treatment. However, for some patients, the symptom is rarely improved after surgery. In addition, symptoms of NPH can also be caused by other degenerative diseases of the brain. Therefore, we performed a histological analysis of the possibility that other degenerative brain diseases that may cause typical symptoms of NPH may be combined with hydrocephalus.

Methods: In 2016, we analyzed 12 patients who underwent shunt surgery for hydrocephalus and who underwent brain biopsy at the same time. Patients underwent preoperative FDG, 18FP-CIT and Amyloid PET examinations. The histologic analysis was performed with various staining methods to identify other degenerative diseases overlapping with hydrocephalus.

Results: Of the 12 patients, four patients had brain biopsies with significant results suggesting other degenerative brain diseases. Among them, two patients had senile plaques due to beta amyloid staining and they were likely to have Alzheimer disease. One patient had amyloid angiopathy and the other one had p62 neuronal accumulation, suggesting the possibility of frontotemporal dementia. All patients had gait disturbances, and 1 month after surgery, gait symptoms improved in 7 patients. The improvement of other symptoms was not clear. Patients with Alzheimer disease on biopsy had symptomatic improvement at 1 month but deteriorated at 3 months after surgery. Other Patients with other neurodegenerative diseases had no improvement after surgery. There was no significant association was observed between PET scan and clinical symptoms and biopsy results. The patients with Alzheimer had showed increased uptake in amyloid PET.

Conclusion: Symptoms of NPH can have a significant effect on surgical treatment. However, overlapping other degenerative brain diseases that may cause similar symptoms can lead to confusion in clinical evaluation. The current study also revealed the possibility of other degenerative brain diseases in patients whose clinical symptoms did not improve significantly after surgery. Therefore, in patients with NPH, if there is no specific improvement in the experimental CSF drainage or other degenerative disease was suspected, it is recommended that a test or brain biopsy be performed to identify other degenerative brain diseases. We thought that it would be able to give accurate diagnosis and effective treatment to the patients.

Chang Kyu PARK (Seoul, KOREA), Na Young JUNG , Si Woo LEE, Won Seok CHANG, Byoung Seok YE, Hyun Ho JUNG, Se Hoon KIM, Jin Woo CHANG
08:00 - 18:00 #10168 - P156 Accuracy of intraoperative CT-based frameless stereotaxy compared with frame-based stereotaxy.
Accuracy of intraoperative CT-based frameless stereotaxy compared with frame-based stereotaxy.

Objective:
Frameless stereotaxy is known to have the disadvantage of a possible mismatch of between 2 and 6 mm, depending on co-registration technique and patient positioning. Combination of frameless stereotaxy with intraoperative CT-based automatic co-registration might increase the overall accuracy.

Methods:
Since introduction of a Brainlab Airo CT Scanner, a consecutive series of 5 patients received frameless stereotactic biopsies of deep seated brain lesions. After insertion of the biopsy needle, a second CT scan was taken with the needle still in place. The intraoperative scan was fused with the planned trajectory and deviation from the trajectory was measured.

Results:
In all 5 cases, deviation from the planned trajectory at the target was below 1 mm. No adverse events occured during surgery.

Discussion:
In a small series of 5 patients, only careful interpretation is possible. The results indicate, that combination of frameless stereotaxy with intraoperative CT leads to a high accuracy comparable with frame-based stereotaxy. A prospective study on this topic is planned.

Lennart STIEGLITZ (Zurich, SWITZERLAND)
08:00 - 18:00 #10246 - P157 Effects of two different registration methods on the accuracy of the robotized stereotactic assistant system.
Effects of two different registration methods on the accuracy of the robotized stereotactic assistant system.

Objective: To investigate the effects of two different registration methods on the accuracy of the robotized stereotactic assistant (ROSA) system via experiments simulated by the skull model. Methods: Using the skull model, bony landmark group (bonylandmark registration) and laser group (laser registration) were applied to simulate implantation of electrode by 20 times. The deviation range of the distance was observed between microelectrode recording needle tips and designed targets. Results: In bony lanfmark group, the average distance error of 20-time experiments was 0.41 mm (maximum 0.51 mm, minimum 0.30 mm), and the average time was 3 minutes 15 seconds, with the whole microelectrode recording needle tips arrived to the scope of 1 mm diameter hollow screw inner ring. But in laser group, the average time was 17 minutes 22 seconds, with 7 records of needle tips pointed to 1 mm diameter hollow screw inner ring, while the other 13 times only meeting the standard of 1.6 mm diameter hollow screw inner ring. Conclusions: ROSA system has a high precision, and bony landmark registration method is more accurate than the laser registration method. 

Yingqun TAO (Shenyang, CHINA), Feng XU, Hai JIN
08:00 - 18:00 #10247 - P158 The application of computed tomographic angiography in the deep brain stimulation assisted by robotized stereotactic assistant system.
The application of computed tomographic angiography in the deep brain stimulation assisted by robotized stereotactic assistant system.

Objective: To evaluate the application value of computed tomographic angiography (CTA) in the deep brain stimulation (DBS) assisted by robotized stereotactic assistant (ROSA) system. Methods: A total of 18 Parkinson's disease patients and 2 essential tremor patients undergoing DBS assisted by ROSA system. The ROSA system was used to observe the overlap of the puncture path and the vessel on the images of CTA. Results: A total of 39 planned implant electrodes were successfully implanted in all 20 patients. Thirty-seven electrodes were implanted into the subthalamic nucleus and 2 into the ventral intermediate nucleus. A total of surgical planning of 17 side overlapped with vascular images of CTA, and the surgical path was readjusted. Conclusions: CTA helps to improve the safety and accuracy when applied to DBS assisted by ROSA system. 

Yingqun TAO (Shenyang, CHINA), Hai JIN, Feng XU
08:00 - 18:00 #10805 - P159 Project RONNA – robotic neuronavigation.
Project RONNA – robotic neuronavigation.

Introduction: Project RONNA – robotic neuronavigation, innovative and commercially competitive robotic system for applications in neurosurgery, was initiated by a group of researchers within the Department of Robotics and Production System Automation at the Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb.

Methods and results: The RONNA system was tested through rigorous preclinical trials which resulted in numerous improvements and in the development of the new RONNA G3 system. RONNA G3 is used for stereotactic neuronavigation procedures and in its basic version has three main components: a) a robotic arm on a universal mobile platform, b) a planning and navigation system and c) a global optical tracking system (OTS). One specific characteristic of the RONNA G3 system in respect to most current state of the art robotic neurosurgical systems is an additional mobile platform equipped with a compliant and sensitive robotic arm. The extended version of the RONNA G3 which uses the compliant robotic arm is intended for automated robotic bone drilling applications and manipulation of surgical instruments. The second arm was not used in this case study. The global optical tracking system uses an infrared stereo camera and two reference frames, one attached to the patient in form of a "x" shaped localizer and the other to the robotic arm. The OTS is only used for coarse positioning of the robot with respect to the patient in the global localization phase of the procedure. We have further developed a specific infrared stereovision system which uses macro lenses in order to obviate any errors that may arise from the low resolution and wide field of view of the global OTS.  

Conclusion: Benefits of using the RONNA system in neurosurgery are: better and faster performance of surgical procedures, less invasive procedures, faster recovery of the patient (shorter hospital stay, reduced costs), better utilization of operational resources of the hospital, mastering new skills within a clinical team and introduction of new technologies in medical practice.

Domagoj DLAKA, Fadi ALMAHARIQ (Zagreb, CROATIA)

Monday 26 June

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08:00 - 18:00 #10298 - P160 Electrode tip localization in rats using CT imaging and BlockFace is accurate, fast and cheap as compared to histology.
Electrode tip localization in rats using CT imaging and BlockFace is accurate, fast and cheap as compared to histology.

Introduction

While brain implants, such as electrodes, used in laboratory animals are becoming more and more sophisticated, implant tip localization methods have not evolved over the last century. Even nowadays, histology and copying to stereotactic atlases remains not only the gold standard but also the most commonly used method for implant tip localization. We aim to compare various modalities for electrode tip localization in terms of accuracy, time and costs.

 

Material and Methods

In 24 male rats (289g Wistar, n=12; 424g Sprague-Dawley, n=12), pre-operative computed tomography (CT) imaging was followed by stereotactic implantation of 2 electrodes (1 per hemisphere). After in vivo postoperative CT imaging, all rats were euthanised. Now, ex vivo postoperative CT with skull and electrodes in place was followed by a 14-day iodine immersion and a new CT with and without skull and electrodes in place in half of the specimens. Finally, BlockFace (a 3D reconstruction of photographic images acquired with a digital camera facing the remainder of the paraffin block on the microtome) and histology were performed in all specimens. Electrode tips were picked by 6 researchers with different levels of experience.

For co-registration of the images to the Johnson-Paxinos MR-atlas, we first constructed a CT atlas based on the preoperative images of the Wistar rats. The postoperative CTs with bony anatomy were co-registered to this CT-atlas and via this atlas to the MR-atlas, while the modalities without bony anatomy were co-registered directly to the MR-atlas.

 

Results

All CT modalities and BlockFace allowed for electrode tip localization, both in rats identical to and different from those used to create atlases, with low inter- and intra-observer variability. There was a high correlation with histology, although the correlation between the different CT modalities was even higher.

Average total time needed for localization of 2 electrodes in 1 rat brain ranged from 27 minutes (in vivo CT) to 94 minutes (histology).

Average costs, as charged in our institution, for localization of 2 electrodes in 1 rat brain ranged from 5.50 euro (CT ex vivo) to 21.24 euro (histology).

 

Conclusion

We conclude that CT imaging techniques and BlockFace are valuable alternatives to histology for electrode tip localization, and are both faster and cheaper as compared to histology.

Philippe DE VLOO (Leuven, BELGIUM), Janaki Raman RANGARAJAN, Kelly LUYCK, Marjolijn DEPREZ, Kris VAN KUYCK, Greetje VANDE VELDE, Johannes VAN LOON, Frederik MAES, Bart NUTTIN
08:00 - 18:00 #10335 - P161 A review of clinical outcomes with diffusion tensor imaging during deep brain stimulation.
A review of clinical outcomes with diffusion tensor imaging during deep brain stimulation.

Introduction: Deep brain stimulation (DBS) is a restorative neurosurgical treatment for an expanding list of intractable neurological and psychiatric conditions. The purpose of this study was to review the use of diffusion tensor imaging (DTI) tractography in DBS to improve clinical outcomes.

Methods: A search of PubMed was performed to identify all articles using the search terms “(diffusion tractography OR diffusion tensor imaging OR DTI) AND (deep brain stimulation OR DBS)”. Studies were included if they described clinical outcomes, and DTI was used. The studies were categorized into whether DTI was used in surgical planning to guide electrode implantation, or used to evaluate the location of the implanted electrode retrospectively. Proximity of the final electrode position to the tract of interest and the correlation for clinical outcomes was analyzed.

Results: A total of 32 studies were identified reporting the use of DTI in DBS for movement disorders (15 studies), psychiatric disorders (10 studies), and pain disorders (7 studies). Out of the 32 studies, 9 studies with a median sample size of two patients (range 1-7) used DTI during surgical planning. The remaining studies used DTI for retrospective evaluation of electrode implantation location with a median sample size of six patients (range 1-22 patients). Both deterministic and probabilistic tractography were used. Overall, these studies show that the use of DTI for surgical planning is feasible, provide additional information over conventional targeting methods, and can be used to improve surgical outcome.

Discussion: Advances in surgical planning using DTI in DBS can lead to improved surgical outcome. The use of DTI in DBS planning appears under-utilized and further studies are warranted given that surgical outcome may by optimized using this non-invasive technique.

Angela An Qi SEE, Nicolas Kon Kam KING (Singapore, SINGAPORE)
08:00 - 18:00 #10524 - P162 Ex vivo iodine immersion of rat brains yields higher internal brain CT contrast but affects histological quality.
Ex vivo iodine immersion of rat brains yields higher internal brain CT contrast but affects histological quality.

Introduction

Histology is historically considered as the gold standard for localising brain implants such as electrodes in rats. However, imaging techniques such as Computed Tomograpy (CT) and Magnetic Resonance Imaging (MRI) for small laboratory animals are available. MRI is prone to artefacts from metal implants, is relatively time-consuming , costly and has a lower availability as compared to CT. On the other hand, the main disadvantage of CT is in its very low internal brain contrast. We use an iodine immersion protocol to enhance the internal brain contrast of ex vivo CT in rats. In this study, we aim to optimise the immersion time and iodine concentration, and to assess the quality of histology after iodine immersion with and without iodine wash-out.

 

Materials and methods

Sprague-Dawley rat brains (n=9) were soaked into iodine (n=8) or used as a reference for histology (n=1). The brain CT density and internal contrast, measured as contrast-to-noise ratio (CNR) and signal-to-noise (SNR) ratio for grey matter, white matter and cerebrospinal fluid was assessed over 6 months, using 3 different iodine concentrations (100, 200 and 300 mg iodium/ml) with and without skull (n=6). Next, in the specimens immersed in 200 mg iodium/ml (n=4), the quality of Cresyl Violet stained histology was compared qualitatively and quantitatively to reference histology (n=1), either with (n=2) and without (n=2) a 5-day iodine wash-out protocol.

 

Results

Iodine immersion significantly improves internal brain contrast from 1 day onwards. Peak SNR and CNR were obtained with 100 and 200mg iodium/ml at 5 and 7 weeks, respectively, after which SNR and CNR remained constant.

Compared to a non-iodine immersed rat brain, the histological quality, SNR and CNR were lower in iodine immersed rat brains, although this was largely reduced by a 5-day wash-out protocol.

 

Conclusion

Iodine immersion of rat brains yielded higher brain CT density and internal contrast after 100 and 200mg/ml iodium immersion for 2 months, and histology remains possible after a short wash-out period.

Philippe DE VLOO (Leuven, BELGIUM), Janaki Raman RANGARAJAN, Marjolijn DEPREZ, Kelly LUYCK, Bart NUTTIN
08:00 - 18:00 #10528 - P163 Exploring Local Diffusion MRI Properties for Vim Localization: Evaluation in Clinical Cases.
Exploring Local Diffusion MRI Properties for Vim Localization: Evaluation in Clinical Cases.

The lack of possibility to directly visualize the Ventro-intermediate thalamic nucleus (Vim) on current routine MRI lead to application of indirect targeting methods in stereotactic neurosurgical procedures, such as Gamma Knife Surgery (GKS) and Deep Brain Stimulation (DBS), for treatment of drug-resistant tremor.

Recently, our group proposed an automated robust and reproducible method across healthy subjects and tremor patients for parceling the thalamus in seven main groups of nuclei while exploring the local diffusion information from the spherical harmonics representation of the orientation distribution functions (ODFs) in k-means clustering framework. One among the resulting parcel is the Ventral-Lateral-Ventral group (VLV) enclosing all motor-related nuclei including the Vim. We aim at further automatic subdivision the VLV cluster. To this end, within the VLV, we first build a k-nn graph with edges corresponding to the respective ODFs distances and then, we perform a partition in 3 sub-clusters using the Normalized Cut algorithm.

The outcome of the proposed subdivision was compared to the radiological response in the follow-up images of 17 patients treated for tremor with GKS unilaterally. The MRI protocol included pre-operative diffusion-weighted images with 64 (or 72) gradient direction, b=1000s/mm2 and voxel size of 2.2x2.2x2.2mm3, pre-operative and post-operative MPRAGEs with isotropic resolution of ~1mm3, all of them acquired at field of 3T. In general, the sub-partition followed a spatial-distribution pattern and for 12 out of 17 cases we observed that one specific sub-cluster encloses entirely or the major part of the contrast enhancement corresponding to the GKS target that appeared on the follow-up images.

The evaluation of the sub-partition outcome was further extended in one additional tremor patient treated with DBS, bilaterally. Similar pre-operative MRI data as for the GKS-treated patients was acquired. We observed that in each hemisphere both initial targeting point and the final position of the electrode are inside the anticipated sub-cluster.

This study shows that the diffusion-MRI-based sub-clustering of the VLV thalamic nuclei could potentially allow, in an automated manner, to narrow the area of Vim’s localization. Our preliminary results will be further investigated in a larger cohort of patients (treated by either GKS or DBS) and on diffusion images with higher spatial resolution.

Elena NAJDENOVSKA, Constantin TULEASCA (Lausanne, SWITZERLAND), Jocelyne BLOCH, Philippe MAEDER, Nadine GIRARD, Tatiana WITJAS, Jean RÉGIS, Jean-Philippe THIRAN, Meritxell BACH CUADRA, Marc LEVIVIER
08:00 - 18:00 #10539 - P164 Identification of Stria Medullaris Fibers in the Massa Intermedia Using Diffusion Tensor Imaging.
Identification of Stria Medullaris Fibers in the Massa Intermedia Using Diffusion Tensor Imaging.

Background

The massa intermedia(MI) or interthalamic adhesion is an inconsistent band spanning between bilateral medial thalami that is absent in up to 20-30% of individuals. Little is known of its significance, especially in regards to functional pathways. Probabilistic diffusion tensor imaging(DTI) has recently been used to seed the lateral habenula(LHb) and define its afferent white matter pathway, the stria medullaris thalami(SM). We sought to determine if the MI serves as a conduit for crossing of limbic fibers such as the SM.

Methods

Probabilistic DTI was performed on ten subjects who had presence of a MI as visualized on magnetic resonance imaging(MRI). Tractography was also performed on two subjects without MI. Manual identification of the LHb on axial T1 weighted MRI was used for the initial seed region for tractography.

Results

In all subjects, the SM was reliably visualized. In 7 out of the 10 subjects with MI, there was evidence of SM fibers that crossed to the ipsilateral hemisphere. Three subjects with small diameter MI did not have tractographic evidence of crossing SM fibers. Of the 7 subjects with crossing SM fibers within the MI, 5 showed predilection toward the right orbitofrontal cortex from both the left and right seed regions.

Conclusions 

Probabilistic DTI provides evidence of SM fibers within the MI. Given its anatomic location as a bridging pathway between thalami, further studies are necessary to assess its role within the limbic functional network.

Ryan KOCHANSKI, Robert DAWE, Kocak MEHMET, Sepehr SANI (Chicago, USA)
08:00 - 18:00 #10554 - P165 Postmortem Diffusion Tensor Magnetic Resonance Tractography for preclinical studies in psychiatric Deep Brain Stimulation.
Postmortem Diffusion Tensor Magnetic Resonance Tractography for preclinical studies in psychiatric Deep Brain Stimulation.

Introduction:

Different targets have been proposed for Deep Brain Stimulation (DBS) in refractory depression. Stimulation of the superolateral branch of the medial forebrain bundle (slMFB) has shown promising clinical results. (Schlaepfer 2014)

Diffusion tractography is an important tool to assist neurosurgical procedures. Tractography in postmortem brains has been recently developed, with the steady state free precession (SSFP) sequence, but no description of more complex and interconnected tracts like MFB has been made.

Our aim is to show the MFB, its course and connections for later validation, comparing imaging with  histological sections of the same brains, and also to evaluate reproducibility of postmortem DTI.

Methods:

We acquired SSFP diffusion from 3 postmortem brains, with no neurological pathologies. A fitting box for the brain was used with Perfluoropolyether (Galden, PFPE, Solvay Inc). The data was analyzed using a MATLAB-based-in house toolbox for fiber tracking (Uniklinik, Freiburg), and a single seed was set in the Ventral tegmental area (VTA).

Results:

The MFB was reconstructed and its course was shown. The technique was reproducible in the 3 brains. Two branches were shown anterior to VTA; The inferomedial branch follows the lateral wall of the 3rd ventricle into the lateral hypothalamus. The superolateral branch travels through the Thalamus into the anterior limb of the internal capsule and ends in the frontal lobe, with less marked and reproducible tracts in the prefrontal cortex. 

Conclusion: In this postmortem  study, the human MFB was reproducible in all brains, showing similar depiction, course and relation to other brain regions. More variability was shown in the frontal end of the tracts. SSFP is a reproducible sequence for postmortem DTI and it could be helpful for validating clinical tractography.

Maria Jesus ALVAREZ HOLZAPFEL (Freiburg im Breisgau, GERMANY), Máté DÖBRÖSSY, Marco REISERT, Hansjörg MAST, Karla MILLER, Volker Arnd COENEN
08:00 - 18:00 #10734 - P166 DTI analysis of major white matter tracts involved in temporal lobe epilepsy.
DTI analysis of major white matter tracts involved in temporal lobe epilepsy.

Introduction:Patient selection for epilepsy surgery remains a challenge, and using invasive electroencephalographic techniques is often necessary to help identify the epileptogenic foci in patients with temporal lobe epilepsy (TLE). The diffusion tensor image (DTI) allows us to detect small changes in the diffusion parameters of the different white matter tracts involved in TLE, so we hypothesize that preoperative DTI analysis might help lateralize seizure origin in patients with TLE. The goal of our study is to evaluate the utility of preoperative DTI in the lateralization diagnosis of TLE.

Material and methods:Twelve patients with TLE, who had undergone temporal lobectomy and amigdalectomy according to modified Spencer technique, were enrolled. They were selected for surgery following our Epilepsy Surgery Unit Protocol. A 1.5T MRI was used to obtain 25 diffusion gradient direction images per subject. All image processing and tractography analyses were completed using 3D Slicer software. In six patients, MRI showed the existence of signs suggestive of temporal mesial sclerosis, whereas the remaining MRIs were informed as normal. Twelve age and gender matched controls were also included in the study.Five pairs of white matter fiber tracts were traced, and fiber tract fractional anisotropy (FA) and mean diffusivity (MD) were calculated.

Results:Whole tract diffusion characteristics of patients with TLE were significantly different between patients and controls (p <0.05).Patients with TLE demonstrated a decreased FA in fascicles arcuate, inferior longitudinal, fornix, uncinate and cingulate in the hemisphere ipsilateral to the epileptogenic focus relative to the same side in controls.Whereas in right TLE these differences were more pronounced in ipsilateral side, in left TLE, there were changes both in the ipsilateral and the contralateral side. In the subgroup of patients with normal MRI, we found a statistically significant decrease in FA (p <0.05) in fascicles: cingulate, fornix, inferior longitudinal and uncinated.There were no differences in MD.

Conclusions:Our results suggest that there are alterations in diffusion in different white matter tracts in patients diagnosed with TLE. These alterations are more pronounced in the hemisphere ipsilateral to the epileptogenic focus.The study of DTI could be a useful presurgical tool to help establish the laterality of TLE. Further studies with a larger number of patients would be necessary to confirm these results.

M. Ángeles GARCÍA-PALLERO (Madrid, SPAIN), Mojgan HODAIE, Jidan ZHONG, Rafael MANZANARES SOLER, Marta NAVAS GARCÍA, Jesús PASTOR, Lorena VEGA ZELAYA, Juan DELGADO FERNÁNDEZ, Rafael GARCÍA DE SOLA, Cristina TORRES DÍAZ
08:00 - 18:00 #10739 - P167 Comparison of diffusion imaging tractography in live and non-fixed post-mortem porcine brains.
Comparison of diffusion imaging tractography in live and non-fixed post-mortem porcine brains.

Objectives

Tractography based targeting is gaining an increasing role, particularly in non-invasive lesioning methods of treatment. This requires the use of models such as post-mortem brains to complement in vivo diffusion studies. Most post-mortem brain studies use specimens that have been formalin-fixed or excised from their original biological environment, processes both of which are known to affect diffusion parameters. This study presents a method of diffusion imaging and tractography and a comparison of white matter diffusion metrics in a number of intracranial regions of interest. Diffusion data is compared for both in vivo and non-fixed post-mortem piglet brains.

Methods

Twelve live and nine post-mortem (age: 22±3 days, weight: 6.7±1.1 kg) piglets were studied. Post-mortem scan interval was <24 hours. T1 anatomical and diffusion weighted imaging (DWI) scans were acquired on a 3T MRI. DWI scanning parameters included 128 directions, 1.6 mm isotropic voxels, and b=800s/mm2. Eddy current, motion, and susceptibility corrections were performed. Using MRTrix3, deterministic tractography was performed to reconstruct tracts of the corpus callosum, fornix, optic nerves and tracts, and trigeminal nerves. Tracts guided region of interest (ROI) placement to measure diffusion metrics of fractional anisotropy (FA), mean (MD), axial (AD), and radial (RD) diffusivity. Comparisons were performed across ROIs in live and non-fixed post-mortem brains.

Results

Visual reconstruction of all selected white matter bundles was successfully performed in both in vivo and post-mortem piglet brains. Across all ROIs, significant decreases of 68-88% were observed in the MD, AD, and RD of post-mortem subjects (p<0.0005). FA, however, was found to be unaltered between groups with no statistically significant differences observed for any white matter structure (p>0.068).

Conclusion

Consistent reconstruction of white matter tracts both in vivo and post-mortem was achieved. We observed unaltered anisotropy in both groups despite a five-fold reduction in diffusion post-mortem. This suggests that the barriers which restrict the motion of water persist following post-mortem status while the absolute rate of motion is inhibited. This decreased diffusivity is likely due to lower tissue temperature and diminished axonal transport rate post-mortem. Our study validates the use of post-mortem animal models for methodological development without the need for tissue fixation or scanning modification.

 

Matthew WALKER, Jidan ZHONG, Adam C WASPE, Thomas LOOI, Karolina PIORKOWSKA, James DRAKE, Mojgan HODAIE (Toronto, Canada, CANADA)
08:00 - 18:00 #10764 - P168 SPECT neuroimaging and neuropsychological functions in different stages of Parkinson’s disease.
SPECT neuroimaging and neuropsychological functions in different stages of Parkinson’s disease.

Study's objectives: The present study investigated differences and associations between cortical perfusion, nigrostriatal dopamine pathway and neuropsychological functions in different stages of Parkinson’s disease (PD). Methods: We recruited 53 non-demented PD patients divided into four groups according to the Hoehn and Yahr (HY) staging system and 20 healthy controls who were used in the comparison of the neuropsychological findings. Each patient underwent two separate brain single photon emission computed tomography (SPECT) studies (perfusion and dopamine transporter binding) as well as neuropsychological evaluation. Perfusion images of each patient were quantified and compared with a normative database provided by the NeuroGam software manufacturers. Mean values obtained from the cortical areas and neuropsychological measures in the different groups were also compared by analysis of covariance (ANCOVA) controlling for disease duration and educational level. Results: We found cognitive deficits especially in the late PD stages (HY 3, 4 and 5) compared to the early stages (HY 1 and 2) and associations between cognitive decrements and cortical perfusion deterioration mainly in the frontal and posterior cortical areas. Compared with controls, PD patients showed impairments of cognition and cerebral perfusion that increased with clinical severity. Furthermore, we found a significant correlation between the performance on the phonemic fluency task and regional cerebral blood flow (rCBF) in the left frontal lobe. Dopamine transporter binding in the left caudate nucleus significantly correlated with blood flow in the left dorsolateral prefrontal cortex (DLPFC), but not with measures of executive functions. Conclusion:There are significant cognitive and perfusion deficits associated with PD progression, implying a multifactorial neurodegeneration process apart from dopamine depletion in the substantia nigra pars compacta (SNc).

Constantine CONSTANTOYANNIS, Miltiadis GEORGIOPOULOS (Patras, GREECE), Anna PASCHALI, Pavlos VASSILAKOS
08:00 - 18:00 #10824 - P169 Establishing a DTI model of trigeminal neuralgia in piglet brains.
Establishing a DTI model of trigeminal neuralgia in piglet brains.

There is increasing interest in the role of diffusion tensor imaging (DTI) in the neuroimaging of pain and trigeminal neuralgia (TN). DTI permits the study of neural microstructure, its alteration in TN and the study of treatment effects as more novel methods are being explored. MR guided focused ultrasound (MRgFUS) has become a technical innovation in non-invasive lesioning, but has not been used for the treatment of TN. Here, we aim to establish a DTI-based piglet model to compare its diffusivity metrics and nerve characteristics with healthy human trigeminal nerves. A piglet brain model was used due to its size practicality, compatibility with the MRgFUS machine and overall ease of handling of animals.

 Methods:

The study group included MR imaging from 8M healthy humans (range 23-27Y), and 8M Yorkshire piglets 22±6 days, (6.1±1.2kg). 3TMR imaging included diffusion-weighted and T1 anatomical scans. Humans were scanned on an eight-channel 3TGE-Signa HDx-MRI; pigs were imaged in a 32-channel head coil Philips 3T Achieva. Preprocessing was done in FSL for both pigs and humans, FSL 4.1.8 FMRIB Diffusion Toolbox and FSL Topup respectively. Final processing included creation of colour by orientation maps, superimposition of trigeminal tracts on anatomical images, calculation of axial, radial, mean diffusivities and fractional anisotropy (FA). Trigeminal nerves root entry zone (REZ) and cisternal segment diffusivities in pigs and humans were compared using independent t tests.

Results:

Piglet trigeminal nerves are large, robust and easily trackable. Axial, radial and mean diffusivities were significantly different between the cisternal segments of piglets and humans, however no statistical difference was observed between the two groups REZ. Statistical significance was much more pronounced for axial diffusivity (P<0.001), followed by mean (p<0.01) and radial (p<0.05). There was no significant difference between FA values in either group.

Discussion:

Trigeminal nerve REZ diffusivities were similar between the two groups. The cisternal segment showed pronounced differences across all diffusivities, likely due to the piglets’ developmental stage, yet when calculated proportionally (FA), no statistically significant difference was seen. Similarity between REZ values and cisternal segment FA suggests that the piglet trigeminal nerve is a viable option for a DTI model of TN and the study of role of MRgFUS as a novel non-invasive form of its treatment. 

Kaitlin MONTANERA, Matthew WALKER, Jidan ZHANG, Hung PETER SH, Adam WASPE, Thomas LOOI, James DRAKE, Mojgan HODAIE (Toronto, Canada, CANADA)

Monday 26 June

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08:00 - 18:00 #10097 - P170 Burst motor cortex stimulation in neuropathic trigeminal pain - first experience.
Burst motor cortex stimulation in neuropathic trigeminal pain - first experience.

Objective

Motor cortex stimulation offers a therapeutic option in patients suffering from chronic neuropathic pain unresponsive to conventional means. Although best results are commonly observed in patients suffering from trigeminal neuropathy, sufficient pain reduction cannot be achieved in all patients. Some patients report stimulation induced side effects. Burst stimulation might be an add on option to increase responder rate, therapeutic efficacy and reduce side effects.

 

 

Methods

A 39y female patient suffered from severe neuropathic trigeminal pain following repeated neurovascular decompression procedures. Tonic motor cortex stimulation lead to some pain reduction (reduction VAS 10 to 3) in the first place. Over the time of 6 months treatment efficacy was partially lost and stimulation induced side effects (unpleasant stimulation sensation) occurred. Reprogramming did not solve these. We therefore decided to switch to burst stimulation.

 

 

Results

Reprogramming was done in an inpatient setting. Classic burst stimulation as used in spinal cord stimulation was applied (40-Hz burst, 5 spikes at 500 Hz per burst) with the lead configuration unchanged and stimulation intensity set at 60% of the motor threshold.  

Following a latency of around 20 hours the patients reported a significant decrease in pain intensity and side effects. Although stimulation induced side effects were still palpable for the patient these were not unpleasant. Pain reduction was again at 2-3/10 on the VAS. These results were stable at three month follow-up (9 months postoperative).

 

 

Conclusion

Burst stimulation seems to be an option in patients with loss of treatment effect and stimulation induced side effect in motor cortex stimulation for trigeminal pain. Regarding long term efficacy and safety and the question whether burst should be used as a first line stimulation setting further studies will be done. One has to keep in mind that burst stimulation has a high energy consumption, rechargeable device are mandatory. Further studies are warranted to proof this concept.

 

Philipp SLOTTY (Düsseldorf, GERMANY), Youssef ABUSHABA, Jarek MACIACZYK, Jan VESPER
08:00 - 18:00 #10497 - P171 Efficacy of burst spinal cord stimulation on central neuropathic pain caused by traumatic brain injury.
Efficacy of burst spinal cord stimulation on central neuropathic pain caused by traumatic brain injury.

Introduction

Central neuropathic pain, which is very challenging to treat, occurs directly from central nervous system injury and often begins over months to years. Central neuropathic pain is common in a sequela of stroke, multiple sclerosis, or spinal cord injury but it is rarely caused by trauma. Burst spinal cord stimulation may cause pain reduction more effectively without eliciting paresthesia such as tonic stimuli in patient with central neuropathic pain due to traumatic brain injury.

 

Case

This case report describes a 52-year-old man with intractable, cold, throbbing, and shooting pain mainly on the left lower limb. He has complained the neuropathic pain during rehabilitation after having undergone craniotomy for multiple cerebral injuries resulting from a motorcycle accident five years ago. Burst spinal cord stimulation was then proposed due to his refractory pain and the result remains good.

 

Conclusion

Through burst spinal cord stimulation, we have successfully treated a patient with medication-resistant central neuropathic pain associated with traumatic brain injury, and in view of this fact, burst spinal cord stimulation may be effective in certain neuropathic pain syndromes.

Deok Ryeong KIM (Seoul, KOREA)
08:00 - 18:00 #10584 - P172 The role of psychological factors in the effecasy of motor cortex stimulation.
The role of psychological factors in the effecasy of motor cortex stimulation.

Motor cortex stimulation is one of the reliable and effective methods of management of pain in patients with refractory pain syndrome. However, it is not effective in some patients. This creates the need to explore predictors of neurostimulation. In the literature quite a long discussion about the influence of psychological factors on the efficacy of neurostimulation.  

Material and methods: Twelve patients (10 men and 10 women) with diagnosed neuropathic pain syndrome with an average age of 52 years participated in our series.All patients were tested DN4, Pain Detect, LANSS. Pain intensity were diagnosed with PQLC – Pain and Quality of Life Card before and after operation and in catamnesis. We appreciated the average of pain intensity, maximal and minimal values of pain, frequency, the effect of pain on daily activities.

Results: Average pain history made up of 3.75 years. Average follow-up amounted to 26.75 months. In our study  motor cortex stimulation in test period was effective in 19 (95%) patients.Average intensity of pain before stimulation was 7±0.4 (VAS) and 3±0.4  three month after stimulation. The level of analgesia from 37.5% to 90%. In the long-term catamnesis (12-96 month) 73.7% of the patients had effective results.The indicators on the scale of emotional relationship to pain in all our patients was very high. Two patients have demonstrated a particularly high level of neuroticism (up to 6 points). They both were sick for several years, and already at the first examination exhibited poor fixation on their pain and painful experiences. However, in one clinical case the patient has Central tetraparesis after spinal cord injury with a good response to neurostimulation was observed a decrease in clinical effect. at the same time, in the psychological tests he was diagnosed with a high level of neuroticism.  Another patient with the absence of impaired motor functions and also a positive result of employment of TKMS, stimulation lost its effectiveness in the test period. It should be noted that this observation comes to the fore other, more significant prognostic factor is the severity of the psychogenic component of pain, which we were unable to identify prior to the test stimulation.At the same time, stimulation of the motor cortex is effective in patients with phantom pain.

Сonclusion: Psychological factors may be predictors of efficacy of the motor cortex stimulation, but it requires further research.

 

Emil ISAGULYAN (Moscow, RUSSIA), Alexey TOMSKY, Elisaveta MACKASCHOVA, Vladimir SHABALOV
08:00 - 18:00 #10771 - P173 Use of continuous focal stimulation of the dorsal anterior cingulate white matter to produce euphoria and anxiolysis without sedation in an epilepsy patient undergoing awake craniotomy.
Use of continuous focal stimulation of the dorsal anterior cingulate white matter to produce euphoria and anxiolysis without sedation in an epilepsy patient undergoing awake craniotomy.

Objective: We sought to elucidate the mechanism of a serendipitous finding of evoked laughter, positive affect, and anxiolysis in an epilepsy patient undergoing a stimulation research paradigm. Stimulation was later applied during an awake neurosurgery to assist with anxiolysis and facilitate language functional screening during resection.

Methods: A 25-year-old woman with epilepsy and anxiety underwent grid, strip and stereotactic depth electrode implantation for seizure focus localization. Stimulation testing occurred during the intracranial monitoring phase, where electrical stimulation was delivered via a current-controlled cerebral stimulator. Subjective effects of stimulation were recorded via video, and objective effects were quantified in terms of network-evoked potentials, autonomic responses, and shifts in affective bias, a cognitive proxy for emotional state.

Results: Focal stimulation to the dorsal anterior cingulum bundle was observed to produce involuntary laughter and smiling which emanated from the side of the face contralateral to stimulation. The patient reported happiness and relaxation that persisted over the course of twenty minutes of stimulation. Stimulation was accompanied by a significant positive shift in emotional bias (p=.023), as well as dose-dependent transient increases in skin conductance and heart rate. Examination of local field potentials recorded prior to sham and active stimulation conditions revealed significant reductions in 6-11hz power as well as network coherence following stimulation (ps<.0001). Neuroimaging revealed stimulation engagement of the cingulum bundle and fibers innervating the supplementary motor area and dorsal prefrontal cortex. The patient’s clinical team (neurosurgeon, neurologist, psychologist, and anesthesiologist) determined that cingulum stimulation was likely to provide substantive relief to the patient’s anxiety during surgery, and it was successfully applied in the operating room to produce anxiolysis without sedation which facilitated a language screening procedure during resection.

Conclusion: The current findings significantly expand the literature on the role of the anterior cingulate on positive emotional function. The novel application of this stimulation to produce euphoria and anxiolysis without sedation during the patient’s awake resection suggests it may be a novel target for anxiety management, especially in the context of awake neurosurgical procedures.

Kelly BIJANKI (Atlanta, USA), Joseph MANNS, Ki Sueng CHOI, Cory INMAN, Nigel PEDERSEN, Daniel DRANE, Helen MAYBERG, Jon WILLIE

Monday 26 June

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08:00 - 18:00 #10118 - P174 Long term results of simultaneous trial of deep brain and motor cortex stimulation in refractory neuropathic pain.
Long term results of simultaneous trial of deep brain and motor cortex stimulation in refractory neuropathic pain.

Objective: Although deep brain stimulation (DBS) and motor cortex stimulation (MCS) have been reported

to be effective in selected patients with refractory neuropathic pain, their application is still empirical and there

is no consensus on which one is better.

Methods: To enhance the success rate of test stimulation of invasive brain neuromodulation techniques and

identify more proper stimulation targets in an individual patient, we performed a simultaneous trial of thalamic

ventralis caudalis (Vc) DBS and MCS in 11 patients with chronic neuropathic pain and investigated the results

of the stimulation trial and long-term pain relief. (Table 1, Fig. 1)

Results: Of the 11 patients initially implanted with both DBS and MCS electrodes, nine (81.8%) had

successful trials. Seven of these nine patients (77.8%) responded to MCS and two (18.2%) responded to Vc

DBS. With long-term follow-up (56±27.5 months), the mean numerical rating scale (NRS) decreased

significantly (p<0.05). Percentage pain relief values in the chronic MCS (n=7) and chronic DBS (n=2) groups

were 34.1±18.2% and 37.5%, respectively, and there was no difference (p=0.807). Five out of the seven MCS

patients (71%) and both patients with DBS were assessed successful with long-term success defined as more

than 30% pain relief compared with baseline. (Table 2)

Conclusions: With the simultaneous trial of DBS and MCS, we could enhance the initial success rate of

invasive trials. Considering the initial success rate and the less invasive nature of epidural MCS over DBS, we

think MCS may be a more reasonable, initial means of trial in chronic intractable neuropathic pain. Further

investigation including other subcortical target-associated medial pain pathway may be warranted.

Stephen AHN (Seoul, KOREA), Byung-Chul SON, Jin-Gyu CHOI, Sang-Woo HA, Hak-Cheol KO
08:00 - 18:00 #10122 - P175 Long-term Results of Motor Cortex Stimulation in the Treatment of Chronic, Intractable Neuropathic Pain.
Long-term Results of Motor Cortex Stimulation in the Treatment of Chronic, Intractable Neuropathic Pain.

Background/Objectives: Although motor cortex stimulation (MCS) has been used for more than 20 years in the treatment of chronic neuropathic pain, there is still a debate about the efficacy of MCS.

Methods: To investigate the long-term results and the factors associated with long-term success of chronic MCS, 21 patients who underwent MCS trial were classified as having central poststroke pain (CPSP), central pain after spinal cord injury (SCI pain), and peripheral neuropathic pain (PNeP), and we investigated the clinical factors associated with long-term success and degree of pain relief.

Results: Of the 21 patients, 16 (76.2%) had a successful trial and underwent chronic MCS. In the long-term follow-up (53 ± 39 months), only the diagnosis (CPSP and PNeP) was associated with long-term success defined as more than 30% pain relief compared with baseline (p<0.05, chi-square test). The difference in pain relief was not significant in patients having SCI pain (p>0.05, one-way Anova). The other variables did not show any significant influence in the long-term success and degree of pain relief (p>0.05, one-way Anova).

Conclusions: MCS was more effective in the treatment of chronic neuropathic pain of CPSP and PNeP types than in the treatment of SCI pain in the long-term follow-up.

Youngjin KIM (Seoul, KOREA), Byung-Chul SON, Jin-Gyu CHOI, Sang-Woo HA, Hak-Cheol KO
08:00 - 18:00 #10146 - P176 Charge Injection Patterns of Spinal Cord Stimulation for Good Clinical Outcomes in Patients with Chronic Neuropathic Pain Syndromes.
Charge Injection Patterns of Spinal Cord Stimulation for Good Clinical Outcomes in Patients with Chronic Neuropathic Pain Syndromes.

Spinal cord stimulation (SCS) is developed for medically intractable chronic pain, and its efficacy and clinical role has been extensively studies for several decades. Even SCS is widely performed by many clinicians, however, an exact mechanism how SCS plays a role in the central nervous system is yet to be investigated. Moreover, several issues, including role of stimulation induced paresthesia, proper stimulation parameters, and long-term benefits, is still under controversies. In this study, we addressed these issues based on our recent clinical experiences performed in our specific clinical strategy.

Methods: Between March 2014 and December 2016, nine patients were underwent spinal cord stimulation for chronic neuropathic pain syndromes. Electrical charge injection patterns was classified by four variables, distance between the active cathode and the midline of dorsal column, relative position of anode to the cathode, and frequency and pulse width of electrical pulses. Meanwhile, amplitude of SCS was not considered as a determinant factors for the classification because it is always dependent to other variables described above. Clinical status and stimulation variables were evaluated at the baseline and the last follow-up.

Results: There were distinct three groups of clinical outcomes (good, moderate, and poor outcome groups). Patients with good outcome (n=6) were able to back to their normal life with intermittent experience of bearable pain. One patient was regarded moderated outcome because he experience tingling sense on both low extremities even though his arm pain was significantly reduced after cervical SCS. Patients with both good and moderate outcome were operated using paddle type SCS device. Patients with poor outcomes (n=2) presented little or no benefits from SCS even though they had experienced significant pain reduction in a short-term. Average ± SD distance of active cathode from the midline was 2.34 ± 1.21 mm for good outcome group. Average ± SD frequency and pulse width of good outcome group were 26.3 ± 17.9 Hz and 567 ± 216 µsec, respectively.

 Conclusion: This study support that clinical benefit SCS may play their beneficial role by stimulating several sensory relay neurons sitting beside dorsal column such as wide dynamic range neuron, postsynaptic dorsal column neuron and spinocervical tract neurons rather than by stimulating dorsal column.

Moonyoung CHUNG (Bucheon, Gyeonggi-do, KOREA), Ryoong HUH
08:00 - 18:00 #10583 - P177 Motor cortex stimulation in patient with post-stroke pain syndrome.
Motor cortex stimulation in patient with post-stroke pain syndrome.

Chronic pain after stroke found in up to one-half of stroke patients, it affects the quality of life of patientsand is often refractory. Motor cortex stimulation one of the save and efficacy method in management pain syndromes, including after-stroke pain. In our submission we had conducted analysis our small series patients with after-stroke pain to prepared in Nikolay Nilovich Burdenko Neurosurgery Institute during eleven years.

Participans: four patients had poststroke pain syndrome, while three of these patients suffered hemorrhagic stroke and one patient was ischemic stroke. Among patients who suffered a hemorrhagic stroke, two the hemorrhage was localized directly in the thalamus, and one, in subcortical nuclei, including the thalamus.

Materials and methods: All patients were tested DN4, Pain Detect, LANSS. Pain intensity were diagnosed with PQLC – Pain and Quality of Life Card before and after operation and in catamnesis. We appreciated the average of pain intensity, maximal and minimal values of pain, frequency, the effect of pain on daily activities. The stimulation parameters that were used in our study: amplitude of 1.0-5.5 V, frequency 20-50 Hz, pulse duration – 60 - 210 microseconds) Observation in the postoperative period and in follow-up.

Results:Average pain history made up of 3.75 years. Average follow-up amounted to 26.75 months. The stimulation parameters that were used in our study: amplitude of 1.0-5.5 V, frequency 20-50 Hz, pulse duration – 60 - 210 microseconds). Three patients received adequate therapy in adequate doses prior to the stimulation. The results of the employment of transcranial magnetic stimulation was positive in all patients.

The efficacy criterion was considered to decrease in pain of 50% or more at a threshold value of the pulse after two series of stimulation. The level of analgesia from 37.5% to 90%. One of the patients 3 months after implantation of the system has arisen purulent inflammation in the pocket of the pulse generator and the pressure sore over site of implantation of the connectors. The system was removed, in spite of the good analgesic effect.

Conclusion: Motor cortex stimulation may be used in patient with after - stroke pain. The use of modern schemes of antibiotic prophylaxis may reduce complications, which is one of the most important factors for the preservation of clinical effect

Emil ISAGULYAN (Moscow, RUSSIA), Alexey TOMSKY, Elisaveta MACKASCHOVA, Vladimir SHABALOV
08:00 - 18:00 #10694 - P178 Long-term experience and outcomes of simultaneous intrathecal drug delivery and spinal cord stimulation for chronic pain.
Long-term experience and outcomes of simultaneous intrathecal drug delivery and spinal cord stimulation for chronic pain.


Introduction: 

There exists an evidence gap concerning the management of chronic neuropathic pain, including failed back surgery syndrome (FBSS), using combined intrathecal analgesia and spinal cord stimulation (SCS).


Materials and Methods: 

This single-centre case series reports the experiences and outcomes of five consecutive patients receiving dual intrathecal drug delivery (IDD) and SCS at an academic neurosurgical pain service in central Germany. Relevant data were extracted from the patients’ electronic medical records and paper-based hospital notes.


Results: 

Five patients (4 male, 1 female) received simultaneous IDD and SCC during the study period. The therapeutic indications were: FBSS (2 patients), cervical myelopathy (1 patient), tumor-associated conus medullaris syndrome (1 patient), and pudendal neuralgia (1 patient). 4/5 patients received SCS before IDD was initiated after a mean period of 19 months (range 12-25 months). 1/4 of these SCS-first patients additionally went on to receive additional permanent peripheral nerve stimulation therapy after a further 36 months. The remaining patient suffered from a conus medullaris syndrome and first received IDD, followed by SCS 10 years later. All patients reported a reduction in their mean level of pain (according to the numerical rating scale) after initiation of the second therapy. The complication rate was within the expected margin. To date, each of these patients continues to be managed with combined SCS and IDD.


Conclusion: 

This study presents our positive experience of combined IDD and SCS. Dual therapy, when clinically indicated and in the setting of careful candidate selection, appears to be safe and well tolerated, leading to pain reduction and patient satisfaction. Further high quality studies are needed to confirm these findings.

Aaron LAWSON MCLEAN (Jena, GERMANY), Jan WALTER, Rolf KALFF, Rupert REICHART

Monday 26 June

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08:00 - 18:00 #10273 - P179 Neural oscillations regulate somatosensory processing at the level of the human spinal cord.
P179 Neural oscillations regulate somatosensory processing at the level of the human spinal cord.

Functional imaging shows that pain processing in the spinal cord is under top-down control by the brain, specifically by attention and expectation, mediating for example, placebo analgesia(Eippert et al., 2009; Sprenger et al., 2012). Understanding the neural signals and mechanisms underlying this top-down control coud enhance pain therapy, e.g., by optimizing spinal cord stimulation protocols. In the brain, sensory processing is regulated via neural oscillations ( Jensen and Mazaheri, 2010; Arnal and Giraud, 2012; Bauer et al., 2014). Here, we ask whether  neural oscillations play a similar role in gating sensory processing at the level of the human spinal cord. in our ongoing study we are recording local field potentials ( LFPs) from epidural spinal electrodes implanted for pain relief in patients with different pain syndromes. Spedifically, we recorded LFPs as patients attend to electrical shocks on th skin whose onset is either predictable or unpredictable, i.e., which are expected or relatively unexpected. Preliminary results show a stimulus-induced gamma-increase at the level of sensory cortex.Importantly, when shocks are predictable, this  stimulus-induced gamma-decrease in spinal LFPs is diminished. In addition, stimulus expectation suppresses the power of alpha- and low beta-oscillations in the spinal cord prior to stimulus onset. This anticipatory signal mirrors a well-known, similar phenomenon at the level of sensory cortex. Our preliminary data support the idea that neural oscillations, both pre-stimulaus and stimulus-induced, regulate somatosensory processing at the level of the spinal cord. Understanding these signals could inform physiologically guided protocols for optimized spinal cord stimulation in the future.

Lars BUENTJEN (Magdeburg, GERMANY), Tino ZAEHLE, Ariel SCHOENFELD, Hans-Joachim HEINZE,, Jürgen VOGES, Max Philipp STENNER
08:00 - 18:00 #10448 - P180 Mapping of motor evoked potentials to detect the motor side effects threshold during the DBS surgery.
P180 Mapping of motor evoked potentials to detect the motor side effects threshold during the DBS surgery.

Introduction

One of the main reasons to perform the DBS surgery in awake patient is the possibility to detect activation threshold of descending motor tracts, since this can be a therapy-limiting side effect. The current standard technique of such detection is based on the visual observation of muscle contraction during stimulation with conventional DBS stimulation parameters. The recording of motor evoked potentials (MEP) during DBS surgery are feasible, as already shown in the literature. We investigate the value of MEP mapping in as an alternative method to detect motor side effects threshold.

Patients and methods

This study includes the results of the 20 patients who undergone bilateral DBS surgery in STN, VIM and GPI in 15 cases as in awake surgery and 5 under general anesthesia (GA). The recording data of 45 trajectories and 54 stimulation sites were available. A cathodal stimulation in the stereotactic target on the macroelectrode tip was applied using train-of-five technology in 1 mA steps of 0 to 5 mA. The recordings were obtained using surface electrodes in awake and needle electrodes in GA in the projection of m.mentalis, m. flexor dig., m. abd. policis brevis, and m. tibialis anterior on the contralateral side of the stimulation. The visual detection of the motor contraction under 130 Hz 60 μs stimulation in 1 mA steps (0-5 mA) was used as a standard control parameter.

Results

The MEP registration was successful in all stimulation sites. The MEP threshold correlates with visible muscle contraction at 130 Hz stimulation intraoperatively and with postoperatively documented DBS sideeffects. The recognition of activation of muscle response was muscle specific, more sensitive than visible muscle contraction, and remained stable under repeated stimulation. Patients described no complaints during the MEP mapping, only minimal contractions of the muscles, comparable to much more unpleasant, sometimes painful muscle contraction under classical detection of the motor capsule threshold with 130Hz-stimulation. The MEPs was easily obtainable in all cases under GA and showed comparable threshold values as the 130 Hz stimulation postoperatively.

Conclusion

The MEP mapping is a safe and robust alternative to the conventional testing of the motor capsule effects, which can improve the safety and comfort of the DBS operation. The motor thresholds of MEP and 130 Hz stimulation correlate well and can be reliably recorded under general anesthesia.

Yaroslav PARPALEY (Dortmund, GERMANY), Lars SCHÖNLAU, Sabine SKODDA
08:00 - 18:00 #10480 - P181 A wireless brain prosthesis for epilepsy surgery and BCI.
P181 A wireless brain prosthesis for epilepsy surgery and BCI.

A novel wireless brain prostheses(ECOG-64-D) has been developed by AB Medica® in order to allow prolonged cortical recording in the context of epilepsy surgery. The system can also provide a platform for close-loop seizure control and for BCI. ECOG-64-D has 3 components: a subdural grid hosting 128 contacts, half of them dedicated to recording, the other half to stimulation; 4 intracranial connecting cables; a PEEK case allowing wireless transmission and recharge. Wireless ECOG recording is performed through 64 dedicated recording channels while cortical stimulation can be performed through a combination of each of the dedicated 64 stimulating channels. The grid can be divided in two simmetric parts to tailor the recording/ stimulation over multiple lobes. An external kit allows wireless recharge of the case. After preliminary experience on non-human primates and further testing on pigs , ECOG-64-D is now approaching clinical testing during epilepsy surgery. 

Pantaleo ROMANELLI (Milano, ITALY)

Monday 26 June

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08:00 - 18:00 #10363 - P182 Effect of spinal cord stimulation on microcirculatory function and pain relief in patients with peripheral vascular disease.
Effect of spinal cord stimulation on microcirculatory function and pain relief in patients with peripheral vascular disease.

Introduction: Since 1976 spinal cord stimulation (SCS) is the option for treatment of peripheral vascular disease. The efficacy of technology in pain relief not only for neuropathic but ischemic genesis of pain is obvious. Besides, there is statement about improvement in microcirculatory function of damaged limb after SCS implantation.

Materials/Methods: We conducted a prospective analysis of 38 consecutive patients with non-reconstructable peripheral vascular disease who underwent spinal cord stimulation in Siberian Federal Biomedical Research Center (Novosibirsk) between 2012 and 2016. Preoperative and follow up LDF were performed in 16 patients. Pain relief was assessed by visual analog scale (VAS) in all 38 patients.

Results: Our study included patients with IIB (6 patients, 15.8%), III (23 patients, 60.5%) and IV (9 patients, 23.7%) stage by Fontaine classification with mean age of 64.68 (range 39-83)At baseline, the mean (±SD) index of LDF before operation was 2.97±2.671 ml/min/100g and on mean follow up of 19.7 months was 7.29±4.76 ml/min/100g. Only Valsalva functional test have demonstrated significant improvement in postoperative probes (p=0.006). Orthostatic and postocclusive probes showed no difference between results of pre- and postoperative tests (p=0.5317 and p=0.0651). There were 2 patient who had required postoperative amputation during follow up (5.2%). The patients showed 9.43±1.25 mean mark according to VAS before operation and pain relief to 1.03±0.1 on follow up (p<0.001).

Discussion: Our analysis of patients showed significant improvement in symptoms relief after SCS implantation. It proves effect of neuromodulation to microcirculatory function of damaged limbs. But results of functional tests were multidirectional and paradoxical in most cases. It claims that despite improvement in microcirculation, functional reactivity of damaged limb was not recovered enough after spinal cord stimulation.

Conclusions: Spinal cord stimulation is absolutely efficient modality in pain relief for patients with non-reconstructable peripheral vascular disease. But some improvements in microcirculatory function is also evident. Our results of functional probes (Valsalva test) prove the enlargement in microcirculatory reserves and improvement in collateral circulation in damaged limb after SCS procedure. However, further clinical trials with larger sample sizes and extended follow-up are required.

Andrey ASHURKOV (Novosibirsk, RUSSIA), Vladimir MURTAZIN, Roman KISELEV, Kirill ORLOV, Vladimir SHABALOV, Alexey KRIVOSHAPKIN
08:00 - 18:00 #10364 - P183 The siberian experience of spinal cord stimulation for refractory angina pectoris.
The siberian experience of spinal cord stimulation for refractory angina pectoris.

Introduction: Refractory angina pectoris (RAP) is a chronic pain conditions caused by coronary artery diseases, which cannot be adequately controlled neither by combination of medical therapy nor by vascular surgery treatment (angioplasty or CABG). Spinal cord stimulation (SCS) is a neuromodulation therapy that appears to be an effective and safe treatment for these patients.

Materials/Methods: We had applied SCS in 17 patients with RAP. The first step procedure was trial neurostimulation to reveal the efficacy of pain relief before the second step to implant the permanent neurostimulation system. The leads were inserted in the epidural space at the Th1-Th2 level. Myocardium perfusion scintigraphy (MPS) was performed on admission, on the 7th day and in 1 year after procedure. The visual analogue scale (VAS) was used to assess the degree of pain both in rest and physical activity in all patients.

Results: The patients showed 8,49±0,14 marks according VAS before the procedure and pain relief to 1,25±0,73 marks (p<0,01) after 1 year of procedure. All the patients demonstrated the rise of tolerance to the physical activity. MPS detected the decrement of perfusion's defect from 13,36±4,16 to 10,14±3,35 prearranged units (which means increase in coronary reserve up to 24%). The quality of life according to SAQ increased by 60,29% (TS scale - 58,12% amount of growth and PL scale - 64,65%). There were no any procedural complications. But we had registered 1 patient's death from cardiac infarction in one-year catamnesis.

Discussion: According to 2002 American Heart Association guidelines, SCS is a class IIb alternative therapy for treatment of RAP. But based on recent comparative randomized studies reporting significant improvements and according to recommendations of Neuromodulation Appropriateness Consensus Committee (NACC), SCS now can be recommended as evidence level 2a, degree of recommendation A, for the patients with RAP.

Conclusions: Our experience confirmes that SCS is a minimally invasive technique to reduce the pain and improve quality of life with vascular reserve enhancement in RAP patients.

Vladimir MURTAZIN (Novosibirsk, RUSSIA), Andrey ASHURKOV, Roman KISELEV, Kirill ORLOV, Vladimir SHABALOV, Alexey KRIVOSHAPKIN
08:00 - 18:00 #10642 - P184 Voiding disorders clinic. The role of functional Neurosurgery.
Voiding disorders clinic. The role of functional Neurosurgery.

The scope pf this presentation is to provide neurosurgeons with the details on how to form part of an interdisciplinary clinic for the management of voiding disorders. General Neurobiology of continence is reviewed. The general mission of the clinic is to provide comprehensive diagnostic studies, medical and surgical treatments and clinical research of primary and secondary pathologies causing total or partial inability to control micturition and defecation. Urinary/fecal incontinence is a highly disabling disorder that significantly alters quality of life and poses health at risk of complications, among them sepsis, renal failure, skin ulcers. Our incontinence clinic was developed after recognizing that it is a complex problem, with neurogenic and non neurogenic causes, that requires an interdisciplinary approach. Needed specialties are Urology, coloproctology, Neurology, Functional Neurosurgery, Gastroenterology, Physiatry and Pelvic floor therapy and Psychotherapy Specialists. Every performed treatment is the result of collegial discussions. Functional Neurosurgery is an unique position to participate or to conduct neuromodulation therapies, research and to offer neurosurgical treatments in patients with neurogenic causes. Our general experience in neuromodulation for voiding disorders is discussed.

M ESPINOZA (Bogotà, COLOMBIA), J CASTAÑO , J AZUERO

Monday 26 June

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08:00 - 18:00 #10140 - P185 Deep Brain Stimulation for OCD: using an individual patient-level registry to explore patient characteristics and clinical outcomes.
Deep Brain Stimulation for OCD: using an individual patient-level registry to explore patient characteristics and clinical outcomes.

Objectives We used an individual patient-level registry constructed from published reports, to describe the characteristics of patients undergoing DBS for OCD between 2003 and 2017.

Method Data for individual patients were extracted and studies were examined for duplicate publication. Extracted data included: DBS target; information on demographics; symptom severity scores. Percentage change on the Y-BOCS was calculated along with 'responder' status. If individual-level data were not reported, then average values for the whole sample were applied.

Results The registry currently includes 61 reports, covering 369 patient outcomes. The total no. of unique patients was 178 (from 33 primary studies), indicating that only 48.2% of patients reported are unique. The median number of patients per included study was 3. The duration of follow-up in all studies was 12-months, or longer, in only 58.3%. Duration wasn’t reported for 23.6% patients. Eleven unique targets were reported. The most common targets for DBS in the 175 unique patients was: VC/VS (33.7%); NAcc (27.0%); BNST (14.0%); STN (9.6%); and ALIC (6.7%). The mean ± SD age of patients undergoing DBS for OCD was 38.8 ± 8.8 years. The mean ± SD duration of illness was 21.7 ± 9.0 years. Another primary psychiatric disorder was reported in 38.8% of patients, with the most common being: major depression (31.5%); bipolar disorder (2.8%); other anxiety disorder (2.8%); and substance misuse (2.2%). The degree of 'treatment resistance' was poorly reported. The number of robust antidepressant trials was unreported in 78.7% of all studies. The number of previous psychotherapy trials was unreported in 86.0% of studies. Information about 'adequacy' of previous treatments is unknown. The percentage improvement in Y-BOCS score for the targets with more than 10 unique patients was: VC/VS (41.2%); NAcc (33.6%); BNST (46.8%); STN (76.9%); and ALIC (40.6%). The overall percentage improvement for all patients was 40.6%. The percentage response for all targets was 38.8%, but it was unknown in 33.1%.

Conclusion Duplicate publication in the DBS for OCD literature is common. Currently, at least 11 targets are reported, with only three (VC/VS, NAcc, BNST) having more than 25 patients. Fifty-percent of all published reports have 4 or fewer patients. Although overall response rate across all targets and all studies was 38.8%, sparse details on patient characteristics and extent of previous treatments make generalisability difficult.

David CHRISTMAS (Dundee, Scotland, UK), Keith MATTHEWS
08:00 - 18:00 #10786 - P186 Deep Brain Stimulation of the bed nucleus of the stria terminalis for obsessive-compulsive disorder, 12 months follow-up.
Deep Brain Stimulation of the bed nucleus of the stria terminalis for obsessive-compulsive disorder, 12 months follow-up.

Deep brain stimulation (DBS) is a save and reversible neurosurgical procedure of implantation electrodes to selected area of brain. Obsessive-compulsive disorder (OCD) is a chronic psychiatric disorder that affects up to 2% of the general population. This is a case report presenting a 12 months follow up after deep brain stimulation procedure in 43 year old female with a 16 years history of psychiatric treatment for obsessive-compulsive disorder.

Patient was evaluated before surgery and on three follow-up visits, respectively 3 weeks, 6 and 12 months after the surgery, with Hamilton Depression Rating Scale, Beck Depression Inventory, Snaith–Hamilton Pleasure Scale, Brief Psychiatric Rating Scale, Young Mania Scale, Yale-Brown Obsessive Compulsive Scale.

The result of treatment was satisfying and improvement in all scales was significant and long term. A significant event was reported - on the follow up visit after 6 months patient reported a noticeable connection between a voltage on the left stimulator and drive, and voltage on right stimulator and mood. On the left stimulation a patient controll mode was turned on.

 Deep brain stimulation for obsessive-compulsive disorder may have a positive therapeutic effect.

Krzysztof SZALECKI (warszawa, POLAND), Anna ANTOSIK-WÓJCIŃSKA, Łukasz ŚWIĘCICKI, Tomasz MANDAT

Monday 26 June

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08:00 - 18:00 #10101 - P187 Intraoperative Neurophysiological Monitoring during Dorsal Root Entry Zone Lesioning for Brachial Plexus Avulsion Pain.
Intraoperative Neurophysiological Monitoring during Dorsal Root Entry Zone Lesioning for Brachial Plexus Avulsion Pain.

Objectives Although the importance of intraoperative neurophysiologic monitoring (IONM) is being stressed in intraparenchymal spinal cord surgery, its importance in dorsal root entry zone (DREZ) lesioning for brachial plexus avulsion pain has not yet been reported.

Materials and Methods Muscle motor evoked potential (mMEP) to monitor the motor pathways and somatosensory evoked potential (SSEP) to assess the integrity of the dorsal column were applied to the ipsilateral or bilateral upper and lower extremities during DREZ lesioning for brachial plexus avulsion pain. (Table 1)

Results IONM of mMEPs and SSEPs was feasible for monitoring of the spinal cord during DREZ lesioning (Table 1, 2). With exception of 3 unrecordable mMEPs in ipsilateral arms, mMEPs were preserved and referenced to look for intraoperative changes according to DREZ lesioning in 6 upper extremities (66.6%) and 8 lower extremities. All 3 patients with >50% reduction in baseline mMEP amplitude after lesioning in either the ipsilateral upper or lower extremities showed postoperative ataxia and weakness of the lower extremities (100%) (Fig. 1). In addition, only 2 out of 9 patients (22.2%) with brachial plexus avulsion pain had discernible baseline SSEPs in the ipsilateral upper extremities. One of 2 patients with discernible SSEPs in the upper extremities showed significant SSEP events during the DREZ lesioning and experienced postoperative ataxia and weakness in the legs despite the absence of an SSEP event in the lower extremities (Fig. 2).

Conclusions Significant events on IONM were common during DREZ lesioning for brachial plexus avulsion pain and were closely related to the occurrence of postoperative neurologic deficits (Table 3). 

Son BYUNG-CHUL (Seoul, KOREA), Choi JIN-GYU, Ha SANG-WOO, Kim DEOG-RYEONG, Ko HAK-CHOEL
08:00 - 18:00 #10103 - P188 Comparison of clinical efficacy and computed tomographic analysis of lead position between three-column and five-column paddle leads spinal cord stimulation for failed back surgery syndrome.
Comparison of clinical efficacy and computed tomographic analysis of lead position between three-column and five-column paddle leads spinal cord stimulation for failed back surgery syndrome.

Objectives The authors investigated the difference in clinical outcome and the position of paddle lead spinal cord stimulation (SCS) between three-column and five-column paddle lead SCS in patients with FBSS. Materials and Methods In 21 patients who underwent paddle lead SCS at T9 (three-column, n = 9; five-column, n =12) for FBSS, a 12-month follow-up numerical rating scale, percent pain relief, and CT assessment of contact angle and percent reduction of T9 canal area were investigated (Table 1, 2).

Results There was no difference in paresthesia coverage of the painful area, trial success rate, clinical outcomes, and percent pain relief between the two groups (p>0.05). The contact angle in the five-column group was generally greater than that of the three-column group (p=0.067) (Table 3, 4, Fig. 1-4). Overall reduction of 35.51 ± 4.76% in the T9 canal was observed and there was no difference between two groups (p>0.05) and no correlation between the contact angle and percent T9 spinal canal reduction (r = -0.247, p>0.05) (Table 4, Fig. 3-4).

Conclusions Although clinical efficacy of SCS using three-column and five-column paddle lead was not significant different from each other, significant inclination of paddle lead in posterior epidural space with significant reduction in T9 canal area were observed in both groups. The degree of inclination in the five-column group was greater than that in the three-column lead group. Close approximation of paddle lead contacts to dorsal spinal cord with reduced dorsal CSF space and intraoperative neurophysiologic guidance might have contributed to the high rate of trial success and long-term pain control.  

Son BYUNG-CHUL (Seoul, KOREA), Choi JIN-GYU, Ha SANG-WOO, Kim DEOG-RYEONG, Ko HAK-CHOEL
08:00 - 18:00 #10135 - P189 Motor cortex stimulation for poststroke pain.
Motor cortex stimulation for poststroke pain.

Objectives : We assessed motor cortex stimulation for treatment of poststroke pain. Four patients with poststroke pain were studied. In three arm pain patients, we placed electrode grid in the epidural space to determine the best stimulation point for pain relief. In one leg pain patient, the 16-electrode array was implanted in the subdural interhemispheric fissure to treat lower-extremity pain guiding navigator system. In two patients with pain extending from the extremity to the trunk or hip, dual devices were implanted to drive two electrodes.

 

Material and methods : All patients were male, mean age was 60.6 years(44-78 years). Disease entity was consisted with 1 hemorrhage, 3 infarction patients. Symtom sites was 3 arm pain patients, 1 leg pain patient.

 

Results : All four patients experienced pain reduction (two each with excellent, and fair relief) from motor cortex stimulation. Testing performed with a subdural multiple-electrode grid was helpful in locating the best stimulation point for poststroke leg pain relief.

 

Conclusion  : Motor cortex stimulation may be effective for treating intractable poststroke pain.

 

Mooseong KIM (Busan, KOREA), Won Hee LEE
08:00 - 18:00 #10150 - P190 Phantom Remodeling Effect of Dorsal Root Entry Zone Lesioning in Phantom Limb Pain Caused by Brachial Plexus Avulsion.
Phantom Remodeling Effect of Dorsal Root Entry Zone Lesioning in Phantom Limb Pain Caused by Brachial Plexus Avulsion.

Introduction: Dorsal root entry zone (DREZ) lesioning has been reported to be effective for phantom limb pain caused by brachial plexus avulsion pain. Most reports on DREZ lesioning for brachial plexus avulsion pain have focused on the results of pain relief without detailed description on phantom sensation following DREZ lesioning.

Material and Method: Two patients (one with amputation and the other non-amputated) with chronic intractable phantom limb pain caused by brachial plexus avulsion underwent DREZ lesioning on the avulsed segments of the cervical spinal cords. Changes of the phantom limb were observed (Fig. 1 and 2).

Results: Immediately following DREZ lesioning, the phantom limb pain disappeared in the amputee, the phantom arm was shortened, and the phantom hand disappeared. The other patient with the non-amputated arm reported an immediate 50% reduction in the size of the phantom hand, pain relief was up to 70% of the preoperative phantom limb pain. There was no further change in the phantom arm and hand during the follow-up of 1.5 to 2 years.

Conclusions: Phantom arms and hands showed a prompt shortening and reduction in size rather than disappearance, following successful DREZ lesioning in patients with chronic phantom limb pain caused by brachial plexus avulsion.

Son BYUNG-CHUL (Seoul, KOREA), Ha SANG-WOO
08:00 - 18:00 #10281 - P191 Spinal cord stimulation alleviates pain in 17 years old boy with Superior mesenteric artery (SMA) syndrome: a case report.
Spinal cord stimulation alleviates pain in 17 years old boy with Superior mesenteric artery (SMA) syndrome: a case report.

Background

Superior mesenteric artery syndrome (SMAS) is a disorder characterized by vascular compression of the duodenum leading to mechanical obstruction. The manifestations of SMAS include early satiety, nausea, diarrhea, reflux, vomiting and extreme postprandial abdominal pain. Surgical intervention indicated in patients who fail standard non-operative management. This report describes the case of 17 years old boy with a refractory debilitating SMAS related abdominal pain which greatly benefited from Spinal cord stimulation (SCS) implantation.

 

Case presentation

The authors report on a 17 year old male patient which presented with abdominal pain at the age of 11. The patient underwent LAAD surgery and was later on diagnosed with SMAS syndrome. The patient continued to complain about abdominal pain, impacting his quality of life and was started on duodenal nutrition followed by total parenteral nutrition, which were later stopped. The patient was later started on several painkiller medications and biofeedback, with no pain relief. The patient underwent two SCS implants, a temporary one and permanent one which helped relief the patient's pain.

 

Conclusion

Spinal cord stimulation (SCS) is an established procedure for treatment of chronic neuropathic pain of peripheral origin, and persistent postoperative neuropathic pain. This case report exhibits the option of using a spinal cord stimulator to treat refractory pain caused by superior mesenteric artery syndrome.

 

Lior UNGAR (Rehovot, ISRAEL), Zion ZIBLY
08:00 - 18:00 #10390 - P192 O-arm guided percutaneous radiofrequency cordotomy.
O-arm guided percutaneous radiofrequency cordotomy.

Background

There is a great importance to deliver good pain management to cancer patients suffering from advanced metastatic disease. Patients with localized pain refractory to medical treatment can benefit from selective percutaneous cordotomy that disconnects the ascending pain fibers in the spinothalamic tract. Over the past year we have been performing percutaneous radiofrequency cordotomy with the use of the O-Arm intraoperative imaging system that allows both 2D fluoroscopy in addition to 3D reconstructed computed tomography imaging.

We present our experience using this technique focusing on technical nuances and complications.

Methods

Retrospective analysis of all patients who underwent percutaneous cordotomy between January 2016 and January 2017.

Results

Sixteen patients underwent percutaneous cordotomy. 15/16 patients experienced excellent immediate pain relief (90-100%). One patient with iodine sensitivity in whom no intra-thecal contrast was used experienced only 50% pain reduction. At one month 13/16 had good outcome. At 3 months 9/12 patients available for follow-up were still pain free.

Mirror pain developed in 5 patients (31%), but was usually mild and controlled with medications. We had 1 complication (6.25%) of ipsilateral hemiparesis.

 Conclusion

Percutaneous cordotomy using the O-Arm is safe and effective in the treatment of intractable oncological pain.

Ido STRAUSS (Tel Aviv, ISRAEL), Assaf BERGER, Uri HOCHBERG, Rotem TELLEM
08:00 - 18:00 #10421 - P193 Clinical outcome of DREZotomy for intractable paraplegic pain: a single center experience.
Clinical outcome of DREZotomy for intractable paraplegic pain: a single center experience.

OBJECTIVE:

Generally, it is difficult to control a paraplegic pain due to spinal cord injury. Although strong opioids and anticonvulants are effective to reduce the pain scale, most of patients with paraplegic pain is necessary to surgical interventions. A microsurgical DREZotomy (MDT) is one of the treatment of choice in paraplegic pain. But the traditional MDT has poor outcomes when the nature of pain is diffuse, thermal, and continuous pain. So, we report clinical outcomes in these neuropathic pain conditions using a modified MDT technique.

METHODS:

Surgical procedure is done with prone position. Spinal cord is exposed from above 2 vertebral level of injured cord to below the level of injured cord level. A careful inspection of the level of intact nerve rootlets, MDT is started from the level of just below intact rootlets cord level and extended to the caudal exposed spinal injured level. At the level of injured cord, injured, atrophied and fused rootlets are cut and MDT is performed on imaginary line of dorsal root entry zone.

RESULTS:

In 66 patients with paraplegic pain resulting from a spinal cord injury occurring within the preceding 10 years, 32 of 38 patients (84%) with a diffuse pain distribution had a good reduction in pain. 27 patients (86%) with continuous pain noted good pain relief. In patients with thermal pain,3 patient (23%) demonstrated a good response to the investigational procedure.

CONCLUSION:

These procedures, including the modified MDT technique, may be helpful in controlling various type of paraplegic pain due to spinal cord injury.

Ryu JE IL, Chun HYOUNG-JOON , Kim YOUNG SOO (Seoul, KOREA)
08:00 - 18:00 #10471 - P194 A Novel - High Effective - Methode Against Neuropathic Pain Syndromes.
A Novel - High Effective - Methode Against Neuropathic Pain Syndromes.

Introduction: In the last 25 years neuromodulation by deep brain stimulation gained widely acceptance starting in the field of movement disorders and getting further indications in pain syndroms and mood disorders. The highly acclaimed success of deep brain stimulation in parkinsons disease, essential tremor, dystonia, chorea huntington, tourette syndrome, cannot be translated 1:1 to neuropathic pain syndromes. The EFNS guidelines on neurostimulation therapy for neuropathic pain published in the European Journal of Neurology 2007, 14: 952–970 revealed DBS against pain to be less effective than in movement disorders which still remains the same in the literature until now. The publication identified several reviews and one meta-analysis, which conclude that DBS is more effective for nociceptive pain than for neuropathic pain (63% vs. 47% long-term success). Moderately higher success rates were seen in patients with peripheral lesions. Because neuropathic pain syndromes are a complex compilation of missing information in different pathways to and within the brain resulting in the different aspects of pain consisting of sensation, perception, mood, emotion and vegetative aspects. Simply said 50% pain reduction in DBS against neuropathic pain is covering only 50% of the cortical imput!

Material and Methodes: We will demonstrate 19 patients with three different neuropathic pain syndromes following neurosurgical stereotactic interventions for neuromodulation according to our development finished in 2012. We selected from all structures in the pain matrix two main input areas namely the sensory thalamus and the posterior limp of the internal capsule. We modified the implantation site in the internal capsule because of ineffectiveness of the historical target and an anatomical chaos in the literature on the anatomical construction of the posterior limp of the internal capsule. By doing so we are able to cover all essential afferent fibers to the sensori-motor and the parietal cortex. Fiber tracking is utilized in all cases. In comparison to all other methods or other implantation centers a minimum of 2 stimulation electrodes has to be implanted per cerebral hemisphere. We treated 4 trigeminal neuropathia (3 analgesia dolorosa) patients, 2 peripheral nerve injury patients, 10 post stroke patients and 3 post infection pain syndromes. Preoperative and postoperative testing included neuropsychological testing of cognition and memory, Mc. Gill Pain questionnaire, SF-36, EQ-5D, body region VAS, sensory testing of temperature, discrimination, reaction on repetitive stimuli. MRI evaluation of electrode position in relation to fiber tracts is performed in all cases.

Results: All patients had at least 90% pain reduction and improvement in sensory function and no deterioration in cognition.

Discussion: Our method is safe and reliable. Our results are better than the results in the international literature. The methode is proving since more than three years a stable effectivity.

Prospective randomized double blind studies in neuromodulation against neuropathic pain are still missing and will be conducted in the near future.

Wilhelm EISNER (Innsbruck, AUSTRIA), Sebastian QUIRBACH, Florian SOHM, Raphael REHWALD, Johannes KERSCHBAUMER
08:00 - 18:00 #10476 - P195 Possible reason for the loss of effectivity of motor cortex stimulation.
Possible reason for the loss of effectivity of motor cortex stimulation.

Introduction:

Over 300 cases reported in the medical literature since 1991 indicate that Motor Cortex Stimulation (MCS) using 4 or more contact electrode paddles is effective for the treatment of neuropathic pain, in particular for central post-stroke pain (CPSP) and trigeminal neuropathic pain (TGN) /facial pain.

 

Methodes:

We experienced in 8 patients a reduction in effectivity of treatment after two years of treatment. Some patient could life with that because they had a stable amount of pain reduction after two years of treatment and some therapeutic effect but reduced in all possible settings. The therapeutic effect got reduced slowly following a stable period of effectvity of 18 months. In three patients the therapeutic effect was reduced tramatically. We offered Deep Brain Stimulation for neuropathic pain therapy. One patient wanted the stimulator which was almost empty to be removed and for the moment no further therapy. Two patients had such a worsened situation that they were willing to suicide. We offered DBS of the thalamus and the capsula interna. For performing a stereotactic planning MRI for DBS we had to remove the electrode .

 

Results:

We removed the systems by recraniotomy the patients. After removing the resume round electrode we found scare tissue between dura and electrode. After removing the scare tissue we discovered a calcified plate. Now we knew why we had no psotive stimulation effects anymore despite of full integrety of the stimulation system. The other patient had a thick scare tissue isolating the electrode.

 

Conclusions:

Outside the brain isolating scare tissue is distributed by the organism to exclude current sources other than the organism to protect the functional integrity of the nervous system and the cardiac system. In the seventies we used percutaneous electric therapy for difficult fractures in athletes with some effectivity. In a few patients with surgical spinal chord electrodes we discovered spinal stenosis only in the area of the electrode. We did not have these findings in the percutaneous electrodes at all.

Wilhelm EISNER (Innsbruck, AUSTRIA), Sebastian QUIRBACH, Florian SOHM, Johannes KERSCHBAUMER
08:00 - 18:00 #10478 - P196 Mesencephalic Rostral Reticulotmy for Cancer Pain.
Mesencephalic Rostral Reticulotmy for Cancer Pain.

Introduction: Cancer pain is one of the most distressing events for cancer patients, substantially reducing their quality of life. Advances on the pharmacopoeia, improvement of opioids, understanding of the adjuvant drugs, and the approach by a multidisciplinary team brought down its incidence, but it is still refractory to the best conservative management in 5% to 15% of these patients. Surgical treatment may be an option in such cases. We here present our series of 8 cancer patients with primary or secondary lesions affecting the cranio-facial-cervico-brachial regions and pain resistant to clinical treatment and surgical peripheral approaches submitted to medial mesencephalotomy (MM) aiming the interruption of the reticulothalamic tract.

Methods:  Between Aug 2015 and Feb 2017, eight patients (2F/6M), mean age of 60.6 (23-80) years, presenting with nociceptive (n=4) or mixed (nociceptive+neuropathic pain, but predominantly neuropathic) treatment-resistant pain underwent stereotactic MM in one of our institutions. The visual analogical scale (VAS) was used to determine the intensity of pain. The following coordinates were used: 5.0mm posterior, 5.0mm inferior, and 5.0mm lateral to PC. Appropriate electrode placement was confirmed by macrostimulation with 5/75/100Hz and 0.5-5.0V. In the absence of adverse effects, a single radiofrequency lesion was performed with a 1.1mm in diameter and 3.0mm exposed tip electrode with 65º/60” after a successful test lesion with 50º/30”. MR or CT was performed on the second postoperative day in all patients.

Results: After a mean follow-up of 5 (0.5-18) months, the intensity of pain decreased from a mean of 7.9 (6-9) to 1.4 (0-4). Postoperative neuroimaging showed well placed lesions located on the superior/inferior colliculi transition (coronal plane), and 4.0-6.0mm lateral to the Sylvius aqueduct (axial plane). The only adverse effects observed were transient diplopia (n=2), and mild cognitive decline (n=1). Recurrence of pain occurred in one patient after a follow-up of 12 months.

Conclusions: Modern MM seems to be an underutilized, cheap, effective and safe procedure for the treatment of both nociceptive and neuropathic pain in cancer patients in this short-term follow-up study. Based on these results, we strongly recommend the use of this technique for the treatment of refractory nociceptive and neuropathic pain in cancer patients.

 

Romulo MARQUES (Goiania, BRAZIL), Rodrigo CAVALCANTE, Vladimir Arruda ZACCARIOTTI, Joao Batista ARRUDA, Ivam Sousa BARBOSA JÚNIOR, Satyaki Afonso NAVINCHANDRA, Osvaldo VILELA-FILHO
08:00 - 18:00 #10523 - P197 Deep brain stimulation targeting the thalamic cavity wall in a rat model for thalamic syndrome.
Deep brain stimulation targeting the thalamic cavity wall in a rat model for thalamic syndrome.

Introduction

Thalamic syndrome, first described by Dejerine and Roussy, is a central neuropathic pain syndrome occurring after thalamic stroke, often associated with a mild paresis. It is a form of central post-stroke pain. Treatment is challenging and often not satisfying.

 

Material and Methods

30 rats were tested for thermal and mechanical pain and motor performance, and were then randomly allocated into an experimental group (E; electrolytic thalamic lesioning; n=22) and a control group (C; sham surgery; n=8). Pain and motor tests were repeated weekly over the next 4 weeks. Next, using stereotaxy planning based on pre-implantation CT and MR imaging, 3 linear twisted bipolar electrodes were implanted. E was randomly divided into a cavity wall electrode group (W; electrodes targeting the ventral cavity wall; n=11) and a random electrode group (R; electrodes targeting a random brain region not known to be related to motor or pain behaviour; n=11). In C, electrodes were implanted at the same coordinates as in W. Motor tests were then repeated during deep brain stimulation (DBS; biphasic, 130Hz, 200µs at 0%-50%-75%-100% of the highest tolerated amplitude (HTA; amplitude above which side effects are observed)) and local field potentials were recorded.

 

Results

After but not before lesioning, motor scores were significantly (P<.05) worse in E vs. C, while pain scores did not differ.

In W, DBS at 50%, 75% or 100% HTA did not improve motor scores significantly as compared to 0% HTA in W or to DBS in R or C.

LFPs recorded from the cavity wall in W were significantly different and mainly hyperactive vs. LFPs recorded from identical anatomical locations in C.

 

Conclusion

In a thalamic syndrome rat model with motor deficits but no mechanical or thermal hyperalgesia, the tested DBS parameters did not alleviate symptoms.

Philippe DE VLOO (Leuven, BELGIUM), Els CRIJNS, Janaki Raman RANGARAJAN, Kris VAN KUYCK, Alexander BERTRAND, Bart NUTTIN
08:00 - 18:00 #10585 - P198 Clinical and neurophysiological evidence that spinal cord stimulation works through dorsal column fibres. What about dorsal root ganglion stimulation?
Clinical and neurophysiological evidence that spinal cord stimulation works through dorsal column fibres. What about dorsal root ganglion stimulation?

SCS is a well-established treatment of several neuropathic pain syndromes and is the mainstay of neuromodulation for pain. Examining evidence pointing towards probable mechanisms led to the conclusion that SCS mainly works through long loops of dorsal column (DC) fibres.  

 

Conscious perception of paresthesia in SCS may raise the question of a super-imposed placebo-effect. However, SCS has been shown to have a depressing effect on nociceptive RIII EMG reflex, objectively demonstrating that SCS modulates physiologic mechanisms in the DH circuitry. Local modulation at the level of the DH requires however functionally valid DC fibres. In a retrospective series correlating the long-term effect of SCS and the anatomical location of the lesions we found that interruption of primary afferent neurons central to the dorsal root ganglion (DRG) is associated with a very high rate of failure. Further, in a prospective study connecting the values of the central conduction time (CCT) of the somatosensory evoked potentials (SSEP) and the long-term effect of SCS, we established that when CCT was significantly abnormal the success rate was nil. This clinical and neurophysiological evidence that SCS works through dorsal column fibres to generate supraspinal mechanisms and descending inhibitory pathways to decrease activity of the DH.

Similarly, on the opposite (peripheral) side the DRG should no longer be considered a passive transducer of the peripheral influxes to the spinal cord. The sensory fibres connect by a T – junction to their cell body; this sets a low-pass filter for action potentials propagation to the DH. The DRG-neurons are surrounded by satellite glial cells, which-through production of cytokines regulate the signal processing.

In pain from peripheral afferent fibres lesions DRG stimulation can decrease hyperactivity of the DRG neurons. Relief results from either downstream effect of vasodilation and stabilisation of the sensitized peripheral receptors and/or upstream effects of deactivating the WDR DH neurons.

Based on these mechanisms principal logical indications are neuropathic pain from PAF damages and CRP Syndromes. Clinical studies enforce this hypothesis although further confirmation is needed.

 

Whatever the differences between the two methods, we advise that preoperative assessment of the functionality of the DC fibres using SSEP (CCT) should be a prerequisite before deciding implantation or even percutaneous trial for both techniques.

Marc SINDOU (Lyon), Andrei BRINZEU
08:00 - 18:00 #10679 - P199 Treatment of axial low back pain with boston scientific spinal cord stimulation.
Treatment of axial low back pain with boston scientific spinal cord stimulation.

•Introduction:  The use of Spinal Cord Stimulation (SCS) for management of a variety of pain disorders has been well documented in the literature.  What has been noted is that patients who present with radicular pain, or limb pain, often have better response to SCS than those patients who are treated strictly for axial low back pain.  Here we present out data of patients 17 patients implanted with Boston Scientific Precision Spectra spinal cord stimulator for treatment of radicular and axial low back pain.
•Methods:  Seventeen patients had implantation of Boston Scientific Precision Spectra after having undergone a successful trialing period.  Patients were assessed using the Visual Analogue Scale as well as a pain diary.  One patient had only axial low back pain, one patient had only radicular pain, fifteen patients had both axial low back pain and radicular pain.
•Results:  For our cohort of patients 94% were being treated for axial low back pain.  In follow up with patients it was found that there was an 81% average pain reduction specific to axial low back pain.  Of the patients whose pain improved 40% had used multiple waveforms in their programming via the Multiwave Platforms. 
•Conclusion:  Greater pain control for patients with axial back pain may be achieved through greater programming abilities that were attained with Boston Scientific’s Ilumina 3D and Multiwave Platforms.  Further research in to different programming modalities is needed to further illuminate the possibilities of expanding pain control with SCS.  

Yehuda HERSCHMAN (Newark, USA)
08:00 - 18:00 #10705 - P200 Decompression of the greater occipital nerve in occipital Neuralgia.
Decompression of the greater occipital nerve in occipital Neuralgia.

Introduction

Occipital neuralgia (ON) is an uncommon, specific syndrome of paroxysmal severe lightening-like sharp headache in the distribution of the greater or lesser occipital nerves (GON, LON). Although most cases of occipital neuralgia are considered idiopathic, they may be related to specific secondary causes. Most surgical treatment of ON has been reported in those occurred by peripheral compression of the GON. We report 4 cases of successful surgical decompression for ON due to entrapment of the GON and the LON.

Patients and methods

4 cases of refractory ON were treated with surgical decompression. The causes of GON/LON entrapment were; entrapment of GON within semispinalis capitis muscle (n=1), peripheral entrapment due to pathologic arterial contact of the occipital artery to GON (n=2), and LON entrapment within the C2/3 foraminal stenosis (n=1).

Results

In ON, typical symptoms of ON along with referred trigeminal pain and trigeminal sensory change was the clues in decision of exploration of GON. In 2 cases of chronic ON with referred trigeminal pain, pathological arterial contact with adhesion to the occipital artery was found. In another patient, the entrapment was the found at the piercing point within the semispinalis capitis. All 3 GON neuralgia and one LON neuralgia were immediately relieved along with neuralgic pain and hemifacial pain.

Conclusion

Decompression of the GON was effective in selected patients with chronic ON. Possible cause of entrapment of GON and LON should be thoroughly addressed before decompression. Hemifacial pain and sensory change following occipital neuralgia may be a symptomatic clue in decision of the exploration of GON.

Son BYUNG-CHUL (Seoul, KOREA), Ko HAK-CHOEL
08:00 - 18:00 #10825 - P201 Improved ONS efficacy and increased pain relief in Occipital Neuralgia with Burst stimulation: Two Cases.
Improved ONS efficacy and increased pain relief in Occipital Neuralgia with Burst stimulation: Two Cases.

Introduction: Occipital Nerve Stimulation (ONS) is an effective treatment for refractory Occipital neuralgia (ON). ON is a disorder characterized by sharp, electrical, paroxysmal pain, originating from the occiput and extending along the posterior scalp, in the distribution of the occipital nerve. Traditionally ONS delivers low frequency stimulation with a fixed pulse width--usually 300-500 μsec--and frequency between 30-60 Hz. While new paradigms for spinal cord stimulation (SCS) including high frequency and burst stimulation have been introduced over the past several years, these stimulation techniques have not been investigated extensively in ONS.

Methods: We describe the use of burst stimulation in two patients previously implanted with ONS and receiving moderately effective conventional ONS. Stimulation parameters, VAS scores, medication use, and pain diary entries were tracked over an eight-week interval. As stimulation paradigms were adjusted, measurements of these parameters were tracked at several intervals, from baseline measurements during conventional stimulation, through a washout period and across during two separate phases of burst stimulation.

Results: VAS score prior to ONS implantation was 8-9. Scores fluctuated after implantation, ranging from 4-5 at their best to 8-9 at their worst. During baseline diary, VAS was 7-8. After burst stimulation was activated, the patient VAS for patient A consistently maintained between 3 and 4 (an overall reduction of over 50%) and for patient B between 4 and 6 (just under 50%). Medication use decreased, and Patient A discontinued all opioid medications by the end of the trial period. Patient satisfaction attained at its highest point since ONS implantation at the conclusion of the eight-week trial period.

Conclusion: Burst stimulation has been effective for spinal cord stimulation and there has been a “salvage” utility in implementing burst stimulation for patients with suboptimal results using convention stimulation to address back and leg pain. The significant decrease in VAS in these cases of refractory occipital neuralgia suggests that a similar benefit may be attainable in using burst stimulation in ONS. A larger prospective investigation of burst stimulation for ON and other craniocervical pain syndromes may be warranted. Furthermore, a more detailed investigation should be undertaken into the optimal waveforms to accomplish most effective pain control.

Erika PETERSEN (Little Rock, USA)

Monday 26 June

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08:00 - 18:00 #9940 - P200b Malignant life-threatening deep brain stimulation withdrawal syndrome . The Hariz-Johansson initial description.
Malignant life-threatening deep brain stimulation withdrawal syndrome . The Hariz-Johansson initial description.

OBJECTIVES

After the initial description by Hariz and Johansson in January 2001 in the Journal of Movement Disorders, drawing attention to the consequences of the abrupt cessation of chronic STN DBS (Subthalamic Nucleus Deep Brain Stimulation) in PD (Parkinson´s Disease) patients, describing how this therapy can change patients´ symptomatology into an acute condition with severe rebound of PD symptoms requiring emergency care if chronic stimulation fails, this condition has remain hidden in some way.

METHODS

We present 2 cases with PD, male and female, 50 and 74 yrs old. In both cases initial DBS induced a significant improvement of symptoms without adverse effects. They were operated as usual using a Frameless System. Awake microrrecordings and stimulation were always obtained to assess STN targeting and absence of adverse side-effects.

In the first case admission to Hospital in the ICU was due to a pneumonia, and after 10 days and verified the battery was off its replacement was performed. His Hoehn & Yahr state changed from 5 to 2 after operation.

In the second case two similar episodes were present, the first 4 yrs after the first operation with pneumonia, the stimulator being replaced one month after admission, and a second one 3 yrs afterwards, the battery being replaced after 10 days, for a severe urinary tract infection and septic state. Her Hoehn & Yahr state changed from 5 to 3 after replacement.

Both cases presented with severe systemic and neurological deterioration, including rigidity, akinesia, dysphagia, pneumonia and severe respiratory distress  

RESULTS

In both cases quickly after the stimulator run out of battery, patients deteriorated unadvertedly systemic and neurologically early with severe rigidity and urinary or lung infections, that were attributed to their previous neurological condition and even required its emergency admission to the ICU.

Emergency replacement of the stimulator stopped the deterioration of the patient. Dopaminergic medication was not an effective treatment. Just the stimulator replacement changed the clinical course. Some deterioration in their neurological state remained even after replacement.

CONCLUSIONS

Other reports including the parkinsonian hyperpyrexia syndrome or psychiatric conditions related to DBS are not related. Deterioration was due to battery depletion shortly before replacement. Emergency stimulator replacement is mandatory in these cases.

Pedro ROLDAN, Pedro ROLDAN (VALENCIA, SPAIN), Luis REAL, Antonio SALVADOR, Diego TABARES, Pau CAPILLA, Felix PASTOR, Jose-Miguel LAINEZ-ANDRES, Jose GONZALEZ-DARDER
08:00 - 18:00 #10245 - P202 The accuracy of deep brain stimulation assisted by robotized stereotactic assistant system(ROSA).
The accuracy of deep brain stimulation assisted by robotized stereotactic assistant system(ROSA).

Objective: To evaluate the accuracy and safety of deep brain stimulation (DBS) assisted by robotized stereotactic assistant (ROSA) system. Methods: A total of 18 Parkinson's disease patients and 2 essential tremor patients undergoing DBS assisted by ROSA system. The maximum and minimum distances of electrode deviation were recorded according to postoperative CT and the average distance was calculated. The intraoperative electrode related bleeding events and postoperative complications were also recorded. Results: A total of 39 planned implant electrodes were successfully implanted in the 20 patients. Thirty-seven electrodes were implanted into the subthalamic nucleus and 2 into the ventral intermediate nucleus. The maximum deviation distance of x-axis was 2.13 mm, and the minimum was 0.09 mm, with an average of 0.68±0.43 mm. The maximum deviation distance of y-axis was 1.50 mm, and the minimum was 0.21mm, with an average of 0.63±0.29 mm. Conclusion DBS electrodes implanted with the assistance of ROSA system is safe and accurate in implanting. 

Yingqun TAO (Shenyang, CHINA), Feng XU, Hai JIN
08:00 - 18:00 #10257 - P203 An investigation into the effects and prognostic factors of cognitive decline following subthalamic nucleus stimulation in patients with Parkinson’s disease.
An investigation into the effects and prognostic factors of cognitive decline following subthalamic nucleus stimulation in patients with Parkinson’s disease.

We retrospectively investigated the effects of subthalamic nucleus stimulation (STN-DBS) on new postoperative onset of cognitive decline and prognostic factors for advanced Parkinson’s disease (PD). We studied 39 PD patients who had received bilateral STN-DBS. Clinical symptoms, cognitive function, psychiatric function, and health-related quality of life (HRQOL) were assessed before and six months after surgery. Based on the results of neuropsychological examinations six months after the surgery, the subjects were divided into those with and those without cognitive decline. We compared pre- and post-operative assessments between the two groups. Prognostic factors were investigated using multiple logistic regression analyses. Seven patients had cognitive decline six months after the operation (17.9%); they were significantly older than those without cognitive decline. Preoperative neuropsychological examinations revealed impairments in language and executive function. No differences were found in clinical symptoms. Patients with cognitive decline had significantly worse apathy scale scores. The HRQOL revealed significant declines in the Mental Component Summary (MCS), vitality, and mental health (MH) domains. Postoperative comparisons revealed novel significant differences in activities of daily living in the “on” and “off” states and in daytime drowsiness. Preoperative differences seen in the MCS and vitality indices were no longer present. Word fluency, and apathy scale and MH scores were independent preoperative prognostic factors for cognitive decline. New postoperative onset of cognitive decline due to STN-DBS affected activities of daily living and psychiatric function. Preoperative non-motor symptoms may be prognostic factors for new onset of cognitive decline. 

Taro NIMURA (Miyagi, JAPAN), Ken-Ichi NAGAMATSU, Tadashi ANDO, Arifumi MATSUMOTO, Kinya HISANAGA , Tominaga TEIJI
08:00 - 18:00 #10270 - P204 Improved sleep quality and nocturnal autonomic symptom after deep brain stimulation of globus pallidus internus.
Improved sleep quality and nocturnal autonomic symptom after deep brain stimulation of globus pallidus internus.

Introduction: Sleep disturbance in Parkinson’s disease is composed of multifactorial problems. Improved sleep quality after deep brain stimulation of subthalamic nucleus (STN-DBS) are frequently reported, while the effect of that of globus pallidus internus (GPi-DBS) has not been as clear.

Methods: We evaluated the baseline sleep quality of 18 patients (age: 62.2 ± 8.3 years; males: 6, females: 12) using Parkinson’s disease sleep scale (PDSS). We obtained postoperative PDSS profile from 14 of them (age: 61.2 ± 7.7 years; males: 5, females: 9; 16.2 ± 21.3 months after surgery). Clinical profiles were evaluated by Unified Parkinson’s disease rating scale (UPDRS) motor score, mini-mental state examination (MMSE) and levodopa equivalent daily dose (LEDD). Statistical significance was evaluated by Wilcoxon matched-pairs signed rank test and Pearson’s correlation test.

Results: The total PDSS score increased from 100.9 ± 14.0 to 111.8 ± 17.1 after GPi-DBS. Among each item, only the item 8 (question about night urinary symptoms) improved significantly. The baseline PDSS total score correlated with disease duration (Pearson r = -0.51, p = 0.03).

Conclusions: Sleep quality evaluated by PDSS improved after GPi-DBS. DBS could alleviate nocturnal autonomic symptoms.

Namiko NISHIDA (Osaka, JAPAN), Hiroki TODA, Hidemoto SAIKI, Sadayuki MATSUMOTO, Koichi IWASAKI
08:00 - 18:00 #10540 - P205 A Method for Predicting the Outcomes of Subthalamic Deep Brain Stimulation Surgery for Parkinson’s Disease.
A Method for Predicting the Outcomes of Subthalamic Deep Brain Stimulation Surgery for Parkinson’s Disease.

Introduction

Although significant progress has been made in computational simulation of deep brain stimulation (DBS), very few of these have been introduced into daily clinical use. Former computational models usually include imaging data in the attempt to give the visualized suggestion for post-operational programming. To date, the clinical characteristics and electrophysiology are not considered, thus traditional models do not accurately predict the simulated therapeutic outcomes of DBS. However, the micro-electrode recordings could provide both electrophysiological status and location information of the DBS electrode, which is worth its inclusion in the simulation model.

 

Methods

Clinical data of 31 patients treated with DBS for Parkinson’s disease, with 107 post-DBS programming visits, were used to create a therapeutic prediction model. Based on the patient-specific clinical data, which included trajectory length within the subthalamic nucleus from micro-electrode recordings and total electric energy delivered by DBS, therapeutic outcomes were predicted using a step-wise multiple linear regression model.

 

Results

Post-operative outcomes were significantly correlated (P < 0.05) to the following parameters: measures of disease duration, age, pre-operative on-state duration, pre-operative non-dyskinesia duration, mini-metal state examination, visit time until surgery, trajectory length within subthalamic nucleus and total electric energy delivered. Using these results, the prediction model was able to predict 43.3% of the variance in motor score (UPDRS III) improvement (R2 = 0.433, P < 0.01). Pre-operative response to levodopa and the reduction of levodopa equivalent dosage was not correlated to the motor score improvement.

 

Conclusions

Our findings provide an insight into the relationship between the therapeutic outcomes and a number of factors such as micro-electrode recordings, patient-specific clinical data and post-operative DBS settings. This multi-variate model represents a novel tool for predicting the therapeutic outcomes and may aid research into the mechanisms of DBS therapy.

 

Lu YANG, Yao CHEN, Wang HAOYUAN, Lu FENGFEI, Zhang SHIZHONG (Guangzhou, CHINA)
08:00 - 18:00 #10553 - P206 Cognitive symptoms in a rat model of Parkinson’s Disease.
Cognitive symptoms in a rat model of Parkinson’s Disease.

Objective: We here investigated the effect of bilateral 6-hydroxydopamine (6-OHDA) lesions, a rat model for Parkinson’s disease(PD), on impulsivity and attention in an auditory oddball paradigm. In PD, the progressive loss of dopamine (DA) neurons in the substantia nigra leads to disturbed motor function, but cognitive disturbances, including attentional deficits and impulsivity, are increasingly recognized as disabling factors. Rats with 6-OHDA induced nigrostriatal lesions of dopamine neurons show significant motor impairment reminiscent of PD, and recent studies also indicate cognitive impairment in this model.

Methods: Rats were trained in a 3-class auditory oddball paradigm, where they had to nose poke a hole after an infrequent correct tone, which was rewarded by a pellet, but to ignore a frequent standard tone and infrequent distractor tone. After reaching a criterion of 90% correct hits, retrograde degeneration of DA neurons in the substantia nigra were induced by bilateral striatal injection of 6-OHDA (10 µg in 1µl PBS; n=12), sham-lesioned rats (controls; n=8) received vehicle. Four weeks after surgery the rats were re-tested in the oddball paradigm.

Results: After 6-OHDA lesions, rats show deteriorated attention, as indicated by a significant decrease in the hit rate to the correct tone. Additionally, the number of impulsive nose pokes was reduced compared to controls, which would indicate less impulsive behavior.

Conclusion: We conclude that rats with bilateral 6-OHDA lesions may be used to investigate the biological basis of attentional deficits in PD, and to develop and test new therapeutic strategies for these symptoms ranging from pharmacological treatment to neurosurgical intervention.

Joost HOLSLAG (Hannover, GERMANY), Anne-Kathrin BECK, Joachim K. KRAUSS, Kerstin SCHWABE
08:00 - 18:00 #10588 - P207 Reward processing modulates subthalamic beta band activity in patients with Parkinson’s disease.
Reward processing modulates subthalamic beta band activity in patients with Parkinson’s disease.

Tonic dopamine levels modulate the power of beta oscillations in the subthalamic nucleus. The physiological role of this relationship, however, remains unclear. Phasic changes in dopamine may be caused by rewards. Here, we investigated whether beta activity might therefore be related to reward processing. We recorded local field potentials (LFPs) from the subthalamic nuclei of 19 patients with Parkinson’s disease who performed a computer-based reinforcement-learning task. Afterwards, we correlated the magnitudes of patients’ obtained rewards with task-related power changes in their LFP oscillations. During reward presentation, beta activity was positively correlated with reward magnitudes. During responding, moreover, alpha and low beta activities were negatively correlated with previous reward magnitudes, while the likelihood of repeating the previous response correlated positively. Our results thereby suggest a role of beta activity in the processing of rewards, while alpha and low beta activity might be involved in reward-based response adaptation.

Henning SCHROLL, Andreas HORN, Joachim RUNGE (Hannover, GERMANY), Axel LIPP, Gerd-Helge SCHNEIDER, Joachim K. KRAUSS, Fred H HAMKER, Andrea A KÜHN
08:00 - 18:00 #10667 - P208 Predicting psychiatric symptoms after subthalamic deep brain stimulation for Parkinson's disease.
Predicting psychiatric symptoms after subthalamic deep brain stimulation for Parkinson's disease.

Introduction

A proportion of patients undertaking subthalamic (STN) deep brain stimulation (DBS) for Parkinson's disease (PD) develop postoperative psychiatric symptoms including mood and personality changes. For these individuals, quality of life after DBS may worsen rather than improve. We do not have a reliable method for predicting 'at risk' candidates. These symptoms may arise de novo even in individuals without clear pre-surgical neuropsychiatric co-morbidity. 

Methods

We followed 65 PD patients and their spouses in a prospective, longitudinal study, from pre-DBS to 6-months post-STN-DBS. Patients were phenotyped extensively using a range of neuropsychological instruments and rating scales designed to capture neuropsychiatric co-morbidity, with a focus on impulsivity and empathy. The spouse also provided information on the patient's psychiatric symptom profile and the level of carer burden. These measures were repeated iteratively in the follow up period. All patients were reviewed by a neuropsychiatrist with specialist experience in DBS for movement disorders. We collected data on the position of the active electrode contact in relation to the dorsolateral and ventromedial border of the STN and we modelled the relation of the stimulation field to the limbic, associative and motor territories of the STN. We collected high resolution diffusion imaging on 35 patients and reconstructed key white matter tracts that may be modulated by STN DBS, including the hyperdirect pathway. We also modelled the connectivities of simulated stimulation fields in in each patient. 

Results

We analysed the phenotypic data to identify predictors of post-DBS psychiatric change, utlising a Bayesian classifier, lasso and ridge regression and a random forest approach. We used the Calinski-Harabasz index to indentify the optimal number of phenotypic clusters, based on the trajectory of symptom change. We used a support vector machine to classify patients into 'cases' and 'non-cases' based on the position of their electrode contact and the relation of the stimulation field to the sub-territories of the STN. In the diffusion analysis, we used probabilistic tractography to compare streamline counts between key STN-frontal zones amongst cases and non-cases. 

Conclusions

We present a comprehensive data set that may assist with the identification of surgical candidates at higher risk of post-DBS psychiatric symptoms. This information could be used to guide preventative care. 

Philip MOSLEY (Brisbane, AUSTRALIA), David SMITH, Alistair PERRY, Peter SIBURN, Terry COYNE, Michael BREAKSPEAR
08:00 - 18:00 #10687 - P209 Directional deep brain stimulation guided by local field potentials in Parkinson Desease.
Directional deep brain stimulation guided by local field potentials in Parkinson Desease.

OBJECTIVE:

Implementation of the new directional stimulation technique of subthalamic nucleus with segmented leads guided by local field potential recordings in order to personalize DBS parameters , optimize therapeutic window and minimizing side effects.

METHODS:

Since March 2016 to January 2017, 8 patients have been implanted with 15 directional Vercise Cartesia leads (Boston SC). Mean age of patients were 57 years (38-70 years). Postoperatively CT scan and skull x-rays were performed to asses lead placement . Local field potentials of all contacts  from each lead  in bipolar montage were recorded 5 days after surgery to analyze beta band peaks and its correlation to therapeutic window effect for rigidity.

RESULTS:

No postoperative complications after directional leads implantation have been observed in any patient. After analyzing data from local field potentials, contacts with higher beta peak amplitude  have been selected to start stimulation parameters of the subthalamic nucleus with good clinical response, obtaining  after 3 months on chronic stimulation, 75.5% improvement in UPDRS-III score and  85.5% reduction of dopaminergic medication. Directional deep brain stimulation guided by local field potentials in Parkinson Desease increased stimulation thresholds for side effects as compared to spherical stimulation. Statistically significant  correlation (r= -0.31) between beta band peak amplitude and final score for rigidity was found.

CONCLUSION:

Deep brain stimulation of subthalamic nucleus with directional leads is safe and efficient. Local field potentials and beta oscillations could optimize settings parameters and alleviating programming burden as it seems to predict the optimal directional contact for improving rigidity and other motor symptoms. In advance, these neurophysiological parameters may be taken into consideration to personalize directional stimulation and can be time saving tools for programming.

Carla FERNANDEZ GARCIA (Madrid, SPAIN), Fernando ALONSO FRECH, Juan Antonio BARCIA
08:00 - 18:00 #10704 - P210 A novel animal model of Parkinson’s disease using optogenetics: representation of various disease stages by modulating the illumination parameter.
A novel animal model of Parkinson’s disease using optogenetics: representation of various disease stages by modulating the illumination parameter.

The present study aimed to investigate whether a model expressing halorhodopsin (NpHR) in dopaminergic cells of substantia nigra (SN) can induce appropriate Parkinson’s disease (PD) characteristics and whether motor symptom severity depends on the optical stimulation condition. To develop optogenetic PD models, 15 rats received hSynapsin1-NpHR-YFP adeno-associated virus injections targeted at the right SN, and then subjected to light illumination at 590 nm wavelengths for 16 h with 3 illumination conditions of 5 Hz-10 ms (n = 5), 5 Hz-100 ms (n = 5), and 50 Hz-10 ms (n = 5). To establish conventional models, 5 received 6-hydroxydopamine injections into the right medial forebrain bundle (complete model) and 6 received injections into the right striatum (partial model). The optogenetic models showed characteristic PD manifestations similar to those of the conventional models; the severity of forelimb akinesia correlated with the total illumination value (frequency × width). The group with a low illumination value (5 Hz-10 ms) was comparable to the conventional partial model, whereas the groups with high illumination values (5 Hz-100 ms and 50 Hz-10 ms) were similar to the conventional complete model. Immunofluorescent staining assays showed a decrease in tyrosine hydroxylase-positive dopaminergic neurons of SN in all optogenetic models. 

Lee EUN JUNG (Gyeonggi-do, KOREA), Yoon HYUNG HO, Jeon SANG RYONG
08:00 - 18:00 #10751 - P211 Quantitative localization and 3D shape approximation of the Subthalamic Nucleus in Deep Brain Stimulation for Parkinson Disease.
Quantitative localization and 3D shape approximation of the Subthalamic Nucleus in Deep Brain Stimulation for Parkinson Disease.

Background:

Subthalamic nucleus (STN) stimulation is an effective therapy for alleviating Parkinson's symptoms, such as tremor, rigidity and bradykinesia. Extracellular recording using microelectrode is routine for the identification of STN and accurate implantation of deep brain stimulation leads, but it is mostly qualitative. It has been shown that power spectral density (PSD) of the recorded data can be used to accurately and quantitatively identify the STN.

Methods:

We recorded human subthalamic nucleus activity during stereotactic surgery using a tungsten microelectrode (FHC, Inc). We inserted 3 parallel microelectrodes for extracellular recordings in 20 patients with Parkinson disease. Recorded data were filtered using a 500 to 3000 Hz band-pass filter, sampled at a rate of 24 kHz, converted to digital using a Leadpoint system (Medtronic, Inc) and stored in a computer for offline analysis. The PSD was calculated over the 10 second recorded data in each depth by using Welch’s method. We compared PSD at high frequency band (500 to 3000 Hz) in each of the recording depth in order to identify boarders and length of the STN. Then we fitted the best ellipsoid-shape to the 3 entrance and 3 exit points. Ellipsoid was modeled as a quadratic equation by using the least squares approach.

Result:

The high frequency band (500 to 3000 Hz) PSD increased significantly as the electrode entered the STN and remained significantly above the level of the thalamus and decreased as the electrode was exited from the STN. We approximated the 3-Dimension STN shape and orientation as an ellipsoid with respect to the 3 entrance and 3 exit points of the electrodes.

Conclusion:

PSD estimation method can identify the boarders and length of the STN in a quantitative and objective manner. Its accuracy seems to be comparable to visual inspection of the recorded signals by an expert. Intraoperative 3D shape approximation of the STN may help the physician in better placement of the DBS lead.

Ali RAZMKON (SHIRAZ, IRAN, ISLAMIC REPUBLIC), Sina SALEHI, Arsham GHAVASIEH, Amin KHOSROZADEH

Monday 26 June

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08:00 - 18:00 #10342 - P212 Deep Brain stimulation in bed nucleus of stria terminalis and medial forebrain bundle in two patients with generalized anxiety disorder.
Deep Brain stimulation in bed nucleus of stria terminalis and medial forebrain bundle in two patients with generalized anxiety disorder.

Background: Deep brain stimulation (DBS) is under investigation for major depressive disorder (MDD). Here we present two patients with severe generalized anxiety disorder treated with DBS in the medial forebrain bundle (MFB) and in the bed nucleus of stria terminalis (BNST).

Case presentation:

Patient 1: 57-year old male with a childhood onset of anxiety and MDD onset at the age of 43. When evaluated before surgery at baseline the patient scored 44 points on Montgomery-Asberg depresson scale (MADRS) and 40 on Hamilton anxiety scale (HAM-A).

Patient 2: 52-year old male with onset of MDD and anxiety at the age of 20. At baseline the patient scored 49 points on MADRS and 40 on HAM-A.

In both cases there was a history of generalized anxiety inbetween the episodes of MDD. They had tried psychotherapy, several different pharmacological treatments and ECT. After screening and informed consent, they were included in an ongoing study of DBS for MDD.

Method: In both patients two DBS electrodes were bilaterally implanted in the MFB  and in the BNST. The stimulation was started directly after surgery and the patients were randomized to either MFB or BNST DBS for three months, followed by a cross over with three months of stimulation in the other target. The patients and evaluators were blinded as to the target for stimulation.

Results:

Patient 1: Bipolar stimulation in BNST was titrated and at 3 months evaluation MADRS was reduced to 10 points and HAM-A 14. BNST stimulation was then cessated and MFB stimulation activated. After 3 months of MFB stimulation MADRS had increased to to 32 points and HAM-A 28. No adverse effects were seen in either.

Patient 2: Bipolar stimulation in MFB was initiated and at 3 month evaluation MADRS was at 44 and HAM-A 30. MFB stimulation was then cessated and BNST stimulation activated. After 3 months of BNST stimulation MADRS was 24 points and HAM-A 35. Transient visual side effects were noted during MFB stimulation and fatigue following BNST stimulation.

Conclusion: MDD patients with comorbidities such as an anxiety disorders are more likely to develop chronicity and experience a higher relapse rates. Several different brain targets are under evaluation for MDD. In this case report two patients with similar clinical picture and pre-operative symptoms responded differently to MFB and BNST stimulation. When sample sizes permit, studies on DBS for MDD might identify subgroups of patients who may respond differentially to DBS and different targets.

Matilda NAESSTRÖM (Umeå, SWEDEN), Patric BLOMSTEDT, Owe BODLUND
08:00 - 18:00 #10513 - P213 Differences between DBS of the nucleus accumbens and the internal capsule in patients with OCD.
Differences between DBS of the nucleus accumbens and the internal capsule in patients with OCD.

Objective

Several targets have been implicated in the study of the effects of deep brain stimulation (DBS) in patients with obsessive-compulsive disorder (OCD). The most common targeted areas are the nucleus accumbens (NAcc), the internal capsule (IC), the ventral capsule/ventral striatum, and the subthalamic nucleus. To these days, there is still an ongoing debate about the best target for DBS in OCD patients. Some of these structures cannot be considered as completely distinct targets since the NAcc is located immediately underneath the anterior limb of the IC and extends dorsolaterally into the ventral putamen and dorsomedially into the ventral caudate nucleus. Therefore, the differences between contact positions can decide the postoperative effect of DBS. Our objective was to study the correlation between location of active contacts within the NAcc and the IC and the clinical postoperative outcome in OCD patients.

 

Methods

Thirty-one OCD patients underwent implantation of either unilateral (N=3) or bilateral (N=28) electrodes for NAcc DBS. The Yale-Brown Obsessive Compulsive Scale (Y-BOCS) scale was applied pre and postoperatively at different time points to measure OCD symptoms. Location of the active contacts within the NAcc or the IC was determined preoperatively with MRI scans and postoperatively with CT scans.

 

Results

Stimulation parameters for the amplitude ranged between 2.5 and 6.5V (mean 3.7V), for the pulse-width from 90 to 150µs (mean 101µs), and for the frequency from 130 to 145Hz (mean 136Hz). Postoperative follow-up ranged from 9 to 51 months (mean 17 months). Y-BOCS scores from patients with active contacts in the NAcc decreased on average a 43% (p<0.05), while scores of patients with active contacts in the IC decreased a 30% (p<0.05). Interestingly, scores from patients with active contacts located in the transition zone between the NAcc and the IC (maximum distance of 1,5 mm in both directions) decreased a 54% (p<0.01).

 

Conclusions

DBS of the transition zone between the NAcc and the IC showed the best clinical outcome compared to stimulation of active electrodes located more than 1,5 mm of the transition zone in both the NAcc or the IC. Further studies are required to determine if multiple regions of this network are activated after stimulating this area.

Pablo ANDRADE (Cologne, GERMANY), Jens KUHN, Veerle VISSER-VANDEWALLE
08:00 - 18:00 #10535 - P214 Benefits of microvascular decompression on social anxiety disorder and health-related quality of life in patients with hemifacial spasm.
Benefits of microvascular decompression on social anxiety disorder and health-related quality of life in patients with hemifacial spasm.

BACKGROUND

Hemifacial spasm (HFS), an involuntary movement disorder characterized by unilateral spasms of the muscles innervated by the facial nerve, is likely to cause social anxiety disorder due to its significant facial disfigurement and may have a significant influence on a patient’s health-related quality of life (HRQoL). The goal of this study was to investigate the influence of microvascular decompression (MVD) on the severity of social anxiety symptoms and HRQoL in patients with HFS.

METHODS

Patients who underwent MVD from January to May 2015 were included in this study. Demographic data were collected before surgery. Clinical data, including the standardized measures of anxiety and depression (Hospital Anxiety Depression Scale, HADS), social anxiety (Liebowitz Social Anxiety Scale, LSAS), and the severity of HFS were assessed before surgery, 6 months after surgery. HRQoL data were collected before surgery and 6 months after surgery using the Korean version of the short form 36 (SF-36).

RESULTS

Six patients (21.4%) scored 60 or greater on the preoperative LSAS and were considered to have generalized social anxiety disorder (high-LSAS group). The duration of symptom was significantly higher in the high-LSAS group than in the low-LSAS group (7.8 ± 2.2 vs. 4.1 ± 2.6; p = 0.011). The high-LSAS group was more likely to have psychological comorbidities and had a more impaired quality of life than the low-LSAS group at preoperative evaluation. Six months after MVD, a significant improvement, compared to preoperative scores, was observed for the total LSAS score (p=0.007) and anxiety subscale score of HADS (p=0.012) in the high-LSAS group. Other significant improvements were also observed in role-emotional (p=0.039) and mental component summary (p=0.024) of the SF-36 in the high-LSAS group compared to the low-LSAS group.

CONCLUSION

This study shows that HFS patients seem to gain benefits from MVD not only for their facial disfigurement but also for social anxiety symptoms that may be associated with mental health improvements in their quality of life.

Young Goo KIM (Gyeongju, KOREA), Jin Woo CHANG
08:00 - 18:00 #10550 - P215 DBS and lesional surgery for psychiatric disorders.
DBS and lesional surgery for psychiatric disorders.

Introduction:

Neurosurgery for psychiatric patients had gathered interest in 1950s following advent of stereotaxy. However injudicious use and availability of new drugs restricted its application to a few indications practiced essentially at select centers. Following availability of DBS and its applications for treating OCD and depression there has been resurgence in the interest of offering these surgeries to the difficult to treat patients of psychiatric disorders. We report our experience in eleven patients of varied psychiatric disorders treated with DBS and lesioning procedures.

 

Materials & Methods:

The psychiatric surgery program at Jaslok Hospital and Research Centre (JHRC) was setup in accordance to the guidelines of Indian psychosurgery group (2009) and guidelines for neurosurgery for psychiatric disorders (2012), by previous approval of the ethics and scientific committee of JHRC.

From 2009 to 2017, eleven cases were operated which included eight males and three females. This  includes four patients  of Obsessive Compulsive Disorder, four  with major depression, two patients of Tourette syndrome and one having autism with OC behaviour. Four patients were offered lesional surgery and 7 were offered Deep Brain Stimulation.

Results:

Comprehensive preoperative evaluation was carried out by psychiatrist using various scales including YBOCS, MADRS, HAM-D, HAM-A, YGTSC, YBOCS, PUTS, Video Based Tic Score as applicable for the underlying psychiatric disorder. Mean age of patients at the time of surgery was 34 years. The  Postoperative follow-up ranged between 1-84 months. Significant improvement was observed in the Mean values of assessment scales after surgery. The surgical targets included area CG25 for three cases of depression, DBS of NAC for four OCD, bed nucleus of stria terminalis for one OCD DBS, NAC for autism and GPI for TS.

Conclusion:

This is the first case series of lesional surgery and DBS both offered by a single surgeon (PKD) in one centre. The varied disorders treated underscore the importance of developing similar programmes at more centres.

Siva Subrahmanyam CHIVUKULA (mumbai, INDIA), Paresh DOSHI, Bharati KARKERA
08:00 - 18:00