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BASIC SCIENCE

00:00 - 00:00 #36132 - P001 The stereological analysis of neurons in the human subthalamic nucleus.
P001 The stereological analysis of neurons in the human subthalamic nucleus.

The subthalamic nucleus (STN) is a small, lens-shaped structure and an important deep brain stimulation target for the treatment of Parkinson’s disease. Although STN has a vital role in treatment of the PD, there are still many unresolved questions surrounding its anatomical subdivision, cellular composition, and neuronal phenotype. The objective of this study was to determine the number and spatial distribution of STN neurons immunohistochemically stained for 8 neuronal markers (nNOS, NeuN, parvalbumin, calbindin, calretinin, FOXP2, NKX2.1and PAX6). The estimated total number of STN neurons was 281,308 ± 38,967. The largest population of STN neurons were nNOS positive neurons, while the smallest population were calretinin positive neurons. The spatial location of neurons was extracted from stereological dana and a three-dimensional map of spatial distribution for each of the markers was developed. The largest density of STN neurons was observed along the ventromedial border of the STN and density gradually decreased towards the dorsolateral border. All neuronal populations were present throughout the entire STN. Based on our findings we could not divide STN into separate segments. Therefore, we propose that the neurons in the STN are organized as a patchwork of small, distinct neuronal groups with specific phenotypes linked together by connectivity profiles.


Fadi ALMAHARIQ (Zagreb, Croatia), Ema BOKULIC, Tila MEDENICA, Andrija STAJDUHAR, Goran SEDMAK
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EPD02
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EPILEPSY

00:00 - 00:00 #35521 - P002 Robot-assisted insular stereoelectroencephalography in pediatric drug-resistant epilepsy: accuracy and diagnostic value.
P002 Robot-assisted insular stereoelectroencephalography in pediatric drug-resistant epilepsy: accuracy and diagnostic value.

BACKGROUND

Insular epilepsy is a well-known cause of drug resistant epilepsy (DRE) in pediatric population. It can be a source of surgical epilepsy treatment failures when not ruled-out pre-operatively. Non-invasive methods often provide limited information about its existence, being the invasive methods necessary to diagnose it in the vast majority of cases. The most used is Stereo-Electroencephalography (SEEG). We report a series of DRE pediatric patients in which insular SEEG was performed to rule out insular epilepsy.

 

METHOD

We performed a retrospective review of pediatric DRE patients operated on SEEG including insular electrodes between April 2016 and September 2022. We described the different trajectories used (orthogonal or oblique) and surgical technique. After implantation, we assessed electrodes’ precision using three measures: entry point location error (EPLE), target point location error (TPLE) and target deviation (TD). We also reported complications occurred with this technique as well as diagnostic information provided.

 

RESULTS

Overall, 32 DRE patients were operated on SEEG including insular electrodes. 401 electrodes were implanted, 148 (39,91%) of whom were directed to the insula. 112 followed an orthogonal trajectory and 36 were oblique. The mean EPLE was 1,45 mm, TPLE was 1,88 mm and TD was 0,71 mm. Three patients suffered from frontal hematoma, two of them diagnosed on post-operative MRI and one who required surgery, with no sequelae. One patient suffered from meningitis treated with antibiotics with no permanent sequelae. Nine patients (28,13%) had the insula included in the epileptogenic zone.

 

CONCLUSIONS

Insular epilepsy has to be ruled-out in DRE patients when little suspicion is obtained after non-invasive testing. This is especially important in pediatric population, in which seizure semiology is more difficult to characterize and failures to control epilepsy have devastating consequences in neurocognitive development and scholarship. Given its relative low rate of relevant complications and potential benefits, we should consider widening the inclusion criteria for insular SEEG monitoring.


Antonio GONZÁLEZ-CRESPO, Santiago CANDELA (Barcelona, Spain), Ferran BRUGADA-BELLSOLÀ, Javier APARICIO, Jordi RUMIÀ, Jose HINOJOSA
00:00 - 00:00 #35690 - P003 Baby steps into functional and epilepsy surgery: Vagal Nerve Stimulation for Medically Refractory Epilepsy: Experience from N. Macedonia.
P003 Baby steps into functional and epilepsy surgery: Vagal Nerve Stimulation for Medically Refractory Epilepsy: Experience from N. Macedonia.

Introduction: Vagus nerve stimulation (VNS) is a neuromodulatory therapeutic option for drug-resistant epilepsy. In randomised controlled trials, VNS implantation has resulted in over 50% reduction in seizure frequency in 26%-40% of patients within 1 year. Long-term uncontrolled studies suggest better responses to VNS over time;This study aimed to report the experience of VNS therapy in N. Macedonia.

Objective: This study aimed to report the experience of VNS therapy in N. Macedonia. We will go through our first steps into functional neurosurgery with the initial results from our first VNS implantation.

Methods: A prospective analysis was conducted on 10 patients who underwent VNS implantation between July 2021 and February 2023 in North Macedonia. The patients' demographic and clinical data were collected. The mean strength of stimulation and follow-up duration were also recorded. Seizure frequency and side effects were assessed during follow-up.

Result: The study included 6 women and 4 men, with a mean age at implantation of 32.4 years (range: 20-50 years). The follow-up duration ranged from 3 to 22 months, and the mean strength of stimulation ranged from 0.5 to 2.75 mA. Before implantation, all patients had daily seizures. Following VNS therapy, a seizure reduction of 30-50% was achieved. Side effects were observed in 30% of patients, with hoarseness being the most common.

Conclusion:  VNS therapy is a feasible treatment option for patients with medically refractory epilepsy who are not surgical candidates. The therapy resulted in a significant reduction in seizure frequency with an acceptable rate of side effects. Our results are comparable with previous reports. For the future functional neurosurgery in N.Macedonia, these first steps are quite encouraging both to neurosurgeons and neurologists.

                       


Elmedina ASANI (Skopje, North Macedonia), Milenko KOSTOV, Vladimir BASCAREVIC, Menka LAZARESKA, Emilija CVETKOVSKA
00:00 - 00:00 #35695 - P004 Magnetic resonance-guided focused ultrasound thermoablation for a hypothalamic hamartoma with refractary gelastic seizures in a young man: a single case report.
P004 Magnetic resonance-guided focused ultrasound thermoablation for a hypothalamic hamartoma with refractary gelastic seizures in a young man: a single case report.

Introduction. 

Magnetic resonance-guided focused ultrasound (MRgFUS) is an incisionless minimal invasive procedure capable of thermoablation through the focus of multiple acoustic beams with high intensity. Although MRgFUS is currently approved for the treatment of tremor (ET and PD) in adults, its safety and feasibility profile for intracranial lesions in the pediatric and young adult population remains unknown.

Hypothalamic hamartomas (HH) are non-neoplastic congenital gray matter heterotopias in the tuber cinereum region. Since the intrinsic epileptogenic lesions of the HH can cause unique gelastic epilepsy seizures as well as behavioral and cognitive problems, the evolution of the disease is invariably considered unfavorable.

Although open surgery results in good symptom control for HH refractory to medical therapy, there is a high complication rate of up to 30%. Alternatively, minimally invasive procedures such as radiosurgery, interstitial laser thermotherapy, or radiofrequency ablation via the stereotaxic or stereo-endoscopic approach have been shown to be safer than open surgery for HH. We propose another potential procedure, MRgFUS, as a novel treatment modality to improve the quality of life of patients with essential tremor disorders through incisionless transcranial ablative treatments.

Case report.

We report the case of a patient with HH who was successfully treated with MRgFUS for thermoablation as a disconnection surgery. A 19-year-old young man with gelastic epilepsy had been diagnosed HH at 2 years of age, and antiepileptic drugs were administered due to worsening episodes, which became multi-daily (approximately 5-6/day).

He refused surgery, radiofrequency and gamma knife radiosurgery, so he was referred to our hospital to consider MRgFUS treatment.

MRgFUS was performed using an Insightec Exablate 4000 device in a 3 Tesla MRI system, at University Hospital of Verona (AOUI), as an off-label use, according to Italian health ministry approval and patient informed consent.

Magnetic resonance imaging showed a HH (type II of the Delalande and Fohlen classification system) about 6 mm in diameter. To clarify the connections from the HH was been used diffusion tensor tractography (DTT).

The treatment was performed under general anesthesia. The thermocoagulation target was the boundary area of the HH: five therapeutic sonications at 50–53° (mean maximum) were applied to three target sites. No minor and major complications occurred during the procedure.

Clinical follow-up reveal no gelastic crises immediately after treatment. The day and the day after the procedure, MR imaging showed an oval-shaped lesion in the border area as expected.

At the follow-up of 1,3 and 6 months, the patient had a drastic decrease in seizures. The patient was able to concentrate on his work, and reported improved quality of sleep with decreased daytime sleepiness and showed no signs of hypothalamic deficit.

Discussion.

The present case indicates that MRgFUS ablation in the HH border area to disconnect the tract is effective in controlling seizures without adverse events within 6 months of the procedure.

The accuracy of ablation of a possible epileptogenic tract at the HH border without causing any damage to adjacent critical structures is of paramount importance. Effectiveness of seizure control may depend on targeting accuracy, thermolesion coverage, ablative temperature achieved, and targeted area.

Our single case experience suggests that MRgFUS is a safe treatment and may show promise in surgical disconnection epilepsy in highly selected patients with HH refractory to medical therapy, although further clinical trials and longer follow-ups are needed.


Giorgia BULGARELLI (Verona, Italy), Giuseppe Kenneth RICCIARDI, Michele LONGHI, Stefano TAMBURIN, Tommaso BOVI, Stefania MONTEMEZZI, Emanuele ZIVELONGHI, Paolo Maria POLLONIATO, Giampietro PINNA, Francesco SALA, Antonio NICOLATO
00:00 - 00:00 #35714 - P005 Displacement of the deep brain stimulation electrode implanted in the anterior nucleus of the thalamus due to chronic subdural hematoma.
P005 Displacement of the deep brain stimulation electrode implanted in the anterior nucleus of the thalamus due to chronic subdural hematoma.

Background: Anterior nucleus of the thalamus deep brain stimulation (ANT DBS) offers an option for patients with drug resistant epilepsy. This treatment modality is used in cases of epilepsy originating in eloquent brain areas, multifocal epilepsy or in cases with unidentified ictal onset zones. Although ANT DBS reduces the frequency and severity of intractable seizures less than 10 % of patients are seizure-free for specified time period after bilateral ANT DBS. Here, we present a case of left ANT DBS electrode displacement due to chronic subdural hematoma (cSH). This cSH developed after head trauma in the course of bilateral tonic-clonic seizure. To our knowledge, this is the first report of an ANT DBS electrode displacement due to cSH after focal to bilateral tonic-clonic seizure FBTCS.

Methods: A 36-year-old man diagnosed with DRE was referred for an ANT-DBS procedure. Since the age of five, he has been suffering from focal impaired awareness seizures (FIAS) and  focal to bilateral tonic-clonic seizures (FBTCS). On average, he experienced from 2 to 4 FIAS and 5 to 10 FBTCS per month. The SureTune software revealed proper placement of both DBS 3389 leads in ANT.  At 3 months after ANT DBS, the daily seizure reduction was 80 %, at 6 months the patient was seizure-free, 9 months after surgery the seizure reduction was nearly 90 %. After a FBTCS a patient had a head trauma. The computed tomography (CT) revealed small subdural hemorrhage. The repeated CT revealed large cSH over the left hemisphere. The mass effect caused by cSH produced displacement of the left ANT DBS electrode. The patient underwent successful surgery but the electrode remained out the left ANT.

Results At 12 months follow-up, the seizure frequency reduction is still about 60 %. He had 1 to 2 FIAS and 2 to 4 FBTCS monthly. The patient refused the revision surgery for replacement of the left DBS electrode.    

Conclusion

In our case, although the patient was seizure-free for nearly 4 months after ANT DBS, one  FBTCS caused head trauma with subsequent development of a large cSH. This hematoma caused mass effect with displacement of the left ANT DBS. To our knowledge, this is the first report of ANT DBS displacement due to cSH in a patient with DRE.  


Michał SOBSTYL (Warsaw, Poland), Angelika STAPIŃSKA-SYNIEC, Piotr GLINKA
00:00 - 00:00 #35717 - P006 Multifocal drug-resistant epilepsy due to tuberous sclersois complex succesfuly treated by deep brain stimulation – case report.
P006 Multifocal drug-resistant epilepsy due to tuberous sclersois complex succesfuly treated by deep brain stimulation – case report.

Background: Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by the formation of multiple tumors in various organs, mainly in the central nervous system, causing epilepsy in 79-90% of cases. At least one third of TSC patients develop drug resistant epilepsy (DRE). Neuromodulation is an option in cases of multifocal epilepsy, epilepsy originating in eloquent areas, or the inability to identify the ictal onset zone. Here, we present a case of multifocal DRE caused by TSC. A follow-up period of eight months showed that the patient's multifocal DRE was successfully treated by anterior nucleus of the thalamus deep brain stimulation ANT DBS.

Methods: A 48-year-old woman diagnosed with TSC 1 was referred for an ANT DBS procedure due to DRE. Since the age of two, she has been suffering from focal impaired awareness seizures (FIAS). Thereafter she developed at least three other types of focal seizures: visual impressions followed by manual and oral automatisms, loss of awareness lasting a few minutes with postictal confusion and right side tonic-to-bilateral tonic-clonic seizures (FBTCS). On average, she experienced one to four FBTCS per month, and 4 to 8 FIAS. A genetic test revealed a potentially pathogenic substitution for nucleotide c.914-2A-G in TSC 1 gene. There is no record of this mutation in the Human Pathogenic Mutations Database. The patient underwent bilateral ANT DBS. 

Results At the last follow-up, 8 months after surgery, there were recorded only two FIAS with a fall and four FIAS lasting few minutes without fall. None of the recorded seizures were connected with automatismes or clonia. The postictal time was shortened and lasted 30 min to 3 hours without preoperative debilitating headaches. Treatment results were satisfactory to the patient and her family.

Conclusion

In our case, bilateral ANT DBS proved to be a safe and effective way to treat multifocal DRE caused by TSC. It is only a case report with a relatively short follow-up period. More studies involving more individuals with TSC and multifocal DRE with longer follow-up periods are needed to confirm the promising results achieved in this case.

 


Sobstyl MICHAŁ (Warsaw, Poland), Paweł JEZIERSKI, Magdalena KONOPKO, Karol PIWOWARSKI
00:00 - 00:00 #35726 - P007 Impact of Deep Brain Stimulation of the Anterior Nucleus of the Thalamus on quality of life for Lennox-Gastaut syndrome: A case study.
P007 Impact of Deep Brain Stimulation of the Anterior Nucleus of the Thalamus on quality of life for Lennox-Gastaut syndrome: A case study.

Background 

Refractory epilepsy affects 20% to 30% of epileptic patients. Deep Brain Stimulation (DBS) of the Anterior Nucleus of the Thalamus (ANT) has proven its efficacy in seizure reduction for refractory epilepsy, and consequently in the improvement of quality of life. However, patients with Lennox-Gastaut syndrome, an epileptic encephalopathy with an onset in childhood characterized by intellectual disability and multiple types of seizures resistant to pharmacological treatment, are usually not concerned by this surgery due to the severity of their symptoms. Nevertheless, this surgical procedure could considerably improve their quality of life.

 

Methods

We assessed the quality of life of a 35 years-old female with Lennox-Gastaut syndrome who underwent an ANT-DBS surgery despite the severity of her symptoms. Quality of life was evaluated with the “Quality of Life in Epilepsy – 31 inventory” (QOLIE-31), one month before surgery, and 6 months after ANT-DBS. The QOLIE-31 was completed by her mother, considered as her first caregiver, given the patient mental deficiency.

 

Results

At 1-month before surgery, the patient had between 10 and 20 seizures per day. She was bedridden, did not communicate, and the only activities she took part in was eating and grooming. She had a QOLIE-31 overall score of 25/100 (z=-2.34). The emotional/psychological effects were scored 35/100, and medico-social effects were scored 24/100. The lowest score was for the “Social functioning” subscale, with a null score (z=-2.63).

From 2 months after surgery, a major reduction of seizures was reported, with a mean of 5 seizures per day, shorter and less severe. Six months after surgery, the patient’s mother reported no visible seizure for the last 15 days, as well as a significant improvement in her quality of life (Overall score of QOLIE-31 = 62/100 (m=63, sd=16 for moderate epilepsy). The emotional/psychological effects were 67/100, and medico-social effects 61/100, with a respective improvement of 91% and 154%. Social functioning was now scored 46/100. The patient was then able to walk, to communicate, and to concentrate on activities such as completing puzzles or watching TV.

 

Conclusion

This case report suggests that patients with severe refractory epilepsy who undergo ANT-DBS can achieve a significantly improvement of their quality of life. Seizure reduction involve a better cognitive functioning, social functioning, as well as emotional well-being, which contribute to a better global functioning in the daily life.


Axelle COUTURE (MONTPELLIER), Emily SANREY, Philippe COUBES, Gaëtan POULEN
00:00 - 00:00 #35971 - P008 Deep brain stimulation in a patient with progressive myoclonic epilepsy and ataxia due to potassium channel mutation (MEAK).
P008 Deep brain stimulation in a patient with progressive myoclonic epilepsy and ataxia due to potassium channel mutation (MEAK).

Background:

Progressive myoclonic epilepsy is characterized by prominent myoclonus and focal to generalized seizures. The KCNC1 mutation is responsible for specific clinical phenotype of progressive myoclonic epilepsy which has been defined as myoclonic epilepsy and ataxia due to potassium channel mutation (MEAK). We present a case of a patient with genetically proven MEAK who underwent subthalamic nucleus/substantia nigra (STN/SNr) deep brain stimulation (DBS) for his pharmacological-refractory myoclonus and drug-resistant epilepsy (DRE).

Methods:

A medical history of a 44-year-old man diagnosed finally with MEAK at age 41 years is presented. Since the age of 10, he had been suffering from an intention tremor affecting especially the left upper limb, but also the right upper limb. Subsequently, myoclonic jerks intensified, which significantly affected the patient’s performance of daily activities. Subsequently, ataxia involving the upper limbs and walking difficulties worsened. The first bilateral tonic-clonic seizure (BTCS) occurred  at the age of 22. This epileptic seizure was preceded by long work on the computer and fatigue. From the patient’s history, it was known that this BTCS was preceded by focal impaired awareness seizures (FIAS). The FIAS occurred around two years before first BTCS manifestation. The genetic testing revealed the KCNC1 mutation mainly c959G>(p.Arg320His) ultimately diagnosing MEAK. This final diagnosis was made after 31 years after first symptoms appearance. The interesting finding is that the FIAS and first BTCS appeared relatively late delaying the final diagnosis.

Based on a few promising case reports demonstrating improvements of myoclonus and seizures after DBS in progressive myoclonic epilepsy PME, we discussed with the patient this treatment modality. The patient agreed to this form of treatment, and underwent staged bilateral implantation of DBS electrodes placed in the STN/SNr region.

 

Results:

The follow-up lasts more than 24 months. The myoclonic jerks and intention tremor were reduced by nearly 60 % when compared to the baseline preoperative scores. Under bilateral STN/SNr stimulation BTCS were completely abolished.  The FIAS were reduced by around 60 to 70 %. The patient’s ataxia and dysarthria did not improve. The functional benefit consists of improvement in some activities of daily living like eating, drinking and use of the keyboard. During the first year after bilateral STN/SNr the patient was able to walk short distances (10 to 20 meters) with support. Treatment results are satisfactory to the patient and his family.

 

Conclusions:

Early and accurate diagnosis with genetic testing may significantly help in counseling patients and families. The accurate diagnosis enables also to undertake the surgical approach targeting the STN/SNr to reduce disabling myoclonus, intention tremor, and DRE. Although, in the presented case the DBS procedure was performed in advanced stage of disease, the patient due to improvement in myoclonic jerks, intention tremor and reduction of seizures gained functional benefit.

 


Michał SOBSTYL (Warsaw, Poland), Angelika STAPIŃSKA-SYNIEC
00:00 - 00:00 #36048 - P009 The human piriform cortex does not commonly participate in epileptogenic networks.
P009 The human piriform cortex does not commonly participate in epileptogenic networks.

Introduction

The piriform region has emerged as a substrate of purported pathophysiological significance in epilepsy. In particular, the area tempestus – subjacent to the frontal piriform cortex – has been of central interest due to its epileptogenic properties in animal models. Recently, a number of surgical studies on mesial temporal epilepsy have identified that resection or ablation of the temporal piriform region is associated with improved outcomes in mesial temporal epilepsy (MTE). We assessed direct electro-clinical evidence of piriform involvement in the seizure network.

Methods

Patients with medically refractory epilepsy underwent stereo-encephalography (SEEG) for the investigation of temporal or frontotemporal hypotheses. As part of a broader montage, unilateral or bilateral piriform electrodes were implanted in each patient. Piriform contact location was confirmed with imaging, and SEEG recordings were analysed for seizure onset or propagation through the piriform region.

Results

Twenty-two patients (six male) with a mean age of 30 years (SD = 7) underwent piriform SEEG. No patients had mesial temporal sclerosis (MTS). Five patients had bilateral piriform implantation. Eight patients had frontal and fifteen patients had temporal piriform recordings. One patient demonstrated seizure onset in the piriform and was accompanied by olfactory aura. Two patients showed early seizure spread, nine late spread, and nine no involvement at all in the observed seizure network.

Conclusions

The piriform cortex is not commonly directly involved in the seizure network, at least in the absence of MTS pathology. While resection of piriform tissue may lead to improved surgical outcomes for MTE, this proposition may be more germane to MTS patients. In general, our results suggest that either the piriform has an indirect role in seizure generation or the piriform is not as central to epilepsy as has sometimes been proposed.


Ashley RAGHU (Atlanta, USA), Nigel PEDERSEN, Jon WILLIE, Robert GROSS, Kheder AMMAR
00:00 - 00:00 #36193 - P010 Hemispherectomy: surgical treatment in refractory status epilepticus in adult patients.
P010 Hemispherectomy: surgical treatment in refractory status epilepticus in adult patients.

Introduction:

 Super-refractory status epilepticus (SESR) defined as seizures that persist for more than 24 hours after intravenous anesthetic drug treatment. It is associated with high morbidity and mortality, and maximum medical treatment fails in > 30% of cases.

 Methodology;

  We report 4 cases of SESR without the presence of focal masses, treated surgically. All presented SESR as a reason for admission to the ICU; they received maximal pharmacological treatment that included continuous infusion of propofol and/or midazolam. Due to therapeutic failure, hemispherectomy was proposed.

 Discussion: The SESR constitutes a challenge in clinical practice. The bibliography regarding therapeutic options after maximal medical treatment in cases associated with focal cerebral lesions (not masses) is scarce.

 Results: Three of our patients who underwent surgery, Functional hemispherectomy, were completely free of seizures and one persists with medically managed seizures.

 Conclusions: This encouraging experience proposes hemispherectomy surgery as an extreme measure in SERS with focal lesions (non-masses) in which drug treatment has failed.


Miguel VILLAESCUSA, Mauro BESARON, Carlos CIRAOLO (Buenos Aires, Argentina), Pablo Javier FORMICA SAIEG
00:00 - 00:00 #36196 - P011 Preliminary results in refractory focal epilepsy treated with deep brain stimulation (DBS) in the anterior thalamic nucleus.
P011 Preliminary results in refractory focal epilepsy treated with deep brain stimulation (DBS) in the anterior thalamic nucleus.

Introduction

 Brain stimulation of the anterior nucleus of the thalamus (ANT-DBS) is a palliative intervention indicated in patients with drug-resistant focal epilepsy (FFF) who are not candidates for resective surgery or who have not responded to vagal stimulation and/or previous resective surgery.

 Aim

 ANT-DBS reduces the frequency of seizures in patients with EFF, and although the benefits of this stimulation in this population is palliative, previous studies have reported implanted patients who were seizure-free.

 Methodology

 In the present work we analyze the preliminary results of patients implanted with ANT-DBS in our epilepsy surgery program.

 conclusions

 The preliminary analysis of our case series of ANT-DBS for EFF showed that it is a safe and effective procedure, despite the short follow-up time. As in other studies reported in our series, implantation and stimulation did not produce significant complications.

 Clinical experience can help establish the selection of candidates and stimulation parameters, to further optimize the risk-benefit ratio of this treatment.


Miguel VILLAESCUSA, Carlos CIRAOLO (Buenos Aires, Argentina), Mauro BESARON, Pablo Javier FORMICA SAIEG, Zoe AMADO
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EPD03
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IMAGING AND NEURONAVIGATION

00:00 - 00:00 #37581 - P011b Is the automatic quality control method an improvement over the manual technique? A Leksell Stereotactic Phantom study For Deep Brain Stimulation.
Is the automatic quality control method an improvement over the manual technique? A Leksell Stereotactic Phantom study For Deep Brain Stimulation.

Introduction.

Stereotaxic is a surgical technique that enables the precise localization of targets within the brain using a three-dimensional coordinate system. However, regular quality control is essential to ensure the accuracy, reliability, and safety of stereotactic procedures. Studies have shown that, based on manual methods1, stereotactic localization is accurate to within 1mm in all directions2 or follows a gradient3 with greater distortion around the periphery (>1.5 mm). Consequently, our aim is to propose a faster and more reliable automatic method and to assess the effectiveness of both manual and automatic methods.

Method.

3DT1-MPRAGE images were acquired in 1.5T MRI using a Leksell phantom. The manual method involved measuring, with the Framelink software, every 10 slices, the distance of the four ends of the frame by visually pointing out the centers of each node. Using the automatic method, the centers of each node were evaluated for all slices from the centroids with Matlab software. For both methods, the error was calculated corresponding to the difference between the estimated and theoretical distance for each slice and location: right, left, anterior and posterior. The mean error was also calculated for each location.

Results.

The 2 methods were significantly different at the right location of the frame (Figure). A negative mean error was identified at the right and left ends of the frame and a positive average at the anterior and posterior location. The standard deviation was greater using the manual method compared to the automatic method.

Discussion.

Compared to theoretical values, distortion appeared to occur in the image with stretching along the x-axis (left-right) and sagging along the y-axis (anterior-posterior). Further analysis is needed to assess distortion across the entire image, taking into account the grid and especially the center of the frame.

Our study suggest that the automatic method is the most suitable for performing quality control in stereotactic procedures. This method allows for calculations on all slices, resulting in a refined distortion profile and greater precision. Furthermore, the automatic method is faster than the manual method because it does not require manual selection of all centers. This reduces the potential for human error due to visual selection of node centers. Certainly, our results show a lower standard deviation using the automatic method than with the manual method indicating a less variability automatic measurements.

These findings imply that the automatic method provides a more reliable means of performing quality control in stereotactic procedures.

References.

1.     Gaëtan Poulen; Emilie Chan Seng; Nicolas Menjot De Champfleur; Laura Cif; Fabienne Cyprien; Jerome Perez; Philippe Coubes. Comparison between 1.5- and 3-T Magnetic Resonance Acquisitions for Direct Targeting Stereotactic Procedures for Deep Brain Stimulation: A Phantom Study. Stereotact Funct Neurosurg. 2020 Sep; 98(5): 337–344. https://doi.org/10.1159/000509303.

2.     Walton L, Hampshire A, Forster DM, Kemeny AA. A phantom study to assess the accuracy of stereotactic localization, using T1-weighted magnetic resonance imaging with the Leksell stereotactic system. Neurosurgery. 1996 Jan;38(1):170-6; discussion 176-8. doi: 10.1097/00006123-199601000-00038. PMID: 8747966

3.     C Yu, ML Apuzzo, CS Zee, Z Petrovich. A phantom study of the geometric accuracy of computed tomographic and magnetic resonance imaging stereotactic localization with the Leksell stereotactic system. Neurosurgery. 2001 May;48(5):1092-8; discussion 1098-9. doi: 10.1097/00006123-200105000-00025.


Céline CHARROUD (Montpellier), Emily SANREY, Emilie CHAN-SENG, Emmanuelle LE BARS, Nicolas MENJOT DE CHAMPFLEUR, Valérie GIL, Philippe COUBES, Gaëtan POULEN
00:00 - 00:00 #36038 - P012 Systematic error in deep brain stimulation lead placement due to incompatibility between Vantage Leksell frame and Alpha Omega microdrive.
P012 Systematic error in deep brain stimulation lead placement due to incompatibility between Vantage Leksell frame and Alpha Omega microdrive.

Introduction:

Accurate lead placement is crucial to achieve a good clinical improvement in patients who undergo deep brain stimulation (DBS). The use of a stereotactic system is imperative for maximal accuracy and minimal disturbance of the surrounding brain tissue. We recently started using the new Leksell Vantage frame in combination with the Alpha Omega Microdrive.

 

Methods:

During the period of October 2022 to January 2023 six patients underwent DBS for Parkinson’s disease. In the last four cases we observed a significant bilateral symmetrical anteromedial deviation of 1.7mm in Y-axis and 0.7mm in X-axis. This was never observed before. We performed phantom testing with the new frame itself and the combination of the frame with the Alpha Omega Microdrive. In total 23 independent testings were done.

 

Results:

We found a systematic error caused by an incompatibility between the Leksell Vantage frame and the use of a third-party Microdrive, in this case the one of Alpha Omega. The main difference is that this Microdrive is not attached to both a stop holder and a guide holder. It is hypothesized that the stop holder alone is insufficient to direct the device with enough accuracy towards the target. This also accounts for the larger shift in the Y direction in comparison to the X direction. As a result of microelectrode recording and, in some cases, macroelectrode stimulation during surgery, the definitive electrode was consistently placed at the posterior trajectory. All patients experienced good results from stimulation and there was no need for repositioning of the final electrodes.

Further testing was done using the Leksell Vantage frame and an additional guide holder provided by Alpha Omega. So far use of this extra holder is still off label. Due to this adjustment, the margin of error was back as to be expected (less dan 1 mm).

 

Conclusion:

The incompatibility between the Leksell Vantage frame and the Alpha Omega Microdrive is presumably caused by the lack of a guide holder. Since other centers in Europe are using the same set-up, which is promoted by Alpha Omega as compatible, it is important to further investigate this issue.


Fauve PONCELET, Alexander JANSSEN (Brugge, Belgium), Nikolaas VANTOMME, Stijn DEMUYNCK, Alexander VERHAEGHE
00:00 - 00:00 #36070 - P013 The Value of Tractography in Functional Neurosurgery.
P013 The Value of Tractography in Functional Neurosurgery.

Introduction Tractography is a promising technique in stereotactic and functional neurosurgery, specifically deep brain stimulation (DBS), because of its ability to reconstruct a three-dimensional image of the white matter tracts in the brain. It provides three types of anatomic information: connectivity information, as it visualises which parts of the brain are interconnected, (automatic) segmentation of brain areas based on the fiber orientation, and trajectory information by visualising the course of single tracts. However, it requires an additional diffusion weighted imaging (DWI) scan, computational power, knowledge on the use and interpretation and the accuracy in reconstructing the smaller, complex tracts remains debatable.

Aim The aim of this research is to study the value of tractography in functional neurosurgery, for various indications of DBS including Parkinson’s disease, essential tremor and dystonia, obsessive-compulsive disorder and epilepsy.

Method Literature studies on the optimal DBS target position for each of the indications will be conducted, including the need for tractography in determining these target. Additionally, experts opinions will be assembled with an international survey within the European Society of Stereotactic and Functional Neurosurgery (ESSFN). Within this survey the use of tractography in DBS care in Europe is questioned, including the influence of tractography on the decision for awake or asleep surgery and the use of micro-electrode recording during surgery, as well as the experiences of using tractography in academic settings and regular care.

Results The results will be presented in the meeting.

Conclusion With these results, a literature- and experts opinion-based consideration can be made in adding tractography to the standard DBS care for Parkinson’s disease, essential tremor and dystonia, obsessive-compulsive disorder and epilepsy, potentially resulting in higher treatment satisfaction.


Anouk J.m. ZWINKELS (The Hague, The Netherlands), Niels A. VAN DER GAAG, Maria Fiorella CONTARINO
00:00 - 00:00 #36192 - P014 Intracerebral hemorrhage an avoidable complication in deep brain stimulation.
P014 Intracerebral hemorrhage an avoidable complication in deep brain stimulation.

INTRODUCTION

Deep brain stimulation (DBS) is a widely described and effective technique in Parkinson's disease (PD), disabling tremor, and some dystonia resistant to drug treatment. One of the most feared complications is intracerebral hemorrhage during the surgical procedure.

OBJECTIVES

To assess the utility of magnetic resonance susceptibility imaging (SWI-MRI) in surgical planning for DBS.

METHODS

We conducted a prospective study from March 2021 to October 2022, which included patients who underwent DBS for the treatment of disabling movement disorders, operated on by the same surgeon. Demographic variables, comorbidities, targets, blood pressure (BP) recording during corticotomy, micro-recording paths, implanted electrodes, complications were collected. A preoperative brain MRI (1.5T) without contrast-enhanced was performed that included T1, T2, DTI and SWI volumetric sequence; this last window was useful for surgical planning avoiding subcortical and periventricular vessels (It allows to discriminate arterial and venous vessels, as well as deep vascularization). Finally, a post-surgical head CT scan within the first 24 hours to rule out bleeding complications.

RESULTS

A total of 17 patients with DBS were operated on, with a diagnosis of PD in 11 cases, essential tremor in 4 cases, postmeningitis tremor in 1 case, and cervical segmental dystonia in 1 case. Thirty-one electrodes were implanted: 18 in the subthalamic nucleus, 9 in the VIM/ASP, and 4 in the internal globus pallidus. No hemorrhage occurred, 4 cases presented minimal pneumoencephalus. One case presented disorientation and drowsiness in the first 24 hours with spontaneous improvement (related to OFF medication). In all patients, stimulation was turned on in the second day, and on the fourth day they were discharged.

CONCLUSIONS

In our study, using a protocol with MRI and cranial CT without contrast, no bleeding complications were found.

Careful surgical planning, based on the quality of the radiological image, plays a key role in avoiding bleeding complications.


Luis Mariano ROJAS-MEDINA (Madrid, Spain), Lucía ESTEBAN-FERNÁNDEZ
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MOVEMENT DISORDERS

00:00 - 00:00 #33827 - P015 Differences in intrinsic functional networks in patients with essential tremor who had good and poor long-term responses after thalamotomy performed using MR-guided ultrasound.
P015 Differences in intrinsic functional networks in patients with essential tremor who had good and poor long-term responses after thalamotomy performed using MR-guided ultrasound.

OBJECTIVE

Thalamotomy at the nucleus ventralis intermedius using MR-guided focused ultrasound has been an effective treatment method for essential tremor (ET). However, this is not true for all cases, even for successful ablation. How the brain differs in patients with ET between those with long-term good and poor outcomes is not clear. To analyze the functional connectivity difference between patients in whom thalamotomy was effective and those in whom thalamotomy was ineffective and its prognostic role in ET treatment, the authors evaluated preoperative resting-state functional MRI in thalamotomy-treated patients.

METHODS

Preoperative resting-state functional MRI data in 85 patients with ET, who were experiencing tremor relief at the time of treatment and were followed up for a minimum of 6 months after the procedure, were collected for the study. The authors conducted a graph independent component analysis of the functional connectivity matrices of tremor-related networks. The patients were divided into thalamotomy-effective and thalamotomy-ineffective groups (thalamotomy effective group, ≥ 50% motor symptom reduction; thalamotomy-ineffective group, < 50% motor symptom reduction at 6 months after treatment) and the authors compared network components between groups.

RESULTS

Seventy-two (84.7%) of the 85 patients showed ≥ 50% tremor reduction from baseline at 6 months after thalamotomy. The network analysis shows significant suppression of functional network components with connections between the areas of the cerebellum and the basal ganglia and thalamus, but enhancement of those between the pre motor cortex and supplementary motor area in the noneffective group compared to the effective group.

CONCLUSIONS

The present study demonstrates that patients in the noneffective group have suppressed functional subnetworks in the cerebellum and subcortex regions and have enhanced functional subnetworks among motor-sensory cortical networks compared to the thalamotomy-effective group. Therefore, the authors suggest that the functional connectivity pattern might be a possible predictive factor for outcomes of MR-guided focused ultrasound thalamotomy.


Hyo-Jeong KIM, Myung Ji KIM (Seoul, Korea), Chongwon PAE, Won Seok CHANG, Hyun Ho JUNG, Kyung Won CHANG, Jinseok EO, Hae-Jeong PARK, Jin Woo CHANG
00:00 - 00:00 #34416 - P016 Multimodal and multifocal neurosurgical treatment for generalized dystonia.
P016 Multimodal and multifocal neurosurgical treatment for generalized dystonia.

Objective: To evaluate the effectiveness and safety of complex neuromodulation treatment (lesioning and deep brain stimulation (DBS) of globus pallidus and subthalamic nucleus) for generalized dystonia (GD).

Background: Thalamotomy and pallidotomy are the primary ablative stereotactic treatment methods for GD. DBS has become a standard  surgical tool for various movement disorders treatment that includes GD. Complex neuromodulation treatment can be implemented to achieve better clinical results.

Methods: Twelve GD patients with a history of bilateral GPi DBS or thalamotomy or pallidotomy were qualified for a second stage surgical treatment. All of them demonstrated significant improvement that fade away six months to eleven years  after the initial surgery. Five of them, who underwent ablative procedures in the past were qualified for DBS: GPi (3 patients) and STN (2 patients). Four patients, who underwent GPi stimulation in past received additional subthalamic DBS. Three patients who underwent unilateral thalamotomy and bilateral GPi DBS received additional subthalamic DBS.

Results: Multimodal and multifocal DBS have caused sustained improvement in dystonic movement in the whole group. The improvement measured with Unified Dystonia Rating Scale (UDRS) lasted from two years to 11 years follow-up.  No surgical or stimulation related complications were reported.

Conclusions: Combined multimodal and multifocal treatment of dystonia : should be considered when dystonic symptoms aggravate over time.


Pawel ZDUNEK, Victor MANDAT, Bartosz KROLICKI, Krzysztof SZALECKI, Piotr IZDEBSKI, Henryk KOZIARA, Tomasz MANDAT (Warsaw, Poland)
00:00 - 00:00 #35558 - P017 The experiment of the military central hospital’s neurosurgery department in the dbs.
P017 The experiment of the military central hospital’s neurosurgery department in the dbs.

Aims:

Faced with the significant increase in the number of consultations in neurology at the level of our structure, for the management of Parkinson’s disease cases and especially the forms refractory to medical treatment, in the sense that the side effects of therapy have become incompatible with a self-sufficient and decent daily life; which were originally transferred overseas for deep brain stimulation (DBS), we have decided to take care of them in the neurosurgery department.

Methods:

Since 2011 we have taken care of (08) eight patients including (07) seven male and (01) one female.

The treatment consisted of the installation of a deep brain stimulator device in (07) cases including (06) cases of Parkinson’s disease and (01) case of abnormal movements in which we proceeded to a change of the stimulator after 04 years. Another patient treated for Parkinson’s disease also received a replacement of his pacemaker after 06 years of performance.

Results:

The postoperative complications observed are: pneumocephalus, headaches and depression in one case each, hypersexuality and aggressivity in one case as well.

Therefore, our results can be superimposed on all the major series, as clinical improvement and socio-professional reintegration were obtained in all cases.

Conclusions:

It is strongly recommended to manage this pathology surgically as soon as the indication is there, reckoning that the patients’ selection suggested a multidisciplinary approach: neurology, neurosurgery, psychiatry, neuropsychology, and the final decision is made based on evaluations by each discipline.

Keywords: Parkinson, dyskinesia, DBS.


Youcef HADDADI (Algiers, Algeria)
00:00 - 00:00 #35650 - P018 Proteomic profiling in cerebrospinal fluid reveal biomarkers for shunt outcome in idiopathic normal-pressure hydrocephalus.
P018 Proteomic profiling in cerebrospinal fluid reveal biomarkers for shunt outcome in idiopathic normal-pressure hydrocephalus.

Background and Objectives: The pathophysiology of idiopathic normal pressure hydrocephalus (iNPH) is unclear, and the treatment strategy remains suboptimal. This study aims to identify biomarkers for shunt prognosis by cerebrospinal fluid (CSF) proteomic profiling.

Methods: This was a longitudinal case-control study. CSF in 37 iNPH patients and 16 age-balanced controls was collected from September 2020 to March 2022, and analyzed using a mass spectrometry-based proteomics workflow. Clinical evaluation was performed on all iNPH patients, and 32 patients underwent ventriculoperitoneal shunting. The idiopathic normal-pressure hydrocephalus grading scale was used to assess clinical outcome. Postoperative CSF was also collected from 10 iNPH patients who underwent shunting surgery. Bioinformatics analysis and the random forest model were performed to identify CSF proteome changes and predictors of clinical outcome.

Results: There were 39 and 285 proteins that were significantly increased and decreased in iNPH CSF compared to control, respectively. Gene ontology analysis revealed that significantly increased proteins were mainly associated with myeloid leukocyte migration and extracellular matrix (ECM) organization, and significantly decreased proteins were primarily associated with axon development and synapse organization. In iNPH patients with good response to shunt procedure, 11 and 26 proteins were found significantly increased and decreased, respectively, compared to non-responders. A panel of 11 proteins identified using the random forest model was able to predict clinical outcome of shunt procedure in iNPH patients (AUC = 0.86). 65 proteins were significantly upregulated, predominantly associated with axon development and synapse assembly, and 125 proteins were significantly downregulated, predominantly associated with ECM organization, in the responder group after shunt surgery.

Discussion: Our findings provided support for the hypothesis that the pathophysiology of iNPH is characterized by a state of neuroinflammation, ECM remodeling and neurodegeneration, and CSF shunting can reverse such pathological state. Machine learning using preoperative proteomic profiles satisfactorily predicted clinical outcome of shunt procedure in iNPH. Future research targeting specific proteins in iNPH may be warranted to better understand disease mechanism and design patient-tailored treatment.


Zhoule ZHU, Yuqi YING, Wu HEMMINGS (Hangzhou, China), Zhu JUNMING
00:00 - 00:00 #35673 - P019 Preliminary study for validation of automatic segmentation of ventralis intermedius nucleus in tremor treatment.
P019 Preliminary study for validation of automatic segmentation of ventralis intermedius nucleus in tremor treatment.

INTRODUCTION: Essential tremor is the most common movement disorder with a prevalence of 0.9%1. In refractory cases, the ventralis intermedius nucleus (VIM) deep brain stimulation (DBS) is well established as a safe and effective symptomatic treatment1,2. 

Due to the difficulty in visualizing the VIM in MRI, the selection of the target has traditionally been done based on indirect targeting using coordinates derived from autopsy-based atlases, making corrections based on the size of the third ventricle and the distance to the internal capsule.

Nowadays, automatic segmentation technology is available for preoperative planning in numerous targets. However, in contrast to other targets as subthalamus4,5, there are not case series validating its effectiveness.

 

OBJECTIVE:  The aim of this preliminary study is to validate the Brainlab automatic segmentation algorithm in VIM lead planification for tremor DBS.

 

METHODS: We have analyzed retrospectively the differences in leads location between the group of patients treated using atlas planification and the group treated using Brainlab automatic segmentation.

 

RESULTS: We have included 17 patients and 31 leads, in the atlas group there were 10 patients and 15 leads, whereas in the segmentation group, 7 patients and 14 leads. The median age was 58 years (interquartile range (IQR): 39) in the atlas group and 68 years (IQR: 14) in the segmentation group. 90,00% (9/10) in the atlas group and 85,71% (6/7) in the segmentation group were males. The diagnosis in all cases was tremor and the target was VIM; there were 3 cases of unilateral approach because of unilateral tremor in the atlas group. The VIM size in the atlas group was 0,18 cm3 (IQR: 0,05) in the right and 0,17 cm3 (IQR: 0,04) in the left, in the segmentation group was 0,20 cm3 (IQR: 0,03) in the right side and 0,18 cm3 (IQR: 0,05) in the left. In MRI, the lead was within the VIM in 86,66% (2/15) in the atlas group and 92,85% (1/14) in the segmentation group. The lead median length within the VIM in MRI was 3,50 mm (IQR: 2,50) in the atlas group and 4,00 (IQR: 2,50) in the segmentation group. There were not significative differences between both groups for any variable.

 

CONCLUSION: We have not found any differences in the location of the lead between both groups. Thus, the following step will be compared the differences between the theoretical and the final coordinates to quantify the role of microregistration and macrostimulation.


Cristina ROMERO LÓPEZ (Sevilla, Spain), María OLIVER ROMERO, Yamin CHOCRÓN GONZÁLEZ
00:00 - 00:00 #35688 - P020 Agitation in the waiting room as non-motor off-symptom.
P020 Agitation in the waiting room as non-motor off-symptom.

Background – Non-motor fluctuations in patients with Parkinson’s disease (PD) are highly prevalent1 and negatively impact quality of life2. Here, we present the case report of two patients who had an unusual presentation of non-motor off.

Case 1 – A 42-year-old woman with a six-year history of PD was implanted with deep brain stimulation of the globus pallidus internus (GPi-DBS) a year earlier. After DBS, she had fewer motor fluctuations and dyskinesias were well-controlled. 

While waiting for the programming visits, she would often pace in the waiting room and make a nervous and agitated impression. On occasion, she would be impolite towards staff if the appointment was delayed.

Six months after implantation, it became clear that the patient has severe non-motor fluctuations despite having adequate motor control. Amplitude (of the contacts in the dorsal GPi) was increased bilaterally, and entacapone was initiated, allowing for a subtle dose reduction and dose interval increase.

These changes led to fewer non-motor fluctuations. During subsequent follow-up appointments, her behavior improved and she was no longer agitated while waiting for her appointment.

Case 2 – A 50-year-man with a 15-year history of PD was implanted with STN-DBS the year before. Post-surgery, he complained of speech and balance disturbances. Dyskinesias disappeared and the frequency and severity of decreased.

Before every programming visit, he would be very impatient in the waiting room. He was restless, and would consistently stand up from his wheelchair, perform stretching exercises, and sit back down. He became significantly irritable when the waiting time was too long.

Due to bothersome speech and gait issues, the patient was reprogrammed using local field potentials (LFP)-programming (Percept PC, Medtronic) and monopolar review. Contact levels were changed leading to superior motor control (meds-off MDS-UPDRS-III went down from 31 to 23) with improvement of speech and balance. On the new stimulation settings, he reported that his thoughts were less clouded and there was a reduction in anxiety. Notable was the fact that during this follow-up visit, the patient had patiently been waiting in the waiting room without any signs of agitation.

Conclusion – Both of the previously mentioned patients were agitated in the waiting room as they were experiencing non-motor fluctuations, and anxiously anticipating an off-state (motor and non-motor) during the visit. Improving their dopaminergic medication and/or stimulation parameters led to improvement of motor and non-motor fluctuations reflected in decreased anxiety and agitation in the waiting room.


Alexandra BOOGERS (Toronto, Canada), Taline NARANIAN, Renato MUNHOZ
00:00 - 00:00 #35712 - P021 Minimizing hemorrhagic and perioperative complications in deep brain stimulation (DBS) surgery in a series of 191 patients operated over 4 years.
P021 Minimizing hemorrhagic and perioperative complications in deep brain stimulation (DBS) surgery in a series of 191 patients operated over 4 years.

Background

Intracranial hemorrhage (ICH) in functional neurosurgery represents a relatively rare but serious complication. One of the possible risk factors related to ICH is a number of trajectories made for microelectrode recording (MER). The authors who solely rely on macrostimulation using macroelectrodes argue that the incidence of ICH is much lower while maintaining good clinical efficacy of DBS. The present study aimed to assess the incidence of ICH in DBS procedures by reducing to the minimum the number of brain passes and the diameter of guiding cannulas. For this reason, we used one MER guiding cannula exclusively for track making with subsequent macrostimulation done through the implanted DBS electrode.

Methods

All DBS procedures done between January 2018 and January 2022 in the Department of Neu-rosurgery of the Institute of Psychiatry and Neurology in Warsaw were analyzed for possible ICH and other perioperative complications. The DBS lead was implanted by MR image-guided and intraprocedural CT verified approach. No MER was done.

Results

During four years 191 patients underwent 267 DBS lead implantations in 252 stereotactic procedures. The ICH occurred in 2 patients. Both were symptomatic. Adverse symptoms re-solved within a week. 2 DBS leads required replacement. There was 1 case of hematoma at the IPG site and 1 case of pneumothorax due to tunneling of the extension.

Conclusions

Our surgical technique has a low incidence of ICH. The symptomatic ICH affected 2 patients. The other perioperative complications mentioned above required repeated surgeries or con-servative treatment. No patient suffered from permanent deficits.

 


Michał SOBSTYL (Warsaw, Poland), Angelika STAPIŃSKA-SYNIEC, Karol PIWOWARSKI
00:00 - 00:00 #35715 - P022 Pneumothorax as a complication in patients undergoing deep brain stimulation procedures.
P022 Pneumothorax as a complication in patients undergoing deep brain stimulation procedures.

Background:

Deep brain stimulation (DBS) procedure-related adverse events correspond usually to intracerebral hemorrhagic complications. The another possible source of adverse events may be related to the internalization of DBS hardware during tunneling of the connection cables in the neck region and upper thoracic region. Here, we report two cases of pneumothorax encountered just after internalization of DBS hardware.

Methods:

We present two cases of pneumothorax in patients who underwent DBS procedure. The patient numbered 1 suffered from spasmodic torticollis and developed a subcutaneous pneumothorax due to passage of a tunneling tool for placement of a connection cable. This patient after surgery developed a marked subcutaneous pneumothorax. The patient numbered 2 suffered from drug-resistant epilepsy due to tuberous sclerosis complex (TSC). This patient  also developed pneumothorax after tunneling the connection cables. Interestingly, the pneumothorax was more advanced in the left than in the right lung. In both patients the connections cables were tunnel on the right neck side.

Results:

In the patient numbered 1 the subcutanoues pneumothorax spontaneously resolved within 5 days. During this time period the patient was carefully monitored in the neurointensive unit. The patient made a full recovery. The patient numbered 2 required urgent placement of left pleural drainage. Both patients made a full recovery and further treatment was uneventful. In the patient numbered 1 the right lung apex was injured during the tunneling of the connection cable. In the patient numbered 2 who suffered from DRE and TSC the pneurmothorax involved both lungs. Probably, the cause of pneumothorax in patient numbered 2 was not strictly related to the tunneling. Patients with TSC suffer from  pulmonary involvement, which is the third most common cause of TSC-associated morbidity. Classical pulmonary complications of TSC are repeated pneumothorax, chylous effusions, and hemorrhage that leads to hemoptysis. We suppose that comorbid pulmonary TSC involvement was responsible for the development of a large pneumothorax during surgery performed in general anesthesia. 

Conclusions:

These cases demonstrate that this uncommon complication – pneumothorax can also be encountered in patients after DBS procedures. Although it is extremely rare, it must be remembered that this complication can be life-threatening. It can be caused by the mechanical damage of lung apex during tunneling the connections cables or may be related to underlying pulmonary disease in the course of TSC. Proper management of subcutaneous pneumothorax is usually conservative but excessive pneumothorax requires urgent pleural drainage. 

 


Michał SOBSTYL (Warsaw, Poland), Angelika STAPIŃSKA-SYNIEC, Karol PIWOWARSKI
00:00 - 00:00 #35719 - P023 Deep brain stimulation for essential tremor in patients with ventriculomegaly.
P023 Deep brain stimulation for essential tremor in patients with ventriculomegaly.

Essential tremor (ET) is a common movement disorder with a prevalence of 5-6%. First- and second-line medical treatments tend to improve the tremor in approximately 50% of ET patients. When the best medical treatment does not provide adequate tremor suppression, surgical treatments including thalamotomy and deep brain stimulation (DBS) are considered. Deep brain stimulation of the nucleus ventralis intermedius (VIM-DBS) is considered a safe and effective treatment. However, ventriculomegaly as in normal pressure hydrocephalus (NPH), can provide a surgical challenge. Ventriculomegaly increases the risk of breaching the ventricle during the procedure, with potential risk of intraventricular haemorrhage and target displacement. Hence, neurosurgeons may refuse to operate on ET patients with ventriculomegaly.

In this case series, we report successful bilateral VIM-DBS in a 72-year-old and 69-year-old female ET patient with significant ventriculomegaly and an increased anterior and posterior commissure (AC-PC) line. In both patients, surgery was performed under awake conditions, using macrostimulation to verify the position of the microelectrode. Both directional leads (Vercise Carthesia, DB-2203-30, Boston Scientific) were implanted on the predefined targets at AC-PC level. The VIM-DBS therapy provided an excellent tremor response which resulted in an increase of overall quality-of-life. After 5 years, the first patient developed a magnetic gait but no decrease of attention span nor urinary incontinence. Repeated lumbar punctions according to the Fisher test were performed with improvement. After a multidisciplinary team meeting, she was diagnosed with idiopathic NPH with an incomplete Hakim-Adams triad. A ventriculo-peritoneal shunt was implanted using the Keen’s point approach. After the procedure and during a total follow-up period of 6 months, she experienced a significant improvement in gait and cognition as well as an excellent tremor response.

To the best of our knowledge, we present the first report on VIM-DBS in ET patients with ventriculomegaly and illustrate that, with careful preparation, VIM-DBS can provide an excellent tremor response in patients with medically intractable ET, even in the context of marked ventriculomegaly.


Robin BOUTTELGIER (Roeselare, Belgium), Stijn VANDAMME, Frederic VERVERKEN, Wim MAENHOUDT, Du Four STEPHANIE, Jeroen VAN LERBEIRGHE, Dimitri VANHAUWAERT, Olivier VAN DAMME
00:00 - 00:00 #35724 - P024 Efficacy of Deep brain stimulation in a child with genetically confirmed Aicardi Goutières syndrome: A case report.
P024 Efficacy of Deep brain stimulation in a child with genetically confirmed Aicardi Goutières syndrome: A case report.

Variants in ADAR1 are responsible for rare and severe neurological conditions such as Aicardi-Goutieres syndrome type 6. This genetic disease is associated with basal ganglia calcification, leukodystrophy and increased expression of interferon-stimulated genes.  Movement disorders commonly occur in this condition and are often characterized by dystono-dyskinetic syndrome.

To date, Deep brain stimulation (DBS) is an effective surgical treatment for medication-refractory movement disorders. We reported a case of a child positive for ADAR1 gene mutation who underwent bilateral Globus Pallidus intern (GPi) DBS for a generalized dystonia with axial predominance.

From the first month after surgery, bilateral GPi-DBS was associated with significant improvements on both motor and functional aspects of the BFMDRS. The improvement remained stable over time until 10 years’ follow-up. This case adds to the current state of knowledge regarding efficacy and safety of long-term GPi-DBS for symptomatic control of dystono-dyskinetics syndrome related to ADAR1-variants.


Emily SANREY (Montpellier), Emilie CHAN-SENG, Philippe COUBES, Gaëtan POULEN
00:00 - 00:00 #35728 - P025 Quality of Life after Deep Brain Stimulation: A primary versus secondary dystonia comparative study.
P025 Quality of Life after Deep Brain Stimulation: A primary versus secondary dystonia comparative study.

Abstract

Background. Generalized dystonia is a motor disorder causing major limitations in daily living activities. Deep brain stimulation (DBS) is an established therapy for primary disorders, but its efficacy in secondary ones remains variable. Despite quality of life (QoL) assessment appearing to be a key issue in disabling conditions for understanding the whole impact of surgical treatment on daily life, the available questionnaires are not well adapted.

Methods. Herein, QoL after DBS was evaluated using a “homemade” scale. The DBS-QoL scale is a new questionnaire specifically dedicated to generalized dystonia patients.

Results. Twenty-one DYT1 patients and forty cerebral palsy patients underwent GPi-DBS between 1997 and 2010. Clinical improvement was measured on the BFMDRS and compared to the evolution of quality of life on the DBS-QoL. We objectively identified a significant positive impact of DBS on the motor and functional aspects for both groups, with a superior gain in DYT1 patients. In this group, we found a significant feeling of improvement on functional aspects, whereas in perinatal hypoxic patients, the opposite profile was reported, with better satisfaction for wellbeing. With both etiologies, the patients were satisfied about the surgical outcomes (83%).

Conclusions. QoL assessment, using a dedicated scale, was confirmed to be complementary to BFMDRS for enhancing subtle improvements of symptoms in patients treated with DBS.


Emily SANREY, Emilie CHAN-SENG, Lydia ALBERT, Marylou GRASSO, Philippe COUBES, Gaëtan POULEN (MONTPELLIER)
00:00 - 00:00 #35734 - P026 DBS primary cell IPG replacement: safety and performance in the ADROIT study.
P026 DBS primary cell IPG replacement: safety and performance in the ADROIT study.

Background: Deep Brain Stimulation (DBS) is a common therapy for movement disorders, wherein targeted stimulation of structures in the brain is used to ameliorate symptoms of the movement disorder. This therapy utilizes Implanted Pulse Generators (IPG) which may useeither primary cell or rechargeable cell batteries. Primary cell batteries have the advantage that they require no patient interaction to sustain electrical power over their lifetime, whereas rechargeable IPG require regular charging sessions to maintain power. However, once a primary cell IPG battery is depleted, surgical replacement of the IPG is required. This need for periodic surgical replacement of the IPG has let to questions regarding the risks associated with these additional surgical interventions. Additionally, there are some questions on whether therapy performance is maintained following primary cell IPG replacement. The ADROIT trial enrolls patients receiving IPG replacements of Abbott DBS IPGs. This provides a large cohort to explore safety and outcomes associated with primary cell IPG replacement procedures.

Methods: ADROIT is an international, prospective, post-market, observational study of Abbott DBS systems. ADROIT has enrolled patients at 41 centers to collect long-term safety and effectiveness data on DBS therapy. Participants receiving either de-novo IPG implant or IPG replacement are enrolled prior to the surgery and assessed at baseline, followed by and assessment at 6 months and annually for 5 years.

Results: As of December 2022, 8 sites had enrolled 87 participants for replacement of their existing IPGs with an Abbott Infinity IPG. These included 56 replacements of an existing Infinity IPG, and 23 replacements of Legacy Abbott systems. Of the 85 participants with data for the replacement surgery, 1/85 (1.2%) experienced an event adjudicated to be procedure related: worsening of symptoms related to gait which could be partially resolved with programming. Of 30 participants, 19 Parkinson’s disease and 11 disabling tremor, had completed both baseline and 6 month evaluations with medication-on and stimulation-on at the time of this analysis. There was no mean change between baseline and 6 months of MDS-UPDRS part III (0.9 ± 15 (2.6%, p=0.86)) and FTM-TRS (-3.6 ± 11.8 (-9.6%, p=0.68)) for these participants at 6 months.

Conclusions: These data confirm the safety and efficacy of primary cell DBS replacement procedures. Despite the surgical intervention of replacing the IPG, no infections occurred in the 85 logged battery replacements, suggesting that these procedures are very low risk. The only recorded adverse event of worsening gait symptoms resolved through programming changes, is the kind of event that neurologists frequently manage in movement disorder patients, and does not appear to suggest anything about the replacement procedure itself. Clinical evaluations show a small and non-significant worsening of symptoms for the Parkinson’s disease cohort, and a similar small but non-significant improvement in symptoms for the disabling tremor cohort. These findings suggest that replacement of constant current IPG systems like those in this study does not result in significant changes in symptoms after 6 months. These findings can help inform battery selection and its associated risks.  The ADROIT study has thus far shown minimal procedure-related events and effective therapy maintenance, providing continued evidence that with proper surgical technique and use of antibiotics, primary cell battery replacement is safe and effective.


Martin GLASER, Ashkan KEYOUMARS, Alireza GHARABAGHI, Marta NAVAS GARCIA, Michael FRASSICA, Tucker TOMLINSON, Sergiu GROPPA (, Germany)
00:00 - 00:00 #35779 - P027 The tractography a useful tool in brain asymmetry.
P027 The tractography a useful tool in brain asymmetry.

INTRODUCTION

Deep brain stimulation (DBS) is a widely described technique that is highly effective in disabling tremor resistant to drug treatment. Several targets have been described with good results. Advances in radiology could play a fundamental role in surgical planning in complex cases.

OBJECTIVE

We report a clinical case with brain asymmetry, that was underwent to DBS at VIM/PSA, the planning was assisted by tractography to locate the dentato-rubro-thalamic tract (DRTT).

METHODS

52-year-old male left-handed, history of perinatal hypoxia with sequelae right spastic hemiparesis, epilepsy, hypertension. He has presented disabling tremor in the left upper limb for 15 years, resistant to Propranolol (presents syncope when increasing the dose), Primidone and Gabapentin. Fahn-Tolosa-Marín scale was 32 . Preoperative brain MRI (1.5T) was performed with T1, T2 and DTI volumetric sequence, showing area of left hemispheric encephalomalacia, brain asymmetry due to retraction, and displacement of the third ventricle to the left side. Planning of the right intermediate ventral nucleus and posterior subthalamic area (VIM/PSA) was carried out with tractography of the dentato-rubro-thalamic tract (DRTT). A directional electrode and neurostimulator was implanted in the same time without complications. On the second day the stimulation was activated and on the fourth day the patient was discharged.

RESULTS

Twelve months post-surgery, we observed a significant reduction in tremor Fahn-Tolosa-Marín Scale 8, not dysarthria, and independent of his activities (limited only by his spastic hemiparesis). 

Currently, programming stimulation is monopolar 3-; 2.7mA; 60mS; 149Hz, without drug treatment.

CONCLUSIONS

Tremor target planning is usually based on indirect methods using the intercommissural line and the wall of the third ventricle, however a brain asymmetry can lead to a bad position of the lead. Currently, tractography allows us to reconstruct the DTRTT in complex cases, achieving excellent tremor control, fewer adverse effects, and low-intensity stimulation.


Luis Mariano ROJAS-MEDINA (Madrid, Spain), Lucía ESTEBAN-FERNÁNDEZ, Estrella BARRERO RUÍZ, Alberto ACITORES CANCELA, María PÉREZ PÉREZ, Luis LEY URZAIZ
00:00 - 00:00 #35781 - P028 Gait characteristics in Parkinson's Disease: changes over time between patients with or without DBS.
P028 Gait characteristics in Parkinson's Disease: changes over time between patients with or without DBS.

Objectives. In its evolution, Parkinson’s disease (PD) shows a progressive loss of both motor and cognitive functions1. Different studies demonstrate the evidence of gait involvement by executive functions impairment2. Deep brain stimulation (DBS) treatment has also been proven to affect gait parameters3.

Materials. We use standardized clinical scales to assess motor (H&Y, UPDRS-III) and cognitive (MMSE, MoCA, FAB) symptoms of PD patients. Other factors have been taken in account (i.e. Levodopa Equivalent Daily Dose, LEDD). Gait related motor aspects are otherwise described through the use of a medical device (G-Walk®) worn around the waist by patients while performing standardized gait tests (siw minute walking test, 6MWT; and extended Timed Up and Go test, eTUG).

Methods. Patients (n=24) affected by PD were studied among a multicentric observational study considering evolution of the disease during time (Clinical Trial.gov Identifier: NCT04297800). Inclusion criteria considered: diagnosis of idiopathic PD; intermediate phase of disease (H&Y between 2-3); age between 55-74 years. Exclusion criteria consider dementia and those clinical conditions that may limit locomotor capacities or cardio-pulmonary resistance. Although DBS represented an exclusion criterion, we also considered three people with bilateral STN-DBS implantation as long as they carried stable parameters of stimulation by the time of enrollment and because their stimulation parameters remained unchanged during the time of observation. Patients were assessed at baseline and at one-year follow-up.

Results. We enrolled 24 patients (M/F 15/9), with a mean age of 65,08±5,45 years, equally distributed for clinical presentation (rigid-akynetic/tremor-dominant 11/13), mainly in H&Y fase 2 of the disease (83,3%). Along the first year of investigation we observed inconsistent changes in motor characteristics (UPDRS-III); in the 6MWT, mean cycle length and mean speed showed slight decreasing trend (-0,07±0.01 meters, and -0,07±0.01 m/s respectively); patients with DBS showed slightly more severe gait parameters at enrolment and changes after one year were somewhat pronounced (-0,19±0.11 meters, and -0,09±0.2 m/s) respect those without DBS (-0,04±0.01 meters,  and -0,05±0.02 m/s). Cognitive tests showed no significant changes among patients during time, and with not consistency among different tests.

Discussion. The differences observed in DBS patients may be affected by the more severe stage (H&Y 2,5) and longer duration of disease (15,1 VS 5,9 years) in these patients rather than by an actual effect of chronic brain stimulation.

Conlusions. For these findings to be informative, they need further observations on a larger sample of patients. In addition, the completion of the study for the entire planned observation time (three years) could provide further evidence for evaluation.


Dario ALIMONTI, Roberto DONATI (bergamo, Italy), Zangari ROSALIA
00:00 - 00:00 #35857 - P029 Spinal cord stimulation for severe primary progressive freezing of gait.
P029 Spinal cord stimulation for severe primary progressive freezing of gait.

Objective

Primary progressive freezing of gait (PPFG) is a rare disorder associated with atypical parkinsonism which often is refractory to medical treatment. Since deep brain stimulation of targets such as the subthalamic nucleus or the pedunculopontine region have not shown stable longterm improvement, there is a need to explore new treatment paradigms. Here we report on a pilot study of spinal cord stimulation evaluating its safety, tolerability and efficacy in PPFG.

Methods

Both patients had a diagnosis of PPFG with a history of freezing for 5 and 6 years, respectively. Patient 1 was a 77-year-old woman, patient 2 was a 68-year-old man. Freezing was refractory to dopaminergic medication in both instances. There were frequent falls and patients were severely disabled by freezing. Epidural electrodes for spinal cord stimulation were implanted at mid-thoracic levels, in patient 1 via a small laminotomy (plate electrode), and in patient 2 via a transcutaneous approach. Upon test stimulation both patients had marked improvement of freezing which was objectified by standardized videotaping and assessment. For chronic stimulation a frequency of 40 Hz was used at a pulse width of 320 and 450 microsec, respectively, with an amplitude producing paraesthesias (up to 6 V).

Results

Patient 1 benefitted from short-lived improvement for four weeks, and patient 2 for a period up to six months. Thereafter the initial benefit could not be sustained despite multiple attempts of modifying the stimulation settings.

Conclusion

Spinal cord stimulation for severe freezing of gait shows transient benefit, however, with limited longterm perspectives. Future studies are needed to explore alternative stimulation algorithms such as artificial intelligence and adaptive routines.

 


Assel SARYYEVA (Germany, Germany), Joachim RUNGE, Christoph SCHRADER, Joachim K. KRAUSS
00:00 - 00:00 #35860 - P030 Complexity of fractal patterns in motor cortical oscillatory activity in rodent models of Parkinson disease.
P030 Complexity of fractal patterns in motor cortical oscillatory activity in rodent models of Parkinson disease.

Background: Previous studies demonstrated enhanced beta-band activity in rat models (haloperidol (HALO), and 6-hydroxydopamin (6-OHDA)) of Parkinson disease (PD), which was reduced after administration of the dopamine-receptor agonist apomorphine (APO) or deep brain stimulation (DBS) of the subthalamic nucleus (STN), respectively. Fractal dimension (FD) analysis is a nonlinear approach that quantifies the complexity of neuronal activity. Little is known about nonlinear analytic approaches, such as FD analysis, to characterize pathological network activity in PD.

Objective: To investigate whether motor cortical oscillation changes in fractal patterns are associated with a change in the FD in the HALO and the 6-OHDA rat model of PD.

Methods: In the acute HALO rat model of PD, an ECoG array was placed subdurally above the MCtx area in male Sprague-Dawley rats. Thereafter, ECoG was recorded in the free moving rat in three conditions: (1) basal activity, (2) after injection of HALO (0.5 mg/kg), and (3) with additional injection of APO (1mg/kg). In the chronic model, 6-OHDA was unilaterally injected into the medial forebrain bundle, sham-lesioned control rats received vehicle. A stimulation electrode was then implanted in the ipsilateral STN, and an ECoG array placed subdurally above the MCtx area. Thereafter, ECoG was recorded in the free moving rat with two conditions: (1) during basal activity, and (2) during STN DBS. The ECoG signals were band-pass filtered between 1–100 Hz and sampled at 1 kHz. Furthermore, the raw data were down-sampled at 250 Hz and Higuchi's FD algorithm was applied for analysis of the raw ECoG data.

Results: In the MCtx area, the average FD values were higher in both the HALO and the 6-OHDA rat model as compared to basal activity and sham-lesioned control rats. Further, injection of APO or STN DBS decreased the average FD values in both models (P<0.001).

Conclusion: In PD rat models, the neural dynamics can also be characterized by FD. The non-linear analysis of FD allows to detect oscillation-based pattern changes achieving robust temporal resolution. This analytic approach may be integrated into future research concerning therapeutic algorithms for PD, such as adaptive closed loop stimulation, thus providing an alternative and possibly efficient biomarker of pathological network activity in PD.


Arif ABDULBAKI (Hannover, Germany), Alam MESBAH, Milakara DENNY, Joachim K. KRAUSS, Kerstin SCHWABE
00:00 - 00:00 #36009 - P031 Infected internal pulse generator: Enterococcus bacteremia and colon cancer.
P031 Infected internal pulse generator: Enterococcus bacteremia and colon cancer.

Enterococcus is a significant cause of nosocomial infection in the elderly, and multiple portals of entry have been described, including infectious, inflammatory, or infiltrative bowel conditions. One of the rare but devastating complications of deep brain stimulation is internal pulse generator (IPG) infection. In most cases, removal of the device is required, despite appropriate antibiotic therapy. Here, we present a case of Enterococcus faecium bacteremia in a patient with an infected IPG that led to a diagnosis of colorectal adenocarcinoma. The patient was a 62-year-old male with a 12-year history of Parkinson's disease. The patient underwent bilateral subthalamic nucleus deep brain stimulation surgery according to our standard protocol in 2018. While an IPG replacement was planned due to battery depletion, the patient presented with swelling on the IPG site. He was afebrile and clinical examination failed to reveal any symptoms or signs of central nervous system infection. He underwent an ultrasound and computed tomography examination, and the subcutaneous collection was reported as a seroma. A week later, he had spontaneous discharge, and wound discharge cultures revealed gram-positive cocci, further identified as Enterococcus faecium. The susceptibility panel showed no resistance, and vancomycin was initiated at 15 mg/kg every 12 hours. He was hospitalized, and it was decided to remove the IPG and extension cables. During post-operative follow-up, he suffered dyspnea one week later, and a thoracic computed tomography scan revealed a wall thickening at the level of the splenic flexure and a collection containing gas and liquid densities in the mesocolon. Further investigation revealed closed perforation, and the patient underwent a left hemicolectomy. Histopathology of colon mass disclosed moderately differentiated adenocarcinoma (pT3 N0 M_). 4 months later, the IPG was repositioned in a new subcutaneous pocket fashioned superficial to the rectus sheath opposite to the site of the original placement. A new lead extender was then tunneled under the scalp and attached to the DBS leads proximally and to the IPG distally. Post-operative vancomycin was administered, and the antibiotic treatment was continued for one week. At the 1-month follow-up examination, the patient showed no signs of local infection. IPG infections are usually caused by low-virulence organisms; the microorganisms most frequently implicated are the coagulase-negative Staphylococci. However, Enterococci are also capable of causing infections, especially in elderly or debilitated individuals whose mucosal or epithelial barriers of the human gut have been disrupted. There are few reports in the literature of an association between Enterococcus and colorectal adenocarcinomas. Clinicians dealing with deep brain stimulation hardware infections should consider Enterococcus bacteremia as a potential manifestation of colon cancer, especially in patients without a clear source of bacteremia.


Yavuz SAMANCI (Istanbul, Turkey), Ali Haluk DUZKALIR, Özgür ÖZTOP ÇAKMAK, Özlem AYAZ, Mahir KAPMAZ, Selçuk PEKER
00:00 - 00:00 #36028 - P032 Intraoperative local field potential recording used to select the individualized stimulation for Holmes tremor.
P032 Intraoperative local field potential recording used to select the individualized stimulation for Holmes tremor.

Objective:

To evaluate the intraoperative local field potentials (LFPs) recorded from the contacts, related with the effect of tremor suppression retrospectively.

 

Background:

DBS is effective for alleviating the intractable Holmes tremor and usually the ventral intermediate nucleus (Vim) and/or the caudal zona incerta (cZi) are selected. When the lesions of midbrain or thalamus are evident, additional targeting of GPi can be selected (Espinoza Martinez JA et al., Neurosurg Rev. 2015). In order to decide whether GPi-DBS is necessary or not, we considered the intraoperative LFP recordings.

 

Methods:

Three cases are enrolled; case 1 is a forty-one-year old male, and has tremor due to the cerebellar lesion induced by SARS-Cov-2 vaccination; case 2 is a forty-three-year old male and has tremor due to the midbrain and thalamic hemorrhage induced by cavernous hemangioma; case 3 is a sixty-three-year old female and has tremor due to the thalamic hemorrhage. Vim and cZi targets were planned using the MRI and the diffusion tensor imaging (DTI) was referred (BrainLab neuronavigation system). LFPs were obtained with the bipolar recordings from the implanted electrodes (bandpass filter 1-300 Hz, sampling frequency 1 kHz). Kinetic tremor was assessed using the FTM Tremor Rating scale at the upper arm on the affected side as expressed by the improvement rate (100% means full recovery and 0% no recovery).

 

Results:

In case 1, the fibers of the dentaterubrothalamic tact (DRT), which is supposed as the cause of Holmes tremor, were clear around the target before operation and the LFPs were sufficiently recorded. Vim-DBS started and suppressed his tremor (75%). In case 2, the DRT fibers were few but the many fibers came from the red nucleus. The LFPs were sufficiently recorded. Vim-cZi DBS started and suppressed his tremor (100%). In case 3, the fibers which come from the red nucleus were few and the intraoperative LFPs were almost no recorded in Vim but clearly seen in GPi. The GPi-DBS was added and its effect was 75% compared to the effect of Vim-DBS (0 – 25%).

 

Discussion:

The LFPs reflect the sum of membrane potentials and the sufficient activities mean the preserved cell functions which are difficult to predict preoperatively from the MRI and DTI.

 

Conclusion:

Not only the preoperative DTI information but also the intraoperative LFP recordings may be helpful for selecting the optimal targets of DBS for Holmes tremor.


Nagako MURASE (Nara City, Japan, Japan), Mariko TANAKA, Ryuji YAMAKAWA, Takaki HIROSE, Hisashi SAKITA, Keiya OHARA, Kiyoshi NAGATA, Tatsuo SHIMOKAWARA, Hidehiro HIRABAYASHI
00:00 - 00:00 #36052 - P033 Feasibility of Combining Remote Programming and Remote Monitoring Towards a Closed Loop DBS System.
P033 Feasibility of Combining Remote Programming and Remote Monitoring Towards a Closed Loop DBS System.

Background

Deep Brain Stimulation (DBS) is an effective therapy for Parkinson’s Disease (PD). However, it is currently applied in an open loop fashion and symptom management relies on iterative programming. The future of this field is trending towards a closed loop system. Identifying reliable and robust feedback signals is a major challenge in closed loop DBS implementation. Thus, we here aim to combine remote monitoring and programming to identify specific sensor signals that correlate with DBS programming and symptom profile changes.

 

Methods

Ten subjects undergoing STN-DBS implantation for the treatment of PD with the Abbott Infinity DBS system will be included. In addition to remote UPDRS, we will collect several other measures remotely, including PDQ-8 and a programming experience survey. In addition to survey outcomes, we will collect kinematic data from wearables, specifically a smartwatch. Remote programming will be administered using the Abbott Neurosphere Virtual Clinic platform. 

 

Results

The study is currently in data collection phase, with currently only preliminary results from five patients (analysis in progress). Primary endpoints include outcomes from patient reported (PRO) and clinician reported outcome (CRO) surveys, number of remote programming sessions and compliance with remote monitoring. Clinical outcomes will also be assessed at the 6-month time point. Exploratory endpoints will focus on correlating clinical outcomes with motor fluctuations as identified from wearable data.

 

Conclusion

Closed-loop neuromodulation systems require technical capabilities to simultaneously record and stimulate the patient. Here, we aim to establish the feasibility of combining these capabilities with the eventual goal of identifying robust digital biomarkers that can serve as the feedback signal for an automated system.


Ioana-Daria BOGDAN, Mark KUIJF, Douglas LAUTNER, Yagna PATHAK (Plano, TX, USA), Pieter KUBBEN
00:00 - 00:00 #36108 - P034 Radiofrequency Lesioning for hemidystonia: a systematic review.
P034 Radiofrequency Lesioning for hemidystonia: a systematic review.

Background

Radiofrequency lesioning (RL) has been a mainstay in functional neurosurgery to treat dystonic movement disorders, which was replaced by deep brain stimulation (DBS) in the late 1990s. Studies on RL have shown variable benefit in patients with hemidystonia. The aim of this systematic review is to summarize published reports on RL for hemidystonia and to evaluate clinical outcome.

Methods

A systematic literature review was performed according to PRISMA guidelines in PubMed, Embase, and Web of Science using a customized software (UiPath, NY) to identify all case reports, case series, and cohort studies reporting patients with hemidystonia treated with RF. Manuscripts were then automatically searched for the search term "hemidystonia". The selected manuscripts were manually screened to identify appropriate reports.

Results

More than 20 reports were identified with 118 cases published between the years 1982 - 2022. Thalamotomy was performed in 88 cases, pallidotomy in 27 cases, and both in the remaining 3 cases. Until 1998, improvement in hemidystonia was not quantified using standard rating scale. Qualitatively good improvement was reported in 18/39 (50%) patients with hemidystonia after thalamotomy. In addition, newer reports indicated a 35% benefit in BFMDRS total score in 7 patients and 60% in 15 patients, respectively. With respect to pallidotomy, 4/8 (50%) patients for whom individual patient data were available were classified as responders, when considering a 20% cut-off for improvement. The lack of a standardized assessment of the results contributes to the difficulty in interpreting the outcome.

Conclusion

With recent advances in targeting methods, RL may be reconsidered as a treatment option for hemidystonia as an alternative to DBS. Further studies with standardized assessment of outcomes are needed to better characterize variability in outcome and to identify prognostic factors.


Arif ABDULBAKI (Hannover, Germany), Amr JIJAKLI, Paresh K DOSHI, Joachim K. KRAUSS
00:00 - 00:00 #36120 - P035 General anesthesia for deep brain stimulation surgery and anatomy-based targeting for Parkinson’s Disease – 2-year clinical follow-up.
P035 General anesthesia for deep brain stimulation surgery and anatomy-based targeting for Parkinson’s Disease – 2-year clinical follow-up.

Introduction 
Subthalamic nucleus deep brain stimulation (STN-DBS) for Parkinson’s disease (PD) is typically performed in awake conditions with microelectrode recording. 
The advantages /disadvantages of local vs general anesthesia (GA) in long-term clinical outcomes are still in research and controversial. 

Material and Methods 
We retrospectively analyzed the results following bilateral STN-DBS for PD implanted under general anesthesia from November 2019 until January 2023. 
The surgery is performed after determination of the stereotactic coordinates of the STN using direct visualization and targeting on high-resolution 3T-MRI, without MER. Perioperatively, imaging using the O-arm was performed after lead implantation and instantly compared with the preoperative MRI. 
In follow-up we determined the Unified Parkinson’s Disease Rating Scale Part III (UPDRS-3), Parkinson’s disease questionnaire-39 (PDQ-39), Levodopa equivalent daily dose (LEDD), the number of lead trajectories, mean operating time and complication rates, postoperatively at 1 and 2 years. 

Results 
Thirteen patients received bilateral STN-DBS for PD. The mean age at the time of surgery was 63 years. The mean follow-up is 19,5 months and still ongoing. The mean operating time was 303 minutes, including pulse generator implantation. Five out of thirteen patients had a perioperative unilateral lead revision, after evaluation and comparison of the perioperative O-arm CT-scan with the preoperative planned trajectory in the Brainlab software. 

There were no perioperative intracerebral hemorrhages. One patient presented with a chronic subdural hematoma within 3 months postoperatively.

The mean improvement rates in UPDRS-3 were 23,6%, at 6 and 12 months (compared to 16,8% in GALAXY). The mean LEDD decrease was 64,6% and 65,3%, at 6 and 12 months, respectively (compared to 62,1% in GALAXY).

 

Our data was compared and consistent with the results obtained from the GALAXY randomized clinical trial (local vs general anesthesia with MER at baseline vs 6 months postop), as seen in the figures below.


Conclusion 
As compared to recently published data, we obtain similar clinical outcomes with STN-DBS placed under GA. Overall asleep surgery is experienced as less burdensome and is shorter than awake surgery. It is therefore a good alternative in (anxious and claustrophobic) PD’s patients.


Jeroen CORTIER (Ghent, Belgium), Stijn VANDAMME, Wim MAENHOUDT, Stephanie DU FOUR, Jeroen VAN LERBEIRGHE, Dimitri VANHAUWAERT, Olivier VAN DAMME
00:00 - 00:00 #36122 - P036 Thalamic deep brain stimulation surgery for refractory tremor in Bassen-Kornzweig syndrome.
P036 Thalamic deep brain stimulation surgery for refractory tremor in Bassen-Kornzweig syndrome.

Introduction 
Bassen-Kornzweig syndrome or abetalipoproteinemia is a rare autosomal recessive disorder characterized by a malabsorption of dietary fat and fat-soluble vitamins. This deficiency can lead to a variety of symptoms, including hematological (acanthocytosis, bleeding tendency), neurological (tremor, spinocerebellar ataxia), neuromuscular (myopathy), ophthalmological symptoms (retinitis pigmentosa). The thalamic ventral intermediate nucleus (VIM) is a well-established target for deep brain stimulation (DBS) in the treatment of refractory tremor. 

Material and Methods 
We report a 31-year-old male who suffers from abetalipoproteinemia since the age of 17. He underwent bilateral VIM-DBS to treat his disabling refractory intentional tremor at the age of 31. 

Results 
He experienced a very good response regarding his cerebellar tremor with limited stimulation adaptations postoperatively (see video and tabel). The treatment significantly improved his ADL functions and therefore also the QoL. 

Conclusion 
The VIM target for DBS in the treatment of refractory tremor has been extensively reported in the literature. Thalamic VIM-DBS is a safe and effective treatment for a severe, refractory tremor as a neurological symptom caused by abetalipoproteinemia. It also highlights the importance of a multidisciplinary follow-up, to adjust and optimize the stimulation/medication balance after VIM-DBS surgery.


Jeroen CORTIER (Ghent, Belgium), Stijn VANDAMME, Wim MAENHOUDT, Stephanie DU FOUR, Jeroen VAN LERBEIRGHE, Dimitri VANHAUWAERT, Olivier VAN DAMME
00:00 - 00:00 #36138 - P037 Combined Globus pallidus internus and thalamic deep brain stimulation in the management of adult-onset isolated segmental dystonic tremor: case report and systematic review of the literature.
P037 Combined Globus pallidus internus and thalamic deep brain stimulation in the management of adult-onset isolated segmental dystonic tremor: case report and systematic review of the literature.

Introduction

Dystonic tremor is a rare phenotype of segmental dystonia. It is usually medically refractory and responds poorly to Botulinum toxin injection. We report a case of adult-onset isolated idiopathic dystonic tremor that benefited from combined pallidal and thalamic deep brain stimulation (DBS).

Methods

Clinical data was prospectively collected. Pre- and postoperative dystonia and tremor severity, as well as quality of life (QoL) data were quantified using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS), the Fahn-Tolosa-Marin Tremor Rating Scale (FTM) and QoL scales. A systematic review of the literature using PubMed advanced search engine with the words: “deep brain stimulation” and “dystonic tremor” following the PRISMA guidelines was performed.

Case report and Results

A 67-year-old right-handed male, general dental practitioner, presented with a 15-year history of dystonic tremor of the right upper limb. The dystonic tremor precluded him of using his right dominant upper limb for activities of daily living, but mainly for skilled working tasks. He had been previously submitted to throughout neurological investigation and medical management, including electroneuromyography-guided application of Botulinum toxin with unsatisfactory improvement. He underwent combined unilateral DBS of the left posteroventral Globus pallidus internus (GPi) and the Ventral intermediate nucleus of the Thalamus (Vim). Interestingly, isolated Vim stimulation led to a complete resolution of the tremor component, but to insufficient control of his dystonic movements, which responded better to GPi-DBS. Pallidal stimulation alone, on the other hand, was insufficient to provided adequate tremor control. Titration of the stimulation parameters with both GPi and Vim electrodes led to optimal control of his symptoms, with an overall percentage improvement in BFMDRS (preop motor 6, disability 4; postop motor 1, disability 1) and in FTM (preop 26; postop 4) rating scales of 80% and 73%, respectively, at 6-month follow-up, allowing the patient to resume working activities.

Conclusion

A combined GPi and Vim approach aiming to modulate both the pallidothalamic and the dentato-rubro-thalamic-tract fibres should be considered for patients with coexistence of severe isolated segmental dystonic tremor.


Luciano FURLANETTI (Sao Paulo, Brazil), Guilherme RICCIOPPO, Joyce YAMAMOTO
00:00 - 00:00 #36143 - P038 Deep brain stimulation of the intermediate ventral thalamic nucleus for orthostatic tremor - presentation of two successful cases.
P038 Deep brain stimulation of the intermediate ventral thalamic nucleus for orthostatic tremor - presentation of two successful cases.

INTRODUCTION: Orthostatic tremor (OT) was first described in 1977 (Pazzaglia et al.). They described three patients with lower body tremor during standing. Tremor with a frequency of 13–18 Hz can be measured in the muscles of the legs and trunk muscles and are typical finding in OT patients. Medical therapy (Gabapentin, Primidon, Clonazepam) may be helpful in patients with OT, but many patients symptoms do not improve. Deep brain stimulation (DBS) of the ventral intermediate nucleus of the thalamus (VIM) is a well established therapy for movement disorders like essential tremor. Even less common types of tremor like Holmes tremor can be treated with VIM-DBS successfully. Some case reports of OT-patients treated with VIM-DBS show varying results from excellent to absent effect of the stimulation therapy.

METHODS: We present two patients suffering from OT. A 65 years old male Patient with a ten-year-history and a 60 years old female with a six-year-history of orthostatic tremor. Trials with medication including Clonazepam, Primidon, Propranolol and Gabapentin failed to improve the symptoms sufficiently or were not tolerated due to side effects in both patients. Segmented electrodes were implanted in a stereotactic procedure under local anesthesiea using microelectrode recording and awake test stimulation. They were connected to a St. Jude Medical Infinity 7.0 IPG.

RESULTS: The surgical procedures were well tolerated. There were no complications. The postoperative cranial CT-Scan showed the electrodes in correct position. The preoperatice standing time in the male patient was about 30 seconds until onset of tremor of the legs forcing the patient to sit down. The female patients symptoms of tremor in both legs occured after standing up and slow walking leading to recurrent falls. The early postoperative microlesion effects were remarkable with prolongued time since symptom onset to severel minutes.  Initial stimulation with low amplitude did not show any stimulation side effects. Symptoms improved in both Patients. Though there weas no complete remission of symptoms after altering the stimulation during follow-up, patientsatisfaction with the stimulation‘s effect was high and lead to a significant increase of quality of life.

Conclusion: The implantation of DBS-electrodes into the VIM is a safe and approved surgical procedure and can be very effective in the treatment of the OT when medication therapy failed. We present two case with improvement of symptoms after VIM DBS. OT is a rare disease, thus RCTs are needed to evaluate the overall effect of VIM-DBS on OT.


Sönke HELLWIG, Walter STUMMER, Nils WARNEKE (Münster, Germany)
00:00 - 00:00 #36145 - P039 Directional Tuning of Evoked Resonant Neural Activity with Deep Brain Stimulation in Parkinson’s Disease.
P039 Directional Tuning of Evoked Resonant Neural Activity with Deep Brain Stimulation in Parkinson’s Disease.

Introduction: Objective markers of therapeutic deep brain stimulation (DBS) for Parkinson’s disease (PD) are needed to tailor stimulation on a patient-specific basis and to fully leverage directional stimulation capabilities. Evoked resonant neural activity (ERNA) elicited by DBS in the subthalamic nucleus (STN) region or the pallidum may be useful to guide targeting or stimulation parameter selection. However, it is unclear where ERNA is precisely localized or whether ERNA could be used to determine the optimal stimulation direction.

 

Objective: We aimed to determine how ERNA features vary when stimulating in different directions within the STN region in patients with PD.

 

Methods: Intraoperative recordings were acquired in 18 subjects (20 hemispheres) who underwent STN DBS implantation surgery with directional leads for the treatment of PD. Local field potentials were recorded and referenced to a scalp corkscrew electrode. High-frequency stimulation (135 Hz) was delivered in bursts of 10 pulses repeated 10-20 times from each contact sequentially while recording from the other contacts. Offline, the recordings were bipolar referenced, and each burst was aligned to the last pulse to average the evoked responses. The evoked response amplitudes were quantified and compared across subjects and stimulating contacts.

 

Results: ERNA was observed in 15/18 subjects (17/20 hemispheres). The ERNA amplitudes varied depending on the stimulating contact (Figure 1A-B). Stimulating from segment “A” elicited the maximum ERNA amplitude in 11/17 hemispheres (65%), with contact 2A showing the maximum ERNA in 8/11 hemispheres (47%) (Figure 1C). Directional leads are generally targeted with the “A” segments pointing anterior at our center, and contact 2 is often located in dorsal STN. The precise lead localization and orientation will be quantified using neuroimaging.

 

Conclusion: ERNA may be tuned to stimulation in specific directions in the STN region, which suggests its localization could provide spatial context to guide DBS targeting for PD.


Kara JOHNSON, Justin HILLIARD, Kelly FOOTE, Coralie DE HEMPTINNE (Gainesville, Florida, USA)
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00:00 - 00:00 #35982 - P041 Somatosensory evoked potentials recorded from DBS electrodes: the origin of subcortical N18.
P041 Somatosensory evoked potentials recorded from DBS electrodes: the origin of subcortical N18.

Objective:

The different peaks of somatosensory evoked potentials originate from a variety of anatomical sites in the central nervous system. The origin of the subcortical N18 has been studied under various conditions, but its exact generator is still unclear. While it has been claimed to be located in the thalamic region, other studies indicated a generator below the pontomedullar junction. Here, we scrutinized and compared SSEP recordings from median nerve stimulation through DBS electrodes implanted in various subcortical targets.

Methods:

We studied 24 patients with dystonia, Parkinson disease, and chronic pain who underwent quadripolar electrode implantation for chronic deep brain stimulation and recorded median nerve SSEPs from globus pallidus internus (GPi), subthalamic nucleus (STN), thalamic ventral intermediate nucleus (Vim), and ventral posterolateral nucleus (VPL) and the centromedian-parafascicular complex (CM-PF).

Results:

The largest amplitude of the triphasic potential of the N18 complex was recorded in Vim. Bipolar recordings confirmed the origin to be close to Vim electrodes (and VPL/CM-PF) and less close to STN electrodes. GPi recorded only far field potentials in unipolar derivation.

Conclusion:

Recordings from DBS electrodes located in different subcortical areas allow determining the origin of certain subcortical SSEP waves more precisely. The subcortical N18 of median nerve SSEP - to its largest extent - is generated ventral to the Vim in the region of the prelemniscal radiation / Zona incerta.


Arif ABDULBAKI (Hannover, Germany), Johannes C WÖHRLE, Christian BLAHAK, Ralf WEIGEL, Eva GRIPS, Hans-Holger CAPELLE, Hansjörg BÄZNER
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00:00 - 00:00 #33507 - P042 Trans-cerebellar stereotactic biopsy for brain stem lesions,.
P042 Trans-cerebellar stereotactic biopsy for brain stem lesions,.

Tissue diagnosis for lesions in the posterior fossa, such as the brainstem, cerebellar peduncle, and cerebellum, is an important determinant of the next treatment option. Herein, we present our 10-year experience with magnetic resonance imaging (MRI)guided Leksell frameebased stereotactic biopsy for 39 patients with posterior fossa lesions, the largest case se- ries in this matter.

-We sectional study on all patients with posterior fossa lesion admitted to 2 referral centers between 2006 and 2016. We used Leksell Frame G for stereotactic biopsy of all patients. MRI systems of both hospitals were 1.5 T.

RESULTS: We performed analysis on the 39 cases (21 men and 18 women). Age of the patients ranged between 9 and 73 years (mean, 35.4 15.7 years). Localization suc- cess rate was 100%. For 38 patients (97.4%), tissue sample size was enough for tissue diagnosis. For 1 case, it was insufficient and nondiagnostic. In this series, we had no surgery-related complications.

CONCLUSIONS: We present the largest reported series of MRI-guided frame-based stereotactic biopsy of the posterior fossa lesions via a transcerebellar route. We prefer oblique positioning of the frame on the skull and use a transcerebellar route to reduce surgical complications and achieve a greater localization success rate.


Mansour PARVARESH, Aydin OMIDVAR (Tehran, Islamic Republic of Iran), Eshagh BAHRAMI
00:00 - 00:00 #33832 - P043 Headache in Hemangioblastomas: A Histopathology and Structural.
P043 Headache in Hemangioblastomas: A Histopathology and Structural.

Background: Hemangioblastoma (HBL) are rare, benign, s highly vascularized tumor of not well-defined histological origin. highly vascularized tumors that can be found throughout the neuraxis but are mainly located in the cerebellum and in the spinal cord. the most common primary tumor of the posterior fossa in adults. Hemangioblastomas may also occur within the spine. Single tumors may be sporadic, but multiple tumors are almost always associated with von Hippel-Lindau (VHL) disease.

Material and Methods: This meta-analysis was performed to evaluate headache in Hemangioblastoma (HBL) tumors structurally and separately based on randomized controlled trial studies. Electronic databases (PubMed, MEDLINE, Embase, and Cochrane Library) were searched for randomized and controlled trial studies that searched for the results of treatment of brain tumors (Hemangioblastoma type) and headache in Hemangioblastoma (HBL) tumors.

Result: This meta-analysis was performed using Review Manager (Rev Man) software (version 5.2) provided by Cochrane Collaboration. The data used were hazard ratios with 95% confidence intervals calculated for time-to-event data extracted from survival curves and local tumor control rate curves. A consecutive series of patients with hemangioblastomas on between 2010 and 2020 by the senior author (A.AN) is Reviewed.

Conclusion: Adequate knowledge for the treatment and correct use of microsurgical techniques allows complete resection of these tumors with minimal complications and maximum functional improvement. The result appears to be directly related to the preoperative condition.


Bita DINAR VAND, Ali Reza ARABESTANINO, Sina NAGHIBI IRVANI (Tehran, Islamic Republic of Iran)
00:00 - 00:00 #34419 - P044 Abscess or cystic brain tumors? Diagnosis and therapeutic challenge.
P044 Abscess or cystic brain tumors? Diagnosis and therapeutic challenge.

INTRODUCTION

The differentiation of abscess from cystic brain tumors (glioblastomas and metastases) may not always be easy on the basis of CT scan and MRI despite of progression of neuroradiology.

The management of intracranial tumors differs greatly from that abscesses, including the operative procedure. Therefore, precise preoperative discrimination between these two lesions which has a great importance. Because neuroimaging and the clinical picture cannot always differentiate between a brain abscess and a necrotic cyst within a brain tumor, preoperative differentiation remains challenging, and numerous reports have described approaches to accurately differentiating between cystic brain metastasis and brain abscess, based on comparisons of pre-operative images and post-operative histological findings

 

CASES PRESENTATIONS:

The aim of our study is to show three cases operated in our hospital in 2015 for cystic brain tumors.

The first case: a man of 32 years’ old who’s a CT scan and MRI suggest high grade glioma but in per-operative we found an abscess.

The second case: A 57-year-old woman was referred to our hospital for progressive loss of consciousness GCS 09/15. Past clinical history was positive for diabetes mellitus and weakness in the left limbs. A CT scan and MRI documented the presence of a large (5 cm X 3 cm) oval lesion localized at the right parieto-occipital region, suggestive for cystic brain tumors.

The last cases: A middle-aged man presented with headache and nausea. Computed tomography (CT) and magnetic resonance (MR) imaging revealed two lesions, one in each cerebral   hemisphere. Although these lesions appeared to be brain metastases

 

DISCUSSION/CONCLUSION

imaging modalities (CT and MRI) cannot always discriminate between abscess and metastasis which showed peripheral, ring-like contrast enhancement. Diffusion weighted imaging and apparent diffusion coefficient is used to distinguish brain abscesses from cystic or necrotic brain tumors [3]. Additionally, magnetic resonance spectroscopy may assist in obtaining the correct preoperative diagnosis, when it is combined with diffusion-weighted imaging.3

Imaging is not likely to delineate the rare co-existence of both entities, and in the absence of fever, other infectious signs or symptoms, and laboratory abnormalities, a superimposed abscess may not necessarily be suspected until intraoperatively.


Brahim MERROUCHE (ALGIERS, Algeria), Lila MAHFOUF
00:00 - 00:00 #34649 - P045 Contributions of perfusion MRI in stereotactic biopsy intracranial lesions.
P045 Contributions of perfusion MRI in stereotactic biopsy intracranial lesions.

INTRODUCTION

Stereotactic biopsy is always subject to a high risk of errors, and the choice of the target is crucial.

Neovascularization is required for tumor or metastasis growth.

Brain perfusion reflects the microcirculation and evaluates the vascular density in relation to that tumor angiogenesis.

MATERIALS AND METHODS

We performed 35 stereotactic biopsy guided by cerebral perfusion MRI for intra axial lesions, with study of regional cerebral blood volume using the technique of first pass curve in region of interest.

RESULTS

Of the 35 biopsies is noted that there is no exact superposition between taken contrast after injection of gadolinium chelates in T1 and cerebral blood volume values observed in each pixel on the parametric map.

There is also, most often a good correlation between MRI findings and perfusion histopathological results with immuno histochemical studies.

CONCLUSION

This non- invasive technique provides information on the tumor punctiform on 3D, and allows characterization of tumor angiogenesis .

It is an essential element of the grading of gliomas and allows us a better choice of the target for stereotactic biopsy.


Samir Amine BENBOUALI (Alger, Algeria), Amine MAHTOUT, Fateh BOUAOUINA, Rachid GHOUL, Nacer TABET, Linda ZIANI, Karima SEDDIKI, El Mountassir OURRAD
00:00 - 00:00 #34650 - P046 Metabolic study by MRI spectroscopy of cystic craniopharyngiomas, before and after endocavitary treatment.
P046 Metabolic study by MRI spectroscopy of cystic craniopharyngiomas, before and after endocavitary treatment.

Introduction :

Demonstrate the interest of the new data provided by MRS on the cystic portion of the Craniopharyngioma in the diagnosis and follow-up after endocavitary treatment, endocavitary chemotherapy with Interferon Alpha 2b or brachytherapy with Rhenium 186 and Yttrium 90.

Materials and methods :

We carried out studies by spectroscopy MRI on 30 patients with cystic or mixed craniopharyngioma with a cystic preponderance, all the patients benefited from a morphological and metabolic cerebral MRI essentially based on the MR spectroscopy in monovoxel mode, in short echo time 35 msec. and long 135 msec, before and after the therapeutic procedure.

Results :

The data of the study by MR Proton spectroscopy, pre-therapeutic, had found peaks of lipids and lactates in more than 60% of the cysts studied, in post-procedure, a clear reduction of these metabolites was noted, in the cases good post-procedure evolution, a reappearance of these same peaks on spectroscopy during his cystic re-expansion found on the morphological MRI.

Conclusion :

This preliminary study, by MR Proton spectroscopy, has brought us very interesting new data, in the initial diagnosis of cystic craniopharyngioma and in the evolutionary follow-up of this chronic condition.


Samir Amine BENBOUALI (Alger, Algeria), Amine MAHTOUT, Rachid GHOUL, Nacer TABET, Fateh BOUAOUINA, Linda ZIANI, Leila BOUNAB, Karima SEDDIKI, El Mountassir OURRAD
00:00 - 00:00 #34651 - P047 Installation of Rickham reservoir in stereotactic condition assisted by neuronavigation.
P047 Installation of Rickham reservoir in stereotactic condition assisted by neuronavigation.

Introduction :

The placement of a subcutaneous reservoir for the management of a deep intracerebral lesion requires great precision and must be careful to do not damage the various cerebral vasculo-nervous structures.

Materials and methods :

We collected 39 patients with cystic cerebral lesions, 30 cystic craniopharyngiomas and 9 cystic astrocytomas, we used stereotactic tracking by 3D Gado MRI assisted by neuronavigation 3D Gado for the placement of the intracystic catheter.

Results :

This technique offered us more precision and more comfort during this surgery without direct visual control, it allowed us to plan the entire procedure, from the entry point to the trajectory as well as all the vascular-nervous structures to cross and finally the target, and to avoid in certain cases the calcifications of the cystic walls in particular those of the craniopharyngioma.

Conclusion :

The use of stereotaxic tracking coupled with intraoperative neuronavigation offers the surgeon greater comfort in this type of surgery without visual control, while reducing the postoperative morbidity and mortality rate.


Samir Amine BENBOUALI (Alger, Algeria), Amine MAHTOUT, Rachid GHOUL, Nacer TABET, Fateh BOUAOUINA, Leila BOUNAB, Linda ZIANI, Karima SEDDIKI, El Mountassir OURRAD
00:00 - 00:00 #36013 - P048 Preliminary results from MRI and MRS follow up of low-grade gliomas treated by LITT.
P048 Preliminary results from MRI and MRS follow up of low-grade gliomas treated by LITT.

Context and purpose: Magnetic Resonance Imaging (MRI) guided Laser Interstitial Thermal Therapy (LITT), a minimally invasive stereotactic approach, can allow thermal ablation of brain tumors llike low-grade gliomas (LGG) that are difficult to access or located near a high-risk functional area. To our Knowledge, no spectroscopic and metabolic features (by Magnetic Resonance Spectroscopy (MRS)) of LITT-treated LGG have been described in literature. The objective of this prospective study was to describe, using MRI and MRS, the evolution of the effects of LITT on LGG. 

Methods: Five patients were treated by LITT and followed up at Amiens-Picardie University Hospital (since July 2021), with diagnoses of 1 oligodendroglioma, 1 ganglioglioma, 1 subependymoma, and 2 astrocytomas histologically proven.  All patients underwent MRI (T1, T2 FLAIR, T2*, Diffusion and 3DT1 post-Gadolinium) and proton MRS (PRESS sequence with 3 Echo Times of 35 ms, 144 ms and 288 ms) exams on 1.5T GE MRI scanner. MRI and MRS data were collected pre-operatively, at immediate post-operative, at D2/D5, and approximately at M2/M3, M6 and at M9/M10 post-operative. 

Results: MRI revealed the appearance of a ring b1000 diffusion hypersignal and increased volume of FLAIR hypersignal at immediate post-LITT that were more importantl at D2/5 postoperative. The ring b1000 diffusion hypersignal remained present, but less extensive, until M2/M3 postoperative and totally disappeared at subsequent controls. The volume of the FLAIR hypersignal (edema and tumor) decreased compared to the pre-LITT MRI from M3 in 2 patients and continued to decrease in 3 patients. The ring enhanced contrast appeared at immediate post-LITT and at all subsequent controls although it was less intense. MRS revealed that there was an increase in the mI/Cr ratio in immediate post-LITT, that was sometimes higher at the D2/5 control, and decreased from M2/3 although remaining above the normal value. No increase in cell proliferation (the Cho/Cr ratio) was measured in all post-LITT controls of all patients. There was a significant increase of lactate in 3 patients at D2/5, to a lesser degree at M2/3 control, and then decreased at M6/10. The NAA/Cr ratio was often decreased during LITT and then significantly increased at D2/5 and afterwards. There was an increase in CH2-CH3 phospholipids at M2/3, which then decreased starting from M9/M10. [MRS metabolites: Cr: Creatine, NAA, N-acetyl-aspartate, Cho: Choline, mI: Myo-inositol and CH2-CH3 phospholipids].

Discussion and conclusion: Combining MRI and MRS features showed an added-value in the evaluation of LITT efficiency then the use of only MRI.  More cases with a longer follow-up are needed to better analyze these preliminary findings. Further analyses are in progress in order to better understand relations between LITT laser duration/intensity, MRI/MRS features and their impact on LITT efficiency on LGG.


Aurélien LAMBERT, Salem BOUSSIDA, Romain DRAILY, Pauline CARLIER, Adrien PANERO, David LAYANI, Cyril BROUTIN, Christine DESENCLOS, Mathieu BOONE, Michel LEFRANC, Jean-Marc CONSTANS (AMIENS)
00:00 - 00:00 #36036 - P049 Acoustic schwanoma revealed by cranio-cerebral trauma : about 2 cases.
P049 Acoustic schwanoma revealed by cranio-cerebral trauma : about 2 cases.

Introduction :

A declining hearing ability is the most common symptom that leads to the diagnosis of acoustic shwanomma, and the most frequent complication is hydrocephalus.  However, there are some rare discovery circumstances like craniocerebral trauma.

We report two cases of acoustic shwannoma revealed by cranial trauma.

The diagnosis of VS relies on history, physical examination, and audiometry and is solidified by neuroradiologic examination. Audiograms generally reveal high frequency sensorineural hearing loss and speech discrimination is severely affected. High-resolution bone window CT is essential for visualizing bony changes and erosion of IAC, as well as for surgical planning. MRI is the diagnostic tool of choice for all CPA tumors. On T1-weighted MRI images vestibular shwannomas are isointense or slightly hypointense to the normal brain and on T2- weighted images they are hyperintense. They show an intense and homogeneous contrast enhancement with the exception of cystic tumor parts.The number of asymptomatic incidentally discovered small VS is increasing due to the wide spread of MRI facilities. Some of them might not show further growth or might even undergo spontaneous regression. Based on this the conservative approach – observation – is recommended.

 

First case :

A 78 year old man, presented with progressive tetraparesia after benign cranial trauma. On examination, the patients had pyramidal syndrome in four limbs and left deafness. MRI of brain showed compressive bilateral chronic subdural hematoma associate with left Cerebellopontine tumor.

The patient was operated on urgently, the subdural hematoma was drained. In view of the age of patient we decide to send him to radiosurgery.

 

Second case :

A 30 year old man, presented after industrial injury with 13/15 GCS. The CT scan showed several brain contusions, a left acute subdural hematoma and suspected a Cerebellopontine lesion at second control CT scan. MRI confirmed Cerebellopontine tumor evocating a vestibular shwanomma.

The patient was operated, first a ventriculoperitoneal shunt was implanted then secondary the shwannoma was removed.

 

Conclusion :

It must be obtain a good ct scan findings analysed with meticulous care in particular in trauma emergency.


Brahim MERROUCHE (ALGIERS, Algeria), Lila MAHFOUF
00:00 - 00:00 #36085 - P050 Brain metastases of non-small cell lung cancer treated with stereotactic radiosurgery: do molecular biomarkers have an impact?
P050 Brain metastases of non-small cell lung cancer treated with stereotactic radiosurgery: do molecular biomarkers have an impact?

Objective:

To retrospectively compare the response to stereotactic radiosurgery (SRS) in patients with brain metastases (BM) from non-small cell lung cancer (NSCLC) with at least one positive molecular biomarker (EGFR, ALK, ROS1, PD-L1) with response in patients negative for biomarkers.

 

Methods:

We retrospectively analyzed 78 patients with BM from lung adenocarcinoma treated with SRS in our institution from 2017 till the February 2023. A total of 290 (1-19) metastases were treated. Mean age was 65 years, range 35-87 years, 40% females. All patients had known status of molecular biomarkers EGFR, ALK, ROS1 and PD-L1. Patients were divided in two groups depending on molecular biomarkers. Group A had at least one positive biomarker (38 patients/49%) and Group B had all negative biomarkers (40 patients, 51%). EGFR was positive in 11 patients and PD-L1 in 27 patients, ALK and ROS1 were not detected. Median volume of metastases was 7.11 cc (0.1-48.7 cc), with 63 patients treated with single session radiosurgery  and other with 2-3 fractions. Patients with pretreatment and posttreatment brain MRI were eligible for analysis. RANO-BM criteria were used for classifying treatment responses.The patients were treated by the Varian Edge or Cyberknife S7 radiosurgery system. The imaging was performed on a Siemens Skyra 3T MRI system or Siemens 3T Magnetom Vida and the image analysis on a Syngovia software suite.

 

Results:

 Partial response by RANO-BM was confirmed in 33 (42%) patients, stable disease in 31 (40%), progression disease in 13 (17%) and complete response in one (1%) patient. Comparing Group A and Group B partial response, stable disease, complete response and progression disease were detected in 55%, 32%, 0%, 13% and 36%, 45%, 1%, 16% of patients, respectively. Clinical benefit (partial response, stable disease and complete response) were achieved in 87% in Group A and 82% in Group B. The median number of days from the start of the therapy to follow-up MRI was 59 (32-91, average 57.6). The response pattern morphological mostly consisted of lesions shrinking in size, with central necrosis and/or central hemosiderin deposits indicating post-treatment haemorrhage. There was also regression of the perifocal vasogenic oedema. No radiation necrosis of the surrounding normal brain tissue occurred within the follow-up period.

 

Conclusion:

SRS is a valuable tool in treating BM of lung cancer, providing  clinical benefit in majority of patients with favorable results visible in a relatively short time. No significant difference in response was observed in patients regarding molecular biomarkers.

 


Ana MISIR KRPAN (Zagreb, Croatia), Hrvoje VAVRO, Josip PALADINO, Hrvoje KAUCIC, Matea LEKIC, Nevenka PISKAC ZIVKOVIC, Domagoj KOSMINA, Adlan CEHOBASIC, Vanda LEIPOLD, Ivana ALERIC, Sofija ANTIC, Dragan SCHWARZ
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00:00 - 00:00 #34417 - P051 Motor cortex stimulation for deafferentation pain following avulsive injury to brachial plexus.
P051 Motor cortex stimulation for deafferentation pain following avulsive injury to brachial plexus.

Avulsion of the brachial plexus can cause deafferentation limb pain (DLP). The treatment protocols include conservative pharmacotherapy and physiotherapy. The efficacy of the treatment is not high.   Surgical treatment remains a treatment option. The authors present the group of patients with DLP after avulsive injury to the brachial plexus treated with motor cortex stimulation (MCS).

Material and Methods: Three female and five male patients with diagnosed DLP were treated with MCS between 2006 and 2020. The mean age at the implantation was 57±25. DLP lasted from 10 to 19 years (mean 15). Conservative and surgical (drezotomies) treatments were ineffective. With MRI guided frameless stereotactic system electrodes were implanted (3587 A-25, Medtronic Inc). The stimulation was initialized on the first day following surgery. Pain intensity was evaluated with VAS (Visual Analogue Scale) prior to surgery, one month and three months following surgery. Psychological evaluation was conducted before surgery and at the follow-up

Results:  Eight patients from the group reported improvement after surgery (pain intensity decreased by>30%). Three patients responded well to MCS- pain intensity decreased by >50%. No permanent complications were reported among the group. The efficacy of the stimulation remained at stable a level at the follow-up which lasted from 2 to 16 years.

Conclusions: MCS can effectively decrease pain intensity among the group of patients with DLP.


Krzysztof SZALECKI, Victor MANDAT, Bartosz KROLICKI, Pawel ZDUNEK, Piotr IZDEBSKI, Henryk KOZIARA, Tomasz MANDAT (Warsaw, Poland)
00:00 - 00:00 #36154 - P052 Spinal Cord Stimulation for Neuropathic Pain Due to Brachial Plexus Avulsion: A Report of 3 Cases.
P052 Spinal Cord Stimulation for Neuropathic Pain Due to Brachial Plexus Avulsion: A Report of 3 Cases.

Introduction

Neuropathic pain after brachial plexus injury is common. When the injury is due to brachial plexus avulsion, the pain is generally unresponsive to medical treatment. Spinal cord stimulation (SCS) is an effective treatment with low complication rates in the management of deafferentation pain following brachial plexus injury. 


Here, we presented 3 cases who underwent cervical SCS insertion for neuropathic pain due to traumatic brachial plexus avulsion.


Case 1

A 30-year-old male with a history of brachial plexus injury after a motorcycle accident presented with motor weakness, and severe burning pain in the right palm, spreading to his 2nd, 3rd, and 4th fingers. Neurologic examination revealed total loss of right wrist flexion/extension, shoulder adduction/ abduction; forearm extension/flexion/pronation/supination, and finger extension. Brachial plexus MRI showed right C5, C6, and C7 root avulsions. (Figure 1) After a SCS operation at C5-6-7 level, his complaints of hyperalgesia and VAS 7 neuropathic pain in the right C6-7-8 dermatomes reduced to VAS 1. 

Case 2

A 69-year-old male patient with a history of brachial plexus injury after a car accident was referred to us for neuropathic pain(VAS 10) in the right arm radiating to fingers from the shoulder. Neurologic examination revealed plegia of the right arm. On EMG, there was total chronic axonal destruction in the upper, middle and lower trunks of the right brachial plexus. Brachial plexus MRI showed pseudomeningocele at C7-T1 level and adhesions of C5-6-7 roots. (Figure 2) After a SCS operation at C5-6 level, his pain decreased to VAS 4/10.  

Case 3  

A 73-year-old male patient with left arm weakness after a car accident presented with VAS 8 neuropathic pain radiating from the left shoulder to the fingers. Neurologic examination showed 2/5 muscle strength monoparesia on his left arm, hypoestesia on C4-5-6 dermatomes. Brachial plexus MRI showed left C5 root avulsion. (Figure 3) Patient underwent a SCS operation at C3-4-5 level which eventually decreased his pain to VAS 2. 

Conclusion

SCS is highly effective in controlling deafferentation pain due to brachial plexopathy.

 


Hanside Setenay ÜNAL, Pınar ESER (Bursa, Turkey), Ahmet BEKAR
00:00 - 00:00 #36173 - P053 Therapeutic strategy in the management of essential facial neuralgia.
P053 Therapeutic strategy in the management of essential facial neuralgia.

Introduction :

Essential facial neuralgia represents a fairly frequent reason for consultation in our daily practice. It most often affects middle-aged people (50 years and older).

After making the clinical diagnosis of neuralgia and eliminating a dental or ENT origin, magnetic resonance imaging is requested for a double interest:

1-      In order to eliminate the tumoral causes, especially epidermoid cysts that are very prone to facial neuralgia and other medical causes such as multiple sclerosis by showing hyper-signals at the level of the VII nucleus.

2-      confirm the vascular-nervous conflict between a vessel and the trigeminal nerve, most often with the superior cerebellar artery.

Therapeutic component:

§  A drug treatment is always proposed in first intention.

§  After failure or intolerance to medical treatment

ü  A microsurgical decompression is proposed to the patient if the vascular-nervous conflict is confirmed if the patient's karnofski allows it and in the absence of several comorbidities.

ü  If necessary, we offer gasser compression by balloon.

We report our expérience in this area.

 


Brahim MERROUCHE (ALGIERS, Algeria), Lila MAHFOUF
00:00 - 00:00 #36178 - P055 Comparison of Remote Programming with NeuroSphereTM Virtual Clinic and On-site Programming in Patients with SCS and DRG.
P055 Comparison of Remote Programming with NeuroSphereTM Virtual Clinic and On-site Programming in Patients with SCS and DRG.

Introduction

Spinal cord and dorsal root ganglion stimulation (SCS and DRG) are standard of care for patients with chronic neuropathic pain. During the COVID-19 pandemic it was critical to arrange postoperative care. Furthermore, the disparity between travel times and transportation options illuminate a potential association to the individuals’ decision on seeking healthcare. A lack of financial resources could enhance this issue.

Telehealth  in general refers to the exchange of medical information through electronic communication. However, it is usually restricted to video conferences, without interfering with implanted medical devices. NeuroSphere™ Virtual Clinic is a platform for remote programming of those devices. It is accessible via tablets/smartphones and allows  direct contact between a patient and their doctor/pain nurse.

 

Methods

We initiated a pilot study for evaluating safety and performance of remote care in patients with SCSor DRG stimulation. We plan the enrollment of 20 patients, 10 each in the retrospective and the prospective group. Retrospective data has been collected from previously on-site programmed patients in our outpatient clinic.

Prospective data is being collected under the new standard of care in the context of the COVID-19 pandemic remotely programmed patients. We assess ten scores and categories to evaluate the preoperative status, the status at implantation of the system, and the postoperative course. The postoperative data are assessed in the context of video conferences for remote programming or any personal outpatient appointments. 12 months after implantation a final video conference is scheduled.

 

Results:

The study is still ongoing In the retrospective group (n=8) the mean duration of their programming appointment including waiting time was 43 minutes and their mean travel time 71 minutes (mean travel distance 106km). So far, 5 patients have been enrolled for remote programming. Their overall satisfaction with the telehealth system is high. Compared to the retrospective group they do not show a lack of efficacy of their stimulation or pain relief.

 

Conclusion:

While using remote programming patients are reporting an improved comfort and more thorough assessment. The general convenience with the system is high which is conform to previous published data regarding telehealth in general. Witek et al. reported no statistical difference between virtual and in-person assessments and Powers et al showed that wearables can be used for an objective quantification of symptoms without the need for clinic facility time.

 

:

The use of remote programming offers various advantages, e.g. reduced travel times and costs which allow simplified and more frequent programming. Especially in a pandemic or in case of travel limitations it is a very helpful tool.


Andrea DREYER (Düsseldorf, Germany), Phyllis MCPHILLIPS, Philipp SLOTTY, Zarela KRAUSE MOLLE, Jan VESPER
00:00 - 00:00 #36181 - P056 Clinical efficacy of new patient-adapted stimulation patterns for SCS therapy in patients with persistent spinal pain syndrome.
P056 Clinical efficacy of new patient-adapted stimulation patterns for SCS therapy in patients with persistent spinal pain syndrome.

Introduction

In patients with chronic axial back pain, results of spinal cord stimulation are still heterogeneous regrading comparable therapeutic response between systems and stimulation paradigms used. New patient-adapted stimulation seem to lead to a clinically significant pain reduction in this commonly low-responder patient population. We therefore examined the efficacy of two types of patient adapted stimulation on pain intensity in patients with persistent spinal pain (PSP).

Methods

We used two types of patient-adapted SCS systems, in which settings can be customized to address the patients´ individual needs. One system offered stimulation with respect to the glial cell activation (group I), the second one permanent neurophysiological adaptation (group II).

A total of 12 patients were included (PSP, type I and II). Group I: this system was primarily used in PSP type I (surgery naïve) patients. (n=6, m=4, f=2; mean age: 63.3 years). Group II included predominantly patients with PSP type II (with previous surgery (n=6, m=3m f=3, mean age: 64,5 years).

Stimulation was adapted according to the paraesthesia coverage under tonic stimulation (group II) and via glial activation measurement in group I.

For both groups, pain intensity was recorded with the visual analog scale (VAS) at baseline and at follow up (Group I: 12-24 weeks postsurgery, Group II: 6 -12 weeks postsurgery).

Results

The overall pain intensity in group I was mean 6.3/10 points (range 5-8) at baseline and 2.8/10 (range 1-5) postoperatively. In 3 out of the 6 patients, stimulation achieved an average pain relief of >75%. In 5 of 6 patients, the average VAS was reduced by at least 3 points. One patient did not benefit from the therapy (Pain Relief <30%) and was explanted after 6 months.

The pain intensity in group II was given as an average of 7.8/10 VAS (range 6-9) preoperatively and 3.2/10 VAS (range 2-5) postoperatively. Mean pain relief was >50% in 5 of 6 patients and >70% in 2 patients.   

Conclusion

Our preliminary results suggests that patient adapted stimulation improves treatment response, especially in PSP type I patients. Further prospective investigations are necessary to assess future therapeutic approaches in spinal cord stimulation.


Zarela KRAUSE MOLLE (Duesseldorf, Germany), Phyllis MCPHILLIPS, Andrea DREYER, Philipp SLOTTY, Jan VESPER
00:00 - 00:00 #36191 - P057 Results and adaptation of the experience of the DTM system in various targets for pain.
P057 Results and adaptation of the experience of the DTM system in various targets for pain.

INTRODUCTION

 Spinal cord stimulation (NEM), uses electrical pulses at 40-60 Hz, and has been the primary programming modality since the 1960s. With preclinical studies advancing, a new programming approach based on a multiplexed differential target is promising ( DTM), which uses multiple electrical signals varying in intensity, pulse rates, and amplitudes, to stimulate multiple targets. This not only improves the efficiency of neuromodulation and quality of life, but also contributes to the social and health aspect. In our experience, this practice has been widely used for the treatment of failed back syndrome, currently being extended to new spinal targets for upper trunk and cervicocranial pathologies, demonstrating encouraging efficacy.

METHODOLOGY

 Under a qualitative and multidisciplinary vision, the response to pain of patients with TMD was assessed for the management of refractory pain in thoracic and cervicocranial spine pathologies. Thus demonstrating its usefulness in pathologies such as headache, postherpetic pain and SUDEK, among others.

RESULTS

 In this work, we demonstrated that DTM was able to improve not only the quality of life of patients by significantly reducing low back and refractory lower limb pain, but also improving pain in dorsal and cervicocranial pathologies.CONCLUSIONS

 Our experience is one of multiple studies that have shown that the DTM scheduling approach is more effective than classical high and low frequency scheduling. We see that it presents an excellent extension towards other types of pain that are not spinal cord pain such as headaches and neuralgia/neuropathies, thus expanding the application options of neuromodulation.


Pablo Javier FORMICA SAIEG, Carlos CIRAOLO (Buenos Aires, Argentina), Miguel VILLAESCUSA, Mauro BESARON
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00:00 - 00:00 #35736 - P058 Long-term outcome of deep brain stimulation therapy for refractory and treatment-resistant Tourette syndrome.
P058 Long-term outcome of deep brain stimulation therapy for refractory and treatment-resistant Tourette syndrome.

Introduction

We have been performing deep brain stimulation (DBS) on patients with refractory Tourette syndrome at our hospital for 15 years. We report the long-term outcome of DBS, including adverse events and DBS conditions.

Methods

Thirty-six patients with refractory and treatment-resistant Tourette syndrome who underwent centromedian-parafascicular nuclei of thalamus DBS at our hospital were retrospectively reviewed for changes in the Yale Global Tic Severity Scale (YGTSS), adverse events, and current DBS conditions.

Results

There were 29 male patients. The mean age at surgery was 25.6 years. The mean follow-up period was 6.21 (1–15) years. The motor and phonic tics scores on the YGTSS improved from 20.2 and 19.7 preoperatively to 10.9 and 9.6 postoperatively, respectively, at 1 year. YGTSS improved further to 7.6 and 8.2 in 19 patients 3 years after DBS and 7.7 and 7.0 in 11 patients at the last 5-year follow-up. Serious complications included device infections in four patients and electrode breakage in one. Three of the four patients with infection had to have their DBS system removed; two of them had worsening symptoms, and one had to be reoperated, whereas another refused to be reoperated. In one case, symptoms did not worsen after the device was removed. The intracranial electrode in one patient was replaced owing to electrode breakage. Due to the burden of DBS management, four patients wanted to discontinue DBS. After DBS was discontinued, three patients remained in remission with no worsening of symptoms.

Discussion

Although tics improved significantly, various problems occur with long-term DBS use. Patients experience infections and electrode problems more frequently than those with other diseases. DBS may be terminated due to disease remission as some cases have withdrawn from DBS. We should consider the likely problems faced by patients with DBS.

Conclusion

DBS has a long-term tic-suppressing effect. Treatment decisions must be based on the long-term effectiveness of DBS, likelihood of disease remission, and risk of adverse events.


Yuiko KIMURA (Tokyo, Japan), Mayu OOMORI, Takanobu KAIDO, Yukiko KANO, Masaki IWASAKI
00:00 - 00:00 #35746 - P059 Intraoperative local field potential monitoring as an indicator of anatomical location in deep brain stimulation for obsessive-compulsive disorder.
P059 Intraoperative local field potential monitoring as an indicator of anatomical location in deep brain stimulation for obsessive-compulsive disorder.

Introduction:

Deep brain stimulation (DBS) is an established therapy for movement disorders and also used for psychiatric patients with specific therapy resistant conditions, such as obsessive-compulsive disorder (OCD). Optimal targeting of the stimulation electrode during surgery is essential to improve function in these patients. Therefore, real-time monitoring of microelectrode recordings (MER) and local field potential (LFP) activity has evolved as a beneficial tool to monitor electrode location in DBS surgery, primarily for Parkinson’s disease. In this study, we aim to investigate the utility of intraoperatively recorded LFP activity during DBS surgery targeting the nucleus accumbens and anterior limb of the internal capsule (NAcc/ALIC) in OCD patients.

 

Methods:

We intraoperatively recorded LFPs in 10 OCD patients while traversing the surgically planned trajectory during awake bilateral NAcc/ALIC DBS surgery. For each advancement step of one millimeter along the surgically planned trajectory, approx. 60 seconds of raw data were recorded. DBS leads were postoperatively localized using the Lead-DBS software based on the preoperative MRI and the postoperative CT. All recording sites were projected onto a common MNI space and were overlapped with subcortical atlas structures.

 

Results:

Our results indicate frequency-specific changes in LFPs while traversing the surgically planned trajectory towards the target point in the NAcc. The transition from white matter (ALIC) to the NAcc is associated with a pronounced reduction in delta power (0-3 Hz) and a slight increase in alpha band power (8-12 Hz). Moreover, specific electrophysiological signatures were observed in further structures along the crossed trajectory.

 

Discussion:

Our study is a first step towards the implementation of real-time monitoring of LFP recordings in DBS surgery for OCD. We here present results that indicate frequency-specific changes in white and gray matter oscillatory activity that might help to increase implantation accuracy.


Joshua N. STRELOW, Ricardo LOUÇÃO, Petra HEIDEN (Cologne, Germany), Juan Carlos BALDERMANN, Pablo ANDRADE, Veerle VISSER-VANDEWALLE, Thibaut SESIA
00:00 - 00:00 #35981 - P060 Vascular Compression of the Nucleus Accumbens: A Potential Etiology of Obsessive-Compulsive Disorder.
P060 Vascular Compression of the Nucleus Accumbens: A Potential Etiology of Obsessive-Compulsive Disorder.

Background: Although the etiology of obsessive-compulsive disorder (OCD) remains unclearconverging evidence from animal studies implicates cortico-striato-thalamo-cortical circuits dysregulation of OCD. Neuroimaging studies from human indicated that hyperactivity in the prefrontal cortex and nucleus accumbens (NAc) is associated with OCD pathology. Moreover, effective deep brain stimulation (DBS) treatments restored the hyperactivity throughout the fronto-striatal network. For the etiology of hyperactivity, previous hypotheses included neuroinflammation, DNA coding mutations, genetic maternal effects, and neurodegeneration. Based on findings of postoperative reconstructed images and local field potential (LFP) from two OCD patients with DBS of the NAc-anterior limb of the internal capsule, we proposed a novel etiologic hypothesis of hyperactivity in OCD from the perspective of vascular anatomy.

Methods: In both patients, four-contact electrodes (model 1242, SceneRay, Suzhou) were implanted bilaterally in the NAc/ALIC. Parameter testing and adjustment were the same as other patients with effective DBS. The severity of obsessive-compulsive symptoms in patient 1 improved approximately 50% during a follow-up of 2 years. Patient 2 failed to respond with chronic stimulation for 18 months. After battery depletionthese two patients were replaced with a novel implantable pulse generator (model SR1181, SceneRay, Suzhou) with sensing function that can transmit LFP data of DBS targets by blue teeth to the recording computer.

ResultsDuring the process of bipolar LFP recording, we found that the LFPs of the lower two contacts exhibited significant arterial pulsation artifacts in the two patients. Then, we reviewed the postoperative CT fused with preoperative MRI, which showed that the NAc was compressed by middle cerebral artery and/or anterior cerebral artery in both patients. Specifically, the LFPs of bilateral E0-E1 and E1-E2 significantly were affected by artery pulsation. The E2-E3 of LFP was not affected by the artery pulses.

Significance: To our knowledge, this is the first study to investigate vascular compression in the NAc of OCD by using neuroimaging and LFP. The results have important implications for the pathophysiological mechanisms and novel therapeutic treatment hints of OCD. Similar to trigeminal neuralgia and hemifacial spasm, vascular decompression might be an effective approach for OCD.


Botao XIONG, Wei WANG (Chengdu, China)
00:00 - 00:00 #36058 - P061 Behavioural effects of repetitive acute stress on an animal model of depression.
P061 Behavioural effects of repetitive acute stress on an animal model of depression.

Introduction: Major depressive disorder is a common psychiatric disorder, and females are twice as likely to be diagnosed as males. Stress plays a key role in triggering depression, and identical stressors can lead to sex specific responses. The Flinders Sensitive Line (FSL) rat model of depression spontaneously shows several depression-like symptoms; however, anhedonia has only been reported in FSLs when induced via the chronic mild stress protocols.

Methods and Materials: The study investigated i.) the FSLs response to repeated acute stress (RAS) and whether it could induce anhedonia; and ii.) the possible induction by RAS of sexual dimorphisms in the behavioral domain. Eighty-eight male/female and FSL/Sprague Dawley (SD) rats were assigned to Stress or Control conditions. The rats underwent four rounds of behavior tests during which the estrous cycle stages were monitored in females. In each round the Open field (OFT), Elevated plus maze (EPM) and Sucrose consumption test (SCT) were followed by the Open Space Swim Test (OSST). For the RAS condition, the OSST consisted of 24 min of swimming on three consecutive days, while the groups in the Control condition only underwent one day of swimming for 15 min. Post OSST, the groups were retested with the SCT.

Results: The data confirmed the lack of anhedonia and anxiety in FSLs prior to stress exposure. Independent of stress, the FSL animals were overall more mobile and drank more sweet solution. The OSST induced a significant and persisting reduction in swimming distance in FSLs compared to SDs and Controls. However, FSL Controls also showed a decrease in swimming over the four test rounds probably due to the high stress susceptibility of FSLs. In FSLs, but not SDs, the RAS induced increased anxiety, more pronounced in males. Female FSLs showed an initial and transient anhedonia, whereas males expressed persisting anhedonia after stress exposure. The estrous cycle did not show any stress specific changes.

Discussion: RAS augmented depression-like behaviour with anxiety and some signs of anhedonia in FSLs, but not SDs. The stronger effects in males indicate a higher vulnerability to physical stress and the accompanying corticosterone changes, possibly because of higher levels of corticosterone shown by male FSLs in previous studies. Further histology and gene expression analysis will confirm the role of stress and investigate alterations in the reward pathway. Additional characterization of the stress response and sexual dimorphism in depression models will improve our understanding of the correlation between stress, sex and depression.


Lisa RATZ (Freiburg, Germany), Volker Arnd COENEN, Máté DÖBRÖSSY
00:00 - 00:00 #36066 - P062 The input-output relationship of ventral tegmental area in a rodent model of depression.
P062 The input-output relationship of ventral tegmental area in a rodent model of depression.

Introduction. More than 300 million people suffer from major depressive disorder (or depression) globally, and up to 30% of the patients can end up being classified as having treatment-resistant depression. Deep brain stimulation (DBS) is an experimental treatment for the treatment-resistant depression patients. The superolateral branch of the MFB (slMFB), as part of the mesolimbic and mesocortical pathways, is considered to be associated with the processing of emotions. In clinical trials, slMFB DBS had promising antidepressant outcomes, although the mechanisms are elusive. Previous Diffusion Tensor Imaging study showed reduced structure connectivity of the slMFB in depressive patients. Ventral tegmental area (VTA), an important structure of the mesolimbic and mesocortical pathways, plays a key role in reward-orientated behavior, motivation, addiction and several psychiatric disorders such as depression. In order to gain insight into the neural networks associated with depression-like phenotype, we used monosynaptic tracing technique to demonstrate the input mapping of the VTA-nucleus accumbens (NAc, both core and shell) and VTA-prefrontal cortex (PFC) ascending projection neurons in a rodent model of depression.

Methods. Flinders Sensitive Line (FSL) rats were employed as a rodent model of depression and aged and sex matched Sprague-Dawleys (SD) were used as controls. FSL and SD rats (n = 10 each) were assigned into 3 groups: “VTA-NAc core”, “VTA-NAc shell” and “VTA-PFC”. Animals in each group received a helper virus (AAV-TVA-oG-GFP) into the VTA, followed by a genetical-modified rabies virus (EnvA-RbdG-mCherry) injected into one of the output areas (NAc core, NAc shell or PFC). The modified rabies virus expressed monosynaptically and labelled direct inputs to the VTA-output projecting neurons. The whole brain input mapping between FSL and SDs were compared.

Results. Direct input towards VTA ascending neurons were found in 31 brain areas in the FSL and SD rats. Importantly, significant higher afferents from dorsal raphe towards VTA-NAc core projecting neurons and significant lower inputs from the cortex, zona incerta, pretectal area and thalamus towards VTA-NAc shell neurons were identified in FSL rats compared with SDs. No significant afferents difference was found in VTA-PFC group. Furthermore, it has been found that VTA-NAc shell neurons play a more critical role in both FSL and SD rats. In FSL rats, afferents from the striatum to the VTA-NAc shell neurons are significantly higher than in other VTA-output neurons; while in SD rats, afferents from the septum and thalamus are significantly higher to the VTA-NAc shell neurons. Overall, differences in connectivity between FSLs and SDs were observed in several neuronal circuits associated with depression.

Conclusion. Our study shows the whole brain mapping of the VTA ascending projecting neurons in a rodent model of depression. The anatomical approach revealed brain areas in the FSLs, including cortex, zona incerta, pretectal area, thalamus and dorsal raphe, that innervate mesocortical and mesolimbic pathways differently compared to controls. This highlights potential network anomalies associated with depression pathologies. Our findings provide better understanding of the therapeutic network mechanisms observed following MFB neuromodulation.

 


Yixin TONG (Freiburg, Germany), Seonghee CHO, Volker Arnd COENEN, Máté DÖBRÖSSY
00:00 - 00:00 #36067 - P063 Photometric characterization of dopamine nucleus accumbens and calcium ventral tegmental area dynamics: Impact of different medial forebrain bundle deep brain stimulation parameters.
P063 Photometric characterization of dopamine nucleus accumbens and calcium ventral tegmental area dynamics: Impact of different medial forebrain bundle deep brain stimulation parameters.

Introduction: The temporal dynamics or the physiological mechanisms of deep brain stimulation (DBS) in psychiatric disorders are not well understood. New technologies, like fiber photometry (FP), can overcome long-standing methodological limitations and promote a better understanding of neuronal mechanisms. In this study, we used FP to monitor acute and chronic (up to eight weeks) medial forebrain bundle deep brain stimulation (mfb-DBS) evoked accumbal dopamine release, and neuronal activity in the ventral tegmental area (VTA), in freely moving rodents.

Methods and Materials: The experimental design aimed to disentangle the impact of different DBS parameters (frequency and pulse width (PW)) in two different regions, the nucleus accumbens (NAc) and the VTA, using different bioindicators for dopamine (GRABDA2m) and calcium (GCaMP6m), for each region respectively. Moreover, we additionally looked at dopamine dynamics during behavioral tasks. For these purposes, Long-Evans rats underwent unilateral DBS electrode implantation in the mfb, viral injection and optic fiber implantation in NAc and VTA. The measurements were performed daily with a different set of parameters and were randomized within and across weeks. PW effects accounted for 100/250/350 µs during 5s/20s of DBS using the clinically relevant 130 Hz frequency and, frequency effects for 5/20/30/130 Hz employing 80 µs PW during 20s DBS with 50s inter-stimulation time and 20 repetitions.

Results: Our results suggest reliable readouts of dopamine and calcium transients over all recording sessions. We were able to show that mfb DBS is able to elicit an increased dopamine response in NAc and calcium transients in VTA during stimulation. The effect of different DBS PWs also suggests a potential differential effect on the dopamine response. Different frequencies (20, 30 and 130 Hz, but not 5 Hz) were also able to elicit a notably high dopamine and calcium activity, in a frequency-dependent fashion.

Discussion: Our current findings suggest that the platform developed was able to record chronically and register the mediated mfb DBS effects, helping to generate more precise information about neurotransmitter release dynamics and potentially lead to a refinement of therapeutical DBS treatment strategies for depression. Future studies will investigate i.) the acute and chronic transmitter release in freely moving behaving animals, and across rodent models of depression and controls; and multi transmitter/multi region FP will permit the elucidation of the interplay between dopamine and glutamate following mfb DBS.

 


Lidia MIGUEL TELEGA, Volker Arnd COENEN, Máté DÖBRÖSSY (Freiburg, Germany)
00:00 - 00:00 #36189 - P064 The opposing effects of antidepressant on different neural clusters in the lateral habenula: Deep brain stimulation of the lateral habenula for treatment-resistant depression is more complicated than we think.
P064 The opposing effects of antidepressant on different neural clusters in the lateral habenula: Deep brain stimulation of the lateral habenula for treatment-resistant depression is more complicated than we think.

Introduction

Deep brain stimulation (DBS) of the lateral habenula (LHb) has been proposed as a treatment option for treatment-resistant depression (TRD). High-frequency (>100 Hz) stimulation is the preferred paradigms by default. However, based on previously published clinical studies, this treatment remains suboptimal. Esketamine is a novel drug treatment for TRD reported to have its antidepressant effect potentially via LHb. Here we aim to explore optimal stimulation strategy by studying the electrophysiological effect induced by esketamine on LHb in mice and man.

Materials and Methods

5 C57/BL6 mice underwent 10 days of social defeat stress conditioning, followed by acute electrophysiological recordings in the LHb using Neuropixels probes, during which esketamine was injected peritoneally. Elevated plus maze, open field test, and social interaction were used as behavioral paradigms to assess the modeling results. We then performed intraoperative micro-electrode recording in LHb in a patient undergoing clinical trial of LHb DBS for TRD. Simultaneously, a series of behavioral tasks, including baseline resting state, monetary reward omission task, and image-induced emotional response (IAPS database) were employed, followed by esketamine intravenous infusion. Spike analysis using Kilosort and Wave_clus was carried out, and a novel stimulation paradigm was proposed based on our findings.

Results

All 5 mice developed different levels of anxiety- and anhedonia-like behaviors after social defeat stress. After spike sorting, we identified multiple groups of neural clusters in the LHb, some highly activated (significantly higher firing rate than baseline), while others substantially deactivated (significantly lower firing rate than baseline) after esketamine injection. Similar findings were made in the human LHb. Based on these findings, we proposed high- (130 Hz), low- (20 Hz), and dual-frequency (130 and 20 Hz) stimulation paradigms for LHb DBS for TRD. Hamilton Depression Rating Scale scores improved significantly in all three stimulation paradigms (from 20 at baseline evaluation to <10 under all stimulation paradigms), while different aspects of symptom improvement were observed when different stimulation paradigms were applied.

Conclusion

Our findings showed that esketamine had opposing effects on different neural clusters in the LHb in an animal model of depression as well as in a patient with TRD. Although antidepressant effect is achieved with current DBS device, higher spatial resolution with cluster specificity is warranted in LHb neuromodulation for TRD.


Zhoule ZHU, Ning WEI, Chen FENG, Hongjie JIANG, Yu QI, Zhe ZHENG, Yueming WANG, Shaohua HU, Junming ZHU, Hemmings WU (Hangzhou, China)
00:00 - 00:00 #36190 - P065 Multimodal lesion targets to treat Self-Injurious behavior.
P065 Multimodal lesion targets to treat Self-Injurious behavior.

INTRODUCTION

Self-Injurious behavior (SIB) is defined as a behavior where the affected individual inflicts physical injury upon him/herself. SIB is associated with autism spectrum disorder, severe Tourette syndrome, after hypoxic or traumatic brain injury. Medical therapy include mood stabilizers, antipsychotics, psychotherapy and severe cases electroconvulsive therapy. In refractory cases to conventional therapy, the lesion or neuromodulation can be useful. Currently, several targets have been used.

OBJECTIVE

We report a clinical two cases with severe self-Injurious behavior, that was underwent to multimodal lesion targets (bilateral hypothalamotomy, unilateral amygdalotomy and unilateral capsulotomy) a single surgical time.

METHODS

We present two male patients, a 15-year-old case with mental retardation and severe aggression with autism spectrum (DSM-V), and the other 24-year-old with mental retardation, severe aggression and impulse control disorder (DSM-V). The cases were evaluated by psychiatry and neurosurgery at our institution to confirm the surgical indication, and accepted by the Bioethics Committee.

Aggression levels were quantified using the Yudofsky Global Aggression Scale (OAS) before surgery and follow-up. Pre-surgical protocol requested magnetic resonance imaging (MRI), EEG, testosterone hormonal study. Which were normal.

Patients underwent radiofrequency lesions, bilateral posteromedial hypothalamotomy (coordinates: X = 2mm lateral to the wall of the third ventricle, Y = 0mm with respect to the midcommissural point, Z = -4mm from the intercommissural line), amygdalotomy (X= 24mm lateral to the midline, Y = 24mm anterior to the most rostral temporal horn, Z = -15mm from the intercommissural line), anterior capsulotomy (coordinates under direct visualization X and Y within the middle third of the anterior arm of the capsule internal, Z = 5mm above the ventral striatum).

RESULTS

At the 6-month follow-up, patients with a significant reduction in aggressive behaviors with a decrease in the OAS scale score. In the first case from 16 points to 2 points at present and reduction in the use of neuroleptics and antipsychotics and with improvement of functionality at the family level, currently under joint monitoring by the Neuropsychiatry part.

The second case with a reduction of 12 to 6 points even with certain impulsive behaviors and cacophony, without modification even in his medication schedule and the same in follow-up with

Neuropsychiatry with certain containment measures by the family.

There were no complications

CONCLUSIONS

SIB is a very disabling behavioral disorder, it can lead to social isolation, permanent institutionalization, serious physical damages or even death. 

In our cases, refractory to conventional therapy, the multitarget lesions described here that include the hypothalamus, the amygdala, and the anterior arm of the internal capsule are a safe and effective option. It can be considered as a possible alternative in the surgical armamentarium.

Pathological aggressiveness continues to be a therapeutic challenge in many cases and requires care in a comprehensive and multidisciplinary context.


Luis Mariano ROJAS-MEDINA (Madrid, Spain), Julian Eduardo SOTO ABRAHAM
00:00 - 00:00 #36261 - P066 Establishment a new center for psychosurgery in a developing country.
P066 Establishment a new center for psychosurgery in a developing country.

Psychosurgery currently refers to performing ablative procedures (cingulotomy or capsulotomy) or invasive neuroaugmentation procedures (deep brain stimulation - DBS). Although more than 300,000 patients have undergone DBS for movement disorders, no more than 500 cases of DBS have been performed worldwide to address psychiatric disorders. This is mainly due to the negative public opinion, as well as the lack of strong evidence for efficacy of DBS in most psychiatric illnesses. However, the burden of psychiatric disease in every society necessitates the availability of psychosurgery to address most advanced cases.

In this presentation, we will describe the challenges of establishing a new center for performing ablative procedures as well as DBS for patients with Obsessive Compulsive Disorder (OCD) in Shiraz, Southern Iran. Multiple local and cultural dilemma will be discussed in details in this presentation.


Ali RAZMKON (Shiraz, Islamic Republic of Iran)
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00:00 - 00:00 #34714 - P067 Gamma Knife radiosurgery and refractory Glossopharyngeal neuralgia. A single center series.
P067 Gamma Knife radiosurgery and refractory Glossopharyngeal neuralgia. A single center series.

 

Background.

 

  Glossopharyngeal neuralgia (GPN) is defined as severe and paroxysmal pain in areas innervated by the glossopharyngeal nerve and the auricular and pharyngeal branches of the vagus nerve. It is very uncommon and represents 0.2%-1.3% of all facial pain syndromes. Surgical treatment is considered for patients who fail medical therapy including microvascular decompression (MVD), neurothomy, thermocoagulation, and infrequently, Gamma Knife surgery (GKS).

 

  The aim of this study is present our experience with GKS and refractory GPN with long term follow-up. We analyze its usefulness and safety in patients with or without previous surgeries, another concomitant neuralgia, or retreats. In addition, we study some factors that could condition the outcome of this technique. According to the bibliographic review, our follow-up is the longest in the literature.

 

Methods.

 

  We have performed the prospective study of 11 patients submitted to GKS the last fifteen years.

  We employed Leksell-GKS system along with Leksell-G frame. The planning was performed on stereotactic MRI and CT images by using Leksell-Gammaplan software.  The shots were established on the glossopharyngeal meatus.

 The cases were evaluated before and after surgery (3, 6, 12 months and then, annually). The VAS (Visual Analogue Scale) and BNI (Barrow Neurological Institute) scales were used. The data were assessed with SPSS25.

 

Results.

 

  Our series was composed of 8 (72%) women and 3 (28%) men, with an average age of 60.1±12.06 years; range 36 -78 years. Eight patients (72.7%) had one, or more than one, previous surgeries (rizotomy or MVD). Ten patients (90.9%) received a maximum dose of 90Gy, and one patient (9.1%), received a maximum dose of 80 Gy.

The median follow-up time was 7.97±4.93 years (1.08-15.5 years). In the inmediate and short-term postoperative period (1 year), eleven patients (100%) experienced significant pain relief (VAS p=0.003; BNI I-IIIb). After the last interview, 8 patients felt pain relief (72.7%) (BNI Grade I=5; BNI Grade IIIa=3); 3 patients (27.3%) (BNI Grade IV) were retreated (MVD:2; GKS:1).We found no association between patients with long evolution time of disease (p=0.456),previous surgeries (p=0.792), or vascular contact (p=0.903) and worse clinical results after GKS. Both morbidity and mortality were 0%.

 

Conclusions.

 

 

As a general principle, procedures for pain should progress from the non-invasive options to the more invasive options. Our results suggest that GKS for treating drug-resistant GPN with high initial doses, is both a minimally invasive and useful and effective therapeutic strategy, without permanent complications. It presents good results even in patients with one or more previous surgical interventions. These findings encourage us to use this non-invasive technique as initial therapy against the invasive options.


Monica LARA ALMUNIA (Madrid, Spain), Nuria E. MARTINEZ MORENO, Cristina TORRES DIAZ, Jorge GUTIERREZ SARRAGA, Roberto MARTINEZ ALVAREZ
00:00 - 00:00 #35999 - P068 Successful treatment of a rare case of left thalamic arteriovenous malformation causing right allodynia with gamma knife radiosurgery.
P068 Successful treatment of a rare case of left thalamic arteriovenous malformation causing right allodynia with gamma knife radiosurgery.

Background: Allodynia is a rare condition characterized by pain perception in response to non-painful stimuli. It is usually associated with peripheral nerve damage or central sensitization. In some cases, it may also occur as a component of "thalamic pain" due to thalamic ischemic or hemorrhagic strokes or neoplasms. It is an unusual clinical manifestation of cerebral arteriovenous malformations (AVM). We report a unique case of a patient with allodynia caused by a left thalamic AVM and treated successfully with Gamma Knife radiosurgery (GKRS).

Methods: A 24-year-old man presented with a 1.5-year history of diplopia and a 10-day history of progressive right-sided allodynia involving the face, arm and leg, without a history of trauma or other known causes. Neurological examination revealed restricted upward gaze in the right eye and hyperalgesia to light touch on the right side of the face and body. Magnetic resonance imaging (MRI) revealed a Spetzler-Martin grade IV left thalamic AVM (figures 1 and 2). The patient underwent hypofractionated GKRS with a total marginal dose of 30 Gy to the 50% isodose line in 5 fractions (figure 3). After GKRS treatment, the patient was referred to a neurologist and started on amitriptyline+carbamazepine.

Results: Follow-up MRI 2 years after treatment showed complete obliteration of the AVM (figure 4). No radiation induced adverse effects or complications were observed. The patient reported that the drug doses were gradually reduced and stopped completely 18 months after GKRS. He reported complete relief of allodynia and diplopia symptoms.

Discussion: In this rare case of a left thalamic AVM causing right-sided allodynia, we successfully treated the patient with GKRS. To our knowledge, this is the first reported case of an unruptured cerebral AVM causing allodynia in the literature.

Conclusion: The complete obliteration of the AVM and consequent relief of allodynia in our patient emphasizes the importance of considering AVMs in the differential diagnosis of allodynia, especially when associated with other neurological symptoms. This case highlights the potential efficacy of GKRS in the treatment of AVM-induced allodynia and offers a valuable treatment approach for future patients with similar presentations.


Ali Haluk DUZKALIR, Mustafa Yavuz SAMANCI (Istanbul, Turkey), Mehmet Orbay ASKEROGLU, Selcuk PEKER
00:00 - 00:00 #36060 - P069 Gamma Knife Radiosurgery: A dose-staged treatment concept in large or high-risk brain metastases.
P069 Gamma Knife Radiosurgery: A dose-staged treatment concept in large or high-risk brain metastases.

Objective: The aim of the study was to evaluate the clinical outcome in patients with large, high-risk brain metastases (BMs) treated with different dose strategies by use of two-fraction dose-staged Gamma Knife radiosurgery (GKRS).

Methods: Data from 142 patients, who had been treated with two-fraction dose-staged GKRS, were analysed retrospectively. Depending on different marginal doses between the first (GKRS1) and second (GKRS2) GKRS treatment, different strategies were defined: dose escalation, dose maintenance, and dose de-escalation.

Results: The median tumour volume decreased significantly from GKRS1 to GKRS2 and to the last follow-up. Significant changes in BM volume reduction were achieved in all three treatment groups. However, while dose maintenance seemed to be the most effective treatment strategy for BMs from lung cancer or melanoma, dose escalation was the most beneficial treatment option for BMs from breast, gastrointestinal, or genitourinary cancer. The vast majority of patients who underwent dose-staged BM treatment did not show any significant post-radiosurgical complications.

Conclusions: In patients with large, high-risk BMs, dose-staged GKRS treatment exhibits an effective local treatment method with acceptable complication risks. Different dose-strategy options are available that may be chosen according to the primary tumour histology and treatment volume but may also be tailored to the findings at GKRS2.


Brigitte GATTERBAUER (Vienna, Austria), Anna CHO, Josa M. FRISCHER
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00:00 - 00:00 #34114 - P070 Our Experience with Neurosphere Digital Care, six months after implementation.
P070 Our Experience with Neurosphere Digital Care, six months after implementation.

Our Experience with Neurosphere Digital Care, six months after implementation

Introduction

New innovative digital products are important for development of qualitative care and resource utilization at hospitals worldwide. Our clinic offers a variety of neuromodulation modalities, therapies that requires multiple clinical consultations for hardware diagnostics and programming optimizations. Here we will present our experience with Neurosphere Digital Care (NDC), six months after implementation.

 

Method

Twenty-one patients (12 females/9 male, mean age 57) treated for chronic pain, with access to NDC through their stimulation device, were followed up with a digital patient satisfactory survey. Using Google Map also travelling distance and time was registered from the patients address to the hospital. Further, data was collected from the hospital administration system for the number of digital and real-life outpatient consultations performed, and how much time these consultations consumed. This data was compared to the same period a year earlier.

 

Results

All patients accepted to participate in the survey. Patient satisfaction with NDC rated to 9.1 on a 0-10 scale and 81% of patients preferred digital visits before real-life consultations after trying NDC.  19/21 patients would recommend other patients to use NDC and preferred to have future consultations with NDC if possible. A cumulative of 12595 km of travelling distance and 153 hours of travelling time was avoided using NDC, indicating a significant travelling cost saving by the patients.

The administrative data indicates that consultations with NDC consumes less time, enabling more outpatients visits per doctor/nurse. Compared to the same period a year earlier there was an increase of 20% in number of outpatient visits at our centre.

 

Discussion

Our Patients showed a high satisfaction with NDC. Benefits from using NDC are obvious, as patients save both time and costs related to travelling to the hospital. Long travels for patients with chronic pain can often lead to more pain and suffering, which can be avoided using NDC. Several patients however pointed out that they lacked the personal contact in digital consultations.

We could show that clinicians can increase their resource utilization and effectivity by using NDC. Also, accessibility to care was improved. Implementation of new digital systems can however be challenging, as the staff must adopt new technology and ways of working.

 

Conclusions:

After having used NDC for 6 months we can see a high patient satisfaction and significant time and cost savings for the patients. NDC also improved accessibility, effectivity, and resource utilization at our clinic.


Pedram TABATABAEI (Umeå, Sweden), Josef SALOMONSSON, Pavlina KAKAS, Linda BREDEMO, Eva LELJEVAHL
00:00 - 00:00 #35723 - P071 Impact of a standardized music therapy protocol on the quality of life of patients treated with Deep Brain Stimulation : Preliminary Results.
P071 Impact of a standardized music therapy protocol on the quality of life of patients treated with Deep Brain Stimulation : Preliminary Results.

The management of patients treated with Deep Brain Stimulation (DBS) over time could be difficult because of cases of worsening of the motor condition due to the evolution of the disease. A multidisplinary team, taking into account each symptom including anxiety, can contribute to the improvement of the quality of life of patients.We developed in our unit a music therapy room to support patients during their hospitalisation and to promote relaxation and well-being. To evaluate the efficacy of a standardised music therapy protocol on the quality of life of patients treated with DBS, 60 patients were recruited over 24 months and randomised into a music therapy group (14 sessions of 45 min over 3 months) or a control group (standard care). The 2 groups were evaluated at inclusion and at 1 and 3 months’ follow-up. At each endpoint, quality of life was evaluated by Short Form 36 (SF-36) and Hospital Anxiety and Depression Scale (HADS) and well-being with a visual analog scale (EVIBE: "Echelle D'évaluation Instantanée du Bien-Être).Our preliminary results concerned 8 patients enrolled in music therapy group. Improvement in the music therapy group is statistically significant for EVIBE (p=0.039) and a positive trend emerged for the other scores: SF 36 (p= 0.078), HADS (p =0.105).To our knowledge, this is the first prospective, controlled, randomised, non-pharmacological interventional study evaluating music therapy effects in patients treated with DBS. These first results are encouraging and show that this approach could be used in the routine care of patients treated by DBS to improve their quality of life.


Lydia ALBERT (MONTPELLIER), Emily SANREY, Philippe COUBES, Gaëtan POULEN
00:00 - 00:00 #35730 - P072 Submammary Implantation of Internal Pulse Generators for Deep Brain Stimulation: Long-Term Follow-up of Device Acceptance and Quality of Life in Women.
P072 Submammary Implantation of Internal Pulse Generators for Deep Brain Stimulation: Long-Term Follow-up of Device Acceptance and Quality of Life in Women.

Background: A submammary approach to implanting pulse generators is innovative and has yielded good aesthetic results in the current literature. It was our aim to make a comparison of patient device acceptance, tolerance, and complications between submammary and abdominal device locations in deep brain stimulation.

Methods: Twenty-five and 28 patients were included in the submammary and abdominal groups, respectively. Our primary criterion was patient acceptance that was calculated using total Florida Patient Acceptance Survey (FPAS) scores in each group. Secondarily, tolerance was assessed in the submammary group by means of a specific questionnaire.

Results: Total FPAS scores from the submammary group [total FPAS: 77.1 versus 74.7, P = 0.29] revealed no significant difference when compared with the abdominal group. The same similarities were observed regarding the 4 subscales: return to function [16.3 versus 15.8, P = 0.53], device-related distress [22.0 versus 21.3, P = 0.31], body image concerns [9.2 versus 8.6, P = 0.14], and positive appraisal [17.8 versus 17.4, P = 0.58]. Tolerance was reported as good by the majority of the women from the submammary group. There was no evidence of higher infection rates in the submammary implantation (SMI) group.

Conclusions: SMI is a satisfactory alternative to other deep brain stimulation locations. SMI is a feasible option for any young woman who is eligible for deep brain stimulation.


Lucas RIBEIRO, Emilie CHAN-SENG, Valérie GIL, Emily SANREY, Philippe COUBES, Gaëtan POULEN (MONTPELLIER)
00:00 - 00:00 #35829 - P073 Functional neurosurgery projects funded by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG): where are we?
P073 Functional neurosurgery projects funded by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG): where are we?

Objective: Functional neurosurgery is a field that has witnessed many important breakthroughs in translational neuroscience. Germany is one of the countries with significant contributions to this field. The aim of this study was to assess the status quo of functional neurosurgery related research by analyzing projects funded by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG).

Methods: Projects funded by the German Research Foundation (DFG) were extracted using GEPRIS database by using keywords related to functional neurosurgery. Identified projects were screened for pertinence to the addressed theme, and duplicates/triplicates were excluded. Results were categorized by project start and end data, subject setting, design, involved targets, researchers and specialty.

 

Results: In total, 144 projects were found, from which 53 were active conducted studies. Records spanned 19 different disorders. Most projects involved humans (n=74), followed by rodents (n=47), in vitro (n=6), in vivo (n=2), primates (n=2), materials and technology (n=9) and computational models (n=4). The projects were conducted in total by 20 different specialties, including neurology (n=59), neurophysiology (n=20) and neurosurgery (n=10). Targets for functional neurosurgery investigated in these projects were 22, mainly pertaining to the basal ganglia (n=38). Most studies focused on imaging or electrophysiological changes associated with surgery (n=38), followed by therapeutic effect of surgery (n=24) and technological development (n=20).

Conclusions: This overview provides insight into the actual status of functional neurosurgery research in Germany, from which we can anticipate future developments and possible changes in current clinical practice.


Filipe WOLFF FERNANDES (Hannover, Germany), Joachim Kurt KRAUSS
00:00 - 00:00 #35953 - P074 Technical tools for simulation and visualization of DBS research data.
P074 Technical tools for simulation and visualization of DBS research data.

An essential part of deep brain stimulation (DBS) research is to estimate the spatial extension of stimulation. On patient level, a volume of activated tissue (VTA) can be estimated with electric field simulations. On group level, the simulation results can be utilized to create probabilistic maps for improvement or adverse effects. To share technical developments and research results, we have released three applications for free download (https://liu.se/en/article/ne-downloads) which support the process of simulation and provide an extensive visualization of research results.

The first two apps are related to patient specific electric field simulation [1]. ELMA is a Matlab based tool for creating patient specific brain conductivity models based on MRI tissue segmentation. The conductivity model serves as input to DBSim (based on COMSOL Multiphysics, Sweden), where the electric field can be simulated around the active DBS contact according to the stimulation settings. The simulation result can be visualized together with the patient MRI in DBSim or exported for processing and visualization in external software’s. With these apps, patient specific simulations both with regards to the tissue conductivity and the DBS lead placement can be performed.

The third app, DBviS has been developed as an extension to 3DSlicer (www.slicer.org) for distribution and visualization of DBS research data. With the utilization of the 3DSlicer platform including advanced medical imaging tools, data from different studies have been gathered for visualization. The data include results from probabilistic mapping studies of improvement or side effects in different disorders (Parkinson’s disease, essential tremor, obsessive compulsive disorder etc.) [2-4]. Further, data is provided to visualize the effect of different modelling choices such as anisotropic tissue conductivity [5], the effect of cystic cavities in the vicinity of the DBS lead [6], and how probabilistic mapping is impacted by different parameters [4]. With this tool, researchers and students can investigate full 3D volumes from different research studies for a comprehensive visualization of probabilistic mapping studies and learning and understanding the effects of simulation and mapping process. In future, there are possibilities to expand this process further by developing a software where the optimal stimulation settings for new patients can be predicted based on available research data.

*Research is financially supported by the Swedish Foundation for Strategic Research (BD15-0032)

[1] J.D. Johansson, K. Wårdell, DBSim and ELMA - Freeware for Simulations of Deep Brain Stimulation, 2022 44th Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC), 2022, pp. 1719-1724.

[2] R. Stenmark Persson, T. Nordin, G.-M. Hariz, K. Wårdell, L. Forsgren, M. Hariz, P. Blomstedt, Deep Brain Stimulation of Caudal Zona Incerta for Parkinson's Disease: One-Year Follow-Up and Electric Field Simulations, Neuromodulation: Technology at the Neural Interface 25(6) (2021) 935-944.

[3] M. Naesstrom, J. Johansson, M. Hariz, O. Bodlund, K. Wardell, P. Blomstedt, Distribution of electric field in patients with obsessive compulsive disorder treated with deep brain stimulation of the bed nucleus of stria terminalis, Acta Neurochir (Wien) 164(1) (2022) 193-202.

[4] T. Nordin, D. Vogel, E. Osterlund, J. Johansson, P. Blomstedt, A. Fytagoridis, S. Hemm, K. Wardell, Probabilistic maps for deep brain stimulation - Impact of methodological differences, Brain Stimul 15(5) (2022) 1139-1152.

[5] T. Nordin, K. Wårdell, J.D. Johansson, The Effect of Anisotropy on the Impedance and Electric Field Distribution in Deep Brain Stimulation, in: T. Jarm, A. Cvetkoska, S. Mahnič-Kalamiza, D. Miklavcic (Eds.) 8th European Medical and Biological Engineering Conference, Springer International Publishing, Cham, 2021, pp. 1069-1077.

[6] F. Alonso, P. Zsigmond, K. Wårdell, Influence of Virchow-Robin spaces on the electric field distribution in subthalamic nucleus deep brain stimulation, Clinical Neurology and Neurosurgery 204 (2021) 106596.


Teresa NORDIN (Linköping, Sweden), Dorian VOGEL, Simone HEMM, Karin WÅRDELL
00:00 - 00:00 #35994 - P075 The state of diversity in open science, education and academic success among consultant neurosurgeons: do name characteristics and face memorability affect their career success?
P075 The state of diversity in open science, education and academic success among consultant neurosurgeons: do name characteristics and face memorability affect their career success?

Background: Equitable representation is key for successful clinical and research work. Inequalities in gender, skin colour, and education have been found among professionals in many medical, surgical and academic fields, but have not been examined yet in the current neurosurgeons’ workforce. Factors unrelated to the quality and quantity of one’s work can often affect one’s scientific career success. The complexity, popularity, perceived ethnicity and perceived gender of names seem to related to success in certain fields, for example name popularity in employability. This study examined whether there are disparities in gender, skin colour, education, academic productivity, and career progression among neurosurgeons, and whether the memorability of neurosurgeons’ faces and the characteristics of their names are related to their career success.

Methods: Data from all consultant neurosurgeons working in the UK (386) or USA (approximately 3500) in 2023 were found via public online resources. Photos of their faces, information about their education and current position were collected. Scopus was used to collect bibliometrics. Resmem, a convolutional neural network model, was used to find the estimated memorability score of each photo.

Results: Analyses are being undertaken at the moment and results will be available by September 2023.

Conclusions: In conclusion, this study is the first study to examine the diversity in open science, education and academic success among consultant neurosurgeons, and whether face memorability and name characteristics affect neurosurgeons’ career success, which are factors unrelated to the amount and quality of their work.


Marianna KAPSETAKI (Heraklion, Greece)
00:00 - 00:00 #36110 - P076 Hemifacial Spasm Caused by Cerebellar Arteriovenous Malformation and Spasm-Relief after Nidus Removal.
P076 Hemifacial Spasm Caused by Cerebellar Arteriovenous Malformation and Spasm-Relief after Nidus Removal.

Secondary hemifacial spasm (HFS) occurs by a conflict between the facial nerve and intracranial pathology, such as cerebellopontine angle tumor or vascular abnormality like arteriovenous malformation (AVM) or aneurysm. HFS caused by AVM is rare, and optimal combination of treatment options has not been established. AVM treatment with or without microvascular decompression (MVD) of the facial nerve was provided in the previous studies, and the outcomes in terms of spasm relief have been successful. Here, we report a case of HFS caused by cerebellar AVM. HFS symptom disappeared after AVM nidus removal without MVD of the facial nerve.


Seunghoon LEE (Seoul, Korea)
00:00 - 00:00 #36159 - P077 Accuracy of augmented reality-guided (AR) drainage versus stereotactic and freehand puncture in intracerebral hemorrhage.
P077 Accuracy of augmented reality-guided (AR) drainage versus stereotactic and freehand puncture in intracerebral hemorrhage.

Minimally-invasive intracranial drain placement is a common neurosurgical emergency procedure in patients with intracerebral hemorrhage (ICH). We aimed to retrospectively investigate the accuracy of conventional (bedside) hemorrhage drain placement and to prospectively compare the accuracy of augmented/mixed reality-guided (AR) versus stereotactic-guided (STX) and conventional drain placement in a phantom model.

A retrospective, single-center analysis evaluated the accuracy of drain placement in 73 consecutive ICH with a visual rating of postinterventional computed tomography data. In a head phantom with a simulated deep ICH, five neurosurgeons performed four punctures for each technique: STX, AR and the conventional freehand technique in randomized sequence (60 operations). The Euclidean distance to the target point and the lateral deviation of the achieved trajectory from the planned trajectory at target point level were compared between the three methods.

Analysis of the clinical cases revealed an optimal drainage position in only 46/73 (63%). Correction of the drain was necessary in 23/73 cases (32%). In the phantom study, accuracy of AR was significantly higher than the conventional method (p < 0.001 for both Euclidean and lateral distances). The Euclidean distance using AR (median 3 mm) was close to that using STX (median 1.95 mm; p = 0.023).

We demonstrated that the accuracy of the conventional technique was low and that subsequent position correction was common. In a phantom model, AR drainage placement was significantly more precise than the conventional method. AR has great potential to increase precision of emergency intracranial punctures in a bedside setting.


Amin STANICKI (Freiburg, Germany), Theo DEMERATH, Roland ROELZ, Christine STEIERT, Marco BISSOLO, Matteo NUNEZ, Christian FUNG, Jürgen BECK, Volker A. COENEN, Peter C. REINACHER
00:00 - 00:00 #36194 - P078 Comparison of initial shunt pressure setting methods.
P078 Comparison of initial shunt pressure setting methods.

There are several approaches to establish the initial valve pressure in shunt patients to obtain clinical response without not over-drainage. Therefore, we attempt to compare starting with a constant fixed pressure and starting from a pressure based each patient’s opening pressure.

 

The group that received the ventriculo-peritoneal shunt (VP shunt) for idiopathic normal pressure hydrocephalus from January to December 2017 and the group that received VP shunt from January to December 2022 were compared. For the group that underwent VP shunt in 2017, the initial shunt valve pressure was determined as a constant fixed pressure, and for the patients who underwent VP sunt in 2022, the initial valve pressure was set slightly lower than the opening pressure.

 

A total of 39 patients were included in the constant fixed pressure method group and 23 patients were included in the pressure based on opening pressure group. There was no difference in opening pressure between the two groups. There was no difference in the length of time taken for shunt pressure adjustments.

 

There was no difference in the time taken for shunt pressure adjustment between the constant fixed pressure method and the pressure setting based on opening pressure method.


Jung Ho HONG (Daegu, Korea), So Hee PARK, Sung Ho KIM