Monopolar stereoelectroencephalography-guided radiofrequency thermocoagulation.

OBJECTIVE: Stereoelectroencephalography (SEEG)-guided radiofrequency thermocoagulation (RFTC) has the advantage of producing a lesion in the epileptogenic zone (EZ) at the end of SEEG. The majority of published SEEG-guided RFTCs have been bipolar and usually performed between contiguous contacts of the same electrode. In the present study, the authors evaluate the safety, efficacy, and benefits of monopolar RFTC at the end of SEEG. METHODS: This study included a series of 31 consecutive patients who had undergone RFTC at the end of SEEG for drug-resistant focal epilepsy in the period of January 2013-December 2019. Post-RFTC seizure control was assessed after 2 months and at the last follow-up visit. Twenty-one patients underwent resective epilepsy surgery after the SEEG-guided RFTC, and the postoperative seizure outcome among these patients was compared with the post-RFTC seizure outcome. RESULTS: Four hundred forty-six monopolar RFTCs were done in the 31 patients. Monopolar RFTCs were performed in all cortical areas, including the insular cortex in 11 patients (56 insular RFTCs). There were 31 noncontiguous lesions (7.0%) because of vascular constraints. The volume of one monopolar RFTC, as measured on T2-weighted MRI immediately after the procedure, was between 44 and 56 mm3 (mean 50 mm3). The 2-month post-RFTC seizure outcomes were as follows: seizure freedom in 13 patients (41.9%), ≥ 50% reduced seizure frequency in 11 (35.5%), and no significant change in 7 (22.6%). Seizure outcome at the last follow-up visit (mean 18 months, range 2-54 months) showed seizure freedom in 2 patients (6.5%) and ≥ 50% reduced seizure frequency in 20 patients (64.5%). Seizure freedom after monopolar RFTC was not significantly associated with the number or location of coagulated contacts. Seizure response after monopolar RFTC had a high positive predictive value (93.8%) but a low negative predictive value (40%) for seizure outcome after subsequent resective surgery. In this series, the only complication (3.2%) was a limited intraventricular hematoma following RFTC performed in the hippocampal head, with spontaneous resolution and no sequelae. CONCLUSIONS: The use of monopolar SEEG-guided RFTC provides more freedom in terms of choosing the SEEG contacts for thermocoagulation and a larger thermolesion volume. Monopolar thermocoagulation seems particularly beneficial in cases with an insular EZ, in which vascular constraints could be partially avoided by making noncontiguous lesions within the EZ.

Development and results of the epilepsy surgery in Armenia: hope for a better future.

Purpose: We present our experience with the national epilepsy surgery program in Armenia by tracing the development of epilepsy surgery in the largest pediatric neurology department at "Arabkir" Medical Center. This development was possible on the basis of a strong collaboration with the Epilepsy Surgery center at the University Hospital "Sofia St. Ivan Rilski," Sofia, Bulgaria. Materials and methods: Our material included 28 consecutive patients with lesional drug-resistant epilepsy evaluated. All patients underwent 3 T MRI and Video-EEG monitoring. Brain 18FDG-PET was done in 13 patients in St. Petersburg. Fifteen patients (53%) had preoperative neuropsychological examination before surgery. All operations were done by the same neurosurgical team on site in Arabkir Hospital. Results: The majority of the patients in our cohort benefited from the epilepsy surgery as 25 (89%) are free of disabling seizures (Engel class I) and three patients (11%) did not improve substantially (Engel class IV). Eleven patients (39%) are already ASM-free after surgery, 4 (14%) are on monotherapy, 11(39%) get two drugs, and 2(7%) are on polytherapy, one of them still continues having seizures. In 12 patients (43%), we were able either to withdraw therapy or to decrease one of the ASM. Conclusion: We believe that, although small, yet encompassing patients along the usual age spectrum and with the most frequent pathologies of drug-resistant epilepsies, our experience can serve as a model to develop epilepsy surgery in countries with limited resources.

Anaplastic ganglioglioma-A diagnosis comprising several distinct tumour types.

AIMS: Anaplastic ganglioglioma is a rare tumour, and diagnosis has been based on histological criteria. The 5th edition of the World Health Organization Classification of Tumours of the Central Nervous System (CNS WHO) does not list anaplastic ganglioglioma as a distinct diagnosis due to lack of molecular data in previous publications. We retrospectively compiled a cohort of 54 histologically diagnosed anaplastic gangliogliomas to explore whether the molecular profiles of these tumours represent a separate type or resolve into other entities. METHODS: Samples were subjected to histological review, desoxyribonucleic acid (DNA) methylation profiling and next-generation sequencing. Morphological and molecular data were summarised to an integrated diagnosis. RESULTS: The majority of tumours designated as anaplastic gangliogliomas resolved into other CNS WHO diagnoses, most commonly pleomorphic xanthoastrocytoma (16/54), glioblastoma, isocitrate dehydrogenase protein (IDH) wild type and diffuse paediatric-type high-grade glioma, H3 wild type and IDH wild type (11 and 2/54), followed by low-grade glial or glioneuronal tumours including pilocytic astrocytoma, dysembryoplastic neuroepithelial tumour and diffuse leptomeningeal glioneuronal tumour (5/54), IDH mutant astrocytoma (4/54) and others (6/54). A subset of tumours (10/54) was not assignable to a CNS WHO diagnosis, and common molecular profiles pointing to a separate entity were not evident. CONCLUSIONS: In summary, we show that tumours histologically diagnosed as anaplastic ganglioglioma comprise a wide spectrum of CNS WHO tumour types with different prognostic and therapeutic implications. We therefore suggest assigning this designation with caution and recommend comprehensive molecular workup.

Theoretical stereoelectroencephalography density on the brain convexity.

INTRODUCTION: Invasive electroencephalography (EEG) remains the "gold standard" for diagnosing the epileptogenic zone in patients with drug-resistant epilepsy and discrepancies between seizure semiology, video-EEG and magnetic resonance imaging (MRI) findings. However, the possibilities of stereoelectroencephalography (SEEG) to explore the brain surface remain a matter of debate and subdural EEG (SDEEG) is still preferred in some centers for cases when the supposed epileptogenic zone is on the brain convexity. The aim of our study was to evaluate the theoretical safe SEEG coverage on the brain convexity and to compare the theoretical SEEG cortical density with the usual SDEEG density. MATERIALS AND METHODS: Our material included 10 hemispheres in 5 patients, who had been already investigated with SEEG for drug-resistant epilepsy. We translated our previously described technique in a theoretical model in an attempt to calculate the maximal number of avascular windows for each cerebral hemisphere. The distance between every entry point and the other entry points for each hemisphere was calculated using a mathematical formula. Subsequently, the theoretical SEEG coverage on the brain convexity was described using the maximal, minimal and average distances between each entry point and the closest 4 neighboring points. This type of measurement allows a direct comparison between SEEG and SDEEG in their ability to explore the brain convexity. RESULTS: Ten hemispheres had 1328 safe entry points with a safety margin of 2.5 mm and a minimal distance of 2.5 mm between 2 entry points (average number of entry points: 132.8 (SD ± 5). The number of entry points in the explored 10 hemispheres varied from 104 to 156. The average distance between each entry point and its 4 neighbors was 11.47 mm. The maximal distance between two entry points in these 10 hemispheres was ranging from 20.28 to 27.23 mm (average: 24.67 mm). The closest entry points for the explored hemispheres were at an average distance of 4.67 mm (range: 2.82 - 5.96 mm). The average convexity surface was 223.68 cm2 (range: 204.63-238.77 cm2). The safe electrode density without electrode collision on the cortical surface was ranging from 0.46 to 0.69 electrodes per cm2 (average: 0.59 electrodes per cm2) (SD ± 0.023). CONCLUSION: The theoretical SEEG cortical density is comparable with the usual SDEEG density. These findings, combined with the better safety profile of SEEG and the possibilities to explore deep cortical structures, explain the progressive shift from SDEEG to SEEG during the last years.

Awake Epilepsy Surgery in Patients with Focal Cortical Dysplasia.

BACKGROUND: Awake craniotomy (AC) and direct electric stimulation emerged together with epilepsy surgery >80 years ago. The goal of our study was to evaluate the benefits of awake surgery in patients with drug-resistant epilepsy caused by focal cortical dysplasia (FCD) affecting eloquent areas. METHODS: Our material included 95 patients with drug-resistant epilepsy and FCD, who were operated on between January 2009 and December 2018. These 95 patients were assigned into 3 groups: AC; general anesthesia (GA) with intraoperative neuromonitoring; and GA without intraoperative neuromonitoring. We investigated the following variables: age at surgery, lesion side, eloquent cortex involvement, brain mapping success rate, epilepsy surgery success rate, intraoperative complications, postoperative complications, and intraoperative changes of the preoperative resection plan according to results of the brain mapping by direct electric stimulation. RESULTS: We found statistically significant differences between the AC and GA groups in the mean age at operation, lesion side, eloquent localization, and postoperative transient neurologic deficit. Seizure outcome in the AC was satisfactory (71% complete seizure control) and comparable to the seizure outcome in the GA groups. Our preoperative plan was changed because of functional constraints in 6 patients (43%) operated on during AC. CONCLUSIONS: AC during epilepsy surgery for FCD in eloquent areas may change the preoperative plan. The good rate of postoperative seizure control and the absence of permanent postoperative neurologic deficit in our series is the main proof that AC is a useful tool in patients with FCD involving the eloquent cortex.

Case Report: Multisystem Autoimmune and Overlapping GAD65-Antibody-Associated Neurological Disorders With Beneficial Effect of Epilepsy Surgery and Rituximab Treatment.

Glutamic acid decarboxylase (GAD) antibodies are associated with disabling conditions such as stiff person syndrome, temporal lobe epilepsy (TLE), limbic encephalitis, cerebellar ataxia (CA), and ocular movement disorders, which are usually chronic and difficult to treat. GAD-related TLE has poor response to anti-seizure medications and immune therapies, and epilepsy surgery is rarely successful. We report on a 47-year-old female with history of migraine, autoimmune thyroid disease, ankylosing spondylitis, and drug-resistant TLE. A video electroencephalography recorded frequent seizures with temporo-insular semiology, correlating to left temporal epileptiform activity and left mesiotemporal hyperintensity on magnetic resonance imaging. GAD autoimmunity was confirmed by very high GAD antibody titers in serum and cerebrospinal fluid. Steroids, immunoglobulins, and cyclophosphamide had no effect, and selective left amygdalectomy was performed based on very restricted hypermetabolism on positron-emission tomography. After transient seizure freedom, significant epilepsy improvement was observed in spite of memory decline. Transient worsening was noted 1 year later during diabetes mellitus manifestation and 5 years later during presentation of progressive CA, which stabilized on rituximab treatment. We believe this case illustrates the diversity and the frequent overlap of GAD-associated disorders, the need of early and aggressive immunotherapy in severe patients, as well as the possible benefit from epilepsy surgery in some GAD-TLE.

SCN1A mutation spectrum in a cohort of Bulgarian patients with GEFS+ phenotype.

BACKGROUND: Dravet syndrome (DS) is the most severe form of Generalized Epilepsy with Febrile Seizures plus (GEFS+) syndrome with a clear genetic component in 85% of the cases. It is characterized by fever-provoked seizure onset around six months of age and subsequent developmental deterioration later in life. METHODS: In the current study, 60 patients with fever-provoked seizures and suspicion either of GEFS+ (50 patients) or of DS (10 patients) were referred for SCN1A gene sequence analysis. RESULTS: SCN1A gene sequencing revealed clinically significant variants in 11 patients (18.3%); seven pathogenic (11.7%) and four likely pathogenic (6.7%). Five of these variants have not been reported previously. Among the preselected group of ten DS patients, five had pathogenic SCN1A variants which confirmed diagnosis of DS. In four patients with preliminary diagnosis GEFS+, the detected SCN1A variant enabled us to specify the diagnosis of DS in these patients. Thus, SCN1A sequencing led to confirmation of the genetic diagnosis in 50% (5/10) of DS patients, as well as clarification of the diagnosis of DS in 8% of GEFS+ patients (4/50). In this study, four patients with truncating mutations had refractory seizures and additional psychomotor abnormalities. Additionally, pathogenic missense mutations were detected in three children with comparable phenotypes, which support the observations that missense mutations in critical channel function regions can cause a devastating epileptic condition. CONCLUSIONS: This is the first systematic screening of SCN1A gene in our country, which expands the spectrum of SCN1A variants with five novel variants from Bulgaria and demonstrates the clinical utility of confirmatory SCN1A testing, which helps clinicians make early and precise diagnoses. It is important for a better followup, choice of proper treatment, avoidance of development of refractory seizures and neuropsychological complications. Identification of pathogenic variants in SCN1A in the milder GEFS+ and severe DS cases, will help to offer adequate prenatal diagnosis and improve the genetic counselling provided to affected families.

Low-grade epilepsy-associated tumour management with or without presurgical evaluation: a multicentre, retrospective, observational study of postsurgical epilepsy outcome.

Low-grade epilepsy-associated neuroepithelial tumours (LEATs) encompass the broad spectrum of tumours associated with epilepsy. Since the postsurgical seizure outcome in LEATs is favourable, it is speculated that epileptological presurgical evaluation (EPE) might not be required for patients with LEATs. A multicentre study involving referring epilepsy and neurosurgery centres was performed, aimed at evaluating postsurgical epilepsy outcome in patients with LEATs, with and without EPE, including long-term video-EEG monitoring (vEEGM). In total, 149 surgically treated patients were enrolled (age: 31±14 years; age at surgery: 26.4±13.1 years; males; 55.7%) with histopathological confirmation of LEATs and follow-up of more than six months. All patients had undergone standard assessment: clinical, routine EEG and brain MRI. In addition to vEEGM, EPE included other additional investigations. Epileptologists did not assess patients treated in neurosurgical centres. The EPE was performed in 51% of patients. Histopathological diagnosis revealed ganglioglioma in 43.6%, DNET in 32.9%, pilocytic astrocytoma in 17.4%, and others in 6.1% of patients. The majority of patients were seizure-free (ILAE epilepsy surgery outcome Class 1; 71.1%). The median follow-up period was 36 months. Patients who were rendered seizure-free were younger (mean age: 24.2±12.2) than those who were not seizure-free (31.8±14.0) (p=0.001). No difference was identified between evaluated and non-evaluated patients with respect to seizure freedom (p=0.45). EPE patients had a longer epilepsy duration (median: 10 years) and a higher proportion of drug resistance (73.6%) compared to non-evaluated patients (median: two years; 26.4%) (p<0.001). Based on a significant difference in major clinical variables, that may well affect postoperative results, the similar postsurgical seizure outcome in groups with and without EPE observed in our study should be considered with caution, and conclusions as to whether there is value in formal presurgical evaluation in LEAT patients cannot be drawn. Our data strongly encourage the clear need for continued discussion around such patients at epilepsy management conferences.

Human cytomegalovirus DNA detection in a recurrent glioblastoma multiforme tumour, but not in whole blood: a case report and discussion about the HCMV latency and therapy perspectives.

In the current study, a 58-year-old male patient presented with recurrent glioblastoma multiforme (GBM). The patient underwent surgical resection, 4 months earlier, followed by radiotherapy and chemotherapy. During the second surgical intervention, tumour tissue and whole blood were sampled and analysed for human cytomegalovirus (HCMV) DNA, immediate early (IE) mRNA and pp65 mRNA. HCMV DNA was detected only in the recurrent tumour tissue but not in the whole blood. Neither IE mRNA nor pp65 mRNA was expressed. Our result suggests HCMV latency in the brain tumour with detectable level of viral DNA. More data are needed to understand the HCMV infection chronology in the brain tumours but our data could be important for further studies of HCMV antigens on the tumour surface and anti-GBM therapy.

A European questionnaire survey on epilepsy monitoring units' current practice for postoperative psychogenic nonepileptic seizures' detection.

BACKGROUND: In cases undergoing epilepsy surgery, postoperative psychogenic nonepileptic seizures (PNES) may be underdiagnosed complicating the assessment of postsurgical seizures' outcome and the clinical management. We conducted a survey to investigate the current practices in the European epilepsy monitoring units (EMUs) and the data that EMUs could provide to retrospectively detect cases with postoperative PNES and to assess the feasibility of a subsequent postoperative PNES research project for cases with postoperative PNES. METHODS: We developed and distributed a questionnaire survey to 57 EMUs. Questions addressed the number of patients undergoing epilepsy surgery, the performance of systematic preoperative and postoperative psychiatric evaluation, the recording of sexual or other abuse, the follow-up period of patients undergoing epilepsy surgery, the performance of video-electroencephalogram (EEG) and postoperative psychiatric assessment in suspected postoperative cases with PNES, the existence of electronic databases to allow extraction of cases with postoperative PNES, the data that these bases could provide, and EMUs' interest to participate in a retrospective postoperative PNES project. RESULTS: Twenty EMUs completed the questionnaire sheet. The number of patients operated every year/per center is 26.7 ( ±â€¯19.1), and systematic preoperative and postoperative psychiatric evaluation is performed in 75% and 50% of the EMUs accordingly. Sexual or other abuse is systematically recorded in one-third of the centers, and the mean follow-up period after epilepsy surgery is 10.5 ±â€¯7.5 years. In suspected postoperative PNES, video-EEG is performed in 85% and psychiatric assessment in 95% of the centers. An electronic database to allow extraction of patients with PNES after epilepsy surgery is used in 75% of the EMUs, and all EMUs that sent the sheet completed expressed their interest to participate in a retrospective postoperative PNES project. CONCLUSION: Postoperative PNES is an underestimated and not well-studied entity. This is a European survey to assess the type of data that the EMUs surgical cohorts could provide to retrospectively detect postoperative PNES. In cases with suspected PNES, most EMUs perform video-EEG and psychiatric assessment, and most EMUs use an electronic database to allow extraction of patients developing PNES.

The importance of semiological information based on epileptic seizure history.

Semiology is the backbone of any correct categorization of seizures, as epileptic or not, focal or bilateral, and is fundamental to elucidating how they are anatomically generated in the brain. An anatomical hypothesis derived from seizure history is the precondition for optimally designed ancillary studies. Without understanding seizure semiology, no rational therapy is possible. This article describes the semiological approach using patient history based on full use of patients' self-reports as well as descriptions by witnesses. Auras represent the subjective aspects of seizures and provide important semiological clues as observable signs, sometimes including rather precise direct anatomical information. Methods of extracting, facilitating and analysing self-reports including linguistic conversation analysis are presented in detail. It is highlighted that prodromes, seizure triggers and reflex epileptic mechanisms can provide crucial information for diagnostics and therapy. Special issues considering seizure semiology in children are discussed in a separate section. Other sections are dedicated to the two most important issues of differential diagnosis: how to distinguish (1) focal from "generalized" epilepsies, particularly when focal seizure phenomena appear in a bilateral epilepsy; and (2) epileptic from a series of non-epileptic events.

Trends in pediatric epilepsy surgery in Europe between 2008 and 2015: Country-, center-, and age-specific variation.

OBJECTIVE: To profile European trends in pediatric epilepsy surgery (<16 years of age) between 2008 and 2015. METHODS: We collected information on volumes and types of surgery, pathology, and seizure outcome from 20 recognized epilepsy surgery reference centers in 10 European countries. RESULTS: We analyzed retrospective aggregate data on 1859 operations. The proportion of surgeries significantly increased over time (P < .0001). Engel class I outcome was achieved in 69.3% of children, with no significant improvement between 2008 and 2015. The proportion of histopathological findings consistent with glial scars significantly increased between the ages of 7 and 16 years (P for trend = .0033), whereas that of the remaining pathologies did not vary across ages. A significant increase in unilobar extratemporal surgeries (P for trend = .0047) and a significant decrease in unilobar temporal surgeries (P for trend = .0030) were observed between 2008 and 2015. Conversely, the proportion of multilobar surgeries and unrevealing magnetic resonance imaging cases remained unchanged. Invasive investigations significantly increased, especially stereo-electroencephalography. We found different trends comparing centers starting their activity in the 1990s to those whose programs were developed in the past decade. Multivariate analysis revealed a significant variability of the proportion of the different pathologies and surgical approaches across countries, centers, and age groups between 2008 and 2015. SIGNIFICANCE: Between 2008 and 2015, we observed a significant increase in the volume of pediatric epilepsy surgeries, stability in the proportion of Engel class I outcomes, and a modest increment in complexity of the procedures.

Three-dimensional neuronavigation in SEEG-guided epilepsy surgery.

OBJECTIVES: Epilepsy surgery is mainly cortical surgery and the precise definition of the epileptogenic zone on the complex cortical surface is of paramount importance. Stereoelectroencephalography (SEEG) may delineate the epileptogenic zone even in cases of non-lesional epilepsy. The aim of our study was to present a technique of 3D neuronavigation based on the brain surface and SEEG electrodes reconstructions using FSL and 3DSlicer software. PATIENTS AND METHODS: Our study included 26 consecutive patients operated on for drug-resistant epilepsy after SEEG exploration between January 2015 and December 2017. All patients underwent 1.5 T pre-SEEG MRI, post-SEEG CT, DICOM data post-processing using FSL and 3DSlicer, preoperative planning on 3DSlicer, and intraoperative 3D neuronavigation. Accuracy and precision of 3D SEEG reconstruction and 3D neuronavigation was assessed. RESULTS: We identified 125 entry points of SEEG electrodes during 26 operations. The accuracy of 3D reconstruction was 0.8 mm (range, 0-2 mm) with a precision of 1.5 mm. The accuracy of 3D SEEG neuronavigation was 2.68 mm (range, 0-6 mm). The precision of 3D neuronavigation was 1.48 mm. CONCLUSION: 3D neuronavigation for SEEG-guided epilepsy surgery using free software for post-processing of common MRI sequences is possible and a reliable method even with navigation systems without a brain extraction tool.

European trends in epilepsy surgery.

OBJECTIVE: Resective surgery is effective in treating drug-resistant focal epilepsy, but it remains unclear whether improved diagnostics influence postsurgical outcomes. Here, we compared practice and outcomes over 2 periods 15 years apart. METHODS: Sixteen European centers retrospectively identified 2 cohorts of children and adults who underwent epilepsy surgery in the period of 1997 to 1998 (n = 562) or 2012 to 2013 (n = 736). Data collected included patient (sex, age) and disease (duration, localization and diagnosis) characteristics, type of surgery, histopathology, Engel postsurgical outcome, and complications, as well as imaging and electrophysiologic tests performed for each case. Postsurgical outcome predictors were included in a multivariate logistic regression to assess the strength of date of surgery as an independent predictor. RESULTS: Over time, the number of operated cases per center increased from a median of 31 to 50 per 2-year period (p = 0.02). Mean disease duration at surgery decreased by 5.2 years (p < 0.001). Overall seizure freedom (Engel class 1) increased from 66.7% to 70.9% (adjusted p = 0.04), despite an increase in complex surgeries (extratemporal and/or MRI negative). Surgeries performed during the later period were 1.34 times (adjusted odds ratio; 95% confidence interval 1.02-1.77) more likely to yield a favorable outcome (Engel class I) than earlier surgeries, and improvement was more marked in extratemporal and MRI-negative temporal epilepsy. The rate of persistent neurologic complications remained stable (4.6%-5.3%, p = 0.7). CONCLUSION: Improvements in European epilepsy surgery over time are modest but significant, including higher surgical volume, shorter disease duration, and improved postsurgical seizure outcomes. Early referral for evaluation is required to continue on this encouraging trend.

Molecular-genetic diagnostics of von Hippel-Lindau syndrome (VHL) in Bulgaria: first complex mutation event in the VHL gene.

Von Hippel-Lindau syndrome is an autosomal-dominant disease characterized by the formation of various tumours and cysts in many different parts of the body. Von Hippel-Lindau syndrome is caused by VHL gene mutations leading to production of impaired tumor suppressor Von Hippel-Lindau syndrome protein or its complete absence. PURPOSE: To study five patients with clinically suspected Von Hippel-Lindau syndrome, who were referred for molecular genetic testing. METHODS: Sanger sequencing of the coding regions of the VHL gene. RESULTS: Five clinically relevant germline mutations were detected. One of the pathogenic variants has not been previously reported. This novel mutation is a complex mutation event combining a duplication and an indel, rearranging exon 3 of the VHL gene - c. [516_517dupGTCAAGCCT; 532_542delCTGGACATCGTinsATTA], p. (Glu173Serfs*4). CONCLUSION: Overall, our results showed that the diagnosis of Von Hippel-Lindau syndrome in our country is difficult most probably because of its heterogeneous clinical manifestation and insufficient knowledge on the diagnostic criteria for the disease. From genetic point of view our results add some novel data on the mutation profile of the VHL gene. In order to prove or revise the diagnosis, early genetic testing is strongly recommended in affected patients and their family members to ensure appropriate follow-up and treatment of the malignancies.

Bilateral pallidotomy for Meige syndrome.

Meige syndrome (MS) is usually described as a combination of blepharospasm with oromandibular dystonia. There are a large number of case reports of deep brain stimulation (DBS) of the globus pallidus internus (GPI) for MS and only one report of unilateral pallidotomy (PT). We report the first case of staged bilateral PT for treatment of a patient with MS using intraoperative high-frequency stimulation in order to predict and prevent postoperative deficit. There was a significant improvement of the Burk-Fahn-Marsden dystonia rating scale from 26 to 3. There were no adverse postoperative neurological and neuropsychological events.

Stereoelectroencephalography Using Magnetic Resonance Angiography for Avascular Trajectory Planning: Technical Report.

BACKGROUND: Stereoelectroencephalography (SEEG) requires high-quality angiographic studies because avascular trajectory planning is a prerequisite for the safety of this procedure. Some epilepsy surgery groups have begun to use computed tomography angiography and magnetic resonance T1-weighted sequence with contrast enhancement for this purpose. OBJECTIVE: To present the first series of patients with avascular trajectory planning of SEEG based on magnetic resonance angiography (MRA). METHODS: Thirty-six SEEG explorations for drug-resistant focal epilepsy were performed from January 2013 to December 2015. A retrospective analysis of this consecutive surgical series was then performed. Magnetic resonance imaging included MRA with a modified contrast-enhanced magnetic resonance venography (MRV) protocol with a short acquisition delay, which allowed simultaneous arterial and venous visualization. Our criteria for satisfactory MRA were the visualization of at least first-order branches of the angular artery, paracentral and calcarine artery, and third-order tributaries of the superficial Sylvian vein, vein of Labbe, and vein of Trolard. RESULTS: Thirty-four patients underwent 36 SEEG explorations with 369 electrodes carrying 4321 contacts. Contrast-enhanced MRA using the MRV protocol was judged satisfactory for SEEG planning in all explorations. Postoperative complications were not observed in our series of 36 SEEG explorations, which included 50 transopercular insular trajectories. CONCLUSION: MRA using an MRV protocol may be applied for avascular trajectory planning during SEEG procedures. This technique provides a simultaneous visualization of cortical arteries and veins without the need for additional radiation exposure or intra-arterial catheter placement.

Radiofrequency thermocoagulation of the seizure-onset zone during stereoelectroencephalography.

OBJECTIVE: To assess long-term outcome and identify prognostic factors of radiofrequency thermocoagulation (RFTC) following stereoelectroencephalography (SEEG) explorations in particularly complex cases of focal epilepsy. METHODS: We retrospectively reviewed the medical charts, video-SEEG recordings, and outcomes for 23 patients (aged 6-53 years) treated with SEEG-guided RFTC, of whom 15 had negative magnetic resonance imaging (MRI) findings, and 10 were considered noneligible for resective surgery after SEEG. Two to 11 RFTCs per patient (mean 5) were produced by applying 40-50 V, 75-110 mA current for 10-60 s on SEEG electrode contacts within the epileptogenic region, which was very close to eloquent cortices in 12 cases. The general features, SEEG findings, and RFTC extent of the patients were analyzed to extract potential preoperative predictors of post-RFTC seizure outcomes. RESULTS: After a mean follow-up of 32 months (range 2-119 months), eight patients experienced a ≥50% decrease of seizure frequency after RFTC (R+, 34.8%), of whom one had a sustained seizure freedom and 15 patients did not benefit from RFTC (R-, 65.2%). The presence of an MRI lesion was the only significant predictor of a positive outcome, whereas location of epilepsy, extent of interictal epileptiform discharges (IEDs) and of the seizure onset zone, induction of seizures by electrical stimulation, as well as the ratio of the coagulated sites did not show a significant correlation to the RFTC response. However, (sub-)continuous IEDs were more frequently found in R+ than in R- patients, thus suggesting that this EEG marker of the epileptogenic tissue might predict a positive outcome even in patients without obvious MRI lesion. SIGNIFICANCE: Our study confirms that RFTC, although less effective than resective surgery, can be a reasonable therapeutic option in complex cases where anatomic constraints make impossible any cortical resection. Further prospective studies are needed to better define RFTC indications and to optimize its methodology.

Current standards of neuropsychological assessment in epilepsy surgery centers across Europe.

We explored the current practice with respect to the neuropsychological assessment of surgical epilepsy patients in European epilepsy centers, with the aim of harmonizing and establishing common standards. Twenty-six epilepsy centers and members of "E-PILEPSY" (a European pilot network of reference centers in refractory epilepsy and epilepsy surgery), were asked to report the status of neuropsychological assessment in adults and children via two different surveys. There was a consensus among these centers regarding the role of neuropsychology in the presurgical workup. Strong agreement was found on indications (localization, epileptic dysfunctions, adverse drugs effects, and postoperative monitoring) and the domains to be evaluated (memory, attention, executive functions, language, visuospatial skills, intelligence, depression, anxiety, and quality of life). Although 186 different tests are in use throughout these European centers, a core group of tests reflecting a moderate level of agreement could be discerned. Variability exists with regard to indications, protocols, and paradigms for the assessment of hemispheric language dominance. For the tests in use, little published evidence of clinical validity in epilepsy was provided. Participants in the survey reported a need for improvement concerning the validity of the tests, tools for the assessment of everyday functioning and accelerated forgetting, national norms, and test co-normalization. Based on the present survey, we documented a consensus regarding the indications and principles of neuropsychological testing. Despite the variety of tests in use, the survey indicated that there may be a core set of tests chosen based on experience, as well as on published evidence. By combining these findings with the results of an ongoing systematic literature review, we aim for a battery that can be recommended for the use across epilepsy surgical centers in Europe.

Intraoperative fluorescein staining for benign brain tumors.

OBJECTIVE: Successful use of high-dose fluorescein-sodium (20mg/kg) with a standard light microscope for resection of high-grade gliomas, meningiomas, hemangioblastoma and metastases was reported. The principle of brain tumor staining by fluorescein-sodium (Fl-Na) consists in the accumulation of fluorescein in brain tumors with impaired blood-brain barrier. The aim of our study was to investigate for the first time the usefulness of high-dose fluorescein in patients operated on for benign neuroepithelial brain tumors (grade I WHO tumors) with contrast enhancement on magnetic resonance imaging. METHODS: Our study included 11 patients operated on for benign neuroepithelial primary brain tumors with contrast enhancement on magnetic resonance imaging (MRI): pilocytic astrocytomas (5 patients), dysembrioplastic neuroepithelial tumors (4) and gangliogliomas grade I (2). In all cases, Fl-Na was injected intravenously (20mg/kg) just after the craniotomy using a peripheral venous line. The dural opening was performed 10min later. Microsurgical tumor resection using conventional neurosurgical microscope guided by the fluorescein staining was performed. RESULTS: Complete resection of the yellow-green stained tissue was achieved in 10 patients confirmed by postoperative control MRI study. Subtotal resection of the colored tissue was achieved in one case with fourth ventricle pilocytic astrocytoma because of the involvement of the medial eminence and functional constraints discovered during intraoperative neuromonitoring. Three patients have had a postoperative volume of resection greater than the tumor volume because of the planed perilesionectomy by our epilepsy surgery team. Surrounding tissue not stained by Fl-Na was obtained in these 3 cases. The histopathological examination did not find tumor tissue in the perilesional Fl-Na negative tissue. On the other hand, all 11 Fl-Na positive specimens presented signs of tumor involvement. We did not observe complications related to the use of high dose Fl-Na. CONCLUSIONS: High doses intravenous Fl-Na seems to be a useful intraoperative technique for delineation of benign neuroepithelial brain tumors with contrast enhancement. Further larger studies may reveal the real value of high doses Fl-Na as intraoperative method for increasing the extent of resection in these particular indications.