Direct resection is a safe and effective strategy to control seizures in patients with hypothalamic hamartoma.

Achieving favorable seizure outcomes is challenging in patients with seizures resulting from hypothalamic hamartoma. Although minimally invasive and non-invasive surgical procedures are used to treat this population, these procedures have limitations. Therefore, we analyzed the outcomes of patients with hypothalamic hamartoma following direct resection. We included 159 patients with hypothalamic hamartoma who underwent direct resection using the transcallosal interforniceal approach between 2011 and 2018. The relationships between clinical parameters and seizure outcomes were analyzed. In total, 55.3% achieved gross total resection and 25.2% underwent near-total resection. Of all patients, 79.2% were overall seizure-free at one year, but this number dropped to 77.0% at more than five years. Moreover, 88.4% (129/146) reached gelastic seizure (GS)-free status at one year and this number increased to 89.0% (97/109) at more than five years. Seventy-one patients took antiseizure medication (ASM) long-term, 68 took it for one year, and 11 took it for one-half year. The duration of ASM consumption (p < 0.001) and extent of hypothalamic hamartoma resection (p = 0.016) were significant independent predictors of long-term overall seizure-free survival, while the duration of ASM consumption (p = 0.011) and extent of hypothalamic hamartoma resection (p = 0.026) were significant independent predictors of long-term GS-free survival. Most patients' behavior, school performance, and intelligence were not affected after surgery. Direct resection is effective and safe strategy for patients with hypothalamic hamartomas. Hypothalamic hamartomas should be removed as completely as possible, and patients should take ASM long-term following surgery to reach long-term overall seizure-free or GS-free status.

Seizure, Motor, and Cognitive Outcomes After Epilepsy Surgery for Patients With Sturge-Weber Syndrome: Results From a Multicenter Study.

BACKGROUND AND OBJECTIVES: Surgery is widely performed for refractory epilepsy in patients with Sturge-Weber syndrome (SWS), but reports on its effectiveness are limited. This study aimed to analyze seizure, motor, and cognitive outcomes of surgery in these patients and to identify factors associated with the outcomes. METHODS: This was a multicenter retrospective observational study using data from patients with SWS and refractory epilepsy who underwent epilepsy surgery between 2000 and 2020 at 16 centers throughout China. Longitudinal postoperative seizures were classified by Engel class, and Engel class I was regarded as seizure-free outcome. Functional (motor and cognitive) outcomes were evaluated using the SWS neurologic score, and improved or unchanged scores between baseline and follow-up were considered to have stable outcomes. Outcomes were analyzed using Kaplan-Meier analyses. Multivariate Cox regression was used to identify factors associated with outcomes. RESULTS: A total of 214 patients with a median age of 2.0 (interquartile range 1.2-4.6) years underwent surgery (focal resection, FR [n = 87]; hemisphere surgery, HS [n = 127]) and completed a median of 3.5 (1.7-5.0) years of follow-up. The overall estimated probability for being seizure-free postoperatively at 1, 2, and 5 years was 86.9% (95% CI 82.5-91.6), 81.4% (95% CI 76.1-87.1), and 70.7% (95% CI 63.3-79.0), respectively. The overall estimated probability of being motor stable at the same time post operatively was 65.4% (95% CI 58.4-71.2), 80.2% (95% CI 73.8-85.0), and 85.7% (95% CI 79.5-90.1), respectively. The overall probability for being cognition stable at 1, 2, and 5 years was 80.8% (95% CI 74.8-85.5), 85.1% (95% CI 79.3-89.2), and 89.5% (95% CI 83.8-93.2), respectively. Both FR and HS were effective at ensuring seizure control. For different HS techniques, modified hemispherotomy had comparable outcomes but improved safety compared with anatomical hemispherectomy. Regarding FR, partial resection (adjusted hazard ratio [aHR] 11.50, 95% CI 4.44-29.76), acute postoperative seizure (APOS, within 30 days of surgery; aHR 10.33, 95% CI 3.94-27.12), and generalized seizure (aHR 3.09, 95% CI 1.37-6.94) were associated with seizure persistence. For HS, seizure persistence was associated with APOS (aHR 27.61, 9.92-76.89), generalized seizure (aHR 7.95, 2.74-23.05), seizure frequency ≥30 times/month (aHR 4.76, 1.27-17.87), and surgical age ≥2 years (aHR 3.78, 1.51-9.47); motor stability was associated with severe motor defects (aHR 5.23, 2.27-12.05) and postoperative seizure-free status (aHR 3.09, 1.49-6.45); and cognition stability was associated with postoperative seizure-free status (aHR 2.84, 1.39-5.78) and surgical age <2 years (aHR 1.76, 1.13-2.75). DISCUSSION: FR is a valid option for refractory epilepsy in patients with SWS and has similar outcomes to those of HS, with less morbidity associated with refractory epilepsy. Early surgical treatment (under the age of 2 years) leads to better outcomes after HS, but there is insufficient evidence that surgical age affects FR outcomes. These findings warrant future prospective multicenter cohorts with international cooperation and prolonged follow-up in better exploring more precise outcomes and developing prognostic predictive models. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that in children with SWS and refractory seizures, surgical resection-focal, hemispherectomy, or modified hemispherotomy-leads to improved outcomes.

Surgical treatment of cavernous malformation-related epilepsy in children: case series, systematic review, and meta-analysis.

OBJECTIVE: Cerebral cavernous malformations (CCMs) are cerebral vascular lesions that occasionally occur with seizures. We present a retrospective case series from IRCCS Gaslini Children's Hospital, a systematic review, and meta-analysis of the literature with the goal of elucidating the post-surgery seizure outcome in children with CCMs. METHODS: a retrospective review of children with cavernous malformation related epilepsy who underwent surgery at Gaslini Children's Hospital from 2005 to 2022 was conducted. We also conducted a comprehensive search on PubMed/MEDLINE and Scopus databases from January 1989 to August 2022. Inclusion criteria were: presence of CCMs-related epilepsy, in under 18 years old subjects with a clear lesion site. Presence of post-surgery seizure outcome and follow-up ≥ 12 months. RESULTS: we identified 30 manuscripts and 223 patients with CCMs-related epilepsy, including 17 patients reported in our series. We identified 85.7% Engel class I subjects. The risk of expected neurological deficits was 3.7%; that of unexpected neurological deficits 2.8%. We found no statistically significant correlations between Engel class and the following factors: site of lesion, type of seizure, drug resistance, duration of disease, type of surgery, presence of multiple CCMs. However, we found some interesting trends: longer disease duration and drug resistance seem to be more frequent in subjects in Engel class II, III and IV; multiple cavernomas would not seem to influence seizure outcome. CONCLUSIONS: epilepsy surgery in children with CCMs is a safe and successful treatment option. Further studies are necessary to define the impact of clinical features on seizure prognosis.

Seizure Outcome After Intraoperative Electrocorticography-Tailored Epilepsy Surgery: A Systematic Review and Meta-Analysis.

BACKGROUND AND OBJECTIVES: Tailoring epilepsy surgery using intraoperative electrocorticography (ioECoG) has been debated, and modest number of epilepsy surgery centers apply this diagnostic method. We assessed the current evidence to use ioECoG-tailored epilepsy surgery for improving postsurgical outcome. METHODS: PubMed and Embase were searched for original studies reporting on ≥10 cases who underwent ioECoG-tailored surgery for epilepsy, with a follow-up of at least 6 months. We used a random-effects model to calculate the overall rate of patients achieving favorable seizure outcome (FSO), defined as Engel class I, ILAE class 1, or seizure-free status. Meta-regression was used to investigate potential sources of heterogeneity. We calculated the odds ratio (OR) for estimating variables on FSO:ioECoG vs non-ioECoG-tailored surgery (if included studies contained patients with non-ioECoG-tailored surgery), ioECoG-tailored epilepsy surgery in children vs adults, temporal (TL) vs extratemporal lobe (eTL), MRI-positive vs MRI-negative, and complete vs incomplete resection of tissue that generated interictal epileptiform discharges (IEDs). A Bayesian network meta-analysis was conducted for underlying pathologies. We assessed the evidence certainty using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE). RESULTS: Eighty-three studies (82 observational studies, 1 trial) comprising 3,631 patients with ioECoG-tailored surgery were included. The overall pooled rate of patients who attained FSO after ioECoG-tailored surgery was 74% (95% CI 71-77) with significant heterogeneity, which was predominantly attributed to pathologies and seizure outcome classifications. Twenty-two studies contained non-ioECoG-tailored surgeries. IoECoG-tailored surgeries reached a higher rate of FSO than non-ioECoG-tailored surgeries (OR 2.10 [95% CI 1.37-3.24]; p < 0.01; very low certainty). Complete resection of tissue that displayed IEDs in ioECoG predicted FSO better compared with incomplete resection (OR 3.04 [1.76-5.25]; p < 0.01; low certainty). We found insignificant difference in FSO after ioECoG-tailored surgery in children vs adults, TL vs eTL, or MRI-positive vs MRI-negative. The network meta-analysis showed that the odds of FSO was lower for malformations of cortical development than for tumors (OR 0.47 95% credible interval 0.25-0.87). DISCUSSION: Although limited by low-quality evidence, our meta-analysis shows a relatively good surgical outcome (74% FSO) after epilepsy surgery with ioECoG, especially in tumors, with better outcome for ioECoG-tailored surgeries in studies describing both and better outcome after complete removal of IED areas.

EEG Ictal Power Dynamics, Function-Structure Associations, and Epilepsy Surgical Outcomes.

BACKGROUND AND OBJECTIVES: Postoperative seizure control in drug-resistant temporal lobe epilepsy (TLE) remains variable, and the causes for this variability are not well understood. One contributing factor could be the extensive spread of synchronized ictal activity across networks. Our study used novel quantifiable assessments from intracranial EEG (iEEG) to test this hypothesis and investigated how the spread of seizures is determined by underlying structural network topological properties. METHODS: We evaluated iEEG data from 157 seizures in 27 patients with TLE: 100 seizures from 17 patients with postoperative seizure control (Engel score I) vs 57 seizures from 10 patients with unfavorable surgical outcomes (Engel score II-IV). We introduced a quantifiable method to measure seizure power dynamics within anatomical regions, refining existing seizure imaging frameworks and minimizing reliance on subjective human decision-making. Time-frequency power representations were obtained in 6 frequency bands ranging from theta to gamma. Ictal power spectrums were normalized against a baseline clip taken at least 6 hours away from ictal events. Electrodes' time-frequency power spectrums were then mapped onto individual T1-weighted MRIs and grouped based on a standard brain atlas. We compared spatiotemporal dynamics for seizures between groups with favorable and unfavorable surgical outcomes. This comparison included examining the range of activated brain regions and the spreading rate of ictal activities. We then evaluated whether regional iEEG power values were a function of fractional anisotropy (FA) from diffusion tensor imaging across regions over time. RESULTS: Seizures from patients with unfavorable outcomes exhibited significantly higher maximum activation sizes in various frequency bands. Notably, we provided quantifiable evidence that in seizures associated with unfavorable surgical outcomes, the spread of beta-band power across brain regions is significantly faster, detectable as early as the first second after seizure onset. There was a significant correlation between beta power during seizures and FA in the corresponding areas, particularly in the unfavorable outcome group. Our findings further suggest that integrating structural and functional features could improve the prediction of epilepsy surgical outcomes. DISCUSSION: Our findings suggest that ictal iEEG power dynamics and the structural-functional relationship are mechanistic factors associated with surgical outcomes in TLE.

Characterizing Frontal Lobe Seizure Semiology in Children.

OBJECTIVE: The objective was to analyze seizure semiology in pediatric frontal lobe epilepsy patients, considering age, to localize the seizure onset zone for surgical resection in focal epilepsy. METHODS: Fifty patients were identified retrospectively, who achieved seizure freedom after frontal lobe resective surgery at Great Ormond Street Hospital. Video-electroencephalography recordings of preoperative ictal seizure semiology were analyzed, stratifying the data based on resection region (mesial or lateral frontal lobe) and age at surgery (≤4 vs >4). RESULTS: Pediatric frontal lobe epilepsy is characterized by frequent, short, complex seizures, similar to adult cohorts. Children with mesial onset had higher occurrence of head deviation (either direction: 55.6% vs 17.4%; p = 0.02) and contralateral head deviation (22.2% vs 0.0%; p = 0.03), ictal body-turning (55.6% vs 13.0%; p = 0.006; ipsilateral: 55.6% vs 4.3%; p = 0.0003), and complex motor signs (88.9% vs 56.5%; p = 0.037). Both age groups (≤4 and >4 years) showed hyperkinetic features (21.1% vs 32.1%), contrary to previous reports. The very young group showed more myoclonic (36.8% vs 3.6%; p = 0.005) and hypomotor features (31.6% vs 0.0%; p = 0.003), and fewer behavioral features (36.8% vs 71.4%; p = 0.03) and reduced responsiveness (31.6% vs 78.6%; p = 0.002). INTERPRETATION: This study presents the most extensive semiological analysis of children with confirmed frontal lobe epilepsy. It identifies semiological features that aid in differentiating between mesial and lateral onset. Despite age-dependent differences, typical frontal lobe features, including hyperkinetic seizures, are observed even in very young children. A better understanding of pediatric seizure semiology may enhance the accuracy of onset identification, and enable earlier presurgical evaluation, improving postsurgical outcomes. ANN NEUROL 2024;95:1138-1148.

Comparison of minimally invasive to standard temporal lobectomy approaches to epilepsy surgery: Seizure relief and visual confrontation naming outcomes.

The purpose of this study was to systematically examine three different surgical approaches in treating left medial temporal lobe epilepsy (mTLE) (viz., subtemporal selective amygdalohippocampectomy [subSAH], stereotactic laser amygdalohippocampotomy [SLAH], and anterior temporal lobectomy [ATL]), to determine which procedures are most favorable in terms of visual confrontation naming and seizure relief outcome. This was a retrospective study of 33 adults with intractable mTLE who underwent left temporal lobe surgery at three different epilepsy surgery centers who also underwent pre-, and at least 6-month post-surgical neuropsychological testing. Measures included the Boston Naming Test (BNT) and the Engel Epilepsy Surgery Outcome Scale. Fisher's exact tests revealed a statistically significant decline in naming in ATLs compared to SLAHs, but no other significant group differences. 82% of ATL and 36% of subSAH patients showed a significant naming decline whereas no SLAH patient (0%) had a significant naming decline. Significant postoperative naming improvement was seen in 36% of SLAH patients in contrast to 9% improvement in subSAH patients and 0% improvement in ATLs. Finally, there were no statistically significant differences between surgical approaches with regard to seizure freedom outcome, although there was a trend towards better seizure relief outcome among the ATL patients. Results support a possible benefit of SLAH in preserving visual confrontation naming after left TLE surgery. While result interpretation is limited by the small sample size, findings suggest outcome is likely to differ by surgical approach, and that further research on cognitive and seizure freedom outcomes is needed to inform patients and providers of potential risks and benefits with each.

Generalisability of epileptiform patterns across time and patients.

The complexity of localising the epileptogenic zone (EZ) contributes to surgical resection failures in achieving seizure freedom. The distinct patterns of epileptiform activity during interictal and ictal phases, varying across patients, often lead to suboptimal localisation using electroencephalography (EEG) features. We posed two key questions: whether neural signals reflecting epileptogenicity generalise from interictal to ictal time windows within each patient, and whether epileptiform patterns generalise across patients. Utilising an intracranial EEG dataset from 55 patients, we extracted a large battery of simple to complex features from stereo-EEG (SEEG) and electrocorticographic (ECoG) neural signals during interictal and ictal windows. Our features (n = 34) quantified many aspects of the signals including statistical moments, complexities, frequency-domain and cross-channel network attributes. Decision tree classifiers were then trained and tested on distinct time windows and patients to evaluate the generalisability of epileptogenic patterns across time and patients, respectively. Evidence strongly supported generalisability from interictal to ictal time windows across patients, particularly in signal power and high-frequency network-based features. Consistent patterns of epileptogenicity were observed across time windows within most patients, and signal features of epileptogenic regions generalised across patients, with higher generalisability in the ictal window. Signal complexity features were particularly contributory in cross-patient generalisation across patients. These findings offer insights into generalisable features of epileptic neural activity across time and patients, with implications for future automated approaches to supplement other EZ localisation methods.

Comparative Analysis of Hemispherotomy in Adults versus Children- A Prospective Observational Series.

BACKGROUND: Hemispherotomy (HS) is an effective treatment for unilateral hemispheric onset epilepsy. There are few publications for HS in adults, and there is no series comparing adults and pediatric patients of HS. OBJECTIVE: To compare the hemispherotomies done in adult patients with pediatric ones in terms of efficacy and safety. METHODS: Data was prospectively collected for HS patients (up to 18 years and more) from Aug 2014 to Aug 2018. Comparison between the groups was made for seizure onset, duration of epilepsy, frequency of seizures, number of drugs, intraoperative blood loss, postoperative seizure control, postoperative stay, postoperative motor functions, and preoperative and postoperative intelligence quotient. Follow-up was one year. RESULTS: A total of 61 pediatric and 11 adults underwent HS. The seizure onset was earlier in children, and the duration of epilepsy was longer in adults. The frequency of seizures per day was more in children being 14.62 ± 26.34 in children, and 7.71 ± 5.21 per day in adults (P - 0.49). The mean number of drugs was similar in the preoperative and postoperative periods in both. Class I seizure outcome was similar in both the groups being 85.24% in children and 90.9% in adults (P - 0.56). Blood loss, postoperative stay, was similar in both the groups. No patient had a new permanent motor deficit. Power worsened transiently in 1 pediatric patient and in 4 adult patients. The visual word reading and object naming improved in both the groups (no intergroup difference), and IQ remained the same in both groups. One adult patient had meningitis, and another had hydrocephalus requiring shunt placement. CONCLUSION: Hemispherotomy is a safe and effective procedure in adults as in children in appropriately selected patients.

Systematic 1 Hz direct electrical stimulation for seizure induction: A reliable method for localizing seizure onset zone and predicting seizure freedom.

OBJECTIVE: To prospectively investigate the utility of seizure induction using systematic 1 Hz stimulation by exploring its concordance with the spontaneous seizure onset zone (SOZ) and relation to surgical outcome; comparison with seizures induced by non-systematic 50 Hz stimulation was attempted as well. METHODS: Prospective cohort study from 2018 to 2021 with ≥ 1 y post-surgery follow up at Yale New Haven Hospital. With 1 Hz, all or most of the gray matter contacts were stimulated at 1, 5, and 10 mA for 30-60s. With 50 Hz, selected gray matter contacts outside of the medial temporal regions were stimulated at 1-5 mA for 0.5-3s. Stimulation was bipolar, biphasic with 0.3 ms pulse width. The Yale Brain Atlas was used for data visualization. Variables were analyzed using Fisher's exact, χ2, or Mann-Whitney test. RESULTS: Forty-one consecutive patients with refractory epilepsy undergoing intracranial EEG for localization of SOZ were included. Fifty-six percent (23/41) of patients undergoing 1 Hz stimulation had seizures induced, 83% (19/23) habitual (clinically and electrographically). Eighty two percent (23/28) of patients undergoing 50 Hz stimulation had seizures, 65% (15/23) habitual. Stimulation of medial temporal or insular regions with 1 Hz was more likely to induce seizures compared to other regions [15/32 (47%) vs. 2/41 (5%), p < 0.001]. Sixteen patients underwent resection; 11/16 were seizure free at one year and all 11 had habitual seizures induced by 1 Hz; 5/16 were not seizure free at one year and none of those 5 had seizures with 1 Hz (11/11 vs 0/5, p < 0.0001). No patients had convulsions with 1 Hz stimulation, but four did with 50 Hz (0/41 vs. 4/28, p = 0.02). SIGNIFICANCE: Induction of habitual seizures with 1 Hz stimulation can reliably identify the SOZ, correlates with excellent surgical outcome if that area is resected, and may be superior (and safer) than 50 Hz for this purpose. However, seizure induction with 1 Hz was infrequent outside of the medial temporal and insular regions in this study.

Outcomes following surgical interventions for hypothalamic hamartomas: protocol for a systematic review and individual patient data meta-analysis.

INTRODUCTION: Hypothalamic hamartomas (HHs) are deep-seated congenital lesions that typically lead to pharmacoresistant epilepsy and a catastrophic encephalopathic syndrome characterised by severe neuropsychological impairment and decline in quality of life. A variety of surgical approaches and technologies are available for the treatment of HH-related pharmacoresistant epilepsy. There remains, however, a paucity of literature directly comparing their relative efficacy and safety. This protocol aims to facilitate a systematic review and meta-analysis that will characterise and compare the probability of seizure freedom and relevant postoperative complications across different surgical techniques performed for the treatment of HH-related pharmacoresistant epilepsy. METHODS AND ANALYSIS: This protocol was developed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Individual Participant Data guidelines. Three major databases, PubMed, Embase and Scopus, will be systematically searched from database inception and without language restrictions for relevant articles using our predefined search strategy. Title-abstract and full text screening using inclusion and exclusion criteria created a priori will be performed by two independent reviewers to identify eligible articles. Conflicts will be resolved via discussion with a third team member. Following data extraction of both study-level and individual patient data (IPD), a study-level and IPD meta-analysis will be performed. Study-level analysis will focus on assessing the degree of heterogeneity in the data and quantifying overall seizure outcomes for each surgical technique. The IPD analysis will use multivariable regression to determine perioperative predictors of seizure freedom and complications that can guide patient and technique selection. ETHICS AND DISSEMINATION: This work will not require ethics approval as it will be solely based on previously published and available data. The results of this review will be shared via conference presentation and submission to peer-reviewed neurosurgical journals. PROSPERO REGISTRATION: CRD42022378876.

Preoperative structural-functional coupling at the default mode network predicts surgical outcomes of temporal lobe epilepsy.

OBJECTIVE: Structural-functional coupling (SFC) has shown great promise in predicting postsurgical seizure recurrence in patients with temporal lobe epilepsy (TLE). In this study, we aimed to clarify the global alterations in SFC in TLE patients and predict their surgical outcomes using SFC features. METHODS: This study analyzed presurgical diffusion and functional magnetic resonance imaging data from 71 TLE patients and 48 healthy controls (HCs). TLE patients were categorized into seizure-free (SF) and non-seizure-free (nSF) groups based on postsurgical recurrence. Individual functional connectivity (FC), structural connectivity (SC), and SFC were quantified at the regional and modular levels. The data were compared between the TLE and HC groups as well as among the TLE, SF, and nSF groups. The features of SFC, SC, and FC were categorized into three datasets: the modular SFC dataset, regional SFC dataset, and SC/FC dataset. Each dataset was independently integrated into a cross-validated machine learning model to classify surgical outcomes. RESULTS: Compared with HCs, the visual and subcortical modules exhibited decoupling in TLE patients (p < .05). Multiple default mode network (DMN)-related SFCs were significantly higher in the nSF group than in the SF group (p < .05). Models trained using the modular SFC dataset demonstrated the highest predictive performance. The final prediction model achieved an area under the receiver operating characteristic curve of .893 with an overall accuracy of .887. SIGNIFICANCE: Presurgical hyper-SFC in the DMN was strongly associated with postoperative seizure recurrence. Furthermore, our results introduce a novel SFC-based machine learning model to precisely classify the surgical outcomes of TLE.

Surgical Outcome of Pharmaco Refractory Epilepsy in the National Epilepsy Center of Sri Lanka.

BACKGROUND: The National Epilepsy Center (NEC) in Sri Lanka was established in 2017. Seizure outcome, effects on quality of life (QOL) and surgical complications among nonpediatric patients who underwent epilepsy surgery from October 2017 to February 2023 are described. METHODS: Nineteen patients (≥14 years) underwent epilepsy surgery at the NEC. We used Engel classification and Quality of Life in Epilepsy 31 (QOLIE-31) questionnaire to assess seizure outcome and QOL respectively. Surgical complications were categorized into neurological and complications related to surgery. RESULTS: Nine female and 10 male patients underwent surgery (mean age 27.5 years (range 14-44 years). The mean follow-up duration was 10.5 months (range 6-55 months). Twelve patients underwent temporal lobe resections. At 6-months follow-up, 83.3% (10/12) had favorable seizure outcomes with Engel class I/II. At 1-year follow-up 6/8 patients (75.0%) and at 2-year follow-up, 5/7 patients (71.4%) had a favorable outcome. Seven patients had extra-temporal lobe surgeries and one defaulted. Seizure freedom was observed in 6/6 at 6 months, 3/3 at 1-year, and 2/2 at 2-year follow-up. Five patients (26.3%) experienced minor post-operative surgical site infection. Two (11.1%) had persistent quadrantanopia. Meaningful improvement in QOL (change in QOLIE-31 score ≥11.8) was observed irrespective of seizure outcome or type of surgery (P < 0.001). CONCLUSIONS: Epilepsy surgery is effective in developing countries. Seizure outcomes in our patients are comparable to those worldwide. Clinically important QOL improvement was observed in our series. This is the first published data on epilepsy surgery outcomes in nonpediatric patients from Sri Lanka.

Negative MRI and a seizure onset zone close to eloquent areas in FCD type II: Application of MRg-LiTT after a SEEG re-evaluation in pediatric patients with a previous failed surgery.

OBJECTIVE: Negative MRI and an epileptogenic zone (EZ) adjacent to eloquent areas are two main issues that can be encountered during pre-surgical evaluation for epilepsy surgery. Focal Cortical Dysplasia type II (FCD type II) is the most common aetiology underlying a negative MRI. The objective of this study is to present three cases of pediatric patients exhibiting negative MRI and a seizure onset zone close to eloquent areas, who previously underwent traditional open surgery or SEEG-guided radiofrequency thermocoagulations (RF-TC). After seizure seizure recrudescence, pre-surgical SEEG was re-evaluated and Magnetic Resonance-guided laser interstitial thermal therapy (MRg-LiTT) was performed. We discuss the SEEG patterns, the planning of laser probes trajectories and the outcomes one year after the procedure. METHODS: Pediatric patients who underwent SEEG followed by MRg-LiTT for drug-resistant epilepsy associated with FCD type II at our Centre were included. Pre-surgical videoEEG (vEEG), stereoEEG (sEEG), and MRI were reviewed. Post-procedure clinical outcome (measured by Engel score) and complications rates were evaluated. RESULTS: Three patients underwent 3 MRg-LiTT procedures from January 2022 to June 2022. Epileptogenic zone was previously studied via SEEG in all the patients. All the three patients pre-surgical MRI was deemed negative. Mean age at seizure onset was 47 months (21-96 months), mean age at MRg-LiTT was 12 years (10 years 10 months - 12 years 9 months). Engel class Ia outcome was achieved in patients #2 and #3, Engel class Ib in patient #1. Mean follow-up length was of 17 months (13 months - 20 months). Complications occurred in one patient (patient #2, extradural hematoma). CONCLUSIONS: The combined use of SEEG and MRg-LiTT in complex cases can lead to good outcomes both as a rescue therapy after failed surgery, but also as an alternative to open surgery after a successful SEEG-guided Radiofrequency Thermocoagulation (RF-TC). Specific SEEG patterns and a previous good outcome from RF-TC can be predictors of a favourable outcome.

The role of preoperative [11C]methionine PET in defining tumor-related epilepsy and predicting short-term postoperative seizure control in temporal lobe low-grade gliomas.

OBJECTIVE: Surgery is the mainstay of treatment for low-grade glioma (LGG)-related epilepsy. However, the goal of achieving both oncological radical resection and seizure freedom can be challenging. PET with [11C]methionine (MET) has been recently introduced in clinical practice for the management of patients with LGGs, not only to monitor the response to treatments, but also as a preoperative tool to define the metabolic tumor extent and to predict tumor grading, type, and prognosis. Still, its role in defining tumor-related epilepsy and postoperative seizure outcomes is limited. The aim of this preliminary study was to investigate the role of MET PET in defining preoperative seizure characteristics and short-term postoperative seizure control in a cohort of patients with newly diagnosed temporal lobe low-grade gliomas (tLGGs). METHODS: Patients with newly diagnosed and histologically proven temporal lobe grade 2/3 gliomas (2021 WHO CNS tumor classification) who underwent resection at the authors' institution between July 2011 and March 2021 were included in this retrospective study. MET PET images were acquired, fused with MRI scans, and qualitatively and semiquantitatively analyzed. Any eventual PET/MRI involvement of the temporomesial area, seizure characteristics, and 1-year seizure outcomes were reported. RESULTS: A total of 52 patients with tLGGs met the inclusion criteria. MET PET was positive in 41 (79%) patients, with a median metabolic tumor volume of 14.56 cm3 (interquartile range [IQR] 6.5-28.2 cm3). The median maximum and mean tumor-to-background ratio (TBRmax, TBRmean) were 2.24 (IQR 1.58-2.86) and 1.53 (IQR 1.37-1.70), respectively. The metabolic tumor volume was found to be related to the presence of seizures at disease onset, but only in noncodeleted tumors (p = 0.014). Regarding patients with uncontrolled seizures at surgery, only the temporomesial area PET involvement showed a statistical correlation both in the univariate (p = 0.058) and in the multivariate analysis (p = 0.030). At 1-year follow-up, seizure control was correlated with MET PET-derived semiquantitative data. Particularly, higher TBRmax (p = 0.0192) and TBRmean (p = 0.0128) values were statistically related to uncontrolled seizures 1 year after surgery. CONCLUSIONS: This preliminary study suggests that MET PET may be used as a preoperative tool to define seizure characteristics and outcomes in patients with tLGGs. These findings need to be further validated in larger series with longer epileptological follow-ups.

Impact of intracranial subclinical seizures on seizure outcomes after SLAH in patients with mesial temporal lobe epilepsy.

OBJECTIVE: To investigate the association between subclinical seizures detected on intracranial electroencephalographic (i-SCSs)recordings and mesial temporal sclerosis (MTS), as well as their impact on surgical outcomes of stereotactic laser amygdalohippocampotomy (SLAH). METHODS: A retrospective review was conducted on 27 patients with drug-resistant mesial temporal lobe epilepsy (MTLE) who underwent SLAH. The number of seizures detected on scalp EEG and iEEG was assessed. Patients were followed for a minimum of 3 years after SLAH. RESULTS: Of the 1715 seizures recorded from mesial temporal regions, 1640 were identified as i-SCSs. Patients with MTS were associated with favorable short- and long-term surgical outcomes. Patients with MTS had a higher number of i-SCSs compared to patients without MTS. The numbers of i-SCSs were higher in patients with Engel I-II outcomes, but no significant statistical difference was found. However, it was observed that patients with MTS who achieved Engel I-II classification had higher numbers of i-SCSs than patients without MTS (P < 0.05). CONCLUSION: Patients with MTS exhibited favorable short-term and long-term surgical outcome after SLAH. A higher number of i-SCSs was significantly associated with MTS in patients with MTLE. The number of i-SCSs tended to be higher in patients with Engel Ⅰ-Ⅱ surgical outcomes. SIGNIFICANCE: The association between i-SCSs, MTS, and surgical outcomes in MTLE patients undergoing SLAH has significant implications for understanding the underlying mechanisms and identifying potential therapeutic targets to enhance surgical outcomes.

Pearls & Oy-sters: Mesial Temporal Seizures in the Absence of the Mesial Temporal Lobe. Seizure Onset vs Seizure Network

Seizure semiology represents the clinical expression of the activation of the several brain regions comprising an epileptic network. In mesial temporal lobe epilepsy (MTLE), this network includes the insular-opercular-neocortical temporal-hippocampal (IONTH) regions. In this study, we present the case of a patient with pharmacoresistant seizures characterized by nausea, lip-smacking, semipurposeful hand movements, and speechlessness, suggesting dominant hemisphere MTLE, with scalp video-EEG findings and left hippocampal sclerosis on brain MRI confirming the diagnosis. She underwent anterior temporal lobectomy with amygdalohippocampectomy and was seizure-free for 14 years before relapsing. Recurrent seizure semiology was similar to preoperative seizures, that is, consistent with left MTLE, despite the medial temporal lobe missing. Seizures were therefore assumed to arise from remnant portions of the IONTH network-the insula, operculum, and posterolateral temporal neocortex. Reinvestigation including MEG localization of spikes and acute MRI changes following a seizure cluster suggested a left opercular region epilepsy. Our patient thus demonstrated the principle that seizures with mesial temporal characteristics may arise from outside the mesial temporal lobe (MTL). MTLE semiology arises from the activation of a set of structures (the seizure network) associated with the MTL, which can be triggered by foci both within and outside the MTL itself, and indeed even in its absence. However, it is not necessary to resect the entire extended network to bring about extended periods of seizure freedom in patients with refractory MTLE.

EEG Source Imaging in Presurgical Evaluations.

SUMMARY: Presurgical evaluations to plan intracranial EEG implantations or surgical therapies at most epilepsy centers in the United States currently depend on the visual inspection of EEG traces. Such analysis is inadequate and does not exploit all the localizing information contained in scalp EEG. Various types of EEG source modeling or imaging can provide sublobar localization of spike and seizure sources in the brain, and the software to do this with typical long-term monitoring EEG data are available to all epilepsy centers. This article reviews the fundamentals of EEG voltage fields that are used in EEG source imaging, the strengths and weakness of dipole and current density source models, the clinical situations where EEG source imaging is most useful, and the particular strengths of EEG source imaging for various cortical areas where spike/seizure sources are likely.

Stereoelectroencephalography: a review of complications and outcomes in a new Australian centre.

BACKGROUND: Surgical management of refractory focal epilepsy requires preoperative localisation of the epileptogenic zone (EZ). To augment noninvasive studies, stereoelectroencephalography (SEEG) is being increasingly adopted as a form of intracranial monitoring. AIMS: This study aimed to determine the rate of complications for patients undergoing SEEG and to report the success of SEEG with regard to EZ detection and seizure outcome following definitive surgery. METHODS: A retrospective cohort design investigated all cases of SEEG at our institution. Surgical, anaesthetic and medical complications with subsequent epilepsy surgery and seizure outcome data were extracted from medical records. Multivariate logistic regression was used to investigate the relationship between both the number of electrodes per patient and the duration of SEEG recording with the rate of complications. RESULTS: Sixty-four patients with 66 implantations were included. Headache was the most common complication (n = 54, 82%). There were no major surgical or medical complications. Two anaesthetic complications occurred. EZ localisation was successful in 63 cases (95%). Curative intent surgery was performed in 39 patients (59%) and 23 patients achieved an Engel class I outcome (59% of those undergoing surgery). The number of electrodes and duration of recording were not associated with complications. CONCLUSIONS: No patients in our series experienced major surgical or medical complications and we have highlighted the challenges associated with neuroanaesthesia in SEEG. Our complication rates and seizure outcomes are equivalent to published literature indicating that this technique can be successfully established in newer centres using careful case selection. Standardised reporting of SEEG complications should be adopted.