Surgical Treatment Of Epilepsy Research Articles

Against vivisection: Charcot and Pitres’ discovery of the human motor cortex and the birth of modern neurosurgery and of the surgical treatment of epilepsy

ABSTRACT This article addresses the discrepancy between Edouard Hitzig’s and David Ferrier’s findings on the cortical localization of movements in animals and Jean-Martin Charcot’s findings in humans. The results of Hitzig’s and Ferrier’s vivisections were criticized by experimentalists in England and France as discordant, irreproducible, and inconclusive, and they were rejected by clinicians as irrelevant. Charcot addressed the gap between animal and human motor function by correlating motor deficits and focal epileptic seizures in patients to their autopsy findings. By this method he discovered the functional organization of the human motor cortex and produced the first accurate human motor brain map. Ferrier, William Osler, and Hughlings Jackson acknowledged Charcot’s findings, and his findings guided the first neurosurgeons in localizing and resecting intracranial mass lesions presenting with focal epileptic seizures. Although his contributions in these fields have been neglected by modern historians, Charcot made significant contributions to the neurobiology of the human motor system, to epileptology, and to the birth of modern neurosurgery.

Canadian Practice and Recommendations on Functional MRI to Lateralize Language in Epilepsy.

Identifying a patient's dominant language hemisphere is an important evaluation performed prior to epilepsy surgery and is commonly assessed using functional magnetic resonance imaging (fMRI). However, the lack of standardization and resultant heterogeneity of fMRI paradigms used in clinical practice limits the ability of cross-center comparisons to be made regarding language laterality results. Through surveying Canadian Epilepsy Centres in combination with reviewing supporting literature, current fMRI language lateralization practices for the clinical evaluation of patients with epilepsy were assessed. To encourage standardization of this practice, we outlined a two-part paradigm series that demonstrates widespread acceptance, reliability and accessibility in lateralizing various aspects of language functioning in individuals with average or near-average IQ and normal literacy skills. The collected data confirm a lack of standardization in fMRI laterality assessments leading to clinical heterogeneity in stimulation and control tasks, paradigm design and timing, laterality index calculations, thresholding values and analysis software and technique. We suggest a Sentence Completion (SC) and Word Generation (WG) paradigm series as it was most commonly employed across Canada, demonstrated reliability in lateralizing both receptive and expressive language areas in supporting literature, and could be readily intelligible to an inclusive population. Through providing recommendations for a two-part paradigm series, we hope to contribute to the standardization of this practice across Canada to reduce clinical heterogeneity, encourage communicability between institutions, and enhance methodologies for the surgical treatment of epilepsy for the benefit of all individuals living with epilepsy in Canada.

Determinants of the Quality of Life in Patients with Drug-Resistant Temporal Lobe Epilepsy: A Comparison of the Results before and after Surgery.

Drug-resistant temporal lobe epilepsy is associated with a reduction in the quality of life of patients. The aim of this study was to compare the quality of life before and after the surgical treatment of epilepsy and to assess factors that may affect the well-being of patients after surgery. The study involved 168 patients with drug-resistant temporal lobe epilepsy. All of them were examined twice: once before and again one year after surgery. Two questionnaires were used in the study: the Quality of Life in Epilepsy Inventory-Patient-Weighted and Hospital Anxiety and Depression Scale and one that collected data on selected demographic and clinical variables. The results showed that patients scored significantly higher in quality of life and lower in depression and anxiety after surgery; however, this only applied to patients with a good outcome of treatment (Engel Class I and Class II). Patients with an unfavorable outcome of surgical treatment (Engel Class III and Class IV) achieved significantly worse results in all examined variables. Correlational analysis showed a relationship between select aspects of quality of life and the level of depression and anxiety, as well as the frequency of seizures and age at epilepsy onset. There was no significant relationship with age, sex, education, or number of prescribed antiepileptic drugs. The study confirms the significant relationship between the quality of life and the effectiveness of surgical treatment, indicating the relationship between patients' well-being and selected clinical indicators.

Steps toward narrowing the surgical epilepsy treatment gap through private practice.

Steps toward narrowing the surgical epilepsy treatment gap through private practice.

<i>DEPDC5</i>-related familial focal epilepsy

Focal epilepsy is the most common type of epilepsy accounting for 60–70% of all cases of this pathology. We present two familial cases of focal epilepsy associated with a nucleotide sequence variant in DEPDC5 gene. Clinical and ancestry examination was performed by using instrumental (magnetic resonance imaging, video-electroencephalography) and genetic testing methods. The nucleotide sequence variants in DEPDC5 gene were found in two probands and paired fathers with epilepsy. Focal cortical dysplasia was detected only in the father of Proband 1 as well as Proband 2 with resistant epilepsy and severe cognitive deficit. Hence, such clinical cases confirm that pathogenic variants in DEPDC5 gene are related with familial focal epilepsy, which clinical manifestation may depend on the type of identified mutation. The study of genotype-phenotype correlations is necessary to apply proper therapy. Before surgical treatment of epilepsy, the genetic testing by whole exome or whole genome sequencing should be performed.

Safety & feasibility of responsive neurostimulation in children with refractory epilepsy: A single-center experience

ObjectivesResponsive neurostimulation (RNS) is a relatively recent addition to the epilepsy surgery armory, gaining FDA approval in 2013 for use in adults with intractable focal epilepsy. Data for the use of RNS system in patients less than 18 years of age is limited. We aim to determine the safety and feasibility of RNS in children with refractory epilepsy. MethodsA retrospective chart review was conducted for all patients who underwent RNS implantation at an urban tertiary children's hospital. Demographics of the patients were obtained, including age at the time of implant, MRI findings, seizure onset zone identification, and RNS targets. ResultsOut of a fourteen patient cohort, one patient had a post-operative complication of infection at surgical site requiring explantation. Thirteen out of 14 patients had immediate post-operative head imaging that was negative for hemorrhage, infarction, or skull fracture; one patient did not undergo head imaging. No patients reported a worsening clinical seizure frequency at a 6-month follow up visit. In the subset of patients who were implanted with RNS and did not undergo concurrent resections, there was a statistically significant reduction in the average number of long episodes at the most recent visit when compared to the 1-month post-operative visit (p = 0.0268). ConclusionsRNS is a feasible and safe option for children as young as six years with refractory epilepsy when appropriate seizure focus identification has been performed with stereo CT and stereo EEG evaluations, and can be used in conjunction with other surgical epilepsy treatment modalities. Two canister RNS placement is achievable for patients with a broad epileptogenic network or multifocal seizure onset zones.

Racial Disparity in Antibody Against A rare High Prevalence Antigen; (Anti-Inb)

Abstract Introduction/Objective Introduction: Ina antigen is very rare except in Iranian and Arab populations (10.6% and 11.8%, respectively). In 1973, Badkere et al. identified this antigen in about 3% of Indians from Bombay. Inb is a very high-prevalence antigen. It is prevalent in 99.9% of Caucasians and blacks, 96% of Indians and South Asians, and 90% of Iranians and Arabs. The Indian blood group system also has two other very high prevalence antigens: INFI and INJA. Indian blood group resides in CD44 glycoprotein that binds to hyaluronate of extracellular matrix. CD44 is an adhesion molecule in lymphocytes, monocytes, and other tumor cells, but its function in RBC is unknown. Ina and Inb are sensitive to proteolytic enzyme treatments and destroyed by disulfide bond-reducing agents 2-aminoethyl isothiouronium bromide (AET) and dithiothreitol (DTT). Methods/Case Report Case study: An 11-year-old female of South-East Indian descent with a history of intractable epilepsy was admitted for surgical treatment for epilepsy. Her antibody screen was positive, and her plasma reacted with all cells in PEG AHG except for the auto control. Ficin and DTT-treated cells weakened the reactivity. Suspecting a high-frequency antibody, the patient's plasma was tested against a series of cells in the rare donor cell inventory, including O Bombay cell and Inb-cell considering the patient's ethnicity. With Inb-negative cells, the plasma tested negative. All major alloantibodies from this rare donor cell were ruled out except for anti-C, anti-E, anti-K, and anti-S due to the availability of the rare cell. Results (if a Case Study enter NA) NA Conclusion Antigen Inb has a high prevalence in all populations. The rare phenotype In(b–) has been observed in approximately 2 of 700 Indian blood donors. A patient may be advised to undergo an autologous transfusion. Fortunately, the patient's procedures were uncomplicated, so a blood transfusion was unnecessary. Awareness on the part of blood bank staff regarding the variability of the blood group phenotype and the unpredictability of Anti-Inb may aid in improving patient care. To prevent further exposure, it is recommended that patients with rare antibodies carry an Antibody ID card indicating the rare antibody they possess.Inb antigen blood donors are under represented in the general donors pool. It is recommended to develop a systematic recruitment for Inb antigen donors

Overexpression of KCNN4 channels in principal neurons produces an anti-seizure effect without reducing their coding ability.

Gene therapy offers a potential alternative to the surgical treatment of epilepsy, which affects millions of people and is pharmacoresistant in ~30% of cases. Aimed at reducing the excitability of principal neurons, the engineered expression of K+ channels has been proposed as a treatment due to the outstanding ability of K+ channels to hyperpolarize neurons. However, the effects of K+ channel overexpression on cell physiology remain to be investigated. Here we report an adeno-associated virus (AAV) vector designed to reduce epileptiform activity specifically in excitatory pyramidal neurons by expressing the human Ca2+-gated K+ channel KCNN4 (KCa3.1). Electrophysiological and pharmacological experiments in acute brain slices showed that KCNN4-transduced cells exhibited a Ca2+-dependent slow afterhyperpolarization that significantly decreased the ability of KCNN4-positive neurons to generate high-frequency spike trains without affecting their lower-frequency coding ability and action potential shapes. Antiepileptic activity tests showed potent suppression of pharmacologically induced seizures in vitro at both single cell and local field potential levels with decreased spiking during ictal discharges. Taken together, our findings strongly suggest that the AAV-based expression of the KCNN4 channel in excitatory neurons is a promising therapeutic intervention as gene therapy for epilepsy.

Analysis of surgical treatment of drug-resistant epilepsy in Ukraine for the period 2014—2020

The aim of the study is analysis of surgical care for epilepsy patients in Ukraine from 2014 to 2020. The results of the surgical treatment of epilepsy patients in three leading neurosurgical institutions of Ukraine, which regularly perform epilepsy surgery were analyzed. They are Romodanov neurosurgery institute (Kyiv), Regional Clinical Center of Neurosurgery and Neurology (Uzhhorod) and Dnipropetrovsk Clinical Psychiatric Hospital (Dnipro). A questionnaire was used to obtain information on the quantity and types of surgical operations carried out in the aforementioned institutions between 2014 and 2020. From 2014 to 2018, surgical treatment was performed on 320 patients, in 2019 — 112 patients, and in 2020 — 61. The etiology of seizures was analyzed, where mesial temporal sclerosis overall years had an advantage over other causes of drug-resistant epilepsy. Accordingly, amygdalohypocampectomy accounted for the majority of surgical interventions in all years, however, other etiological factors and types of surgical treatment were also analyzed in detail. The number of patients who require surgical treatment is increasing. It is necessary to carefully refine the stages of preoperative preparation of patients in order to provide the patient with full-fledged medical care and to be able to perform a detailed analysis of surgical treatment. To achieve this goal, it was decided to develop a registry of epilepsy patients who received surgical treatment, which will allow to fully structure all the information received, track postoperative patients, and clearly evaluate the effectiveness of this type of treatment. Key words: drug-resistant epilepsy, epilepsy surgery, register

Surgical Treatment of Epilepsy with Bilateral MRI Abnormalities

To investigate the surgical outcomes of patients with drug-resistant epilepsy and bilateral brain magnetic resonance imaging (MRI) abnormalities who had undergone various epilepsy surgeries. Patients with drug-resistant epilepsy and bilateral brain abnormalities on MRI who underwent epilepsy surgery at the Severance Children's Hospital between October 2003 and December 2021 were included. The age of seizure onset was 18years or younger. Engel's classification was used to assess seizure outcomes at 1, 2, and 5years after surgery. A total of 40 patients met the inclusion criteria. The median age at surgery was 10.9years (interquartile range [IQR] 6.9-15.1); the median interval to surgery was 7.1years (IQR 2.7-11.5). One year after surgery, a favorable outcome of Engel class I-II was observed in 53% (21/40) of patients. At the 2- and 5-year follow-ups, 56% (20/36) and 63% (17/27) of patients showed good postoperative outcomes, respectively. Approximately, half of the patients with bilateral brain MRI abnormalities achieved seizure freedom after epilepsy surgery. The existence of bilateral brain MRI abnormalities should not hinder resective epilepsy surgery.

Long term outcome after surgical treatment for hypothalamic hamartoma

PurposeTo determine long-term outcome for seizure control and clinical predictors for seizure freedom in patients undergoing surgical treatment for epilepsy associated with hypothalamic hamartoma (HH). Methods155 patients underwent surgical treatment for HHs and treatment-resistant epilepsy at one center (Barrow Neurological Institute at St. Joseph’s Hospital and Medical Center, Phoenix, Arizona, USA) between February 2003 and June 2010. Data collection included medical record review and direct follow-up interviews to determine seizure outcome. Statistical analysis included descriptive summaries of patient characteristics and time-to-event analysis for seizure freedom. ResultsLong-term survival with follow-up of at least five years since first surgical treatment was available for 108 patients (69.7% of the treatment cohort). The surgical approach for first HH intervention consisted of transventricular endoscopic resection (n = 57; 52.8%), transcallosal interforniceal resection (n = 35; 32.4%), pterional resection (n = 7; 6.5%), and gamma knife radiosurgery (n = 9; 8.3%). Multiple surgical procedures were required for 39 patients (36.1%). There were 10 known deaths from all causes in the treatment cohort (6.5%). Of these, one (0.6%) was related to immediate complications of HH surgery, three (1.9%) were attributed to Sudden Unexpected Death in Epileptic Persons (SUDEP), and one (0.6%) to complications of status epilepticus. For surviving patients with long-term follow-up, 55 (50.9%) were seizure-free for all seizure types. Univariable analysis showed that seizure-freedom was related to 1) absence of a pre-operative history for central precocious puberty (p = 0.01), and 2) higher percentage of HH lesion disconnection after surgery (p = 0.047). Kaplan-Meier survival analysis shows that long-term seizure outcome following HH surgery is comparable to short-term results. SummaryThese uncontrolled observational results show that long-term seizure control following HH surgical treatment is comparable to other forms of epilepsy surgery. Late relapse (at least one year after surgery) and SUDEP do occur, but in a relatively small number of treated patients. These results inform clinical practice and serve as a comparable benchmark for newer technologies for HH surgery, such as magnetic resonance imaging-guided laser interstitial thermal therapy, where long-term outcome results are not yet available.

Stereoelectroencephalography-guided radiofrequency ablation of the epileptogenic zone as a treatment and predictor of future success of further surgical intervention.

Stereoelectroencephalography (SEEG)-guided radiofrequency ablation (RFA) is increasingly being used as a treatment for drug-resistant localization-related epilepsy. The aim of this study is to analyze the successes and failures using RFA and how response correlates with surgical epilepsy treatment outcomes. We retrospectively reviewed 62 patients who underwent RFA via SEEGelectrodes. After excluding five, the remaining 57 were classified into subgroups based on procedures and outcomes. Forty patients (70%) underwent a secondary surgical procedure, of whom 32 were delayed: 26 laser interstitial thermal therapy (LITT), five resection, one neuromodulation. We determined the predictive value of RFA outcome upon subsequent surgical outcome by categorizing the delayed secondary surgery outcome as success (Engel I/II) versus failure (Engel III/IV). Demographic information, epilepsy characteristics, and the transient time of seizure freedom after RFA were calculated for each patient. Twelve of 49 patients (24.5%) who had RFA alone and delayed follow-up achieved Engel class I. Of the 32 patients who underwent a delayed secondary surgical procedure, 15 achieved Engel class I and nine Engel class II (24 successes), and eight were considered failures (Engel class III/IV). The transient time of seizure freedom after RFA was significantly longer in the success group (4 months, SD = 2.6) as compared to the failure group (.75 months, SD = 1.16; p < .001). Additionally, there was a higher portion of preoperative lesional findings in patients in the RFA alone and delayed surgical success group (p = .03) and a longer time to seizure recurrence in the presence of lesions (p < .05). Side effects occurred in 1% of patients. In this series, RFA provided a treatment during SEEG-guided intracranial monitoring that led to seizure freedom in ~25% of patients. Of the 70% who underwent delayed surgery, longer transient time of seizure freedom after RFA was predictive of the results of the secondary surgeries, 74% of which were LITT.

Surgical treatment of epilepsy - Initial experience from a comprehensive epilepsy program in coastal South India.

The objectives of this study were to share our initial experience with epilepsy surgery and provide an overview on the surgical treatments of epilepsies. This was a retrospective analysis of the demographics and clinical and investigative features of patients who underwent epilepsy surgery between January 2016 and August 2021. Postoperative seizure outcome was categorized according to modified Engel's classification, and the minimum period of follow-up was 1 year. The study group included 30 patients with an age ranging from 6 years to 45 years (mean: 22.28 years, median: 20 years) and a male: female ratio of 20:10. The epilepsy duration before surgery ranged from 3 years to 32 years (median: 7 years). Majority of our patients underwent resective surgeries (28/30 = 93.3%), and disconnection procedures were done in two patients. This included one functional hemispherotomy and one posterior quadrantic disconnection. Temporal lobe resective surgery was the most common procedure (16/30 = 53.3%), followed by eight frontal lobe and two parietal lobe surgeries. Among resective surgeries, majority were lesional surgeries and the pathologies included mesial temporal sclerosis (4), dysembryoplastic neuroepithelial tumor (8), ganglioglioma (6), cavernoma (4), focal cortical dysplasia (2), gliosis (1), and one case of hypothalamic hamartoma. Intraoperative electrocorticography was used in all cases for optimizing surgical resection/disconnection. Nearly two-thirds of our patients (66.6%) had an Engel's Class I outcome, five patients had Engel's Class II outcome, three patients had Class III outcome, and one patient did not have any worthwhile improvement. Temporal lobe surgery patients had a better seizure outcome compared to extratemporal surgeries (84% vs. 74%). Overall, complications were minimal and short lasting, and comprised meningitis in three patients (5.6%) and transient worsening of hemiparesis following hemispherotomy in two patients. There was no mortality or long-lasting major morbidity in our patients. In carefully selected patients with drug-resistant epilepsy, surgery offers an excellent chance of becoming seizure-free with significant improvement in overall quality of life. Majority of the common epilepsy surgery procedures can be performed through a multidisciplinary approach even in centers with limited resources.

Surgical Treatment for Epilepsy: An Updated Summary of Treatment Modalities and Clinical Evidence

The efficacy of surgical treatment for drug-resistant epilepsy has been proven based on accumulated evidence, such as several randomized controlled trials. There are emerging treatment modalities, including less invasive surgical techniques and neuromodulation devices, which have also been proven to benefit patients by improving seizure control. A recent methodological shift from subdural electrocorticography recordings to stereo-encephalography recordings for intracranialelectroencephalography (iEEG) monitoring has also positively impacted clinical decision-making. Although some of these newer modalities are yet to be implemented in Japan, this article provides updated evidence and a summary of the currently available options for surgical treatment of patients with drug-resistant epilepsy. We hope that this summary will widen the treatment opportunities for patients with this highly impactful disease.

Medical and surgical treatment of epilepsy in older adults: A national survey.

There are no clinical guidelines dedicated to the treatment of epilepsy in older adults. We investigated physician opinion and practice regarding the treatment of people with epilepsy aged 65 years or older. We also sought to study how our opinion and practice varied between geriatricians, general neurologists, and epilepsy neurologists (i.e., epileptologists). We initially piloted our survey to measure test-retest reliability. Once finalized, we disseminated the survey via two rounds of facsimiles, and then conventional mail, to eligible individuals listed in a national directory of Canadian physicians. We used descriptive statistics such as stacked bar charts and tables to illustrate our findings. One hundred forty-four physicians (104 general neurologists, 25 geriatricians, and 15 epileptologists) answered our survey in its entirety (overall response rate of 13.2%). Levetiracetam and lamotrigine were the preferred antiseizure medications (ASMs) to treat older adults with epilepsy. Two thirds of epileptologists and almost half of general neurologists would consider prescribing lacosamide in >50% of people aged >65 years; only one geriatrician was of the same opinion. More than 40% of general neurologists and geriatricians erroneously believed that none of the ASMs mentioned in our survey was previously studied in randomized controlled trials specific to the treatment of epilepsy in older adults. Epileptologists were more likely as compared to general neurologists and geriatricians to recommend epilepsy surgery (e.g., 66.6% vs. 22.9%-37.5% among older adults). Therapeutic decisions for older adults with epilepsy are heterogeneous between physician groups and sometimes misalign with available clinical evidence. Our surveyed physicians differed in their approach to ASM choice as well as perception of surgery in older adults with epilepsy. These findings likely reflect the lack of clinical guidelines dedicated to this population and the deficient implementation of best practices.

Cognitive impairment in temporal lobe epilepsy

Cognitive impairment (CI) is a common comorbid pathology in epilepsy patients that exerts profound negative impact on quality of life. The CI causes may be due to various factors related to etiology, clinical manifestations, and treatment of epilepsy. A typical disorder in temporal lobe epilepsy is memory impairment. However, neuropsychological impairments may be more extensive and involve other neuropsychological domains. The risk of CI in patients with temporal lobe epilepsy may increase in structural brain disorders such as hippocampal sclerosis as well as in frequent seizures, early onset and long course of the disease. Surgical treatment of epilepsy may positively or negatively impact the cognitive function. In recent years, due to development of neurosciences as well as advances in the field of medical technologies, particularly neuroimaging, genetics, immunology, and biochemistry, new data emerged regarding potential mechanisms for developing CI in patients with epilepsy. The aim of the review is to assess available ideas about neurophysiological mechanisms of CI development, cues influencing emergence of neuropsychological disorders in patients with temporal lobe epilepsy.

Therapeutic developments in the surgical treatments of epilepsy: a review

In the 21st century, neurological disease is more complicated with the enhancement of technology; epilepsy is one of them. Currently, 1%-5% prevalence was observed, and 0.5%-1% were in chronic neurological disease. The involuntary spontaneous stimulation and inhibition in the brain caused seizures. The seizures are life-threatening episodes in which inelastic starching of lumber muscles and whole-body trimmers were observed. The period of episodic attack is directly proportional to the severity of the disease. This systemic review is based on developing therapeutic surgeries for epilepsy in the 21st century. The data was collected from Medline, PubMed, Embase, Cochrane library, and Web of Science. Surgical treatment, therapeutic methods, developmental approach in treatment, epilepsy, neurological disorders, and seizure attack words were used as the keywords. A total of 120 articles and reviews were selected, of which 11 were included based on exclusion criteria. The pharmacotherapy of epilepsy is set to undergo significant changes in the following 10 years due to the large quantity of continuing epilepsy and more general neuroscience research and the numerous novel compounds that are now being developed.

Surgical treatment of epilepsy in children with focal cortical dysplasia in central gyri

Assessment of the outcome after epilepsy surgery in children with FCD in central lobules. Nine patients, median age 3.7 ys, IQR=5.7 ys (min 1.8- max 15.7 ys) with FCD in central gyri and DR-epilepsy underwent surgery. Standard preoperative evaluation included MRI and video-EEG. Invasive recordings were used in 2 cases, coupled by fMRI in 2. An ECOG and neuronavigation, as well as stimulation and mapping of primary motor cortex were used routinely during the procedure. Gross total resection was achieved in 7 patients according to postoperative MRI. Six patients with new or worsening of already existing hemiparesis recovered within a year after surgery. At the last FU (med 5 ys) favorable outcome (Engel class IA) has been achieved in 6 cases (66.7%), while two patients with persisting seizures reported seizing less frequently (Engel II-III). Three patients were able to discontinue AED-treatment and four children resumed development with improvement in cognition and behavior.

Localization of epileptogenic zone based on reconstruction of dynamical epileptic network and virtual resection

Drug-refractory epilepsy (DRE) may be treated by surgical intervention. Intracranial EEG has been widely used to localize the epileptogenic zone (EZ). Most studies of epileptic network focus on the features of EZ nodes, such as centrality and degrees. It is difficult to apply those features to the treatment of individual patients. In this study, we proposed a spatial neighbor expansion approach for EZ localization based on a neural computational model and epileptic network reconstruction. The virtual resection method was also used to validate the effectiveness of our approach. The electrocorticography (ECoG) data from 11 patients with DRE were analyzed in this study. Both interictal data and surgical resection regions were used. The results showed that the rate of consistency between the localized regions and the surgical resections in patients with good outcomes was higher than that in patients with poor outcomes. The average deviation distance of the localized region for patients with good outcomes and poor outcomes were 15 mm and 36 mm, respectively. Outcome prediction showed that the patients with poor outcomes could be improved when the brain regions localized by the proposed approach were treated. This study provides a quantitative analysis tool for patient-specific measures for potential surgical treatment of epilepsy.

Is intracranial electroencephalography mandatory for MRI-negative neocortical epilepsy surgery?

MRI-negative focal epilepsy is one of the most challenging cases in surgical epilepsy treatment. Many epilepsy centers recommend intracranial electroencephalography (EEG) for MRI-negative cases, especially neocortical epilepsy. This retrospective study aimed to explore whether intracranial monitoring is mandatory in MRI-negative neocortical epilepsy surgery and the factors that significantly influence the decision on whether to perform intracranial recording. In this study, consecutive surgical patients with focal MRI-negative neocortical epilepsy were recruited. All patients underwent routine preoperative evaluation according to the dedicated protocol of the authors' epilepsy center to determine the treatment strategy. Patients were divided into two groups according to the surgical strategy, i.e., a direct group and a stereo-EEG (SEEG)-guided group. History of epilepsy, seizure frequency, interictal and ictal EEG data, PET data, PET/MRI coregistration data, neuropathological findings, and surgical outcomes were compared between the two groups. Multivariate analysis was performed to identify factors influencing the decision to perform SEEG monitoring. Sixty-four patients were included in this study, 19 and 45 of whom underwent direct and SEEG-guided cortical resection, respectively. At an average follow-up of 3.9 years postoperatively, 56 patients (87.5%) had Engel class I results without permanent neurological deficits. Surgical outcomes were not significantly different between the direct and SEEG-guided groups (94.7% vs 84.4%). PET hypometabolic abnormalities were detected in all patients. There were significant differences between the two groups in the extent of hypometabolism (focal vs nonfocal, p < 0.01) and pathological subtype (focal cortical dysplasia type II vs others, p = 0.03). Multivariate analysis revealed that the extent of hypometabolism (OR 0.01, 95% CI 0.00-0.15; p = 0.001) was the only independent factor affecting the treatment strategy. Careful selection of patients with MRI-negative neocortical epilepsy may yield favorable outcomes after direct cortical resection without intracranial monitoring. PET/MRI coregistration plays an essential role in the preoperative evaluation and subsequent resection of these patients. Intracranial monitoring is not a mandatory requirement for surgery if the focal hypometabolic areas are consistent with the findings of semiology and scalp EEG.