Pediatric epilepsy surgery: could age be a predictor of outcomes?

The Important Role of Hemispherotomy for Rasmussen Encephalitis: Clinical and Functional Outcomes

BACKGROUND

Rasmussen encephalitis (RE) is characterized by pharmacoresistant epilepsy and progressive neurological deficits concurrent with unilateral hemispheric atrophy. Evidence of an inflammatory autoimmune process has been extensively described in the literature; however, the precise etiology of RE is still unknown. Despite data supporting a beneficial effect of early immunosuppressive and immunomodulatory interventions, surgical disconnection of the affected hemisphere is considered the treatment of choice for these patients. The aim of this study was to report a series of children and adolescents who underwent hemispheric surgery (HS) for the treatment of RE, analyzing their clinical, electrographic, and neuroimaging features pre-operatively, as well as their postoperative status, including seizure and functional outcomes.

METHODS

All patients with RE who underwent HS in the Epilepsy Surgery Center (CIREP) of the University Hospital of Ribeirão Preto Medical School, between 1995 and 2020 were retrospectively reviewed. Preoperative and postoperative analyses included gender; age at epilepsy onset; seizure semiology; seizure frequency; interictal and ictal electroencephalographic (EEG) findings; age at surgery; duration of epilepsy; surgical complications; duration of follow-up; histopathological findings; and postoperative seizure, cognitive, and functional outcomes.

RESULTS

Forty-four patients were evaluated. Mean age at seizure onset and epilepsy duration was 6 years and 2.5 years, respectively. Mean age at surgery was 9 years, with an average follow-up ranging from 3 months to 23 years. All patients presented with severe epilepsy and distinct neurological abnormalities on MRI. Before HS, different degrees of abnormal intellectual performance as well as hemiparesis were seen in 86% and 90%, respectively. Histopathology examination confirmed this diagnosis in 95% patients. At the last follow-up, 68% of patients were seizure free, and 70% were classified as Engel Class I or II. Postoperatively, the cognitive status remained unchanged in 64% of patients. Likewise, the gross motor function remained unchanged in 54% of patients and 74% had functional hand ability after HS.

CONCLUSIONS

Considering the progressive damage course of RE, hemispheric surgery should be offered to pediatric patients. It has manageable risks and results in good seizure outcome, and the preoperative functional status of these children is often preserved (even when the left hemisphere is involved), thus improving their quality of life.

Seizure outcomes after resection of primary brain tumors in pediatric patients: a systematic review and meta-analysis

PURPOSE

Primary brain neoplasms are the most common solid tumors in pediatric patients and seizures are a common presenting symptom. Surgical intervention improves oncologic outcomes and seizure burden. A better understanding of factors that influence seizure outcomes in the surgical management of primary brain tumors of childhood can guide treatment approach thereby improving patient quality of life.

METHODS

We performed a systematic analysis using articles queried from PubMed, EMBASE, and Cochrane published from January 1990 to August 2022 to determine predictors of seizure outcomes in pediatric patients undergoing resection of primary brain tumors.

RESULTS

We identified 24 retrospective cohort studies, one prospective cohort study, and one mixed retrospective and prospective study for the systematic analysis. A total of 831 pediatric patients were available for analysis. 668 (80.4%) patients achieved seizure freedom after surgery. Complete tumor resection increased the likelihood of a seizure-free (Engel I) outcome compared to subtotal resection (OR 7.1, 95% CI 2.3-21.9). Rates of Engel I seizure outcomes did not significantly differ based on factors such as age at seizure onset, duration of epilepsy, gender, tumor laterality, or age at surgery, but trended towards significance for improved outcomes in temporal lobe tumors.

CONCLUSION

Primary brain tumors in the pediatric population are commonly associated with seizures. Resection of these lesions reduces seizure burden and is associated with high rates of seizure freedom. Complete resection, compared to subtotal resection, significantly increases the likelihood of seizure-free outcomes.

Early surgical approaches in pediatric epilepsy - a systematic review and meta-analysis

INTRODUCTION

Drug-resistant epilepsy occurs in up to 30% of children suffering from seizures and about 10% qualify for surgical treatment. The aim of this systematic review and meta-analysis is to analyze the potential benefit of early epilepsy surgery in children concerning primarily seizure and developmental outcome.

METHODS

PubMed and Embase databases were searched using a systematic search strategy to identify studies on pediatric epilepsy surgery under 3 years from their inception up to 2022. Outcome measures were seizure outcome, postoperative complications, seizure onset, and reduction rate of antiepileptic drugs. A meta-analysis was thereafter performed for all included cohort studies. A p-value of < 0.05 was considered as statistically significant.

RESULTS

A total of 532 patients were analyzed with 401 patients (75%) receiving resective or disconnective surgery under the age of 3 years and 80 patients (15%) receiving surgery older than 3 years. The remaining 51 patients (9%) underwent VNS implantation. Pooled outcome analysis for resective/disconnective surgery showed favorable outcome in 68% (95% CI [0.63; 0.73]), while comparative analysis between the age groups showed no significant difference (77% early group and 75% late group; RR 1.03, 95% CI [0.73; 1.46] p = 0.75). Favorable outcome for the VNS cohort was seen in 52%, 65% in the early and 45.1% in the late group (RR 1.4393, 95% CI [0.87; 2.4] z = 1.42, p = 0.16). Developmental outcome was improved in 26%. Morbidity rate was moderate and showed no significant difference comparing the age groups, and overall surgical mortality rate was very low (0.1%).

CONCLUSION

Epilepsy surgery in pediatric age, especially under the age of 3 years, is a feasible and safe way to treat intractable epilepsy. Further comparative studies of prospective nature, analyzing not only seizure but also developmental outcome, should be the focus of future studies.

Seizure outcome determinants in children after surgery for single unilateral lesions on magnetic resonance imaging: Role of preoperative ictal and interictal electroencephalography

OBJECTIVE

To determine whether an ictal electroencephalographic (EEG) recording as part of presurgical evaluation of children with a demarcated single unilateral magnetic resonance imaging (MRI) lesion is indispensable for surgical decision-making, we investigated the relationship of interictal/ictal EEG and seizure semiology with seizure-free outcome.

METHODS

Data were obtained retrospectively from consecutive patients (≤18 years old) undergoing epilepsy surgery with a single unilateral MRI lesion at our institution over a 6-year period. Video-telemetry EEG (VT-EEG) was classified as concordant or nonconcordant/noninformative in relation to the MRI lesion location. The odds of seizure-free outcome associated with nonconcordant versus concordant for semiology, interictal EEG, and ictal EEG were compared separately. Multivariate logistic regression was conducted to correct for confounding variables.

RESULTS

After a median follow-up of 26 months (interquartile range = 17-37.5), 73 (69%) of 117 children enrolled were seizure-free. Histopathological diagnoses included low-grade epilepsy-associated tumors, n = 46 (39%); focal cortical dysplasia (FCD), n = 33 (28%); mesial temporal sclerosis (MTS), n = 23 (20%); polymicrogyria, n = 3 (3%); and nondiagnostic findings/gliosis, n = 12 (10%). The odds of seizure freedom were lower with a nonconcordant interictal EEG (odds ratio [OR] = .227, 95% confidence interval [CI] = .079-.646, p = .006) and nonconcordant ictal EEG (OR = .359, 95% CI = .15-.878, p = .035). In the multivariate logistic regression model, factors predicting lower odds for seizure-free outcome were developmental delay/intellectual disability and higher number of antiseizure medications tried, with a nonsignificant trend for "nonconcordant interictal EEG." In the combined subgroup of patients with FCD and tumors (n = 79), there was no significant relationship of VT-EEG factors and seizure outcomes, whereas in children with MTS and acquired lesions (n = 25), a nonconcordant EEG was associated with poorer seizure outcomes (p = .003).

SIGNIFICANCE

An ictal EEG may not be mandatory for presurgical evaluation, particularly when a well-defined single unilateral MRI lesion has been identified and the interictal EEG is concordant.

Preoperative MRI for postoperative seizure prediction: a radiomics study of dysembryoplastic neuroepithelial tumor and a systematic review

OBJECTIVE

In this systematic review the authors aimed to evaluate the effectiveness and superiority of radiomics in detecting tiny epilepsy lesions and to conduct original research in the use of radiomics for preliminary prediction of postoperative seizures in patients with dysembryoplastic neuroepithelial tumor (DNET).

METHODS

The PubMed and Web of Science databases were searched from the earliest record, January 1, 2018, to December 29, 2021, for reports of the detection of epilepsy using radiomics, and the resulting articles were carefully checked according to the PRISMA 2020 guidelines. The authors then conducted original research by evaluating MR images in 18 patients, who were then separated into two groups, the epilepsy recurrence group (ERG) and the epilepsy nonrecurrence group. The tumor region and the edema region were segmented manually by 3D Slicer. The radiomics data were extracted from MR images by using “Slicer Radiomics” running on Mac OS X. Tumor regions were observed with T1-weighted imaging, and edema with FLAIR imaging. Radiomics features with significant differences were selected through comparison according to epilepsy relapses performed with the Mann-Whitney U-test. The edema and tumor regions were also compared within groups to identify their distinctive features. Radiomics features were tested to verify their ability to predict recurrence epilepsy by receiver operating characteristic curve.

RESULTS

This systematic review located 9 original articles related to epilepsy and radiomics published from 2018 to 2021. The reported studies demonstrated that radiomics is useful for detecting tiny epilepsy lesions. Among the radiomics features used, the predictive ability of the area under the curve was more than 0.8. The heterogeneity of the peritumoral edema region was found to be higher in the ERG.

CONCLUSIONS

Satellite lesions in the peritumoral edema region of DNET patients may cause epilepsy recurrence, and radiomics is an emerging method to detect and evaluate these epilepsy-associated lesions.

Seizure control after epilepsy surgery in early childhood: A systematic review and meta-analysis

OBJECTIVE

This meta-analysis aimed to determine the main factors influencing surgical outcomes in children <3 years old with refractory epilepsy.

METHODS

The PubMed and Cochrane database were systematically searched for epilepsy surgery outcomes from December 1, 1991, to March 30, 2021, using the following search terms: "Epilepsy surgery OR Seizure operation" AND "under three years" OR "first three years" OR "early childhood" OR "infancy OR infants." Seizure onset, duration of epilepsy, magnetic resonance imaging findings, age at the time of surgery, surgical methods, resection extent, and pathological findings were considered potential moderators of differences in seizure outcomes. The fixed-effects models, combined effect sizes, and 95% confidence intervals (CI) were used to calculate the influence of potential factors on seizure outcomes.

RESULTS

Thirty two studies (559 cases) were included in the meta-analysis. The significant factors that correlated with a lower seizure control rate were frontal lobectomy (odds ratio [OR]: 0.33, 95% CI: 0.12-0.91; p = 0.03) and malformation of cortical development (MCD) (OR, 0.38; 95% CI: 0.24-0.62; p < 0.01). A higher seizure control rate was observed in children with tumors (92.86%) and Sturge-Weber syndrome (SWS, 91.43%). Frontal lobe epilepsy induced by MCD was related to the worst postoperative efficacy (OR, 0.26; 95% CI: 0.13-0.53; p < 0.01).

SIGNIFICANCE

The results of our meta-analyses revealed that pathology and surgical location play critical roles in the outcome of epilepsy surgery in children <3 years old. Clarification of the etiology of epilepsy before surgery is critical for better postoperative outcomes.

Surgical evaluation in children <3 years of age with drug-resistant epilepsy: Patient characteristics, diagnostic utilization, and potential for treatment delays

OBJECTIVE

Drug-resistant epilepsy (DRE) occurs at higher rates in children <3 years old. Epilepsy surgery is effective, but rarely utilized in young children despite developmental benefits of early seizure freedom. The present study aims to identify unique patient characteristics and evaluation strategies in children <3 years old who undergo epilepsy surgery evaluation as a means to assess contributors and potential solutions to health care disparities in this group.

METHODS

The Pediatric Epilepsy Research Consortium Epilepsy Surgery Database, a multicentered, cross-sectional collaboration of 21 US pediatric epilepsy centers, collects prospective data on children <18 years of age referred for epilepsy surgery evaluation. We compared patient characteristics, diagnostic utilization, and surgical treatment between children <3 years old and those older undergoing initial presurgical evaluation. We evaluated patient characteristics leading to delayed referral (>1 year) after DRE diagnosis in the very young.

RESULTS

The cohort included 437 children, of whom 71 (16%) were <3 years of age at referral. Children evaluated before the age of 3 years more commonly had abnormal neurological examinations (p = .002) and daily seizures (p = .001). At least one ancillary test was used in 44% of evaluations. Fifty-nine percent were seizure-free following surgery (n = 34), with 35% undergoing limited focal resections. Children with delayed referrals more often had focal aware (p < .001) seizures and recommendation for palliative surgeries (p < .001).

SIGNIFICANCE

There are relatively few studies of epilepsy surgery in the very young. Surgery is effective, but may be disproportionally offered to those with severe presentations. Relatively low utilization of ancillary testing may contribute to reduced surgical therapy for those without evident lesions on magnetic resonance imaging. Despite this, a sizeable portion of patients have favorable outcome after focal epilepsy surgery resections.

Surgery for Intractable Epilepsy in Pediatrics, a Systematic Review of Outcomes other than Seizure Freedom

To perform a systematic review evaluating reported outcomes for epilepsy surgery in pediatric patients with pharmacoresistant epilepsy beyond seizure control, including impact on quality of life, behavioral, neurocognitive outcomes as well as complications, and death. We reviewed articles from both EMBASE and MEDLINE/PubMed articles that met formal criteria (patients ≤18 years, those with intractable epilepsy, at least 5 patients in the case series, published in peer-reviewed journal). Each reviewer independently reviewed the articles and those with discrepancies were discussed and consensus was reached. Out of a total of 536 abstracts obtained from EMBASE and MEDLINE/PubMed searches combined with additional cross-referencing, a total of 98 manuscripts ultimately met all inclusion criteria. The manuscripts were divided into 3 outcomes categories: Quality of Life (16), Cognitive Outcomes (60), and Deficits and Complications (50). Several papers fell into more than 1 category. These were separated by surgical types and evaluated. We found that overall reporting in all domains was variable and inconsistent amongst the different studies. This systematic review highlights the lack of completeness in reporting outcomes and complications involving pediatric epilepsy surgery and discordant results. This underscores the importance of multicenter systematic prospective data collection in pediatric patients who undergo pediatric epilepsy surgery.

Epilepsy surgery in children under 3 years of age: surgical and developmental outcomes

OBJECTIVE

Pediatric epilepsy surgery is known to be effective, but early surgery in infancy is not well characterized. Extensive cortical dysplasia, such as hemimegalencephaly, can cause refractory epilepsy shortly after birth, and early surgical intervention is indicated. However, the complication rate of early pediatric surgery is significant. In this study, the authors assessed the risk-benefit balance of early pediatric epilepsy surgery as relates to developmental outcomes.

METHODS

This is a retrospective descriptive study of 75 patients who underwent their first curative epilepsy surgery at an age under 3 years at the authors' institution between 2006 and 2019 and had a minimum 1-year follow-up of seizure and developmental outcomes. Clinical information including surgical complications, seizure outcomes, and developmental quotient (DQ) was collected from medical records. The effects of clinical factors on DQ at 1 year after surgery were evaluated.

RESULTS

The median age at surgery was 6 months, peaking at between 3 and 4 months. Operative procedures included 27 cases of hemispherotomy, 19 cases of multilobar surgery, and 29 cases of unilobar surgery. Seizure freedom was achieved in 82.7% of patients at 1 year and in 71.0% of patients at a mean follow-up of 62.8 months. The number of antiseizure medications (ASMs) decreased significantly after surgery, and 19 patients (30.6%) had discontinued their ASMs by the last follow-up. Postoperative complications requiring cerebrospinal fluid (CSF) diversion surgery, such as hydrocephalus and cyst formation, were observed in 13 patients (17.3%). The mean DQ values were 74.2 ± 34.3 preoperatively, 60.3 ± 23.3 at 1 year after surgery, and 53.4 ± 25.1 at the last follow-up. Multiple regression analysis revealed that the 1-year postoperative DQ was significantly influenced by preoperative DQ and postoperative seizure freedom but not by the occurrence of any surgical complication requiring CSF diversion surgery.

CONCLUSIONS

Early pediatric epilepsy surgery has an acceptable risk-benefit balance. Seizure control after surgery is important for postoperative development.

Increase in cognitive function is seen in many single-operated pediatric patients after epilepsy surgery

PURPOSE

The recurrent seizures of pediatric drug-resistant epilepsy (DRE) are known to impair brain development and can lead to a loss in cognitive functioning. Surgery is increasingly being used to treat children with DRE. This study investigates the pre- and postoperative cognitive function in a pediatric epilepsy surgery cohort as well as predictive determinants of change in intelligence quotient (IQ) following surgery.

METHODS

A consecutive series of 91 Danish children who underwent focal resective epilepsy surgery between January 1996 and December 2016 were included. All underwent preoperative cognitive evaluation and were reevaluated at 1-year and/or 2-year follow-up. Single-operated and multi-operated patients were examined separately.

RESULTS

79 of 91 patients were single-operated. Single-operated patients received less anti-epileptic drugs (AED) and experienced a decrease in seizure frequency postoperatively, p < 0.001. IQ increased postoperatively (IQ change ± standard deviation: 3.3 ± 14.0), p < 0.05. High preoperative seizure frequency was a significant predictor for decreased IQ, p < 0.01. Multi-operated patients did not experience a reduction in AED treatment. Surgery and continued AED treatment did, however, result in significantly better seizure control, p < 0.01. IQ remained unchanged in multi-operated patients.

CONCLUSION

Epilepsy surgery allowed for IQ gains in single-operated patients. Preoperative seizure frequency was a significant predictor of IQ change following surgery. Interactions between other, not included, possible predictors remain to be examined. Single-operated patients had the best cognitive outcome. The inclusion of a non-surgical control group is needed to assess the extent of the beneficial effects of surgery on cognitive ability.

Challenges of Epilepsy Surgery

Though frequently effective in the management of medically refractory seizures, epilepsy surgery presents numerous challenges. Selection of the appropriate candidate patients who are likely to benefit from surgery is critical to achieving seizure freedom and avoiding neurocognitive morbidity. Identifying the seizure focus and mapping epileptogenic networks involves an interdisciplinary team dedicated to formulating a safe and effective surgical plan. Various strategies can be employed either to eliminate the epileptic focus or to modulate network activity, including resection of the focus with open surgery or laser interstitial thermal therapy; modulation of epileptogenic firing patterns with responsive neurostimulation, deep brain stimulation, or vagus nerve stimulation; or non-invasive disconnection of epileptic circuits with focused ultrasound, which is also discussed in greater detail in the subsequent chapter in our series. We review several challenges of epilepsy surgery that must be thoughtfully addressed in order to ensure its success.

The impact of imposed delay in elective pediatric neurosurgery: an informed hierarchy of need in the time of mass casualty crisis

SARS-CoV-2 COVID-19, coronavirus, has created unique challenges for the medical community after national guidelines called for the cancellation of all elective surgery. While there are clear cases of elective surgery (benign cranial cosmetic defect) and emergency surgery (hemorrhage, fracture, trauma, etc.), there is an unchartered middle ground in pediatric neurosurgery. Children, unlike adults, have dynamic anatomy and are still developing neural networks. Delaying seemingly elective surgery can affect a child's already vulnerable health state by further impacting their neurocognitive development, neurologic functioning, and potential long-term health states. The purpose of this paper is to demonstrate that "elective" pediatric neurosurgery should be risk-stratified, and multi-institutional informed guidelines established.

Open Resection versus Laser Interstitial Thermal Therapy for the Treatment of Pediatric Insular Epilepsy

BACKGROUND

Various studies suggest that the insular cortex may play an underappreciated role in pediatric frontotemporal/parietal epilepsy. Here, we report on the postsurgical outcomes in 26 pediatric patients with confirmed insular involvement by depth electrode monitoring.

OBJECTIVE

To describe one of the largest series of pediatric patients with medically refractory epilepsy undergoing laser interstitial thermal therapy (LITT) or surgical resection of at least some portion of the insular cortex.

METHODS

Pediatric patients in whom invasive insular sampling confirmed insular involvement and who subsequently underwent a second stage surgery (LITT or open resection) were included. Complications and Engel Class outcomes at least 1 yr postsurgery were compiled as well as pathology results in the open surgical cases.

RESULTS

The average age in our cohort was 10.3 yr, 58% were male, and the average length of follow-up was 2.43 ± 0.20 (SEM) yr. A total of 14 patients underwent LITT, whereas 12 patients underwent open resection. Complications in patients undergoing either LITT or open resection were mostly minimal and generally transient. Forty-three percent of patients who underwent LITT were Engel Class I, compared to 50% of patients who underwent open insular resection.

CONCLUSION

Both surgical resection and LITT are valid management options in the treatment of medically refractory insular/opercular epilepsy in children. Although LITT may be a less invasive alternative to craniotomy, further studies are needed to determine its noninferiority in terms of complication rates and seizure freedom, especially in cases of cortical dysplasia that may involve extensive regions of the brain.

Measure thrice, cut twice: On the benefit of reoperation for failed pediatric epilepsy surgery

OBJECTIVE

To determine whether clinical outcomes are improved after repeat surgery for medically refractory epilepsy in children.

METHODS

This is a single-center retrospective cohort analysis of all patients who received repeat resective surgery for ongoing seizures from 2000-2017. From a total of 251 consecutive individual epilepsy surgical patients for focal resection, 53 patients met study inclusion criteria and had adequate follow-up documented.

RESULTS

Median age of seizure-onset was 2.0-years-old (IQR 0.3-5.5 years). The median age at first epilepsy surgery was 6.3-years-old (IQR 2.9-9.2 years) and at second epilepsy surgery was 8.4-years-old (IQR 4.7-12.6 years). Overall, 53 % (n = 28) of this series achieved Engel Class I (seizure freedom); with improved seizure control (Engel Class I-II) in 83 % (n = 44) of the cohort. 64 % (n = 34) had one reoperation; 26 % (n = 14) had two; and 9% (n = 5) had three. Pathology: 58 % (n = 31) had focal cortical dysplasia; 13 % (n = 10) tumor; 9% (n = 5) encephalitis; 6% (n = 3) gliosis; 4% (n = 2) mesial temporal sclerosis; and 2% (n = 1) hemimegalencephaly. Tumor pathology was associated with increased chance (p = 0.01) for seizure freedom (90 % of tumor patients had Engel Class I outcome). MTS had worse outcome with both patients having ongoing seizures (Engel II-IV). There were 6 patients who developed post-operative hemiparesis; one was unplanned but resolved.

SIGNIFICANCE

Reoperation for pediatric epilepsy surgery can lead to seizure freedom in many cases and improved seizure control in most cases. Reoperation for brain tumor pathology is associated with a high rate of seizure freedom.

Preoperative evaluation and surgical management of infants and toddlers with drug-resistant epilepsy

OBJECTIVE Despite perioperative risks, epilepsy surgery represents a legitimate curative or palliative treatment approach for children with drug-resistant epilepsy (DRE). Several factors characterizing infants and toddlers with DRE create unique challenges regarding optimal evaluation and management. Epilepsy surgery within children < 3 years of age has received moderate attention in the literature, including mainly case series and retrospective studies. This article presents a systematic literature review and explores multidisciplinary considerations for the preoperative evaluation and surgical management of infants and toddlers with DRE. METHODS The study team conducted a systematic literature review based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, targeting studies that investigated children < 3 years of age undergoing surgical treatment of DRE. Using the PubMed database, investigators selected peer-reviewed articles that reported seizure outcomes with or without developmental outcomes and/or perioperative complications. Studies were eliminated based on the following exclusion criteria: sample size < 5 patients; and inclusion of patients > 3 years of age, when demographic and outcomes data could not be separated from the cohort of patients < 3 years of age. RESULTS The study team identified 20 studies published between January 1990 and May 2017 that satisfied eligibility criteria. All selected studies represented retrospective reviews, observational studies, and uncontrolled case series. The compiled group of studies incorporated 465 patients who underwent resective or disconnective surgery (18 studies, 444 patients) or vagus nerve stimulator insertion (2 studies, 21 patients). Patient age at surgery ranged between 28 days and 36 months, with a mean of 16.8 months (1.4 years). DISCUSSION The study team provided a detailed summary of the literature review, focusing on the etiologies, preoperative evaluation, surgical treatments, seizure and developmental outcomes, and potential for functional recovery of infants and toddlers with DRE. Additionally, the authors discussed special considerations in this vulnerable age group from the perspective of multiple disciplines. CONCLUSIONS While presenting notable challenges, pediatric epilepsy surgery within infants and toddlers (children < 3 years of age) offers significant opportunities for improved seizure frequency, neuro-cognitive development, and quality of life. Successful evaluation and treatment of young children with DRE requires special consideration of multiple aspects related to neurological and physiological immaturity and surgical morbidity.

Voxel-based morphometric magnetic resonance imaging postprocessing in non-lesional pediatric epilepsy patients using pediatric normal databases

BACKGROUND AND PURPOSE

Pre-surgical evaluation of pediatric patients with drug-resistant focal epilepsy and negative (non-lesional) magnetic resonance imaging (MRI) is particularly challenging. Focal cortical dysplasia (FCD), a frequent pathological substrate in such setting, may be subtle on MRI and evade detection. The aim of this study was to use voxel-based MRI postprocessing to improve the detection of subtle FCD in pediatric surgical candidates.

METHODS

A consecutive cohort of pediatric patients undergoing pre-surgical evaluation with a negative MRI by visual analysis was included. MRI postprocessing was performed using a voxel-based morphometric analysis program (MAP) on T1-weighted volumetric MRI, with comparison to an age-specific normal pediatric database. The pertinence of MAP-positive areas was confirmed by surgical outcome and pathology.

RESULTS

A total of 78 patients were included. Forty-four patients (56%) had positive MAP regions. Complete resection of the MAP-positive regions was positively associated with seizure-free outcome compared with the no/partial resection group (P < 0.001). Patients with no/partial resection of the MAP-positive regions had worse seizure outcomes than the MAP-negative group (P = 0.002). The MAP-positive rate was 100%, 77%, 63% and 40% in the 3-5, 5-10, 10-15 and 15-21 year age groups, respectively. MAP-positive rates were 45% in patients with temporal resection and 63% in patients with extratemporal resection. Complete resection of the MAP-positive regions was positively associated with seizure-free outcome in the extratemporal group (P = 0.001) but not in the temporal group (P = 0.070).

CONCLUSION

Our data suggest the importance of using MRI postprocessing in the pre-surgical evaluation process of pediatric epilepsy patients with apparently normal MRI.

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.

Surgical outcomes in two different age groups with Focal Cortical Dysplasia type II: Any real difference?

OBJECTIVE

Focal Cortical Dysplasias (FCDs) represent a common architectural cortical disorder underlying drug-resistant focal epilepsy. So far, studies aimed at evaluating whether age at surgery is a factor influencing surgical outcome are lacking, so that data on the comparison between patients harboring Type II FCD operated at younger age and those operated at adult age are still scarce. We compared presurgical clinical features and surgical outcomes of patients with histopathologically diagnosed Type II FCD undergoing surgery at an earlier age with those operated after 20 years of age.

METHODS

We retrospectively analyzed 1660 consecutive patients operated at the "Claudio Munari" Epilepsy Surgery Centre. There were 289 patients (17.4%) with a neuropathological diagnosis of Type II FCD. We included two different groups of patients, the first one including patients operated on at less than 6years, the second sharing the same seizure onset age but with delayed surgery, carried out after the age of 20. Seizure characteristics and, neuropsychological and postoperative seizure outcomes were evaluated by study group.

RESULTS

Forty patients underwent surgery before the age of 6 and 66 patients after the age of 20. Surgical outcome was favorable in the whole population (72.6% were classified in Engel's Class Ia+Ic), independently from age at surgery. In the children group, 32 patients were classified in Class I, including 30 (75%) children in classes Ia and Ic. In the adult group, 53 belonged to Class I of whom 47 (71%) were in classes Ia and Ic. The percentage of permanent complications, the surgical outcomes, and AED withdrawal did not significantly differ by study group.

CONCLUSION

Our results indicate that there is no difference between the groups, suggesting that outcome depends mainly on the histological findings and not on timing of surgery.

Glioneuronal tumors of cerebral hemisphere in children: correlation of surgical resection with seizure outcomes and tumor recurrences

OBJECT

Glioneuronal tumors are common neoplasms among the cerebral hemisphere during childhood. They consist of several histological types, of which gangliogliomas (GGs) and dysembryoplastic neuroepithelial tumors (DNTs) are most common and often present with seizures. A great majority of glioneuronal tumors are benign. However, there are conflict reports regarding postoperative tumor recurrence rates and seizure control. The authors analyzed and compared these tumors for their locations and histology and the tumor and seizure control following resection.

METHODS

The authors conducted a retrospective analysis of patients with pediatric glioneuronal tumors in the cerebral hemisphere. All histology reports and neuroimaging are reviewed. Seizure group and non-seizure group were compared with their tumor types and locations. The extent of tumor resections were divided into gross total resection (GTR) and subtotal resection (STR). Postoperative tumor recurrence-free survival (RFS) and seizure-free survival for patients who had the initial surgery done at our institution were calculated using Kaplan-Meier method.

RESULTS

There were 90 glioneuronal tumors including 58 GGs, 22 DNTs, 3 papillary glioneuronal tumor, 3 desmoplastic infantile gangliogliomas, 3 anaplastic GGs, and 1 central neurocytoma. Seventy-one patients (seizure group) presented with seizures. The temporal lobe is the most common location, 50 % in this series. GTR was attained in 79 patients and STR in 11. All of the patients with GTR had lesionectomy, and only six of them had extended corticectomy or partial lobectomy. Postoperative seizure outcome showed that 64 (90 %) of seizure group had Engel's class I, but five patients subsequently developed recurrent seizures. Patients with DNTs had a higher seizure recurrence rate. Tumor RFS was 87 % at 5 years and 75.5 % at 10 years. There are no significant difference in tumor recurrences between GGs and DNTs (p = 0.876). Comparison between GRT (67) and STR (9) showed that in spite of the better 5-year tumor RFSs among GRT group (94 %) than STR group (66 %), the 10-year RFSs showed no significant difference between GRT and STR groups (p = 0.719). Recurrent seizures are often related to recurrent tumor.

CONCLUSION

Lesionectomy alone often provides a high-rate seizure freedom. GGs and DNTs are benign tumor, but recurrences of GGs and DNTs are not uncommon. They may show late recurrences in spite of GTR. These patients need longer follow-up for 10 years. Recurrent seizures are often related to a tumor recurrence.