Outcome after corpus callosotomy in children with injurious drop attacks and severe mental retardation

Disconnection Methods in the Surgical Treatment of Epilepsy

Disconnection procedures in epilepsy surgery have become an important tool for the management of multifocal drug-resistant epilepsy. In this chapter, we will review their indications, describe the technical procedures, and review outcome data in the literature. Among the curative approaches, anterior quadrant disconnection, posterior quadrant (PQ) disconnection, and functional hemispherectomy can be performed for patients whose epileptic focus resides in one hemisphere or one quadrant. Seizure freedom rates from these procedures range from 50 to 81% for anterior quadrant disconnections, 50 to 92% for PQ disconnections, and 43 to 93% for hemispherectomy. Although typically performed in the pediatric population, data suggest that carefully selected adult patients could also benefit from a disconnection procedure. Of the palliative approaches, corpus callosotomy has been shown to be effective for drop attacks, resulting in significant improvement in seizure frequency, severity, and quality of life. Minimally invasive alternatives to standard open corpus callosotomies with laser interstitial thermal therapy (LITT) have been proposed. Overall, surgical disconnection procedures are an effective way of treating multifocal epilepsy, with good outcomes that can improve the quality of life for these patients.

Influence of extent and age at corpus callosotomy on seizure outcomes. A single center experience

Corpus callosotomy (CC) is a palliative treatment for drop seizures in patients with drug-resistant nonlocalizable epilepsy. We compared drop seizure outcomes between patients undergoing anterior CC versus complete CC and examined factors impacting outcomes for drop seizures including age at CC and duration of epilepsy. A retrospective review of patients who underwent CC between 2003 and 2022 with a minimum of 6 months postsurgical follow-up was included. Outcome measure for drop seizures included seizure reduction ≥50% from baseline as well as elimination of drop seizures. Thirty-eight patients were included. Overall, ≥50% reduction in drop seizures occurred in nearly 70% (23 out of 33) patients with complete elimination in 58% (19 out of 33). Compared with anterior CC (n = 13), patients undergoing complete CC (n = 25) had increased likelihood of ≥50% reduction (p = 0.006) or elimination (p = 0.024) of drop seizures. Regression analysis showed that complete CC was the primary predictor for improved drop seizure outcomes (elimination, p = 0.014 or ≥50% reduction, p = 0.006), while age at CC and duration of epilepsy did not impact the outcomes. Compared to anterior CC, complete CC was significantly more likely to lead to improvement/freedom from drop seizures. Age at CC or duration of epilepsy did not influence drop seizure outcomes.

The clinical features of patients with seizure freedom and failure after total corpus callosotomy for childhood-onset refractory epilepsy

BACKGROUND

Corpus callosotomy is a palliative surgery for medically refractory epilepsy. We aim to analyze the clinical features of patients with seizure freedom and failure after total corpus callosotomy for childhood-onset refractory epilepsy.

METHODS

We retrospectively reviewed the clinical courses of patients with childhood-onset refractory epilepsy undergoing total corpus callosotomy between May 2009 and March 2019. Seizure outcome at the last follow-up was the primary outcome. The clinical features of patients with seizure freedom and failure after callosotomy were compared.

RESULTS

Eighty patients with childhood-onset refractory epilepsy underwent total corpus callosotomy; 15 (18.8%) obtained freedom from all seizures and 19 (23.8%) had unworthwhile improvement and failure. The mean ages at seizure onset in patients with seizure freedom and failure after callosotomy were 5.7 and 5.9 years; and mean seizure durations were 9.4 and 11.5 years, respectively. Univariate analysis found epilepsy syndrome (p = 0.047), mental retardation (p = 0.007), previous medical history (p = 0.004), ≥10 seizures per day (p = 0.024), theta waves in the background electroencephalogram (p = 0.024), and acute postoperative seizure (p = 0.000) were associated with failure after callosotomy. Seizure freedom after callosotomy was more common among patients with less than 10 seizures per day.

CONCLUSIONS

Total corpus callosotomy is an effective palliative procedure for childhood-onset refractory epilepsy, particularly for patients with specific clinical characteristics. Callosotomy has a high seizure-free rate in well-selected patients.

Long-term follow-up seizure outcomes after corpus callosotomy: A systematic review with meta-analysis

BACKGROUND

Corpus callosotomy (CC) is appropriate for patients with seizures of a bilateral or diffuse origin, or those with seizures of a unilateral origin with rapid spread to the contralateral cerebral hemisphere. The efficiency of CC in patients with drug-resistant epilepsy is a long-term concern because most articles reporting the surgical results of CC arise from small case series, and the durations of follow-up vary.

METHODS

PubMed, Embase, Cochrane Library, and Web of Science were searched to identify papers published before November 8, 2021. The systematic review was completed following PRISMA guidelines. Outcomes were analyzed by meta-analysis of the proportions.

RESULTS

A total of 1644 patients with drug-resistant epilepsy (49 retrospective or prospective case series studies) underwent CC, and the follow-up time of all patients was at least 1 year. The rate of complete seizure freedom (SF) was 12.38% (95% confidence interval [CI], 8.17%-17.21%). Meanwhile, the rate of complete SF from drop attacks was 61.86% (95% CI, 51.87%-71.41%). The rates of complete SF after total corpus callosotomy (TCC) and anterior corpus callosotomy (ACC) were 11.41% (95% CI, 5.33%-18.91%) and 6.75% (95% CI, 2.76%-11.85%), respectively. Additionally, the rate of complete SF from drop attacks after TCC was significantly higher than that after ACC (71.52%, 95% CI, 54.22%-86.35% vs. 57.11%, 95% CI, 42.17%-71.49%). The quality of evidence for the three outcomes by GRADE assessment was low to moderate.

CONCLUSION

There was no significant difference in the rate of complete SF between TCC and ACC. TCC had a significantly higher rate of complete SF from drop attacks than did ACC. Furthermore, CC for the treatment of drug-resistant epilepsy remains an important problem for further investigation because there are no universally accepted standardized guidelines for the extent of CC and its benefit to patients. In future research, we will focus on this issue.

Corpus Callosotomy Is a Safe and Effective Procedure for Medically Resistant Epilepsy

Corpus callosotomy (CC) is an effective surgical treatment for medically resistant generalized or multifocal epilepsy (MRE). The premise of CC extrapolates from the observation that the corpus callosum is the predominant commissural pathway that allows spread and synchroneity of epileptogenic activity between the hemispheres. Candidacy for CC is typically reserved for patients seeking palliative epilepsy treatment with the goal of reducing the frequency of drop attacks, although reduction of other seizure semiologies (absence, complex partial seizures, and tonic-clonic) has been observed. A reduction in morbidity affiliated with evolution of surgical techniques to perform CC has improved the safety profile of the procedure without necessarily sacrificing efficacy.

Retrospective Clinical Analysis of Epilepsy Treatment for Children with Drug-Resistant Epilepsy (A Single-Center Experience)

Objectives: This retrospective cohort study investigated the clinical characteristics and seizure outcomes of patients aged 1−14 years with drug-resistant epilepsy (DRE) who were treated by different typologies of therapy. Methods: Four hundred and eighteen children with DRE were recruited from Sanbo Brain Hospital of Capital Medical University from April 2008 to February 2015. The patients were divided into three groups: medication (n = 134, 32.06%), resection surgery (n = 185, 44.26%), and palliative surgery (n = 99, 23.68%) groups. Demographic characteristics were attained from medical records. All patients were followed up for at least 5 years, with seizure outcomes classified according to International League Against Epilepsy criteria. The psychological outcome was evaluated with the development quotient and Wechsler Intelligence Quotient Scale for children (Chinese version). Results: The most frequent seizure type was generalized tonic seizure in 53.83% of patients. Age at seizure onset in 54.55% of patients was <3 years. The most frequent etiologies were focal cortical dysplasia (FCD). West syndrome was the most common epilepsy syndrome. Favorable seizure outcomes at the 5-year follow-up in the medication, resection surgery, and palliative surgery groups were 5.22%, 77.30%, and 14.14%, respectively. The patients showed varying degrees of improvement in terms of developmental and intellectual outcomes post-treatment. Conclusions: Pediatric patients with DRE were characterized by frequent seizures, a variety of seizure types, and complex etiology. Recurrent seizures severely affected the cognitive function and development of children. Early surgical intervention would be beneficial for seizure control and prevention of mental retardation. Palliative surgery was also a reasonable option for patients who were not suitable candidates for resection surgery.

MRI-guided stereotactic laser corpus callosotomy for epilepsy: distinct methods and outcomes

OBJECTIVE

Several small series have described stereotactic MRI-guided laser interstitial thermal therapy for partial callosotomy of astatic and generalized tonic-clonic (GTC) seizures, especially in association with Lennox-Gastaut syndrome. Larger case series and comparison of distinct stereotactic methods for stereotactic laser corpus callosotomy (SLCC), however, are currently lacking. The objective of this study was to report seizure outcomes in a series of adult patients with epilepsy following anterior, posterior, and complete SLCC procedures and to compare the results achieved with a frameless stereotactic surgical robot versus direct MRI guidance frames.

METHODS

The authors retrospectively reviewed sequential adult epilepsy surgery patients who underwent SLCC procedures at a single institution. They describe workflows, stereotactic errors, percentage disconnection, hospitalization durations, adverse events, and seizure outcomes after performing anterior, posterior, and complete SLCC procedures using a frameless stereotactic surgical robot versus direct MRI guidance platforms.

RESULTS

Thirteen patients underwent 15 SLCC procedures. The median age at surgery was 29 years (range 20-49 years), the median duration of epilepsy was 21 years (range 9-48 years), and median postablation follow-up was 20 months (range 4-44 months). Ten patients underwent anterior SLCC with a median 73% (range 33%-80%) midsagittal length of callosum acutely ablated. Following anterior SLCC, 6 of 10 patients achieved meaningful (> 50%) reduction of target seizures. Four patients underwent posterior (completion) SLCC following prior anterior callosotomy, and 1 patient underwent complete SLCC as a single procedure; 3 of these 5 patients experienced meaningful reduction of target seizures. Overall, 8 of 10 patients in whom astatic seizures were targeted and treated by anterior and/or posterior SLCC experienced meaningful improvement. SLCC procedures with direct MRI guidance (n = 7) versus a frameless surgical robot (n = 8) yielded median radial accuracies of 1.1 mm (range 0.2-2.0 mm) versus 2.4 mm (range 0.6-6.1 mm; p = 0.0011). The most serious adverse event was a clinically significant intraparenchymal hemorrhage in a patient who underwent the robotic technique.

CONCLUSIONS

This is the largest reported series of SLCC for epilepsy to date. SLCC provides seizure outcomes comparable to open surgery outcomes reported in the literature. Direct MRI guidance is more accurate, which has the potential to reduce the risks of SLCC. Methodological advancements and larger studies are needed.

Comparison of seizure outcomes and ADL recovery period after total or anterior corpus callosotomy in adolescent and young adults with drop attacks and severe mental retardation

PURPOSE

The aim of this study was to evaluate seizure outcomes and postoperative neurologic complications, with an emphasis on the recovery period of activities of daily living (ADL) between anterior partial corpus callosotomy (ACC) and total corpus callosotomy (TCC) in adolescent and young adults with drop attacks and severe mental retardation.

METHODS

We retrospectively reviewed the clinical records of consecutive patients with intractable epilepsy who underwent corpus callosotomy (CC) for drop attacks between 2010 and 2019 in the Department of Neurosurgery, Hiroshima University hospital, with a minimum follow-up of one year. Inclusion criteria of this study were 1) age at surgery: 11-39 years, 2) preoperative intelligence quotient <35, and 3) preoperative Barthel index (BI) ≥30. Postoperative full ADL recovery was defined as complete recovery to the preoperative BI score. We compared the postoperative days required for 1) recovery of oral intake ability, 2) discharge from our hospital, 3) returning home from any hospital, 4) returning home with full ADL recovery, and 5) seizure outcomes in patients with ACC versus those with one-stage TCC.

RESULTS

Ten patients with ACC and 14 patients with one-stage TCC met the inclusion criteria. The period for returning home with full ADL recovery was a median of 15 days (range 9-45 days) after ACC, while the median was 21.5 days (range 10-62 days) after one-stage TCC (p = 0.2904). Although there was a tendency for the ADL recovery period to be longer after one-stage TCC, there were no statistically significant differences in any category of ADL recovery period. Eleven of 14 (78.6 %) patients who received a one-stage TCC showed favorable seizure outcomes, with drop attack cessation, which was significantly better than 1 of 10 (10 %) patients with ACC (p = 0.0009).

CONCLUSIONS

From the viewpoint of postoperative seizure outcomes and ADL recovery period, one-stage TCC is preferred to ACC for adolescent and young adults with severe mental retardation.

Developmental outcome after corpus callosotomy for infants and young children with drug-resistant epilepsy

AIM

To examine the developmental and seizure outcomes after corpus callosotomy (CC) in early childhood.

METHODS

We retrospectively identified 106 patients who underwent CC for drug-resistant epilepsy before the age of 6 years, at the Nagasaki Medical Center, between July 2002 and July 2016. Patients' developmental outcomes were evaluated one year after CC using the Kinder Infant Development Scale.

RESULTS

The mean preoperative developmental quotient (DQ) was 25.0 (standard deviation [SD], 20.8), and the mean difference between preoperative DQ and one-year postoperative DQ was -1.6 points (SD, 11.6). However, 42.5% of patients had a mean DQ increase of 6.5 points (SD, 6.4), one year after CC from that before surgery. Factors related to the improvement in postoperative DQ were 'low preoperative DQ', 'developmental gain 1 month postoperatively', and 'postoperative seizure-free state'. Approximately 21.7% of patients were seizure-free 1 year after CC.

INTERPRETATION

Performing CC, in infancy and early childhood for patients with drug-resistant epilepsy and severe developmental impairment, was associated with improved development in 42.5% of patients. Remission of seizures, even if only for a short period, contributed to developmental improvement. From a developmental perspective, CC for drug-resistant epilepsy in early childhood is an effective treatment.

Atonic seizures in children: a meta-analysis comparing corpus callosotomy to vagus nerve stimulation

PURPOSE

Atonic seizures are associated with a particularly poor response to medical treatment. We performed a systematic review and meta-analysis to compare the efficacy of corpus callosotomy (CC) and vagus nerve stimulation (VNS) in the management of atonic seizures in the pediatric population.

METHODS

A literature search was performed in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and recommendations, focusing on atonic seizures, CC, and VNS in pediatric populations. Pertinent clinical data were extracted and analyzed. Pooled effects between groups were calculated as standardized error (SE) with 95% confidence intervals (CIs). To assess for statistical significance, the Z-test was performed, using the pooled effect size (ES) and 95% CI for each intervention.

RESULTS

A total of 31 studies met the inclusion criteria, with 24 studies encompassing 425 children treated with CC and 7 studies encompassing 108 children treated with VNS. Twenty-four studies were included in a meta-analysis. There was a statistically significant difference in the primary outcome of atonic seizure control in favor of CC (overall effect size (ES) 0.73, 95% CI 0.69-0.77 for CC, ES 0.4, 95% CI 0.28-0.51 for VNS, p = 0.003). There was a higher rate of complications requiring reoperation in the CC cohort (6.6% vs. 3.8%) and a 14% rate of symptomatic disconnection syndrome.

CONCLUSIONS

While both techniques are safe, CC provides a much higher chance of effectively managing this morbid seizure type albeit with a higher risk of re-operation and disconnection syndrome.

Endoscopic Interhemispheric Disconnection for Intractable Multifocal Epilepsy: Surgical Technique and Functional Neuroanatomy

BACKGROUND

Callosotomy represents a palliative procedure for intractable multifocal epilepsy. The extent of callosotomy and the benefits of adding anterior and posterior commissurotomy are debated.

OBJECTIVE

To describe a new technique of a purely endoscopic procedure to disconnect the corpus callosum, the anterior, posterior, and habenular commissures through the use of a single burr hole via a transfrontal transventricular route.

METHODS

Our surgical series was retrospectively reviewed in terms of seizure control (Engel's class) and complication rate. Five cadaveric specimens were used to demonstrate the surgical anatomy of commissural fibers and third ventricle.

RESULTS

The procedure may be divided into 3 steps: (1) endoscopic transventricular transforaminal anterior commissure disconnection; (2) disconnection of posterior and habenular commissures; and (3) total callosotomy. Fifty-seven patients were included in the analysis. A favorable outcome in terms of epilepsy control (Engel class 1 to 3) was found in 71.4% of patients undergoing callosotomy coupled with anterior, posterior, and habenular commissure disconnection against 53% of patients with isolated callosotomy (P = .26). Patients with drop attacks had better epilepsy outcome independently from the surgical procedure used.

CONCLUSION

The full endoscopic callosotomy coupled with disconnection of anterior, posterior and habenular commissures is a safe alternative to treat multifocal refractory epilepsy. A gain in seizure outcome might be present in this cohort of patients treated with total interhemispheric disconnection when compared with isolated callosotomy. Larger studies are required to confirm these findings.

Rates and predictors of seizure outcome after corpus callosotomy for drug-resistant epilepsy: a meta-analysis

OBJECTIVE

Corpus callosotomy is a palliative surgery for drug-resistant epilepsy that reduces the severity and frequency of generalized seizures by disconnecting the two cerebral hemispheres. Unlike with resection, seizure outcomes remain poorly understood. The authors systematically reviewed the literature and performed a meta-analysis to investigate rates and predictors of complete seizure freedom and freedom from drop attacks after corpus callosotomy.

METHODS

PubMed, Web of Science, and Scopus were queried for primary studies examining seizure outcomes after corpus callosotomy published over 30 years. Rates of complete seizure freedom or drop attack freedom were recorded. Variables showing a potential relationship to seizure outcome on preliminary analysis were subjected to formal meta-analysis.

RESULTS

The authors identified 1742 eligible patients from 58 included studies. Overall, the rates of complete seizure freedom and drop attack freedom after corpus callosotomy were 18.8% and 55.3%, respectively. Complete seizure freedom was significantly predicted by the presence of infantile spasms (OR 3.86, 95% CI 1.13-13.23), normal MRI findings (OR 4.63, 95% CI 1.75-12.25), and shorter epilepsy duration (OR 2.57, 95% CI 1.23-5.38). Freedom from drop attacks was predicted by complete over partial callosotomy (OR 2.90, 95% CI 1.07-7.83) and idiopathic over known epilepsy etiology (OR 2.84, 95% CI 1.35-5.99).

CONCLUSIONS

The authors report the first systematic review and meta-analysis of seizure outcomes in both adults and children after corpus callosotomy for epilepsy. Approximately one-half of patients become free from drop attacks, and one-fifth achieve complete seizure freedom after surgery. Some predictors of favorable outcome differ from those in resective epilepsy surgery.

Neurosurgical approaches to pediatric epilepsy: Indications, techniques, and outcomes of common surgical procedures

Epilepsy is a common pediatric neurological condition, and approximately one-third of children with epilepsy are refractory to medical management. For these children neurosurgery may be indicated, but operative success is dependent on complete delineation of the epileptogenic zone. In this review, surgical techniques for pediatric epilepsy are considered. First, potentially-curative operations are discussed and broadly divided into resections and disconnections. Then, two palliative approaches to seizure control are reviewed. Finally, future neurosurgical approaches to epilepsy are considered.

Clinical profiles for seizure remission and developmental gains after total corpus callosotomy

PURPOSE

This study was aimed to determine what preoperative profiles were associated with seizure remission after corpus callosotomy and whether such seizure outcome was associated with the postoperative developmental outcome.

METHODS

This retrospective study included 26 consecutive patients with childhood onset epilepsy who underwent one-stage total corpus callosotomy at our institution and were followed up for a minimum of 1 year. The age at surgery ranged from 13 months to 32 years (median 6 years). The association between postoperative seizure freedom and preoperative profiles, post-operative developmental gains was examined.

RESULTS

Five patients achieved seizure freedom (Engel class I), and 10 patients achieved worthwhile reduction of seizures (class III), whereas the remaining patients had a class IV outcome. All five seizure-free patients had "lack of abnormal magnetic resonance imaging findings", "lack of proven etiology of seizures", and underwent "surgery at age 6 years or younger". These three factors were associated with seizure freedom (p<0.05, Fisher exact test). Post-operative gains in developmental quotient were significantly better in patients with seizure freedom than in those without (p<0.05, Mann Whitney U test).

CONCLUSION

Our study replicated the notion that seizure remission can be achieved after total corpus callosotomy in subsets of patients with medically-uncontrolled epilepsy, and suggested that a better developmental outcome can be expected in patients benefiting from seizure freedom.

Callosotopy: leg motor connections illustrated by fiber dissection

Precise anatomical knowledge of the structure of the corpus callosum is important in split-brain research and during neurosurgical procedures sectioning the callosum. According to the classic literature, commissural fibers connecting the motor cortex are situated in the anterior part of the corpus callosum. On the other hand, more recent imaging studies using diffusion tensor imaging indicate a more posterior topography of callosal fibers connecting motor areas. Topographical knowledge is especially critical when performing disconnective callosotomies in epilepsy patients who experience sudden loss of leg motor control, so-called epileptic drop attacks. In the current study, we aim to precisely delineate the topography of the leg motor connections of the corpus callosum. Of 20 hemispheres obtained at autopsy, 16 were dissected according to Klingler's fiber dissection technique to study the course and topography of callosal fibers connecting the most medial part of the precentral gyrus. Fibers originating from the anterior bank of the central sulcus were invariably found to be located in the isthmus of the corpus callosum, and no leg motor fibers were found in the anterior part of the callosum. The current results suggest that the disconnection of the pre-splenial fibers, located in the posterior one-third of the corpus callosum, is paramount in obtaining a good outcome after callosotomy.

Endoscopic-Assisted (Through a Mini Craniotomy) Corpus Callosotomy Combined With Anterior, Hippocampal, and Posterior Commissurotomy in Lennox-Gastaut Syndrome

BACKGROUND:

Corpus callosotomy is a palliative procedure especially for Lennox-Gastaut semiology without localization with drop attacks.

OBJECTIVE:

To describe endoscopic-assisted complete corpus callosotomy combined with anterior, hippocampal, and posterior commissurotomy.

METHODS:

Patients with drug refractory epilepsy having drop attacks as the predominant seizure type, bilateral abnormalities on imaging, and moderate to severe mental retardation were included. All underwent a complete workup (including magnetic resonance imaging).

RESULTS:

Patients (n = 16, mean age 11.4 ± 6.4 years, range 6-19 years) had a mean seizure frequency of 24.5 ± 19.8/days (range 1-60) and a mean intelligence quotient of 25.23 ± 10.71. All had syndromic diagnosis of Lennox-Gastaut syndrome, with the following etiologies: hypoxic insult (10), lissencephaly (2), bilateral band heterotropia (2), and microgyria and pachygyria (2). Surgery included complete callosotomy and the section of anterior and posterior commissure by microscopic approach through a mini craniotomy (11) and endoscopic-assisted approach (5). Complications included meningitis (1), hyperammonemic encephalopathy (2), and acute transient disconnection (5). There was no mortality or long-term morbidity. Mean follow-up was 18 ± 4.7 months (range 16-27 months). Drop attacks stopped in all. Seizure frequency/duration decreased &gt;90% in 10 patients and &gt;50% in 5 patients, and increased in 1 patient. All patients attained presurgical functional levels in 3 to 6 months. Child behavior checklist scores showed no deterioration. Parental questionnaires reported 90% satisfaction attributed to the control of drop attacks. The series was compared retrospectively with an age/sex-matched cohort (where a callosotomy only was performed), and showed better outcome for drop attacks (P &lt; .003).

CONCLUSION:

This preliminary study demonstrated the efficacy and safety of complete callosotomy with anterior, hippocampal, and posterior commissurotomy in Lennox-Gastaut syndrome (drop attacks) with moderate to severe mental retardation.

Long-term seizure and behavioral outcomes after corpus callosotomy

Outcomes of corpus callosotomy (CC) have been mainly focused on seizures. The present study aimed to evaluate the long-term effects of CC on adaptive behaviors and caregivers' satisfaction in addition to seizures and to identify clinical predictors of postsurgical outcomes. Medical records of 26 patients (mean age at study time: 40 years, mean follow-up: 14 years) with childhood-onset epilepsy who underwent anterior or 2-stage complete CC were reviewed. A structured questionnaire was submitted to caregivers asking about relative changes in different seizure types, behavioral functions, and satisfaction with the postoperative outcomes. Formal neuropsychological assessment was carried out in a subgroup of patients. Selected clinical variables including age at surgery, extent of callosal section, length of follow-up, epilepsy syndrome, and presurgical cognitive level were submitted to multiple regression analysis. At the last follow-up visit, a reduction greater than 50% was observed mainly for drop attacks (65% of patients), followed by generalized tonic-clonic seizures (53%), and complex partial seizures (50%). No presurgical variables were significantly associated with seizure outcome. After surgery, more than half of patients showed attention enhancement, which was related to drop seizure improvement. Early age at surgery was associated with better behavioral regulation; complete CC slightly worsened language abilities. Satisfaction with surgery outcomes was expressed by 73% of caregivers and was dependent on drop seizure reduction and improvements in activities of daily living. A long-term positive psychosocial outcome is likely after CC also in severely disabled patients, especially if surgery is performed early.

Anterior corpus callosotomy in school-aged children with Lennox-Gastaut syndrome: a prospective study

AIMS

To compare outcomes of anterior corpus callosotomy (CCT) with anti-epileptic drugs (AEDs) treatment in school-aged children with Lennox-Gastaut syndrome (LGS).

METHODS

Sixty school-aged children with LGS were prospectively enrolled and divided into either the medicine or surgery group according the choice of the patients' caregivers. Cases in the medicine group were treated with multiple rational AEDs and patients in the surgery group underwent anterior CCT. Seizure control at 1-5 years after enrollment and changes of intelligence quotient (IQ) and quality of life (QOL) from pre-treatment to the 2-year follow-up were compared between the two groups.

RESULTS

The percentages of patients who were totally seizure-free in the surgery group were 17.4% at the 1-year follow-up, 13.0% at the 2-year follow-up and 8.7% at the 5-year follow up, and the data for patients in the medicine group were 2.9%, 5.9% and 2.9%, respectively. Significant differences were found in total seizure control between the two groups at 1, 2, and 5-year follow-up (personal χ2 test). Significant differences were found in mean changes of IQ and overall QOL between the medicine and surgery groups at the 2-year follow-up, showing positive results for the surgery group, but these changes were not related to postoperative outcomes of seizure control (t-test).

CONCLUSION

Anterior CCT is a promising treatment for school-aged children with LGS, and can present marked seizure control and improvement in QOL and IQ, all of which were significantly better than the effects of treatment with multiple AEDs.

Outcome after anterior callosal section that spares the splenium in pediatric patients with drop attacks

We report on the efficacy and safety of extended, one-stage anterior callosal section that spares the splenium, which is performed in a large series of pediatric patients with drop attacks. Twenty-nine pediatric patients with drop attacks were studied (19 males and 10 females; mean age: 9.9 years). As presurgical factors, the age at surgery, age at seizure onset, age at drop attack onset, sex, hemiparesis, severe mental retardation, electroencephalograph abnormalities, magnetic resonance imaging abnormalities, and (18)fluorodeoxyglucose positron emission tomography abnormalities were analyzed. All patients had multiple seizure types, including drop attacks, atypical absence seizures, complex partial seizures, tonic seizures, and generalized tonic-clonic seizures. All patients were developmentally impaired and had electroencephalograph results showing marked secondary bilateral synchrony. All patients received an extended, one-stage callosal section, leaving only the splenium intact. The mean follow-up time was 5.2 years. Seizure outcome (cessation of seizures or ≥ 90% seizure reduction) was achieved in 79.3% of patients with drop attacks. The families assessed the overall daily function as improved in 62.1% of the patients, unchanged in 24.1%, and worse in 13.8%. Family satisfaction with callosotomy was achieved in 82.8% of the patients. The majority of the patients had some degree of a transient acute postoperative disconnection syndrome that disappeared within 3 weeks. Postoperatively, patients showed a consistent increase in attention levels. We conclude that extended callosal sectioning that leaves the splenium intact should be considered a good palliative surgical option for pediatric patients with drop attacks and that diminishment of epileptic discharge synchrony is a good prognostic sign following callosotomy. We also found that the postoperative increase in attention levels was as useful as seizure control in improving the quality of life of these patients.

Surgery for drug-resistant focal epilepsy

During the colloquium on drug-resistant epilepsy (DRE) at National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore on August 16-18, 2013, a number of presentations were made on the surgically remediable lesional epilepsy syndromes, presurgical evaluation, surgical techniques, neuropathology of drug resistance focal epilepsy and surgical outcome. This pictorial essay with the illustrative case examples provides an overview of the various surgical techniques for the management of drug-resistant focal epilepsy.

Long-term follow-up after callosotomy--a prospective, population based, observational study

OBJECTIVE

Analyze the long-term outcome of callosotomies with regard to seizure types and frequencies and antiepileptic drug treatment.

METHODS

This longitudinal observational study is based on data from the prospective Swedish National Epilepsy Surgery Register. Thirty-one patients had undergone callosotomy in Sweden 1995-2007 and had been followed for 2 and 5 or 10 years after surgery. Data on their seizure types and frequencies, associated impairments, and use of antiepileptic drugs have been analyzed.

RESULTS

The median total number of seizures per patient and month was reduced from 195 before surgery to 110 two years after surgery and 90 at the long-term follow-up (5 or 10 years). The corresponding figures for drop attacks (tonic or atonic) were 190 before surgery, 100 2 years after surgery, and 20 at the long-term follow-up. Ten (56%) of the 18 patients with drop attacks were free from drop attacks at long-term follow-up. Three of the remaining eight patients had a reduction of >75%. At long-term follow-up, four were off medication. Only one of the 31 patients had no neurologic impairment.

SIGNIFICANCE

The present population-based, prospective observational study shows that the corpus callosotomy reduces seizure frequency effectively and sustainably over the years. Most improvement was seen in drop attacks. The improvement in seizure frequency over time shown in this study suggests that callosotomy should be considered at an early age in children with intractable epilepsy and traumatizing drop attacks.

Corpus callosum and epilepsies

Introduction.Corpus callosum (CC) is the largest forebrain commissure. Structural anomalies and accompanying clinical symptoms are not in the focus of neurologists, epileptologists or neurosurgeons.

Aim and method.Anatomy, embryological development, normal functions, structural abnormalities, additional malformations, clinical symptoms and seizure disorders with CC anomalies are reviewed from the literature.

Review.The detection of callosal anomalies increased rapidly with widespread use of brain imaging methods. Agenesis or dysgenesis of corpus callosum (AgCC) might be considered an accidental finding. Epileptic seizures occur in up to 89% of patients with AgCC. The causal relationship correctly is questioned. However, additional causative malformations of midline and/or telencephalic structures can be demonstrated in most seizure patients. The interruption of bilateral spread of seizure activities acts as the concept for callosotomy as epilepsy surgery. Indications are drug-resistant generalized, diffuse, or multifocal epilepsies. A resectable seizure onset zone should be excluded. Most treated patients are diagnosed as Lennox-Gastaut or Lennox-like syndrome.

Conclusions.In cases with callosal abnormalities and clinical symptoms additional malformations are frequently observed, especially with seizure disorders. Callosotomy is the most effective option against drop attacks. The method probably is underused. After callosotomy a circumscript seizure focus might be unveiled and a second step of resective epilepsy surgery can be successful.

Surgical treatment of pediatric epileptic encephalopathies

Pediatric epileptiform encephalopathies are a group of neurologically devastating disorders related to uncontrolled ictal and interictal epileptic activity, with a poor prognosis. Despite the number of pharmacological options for treatment of epilepsy, many of these patients are drug resistant. For these patients with uncontrolled epilepsy, motor and/or neuropsychological deterioration is common. To prevent these secondary consequences, surgery is often considered as either a curative or a palliative option. Magnetic resonance imaging to look for epileptic lesions that may be surgically treated is an essential part of the workup for these patients. Many surgical procedures for the treatment of epileptiform encephalopathies have been reported in the literature. In this paper the evidence for these procedures for the treatment of pediatric epileptiform encephalopathies is reviewed.

Outcomes After Anterior or Complete Corpus Callosotomy in Children

BACKGROUND:

Corpus callosotomy (CC) is a valuable palliative surgical option for children with medically refractory epilepsy due to generalized or multifocal cortical seizure onset.

OBJECTIVE:

To investigate the extent of CC resulting in optimal seizure control in a pediatric patient population and to evaluate the modification of seizure profile after various CC approaches.

METHODS:

The records of 58 children (3–22 years of age at the time of surgery) with medically refractory epilepsy who underwent CC between 1995 and 2011 were retrospectively reviewed.

RESULTS:

Anterior two thirds callosotomy resulted in resolution of absence (P = .03) and astatic (P = .03) seizures, whereas anterior two thirds callosotomy followed by second-stage completion resulted in resolution of generalized tonic-clonic (GTC) (P = .03), astatic (P = .005), and myoclonic (P = .03) seizures in addition to a trend toward resolution of absence seizures (P = .08). Single-stage upfront complete callosotomy resulted in resolution of absence (P = .002), astatic (P &lt; .0001), myoclonic (P = .007), and complex partial (P = .008) seizures in addition to a trend toward resolution of GTC (P = .06). In comparing a composite of subjects who underwent anterior two thirds callosotomy alone or 2-stage complete callosotomy before the second stage to complete the callosotomy with subjects who underwent upfront complete CC, a more favorable outcome was found in those with the upfront complete CC (P = .02).

CONCLUSION:

Single-stage upfront complete callosotomy is effective in relieving a broader spectrum of seizure types than anterior two thirds callosotomy or 2-stage complete callosotomy in children. The advantages of single-stage complete callosotomy must be weighed against the potentially higher risk of neurological and operative complications.

Critical review of palliative surgical techniques for intractable epilepsy

Approximately one third of epilepsy patients are not adequately treatable by antiepileptic medication. Curative resective epilepsy surgery can be performed in only a subgroup of these pharmacoresistent patients in whom the epileptogenic focus is localizable and does not overlap with eloquent brain areas. To the remaining patients (with bilateral or multiple epileptogenic foci, with epilepsy onset in eloquent areas, or with no identifiable epileptogenic focus) palliative epilepsy surgery can be offered if they suffer from disabling seizures. Standard palliative procedures currently comprise corpus callosotomy, multiple subpial transections, and vagus nerve stimulation. New approaches such as focus distant deep brain stimulation or direct stimulation of the hippocampus have gained the most interest. Feasibility studies, small pilot studies, and, recently, larger multicenter trials showed that direct brain stimulation shall be considered a potential helpful procedure in the field of palliative surgery. Moreover, with the increasing use of stereo-EEG in invasive video-EEG monitoring, stereo-EEG-guided thermocoagulation has the potential for a promising new treatment option in patients not amenable to resective epilepsy surgery. There is no general consensus on which palliative procedure is most effective in patients with difficult-to-treat epilepsy syndromes. The decision must be based on individual factors of a given patient. This review summarizes experience with palliative approaches collected in adult and pediatric patient series over the past decades and may help to thoroughly balance beneficial effects and risks of each procedure.

Outcome of corpus callosotomy in adults

We present, to our knowledge, the first published series of corpus callosotomy (CC) in adults with medically intractable symptomatic generalized epilepsy (SGE). Fifteen adults were followed for the outcome measures of seizure and antiepileptic drug (AED) burden and quality of life (QoL). Five (33%) patients reported >60%, one (7%) reported between 30 and 60%, and nine (60%) reported <30% reduction in the total number of seizures after CC. Seven (47%) patients reported >60%, three (20%) experienced between 30 and 60%, and five (33%) reported <30% atonic seizure reduction. Twelve patients had no change in AED burden. Nine (60%) patients had no change in QoL, while six (40%) reported some improvement. Corpus callosotomy should be considered as a safe option for adults with medically intractable SGE with demonstrated reduction in the frequency of atonic seizures, and some patients experience a meaningful improvement in quality of life.

Pediatric epilepsy surgery

Whereas there is no specific neurosurgical technique in pediatric epilepsy, the frequency of each type of surgery is very different from epilepsy surgery applied in adults, and reflects the underlying etiologies, which are much more diverse in children, with malformations of cortical development and tumors as the prevailing etiologies. Extensive resective or disconnective procedures for extratemporal epilepsy are more frequently performed in infants and younger children, whereas temporo-mesial resection is by far the most common surgical treatment for adults with epilepsy. More recently, less invasive techniques in children with an extensive epileptogenic zone, such as multilobar disconnection, hemispherotomy and other functional hemispherectomy variants, have been introduced in order to reduce duration of surgery, perioperative morbidity and length of hospital stay. Likewise, minimally invasive techniques are utilized, such as the endoscopic disconnection of hypothalamic hamartomas for gelastic epilepsy. This development has been encouraged with the introduction of image-guided navigation systems for the preoperative planning and during surgery. Historically, epilepsy surgery for children has been established much later than for adults. Apart from the particular aspects in perioperative management of younger infants, surgery-related morbidity as well as seizure outcome is in general similar to those in adults, depending rather on each type of surgery.

Predictive value of electroencephalography for seizure outcome following corpus callosotomy in children

Background and Purpose:

This study aimed to determine whether preoperative or postoperative electroencephalography (EEG) can predict surgical outcome for corpus callosotomy.

Methods:

We retrospectively reviewed the medical records of 16 patients enrolled. We compared postoperative seizure outcome according to seizure type, preoperative interictal EEG, preoperative ictal EEG, and postoperative interictal EEG. Seizure outcome was classified according to postoperative seizure reduction, i.e., seizure free, >90%, 50–90%, <50%, and no change or worsened. A seizure reduction of 50% or more was judged as a “favorable outcome”.

Results:

Most patients showed a favorable outcome (12 patients, 75%) and two patients became seizure free (13%). Atonic seizure was most responsive to corpus callosotomy. Preoperative interictal epileptiform discharge had 3 patterns; bilateral independent, generalized, and combination of independent and generalized. None of the preoperative interictal epileptiform discharge (EDs) had significant correlation with seizure outcome. The preoperative ictal rhythm did not predict seizure outcome. However disappearance of generalized EDs on postoperative EEG was correlated with favorable seizure outcome.

Conclusions:

The presence of generalized EDs on postoperative interictal EEG predicted seizure outcome, whereas preoperative EEG did not.

Pediatric epilepsy: The Indian experience

Epilepsy is a common clinical entity in neurology clinics. The understanding of the genetics of epilepsy has undergone a sea change prompting re-classification by the International league against epilepsy recently. The prevalence rates of epilepsy in India are similar to those of developed nations. However, the large treatment gap is a major challenge to our public health system. Perinatal injuries are a major causative factor in pediatric group. We have discussed a few common etiologies such as neurocysticercosis and newer genetic epilepsy syndromes. We have also briefly touched upon the Indian experience in pediatric epilepsy surgery.

Extraventricular corpus callosotomy

Corpus callosotomy offers useful palliation for selected patients with medically intractable seizures, particularly those with uncontrolled and disabling drop attacks. Here the authors present their technique for performing a corpus callosotomy that allows for complete sectioning of the callosum while avoiding entry into the lateral ventricles. The anatomical basis for the technique is the presence of a definable cleft just ventral to the corpus callosum in the midline, formed by the fusion of the two laminae of the septum pellucidum. This small cleft is typically present even in the absence of a cavum septum pellucidum on MR imaging. The authors have found that dividing the body of the corpus callosum by exploiting the cleft of the septum pellucidum in the absolute midline is a simple and expeditious way to perform a callosotomy without entering the lateral ventricles.

Presidential oration: the 18 annual conference of the Indian academy of neurology, trichi, Tamil Nadu, september 24-26, 2010, epilepsy care in developing countries

Nearly 80% of the 50 million people with epilepsy worldwide reside in developing countries that are least equipped to tackle the enormous medical, social and economic challenges posed by epilepsy. These include widespread poverty, illiteracy, inefficient and unevenly distributed health care systems, and social stigma and misconceptions associated with epilepsy. Several studies have reported that a large proportion of patients with epilepsy in developing countries never receive appropriate treatment for their condition, and many, though diagnosed and initiated on treatment, soon discontinue treatment. Unaffordable cost of treatment, unavailability of antiepileptic drugs, and superstitious and cultural beliefs contribute to high epilepsy treatment gap in resource-poor countries. A significant proportion of the current burden of epilepsy in developing countries can be minimized by educating the public about the positive aspects of life with epilepsy and the primary and secondary physicians about current trends in the management of epilepsies, scaling up routine availability of low-cost antiepileptic drugs, and developing cost-effective epilepsy surgery programs.

Endoscopic total corpus callosotomy: cadaveric demonstration of a new approach

BACKGROUND

Callosotomy is a surgical option for treatment of a small number of patients with intractable seizures who are not candidates for surgical resection. The procedure is done conventionally with the aid of a microscope. In this article, we describe a new technique of endoscopic callosotomy through a parasagittal burr hole in a cadaveric model.

METHODS

We utilized this technique with a single frontal burr hole. Callosotomies were performed on 4 silicon-injected cadaver heads in our minimally invasive neurosurgical laboratory.

RESULTS

We were able to successfully perform total callosotomies in all cadaveric specimens without injury to the adjacent neurovascular structures. The advantages of our technique over microsurgery are the minimally invasive nature of the exposure and the improved visualization of the vascular structures near the rostrum and genu of the corpus callosum. A potential disadvantage we anticipate is the difficulty controlling bleeding in the event of vascular injury.

CONCLUSION

We believe that this minimally invasive approach could have potential clinical applications.

The effect of surgery in encephalopathy with electrical status epilepticus during sleep

PURPOSE

We analyzed clinical and electroencephalography (EEG) outcomes of 13 patients with pharmacoresistant encephalopathy with electrical status epilepticus during sleep (ESES) following epilepsy surgery.

METHODS

All patients had symptomatic etiology of ESES and preoperative neuropsychological deterioration. Ten patients had daily atypical absences. Clinical outcome was assessed at 6 months and at 2 years after surgery. Clinical and EEG data were reviewed retrospectively. The spike propagation pattern and area and source strength in source montage were analyzed from preoperative and postoperative EEG studies.

KEY FINDINGS

Preoperative sleep EEG showed electrical status epilepticus during sleep (SES) with one-way interhemispheric propagation in nine patients and with two-way interhemispheric propagation in four. The age of the patients at the time of surgery ranged from 3.6-9.9 years. Focal resection (two patients) or hemispherotomy (one patient with postoperative EEG) either terminated SES or restricted the discharge to one region. Either reduced SES propagation area or source strength was found in four of eight callosotomy patients with postoperative EEG. Of patients who had seizures preoperatively, Engel class I-II seizure outcome was observed in two of three children after focal resection or hemispherotomy and in two of eight children after callosotomy. None of these patients with Engel class I-II outcome had SES with two-way interhemispheric propagation on preoperative EEG. Cognitive deterioration was halted postoperatively in all except one patient. Cognitive catch-up of more than 10 IQ points was seen in three patients, all of whom had shown a first measured IQ of >75.

SIGNIFICANCE

Patients with pharmacoresistant ESES based on symptomatic etiology may benefit from resective surgery or corpus callosotomy regarding both seizure outcome and cognitive prognosis.

Anterior temporal lobectomy combined with anterior corpus callosotomy in patients with temporal lobe epilepsy and mental retardation

AIMS

To investigate the surgical outcomes of anterior corpus callosotomy (aCCT) combined with anterior temporal lobectomy (ATL) in patients with intractable temporal lobe epilepsy (TLE) and mental retardation (MR).

METHODS

Sixty patients with TLE and MR were carefully selected and randomly divided into two equal groups: ATL and aCCT, in which they were treated with ATL or ATL combined with aCCT, respectively. Surgical outcomes, including seizure control, IQ and quality of life (QOL) changes, as well as complications were recorded and analyzed 2 years after operation.

RESULTS

Seizure-free status had been achieved in 66.7% of all patients. The aCCT group had higher percentage in Engle Classes I-II than the ATL group (96.7% vs. 80.0%, P<0.05). 56.7% of patients in ATL group and 63.3% in aCCT group had improved full scale IQ (FIQ) after surgery, while the decline of FIQ in aCCT group was less than that of ATL group (3.3% vs. 30.0%). Compared with pre-operative score, the mean post-operative score of performance IQ in aCCT group had improved. Significant difference in QOL change had been found between two groups (P<0.001). 73.7% of patients in aCCT group had their QOL improved with no long-term complications.

CONCLUSIONS

ATL combined with aCCT can improve QOL and performance IQ in patients with TLE and MR.

Centro-median stimulation yields additional seizure frequency and attention improvement in patients previously submitted to callosotomy

RATIONALE

Deep brain stimulation (DBS) has been increasingly used in the treatment of refractory epilepsy over the last decade. We report on the outcome after thalamic centro-median (CM) DBS in patients with generalized epilepsy who had been previously treated with extended callosal section.

METHODS

Four consecutive patients with generalized epilepsy who were previously submitted to callosal section and had at least 1 year of follow-up after deep brain implantation were studied. Age ranged from 19 to 44 years. All patients were submitted to bilateral CM thalamic DBS. Post-operative CT scans documented the electrode position in all patients. All patients had pre- and post-stimulation prolonged interictal scalp EEG recordings, including spike counts. Attention level was evaluated by means of the SNAP-IV questionnaire. The pre-implantation anti-epileptic drug regimen was maintained post-operatively in all patients.

RESULTS

Post-operative CT documented that all electrodes were correctly located. There was no morbidity or mortality. Seizure frequency reduction ranging from 65 to 95% and increased attention level was seen in all patients. Interictal spiking frequency was reduced from 25 to 95%, but their morphology remained the same. There was re-synchronization of interictal discharges during slow-wave sleep in 2 patients.

CONCLUSION

All patients benefit from the procedure. The CM seems to play a role in modulating the epileptic discharges and attention in these patients. On the other hand, it is not the generator of the epileptic abnormality and appeared not to be involved in non-REM sleep-related interictal spiking modulation.

A prospective study on the cost-effective utilization of long-term inpatient video-EEG monitoring in a developing country

To investigate diagnostic value, therapeutic benefit and cost-effective utilization of video-EEG monitoring (VEM) in a comprehensive epilepsy program in a developing country. The authors prospectively recruited all patients who underwent long-term (> or =3 hours) inpatient VEM during a 10-month period. The cohort was followed to gather information about the proportion of patients in whom long-term management was altered by VEM and resultant impact on direct health care costs. Out of 143 study subjects (median age 22 years), 102 (71.3%) were referred for presurgical evaluation. The median duration of VEM was 61 hours, and median number of events recorded per patient was 3. Video-EEG monitoring helped to clarify the epilepsy syndromic diagnosis in 123 of 132 (93.2%) patients referred with the diagnosis of epileptic seizures. Video-EEG monitoring confirmed coexistent complex partial seizures in 4 of 11 (36.4%) patients with a referral diagnosis of psychogenic nonepileptic events. During mean follow-up period of 2.2 years, 48 patients (33.6%) underwent epilepsy surgery. A significant decrease in antiepileptic drug polytherapy, and minimization in recurring direct medical and nonmedical costs occurred. In addition to immediate diagnostic usefulness, VEM contributes significantly to long-term therapeutic and economic benefits for patients with difficult to diagnose and treat paroxysmal events.

Evaluation of efficacy and safety of anterior corpus callosotomy with keyhole in refractory seizures

PURPOSE

This study was conducted to evaluate the efficacy and safety of anterior corpus callosotomy with a keyhole approach on refractory seizures and to evaluate this procedure for drop attacks (DAs) and generalized tonic-clonic seizures (GTCSs).

METHODS

All refractory seizure patients underwent anterior corpus callosotomy (n=31) without other epilepsy surgery. Seizure response and procedure complications were evaluated.

RESULTS

Seizure types included GTCS (n=26), and atonic or tonic seizures with DA (n=9). In GTCS patients, 84.6% had >or=50% decrease in seizure frequency, and 61.5% had >or=80% reduction. In DA patients, 77.8% had >or=50% decrease in seizure frequency, and 55.6% had >or=80% reduction. There were no statistically significant differences between the groups in final efficacy. Overall complication rate for corpus callosotomy was 12.9%, the permanent complication rate was 3.2%.

CONCLUSIONS

Anterior corpus callosotomy with a keyhole approach produces highly favorable outcomes for both GTCS and atonic or tonic seizures with a low risk for complications.

Long-term seizure outcome after corpus callosotomy: a retrospective analysis of 95 patients

Object

The authors report long-term follow-up seizure outcome in patients who underwent corpus callosotomy during the period 1981–2001 at the Montreal Neurological Institute.

Methods

The records of 95 patients with a minimum follow-up of 5 years (mean 17.2 years) were retrospectively evaluated with respect to seizure, medication outcomes, and prognostic factors on seizure outcome.

Results

All patients had more than one type of seizure, most frequently drop attacks and generalized tonicclonic seizures. The most disabling seizure type was drop attacks, followed by generalized tonic-clonic seizures. Improvement was noted in several seizure types and was most likely for generalized tonic-clonic seizures (77.3%) and drop attacks (77.2%). Simple partial, generalized tonic, and myoclonic seizures also benefited from anterior callosotomy. The extent of the callosal section was correlated with favorable seizure outcome. The complications were mild and transient and no death was seen.

Conclusions

This study confirms that anterior callosotomy is an effective treatment in intractable generalized seizures that are not amenable to focal resection. When considering this procedure, the treating physician must thoroughly assess the expected benefits, limitations, likelihood of residual seizures, and the risks, and explain them to the patient, his or her family, and other caregivers.

Treatment of Lennox-Gastaut syndrome: overview and recent findings

Lennox-Gastaut syndrome (LGS) is a rare, age-related syndrome, characterized by multiple seizure types, a specific electro-encephalographic pattern, and mental regression. However, published data on the etiology, evolution, and therapeutic approach of LGS are contradictory, partly because the precise definition of LGS used in the literature varies. In the most recent classification, LGS belongs to the epileptic encephalopathies and is highly refractory to all antiepileptic drugs. Numerous treatments, medical and non-medical, have been proposed and results mostly from open studies or case series have been published. Sometimes, patients with LGS are included in a more global group of patients with refractory epilepsy. Only 6 randomized double-blind controlled trials of medical treatments, which included patients with LGS, have been published. Overall, treatment is rarely effective and the final prognosis remains poor in spite of new therapeutic strategies. Co-morbidities need specific treatment. This paper summarizes the definition, diagnosis and therapeutic approach to LGS, including not only recognized antiepileptic drugs, but also "off label" medications, immune therapy, diet, surgery and some perspectives for the future.

Outcome after extended callosal section in patients with primary idiopathic generalized epilepsy

PURPOSE

We report the outcome of patients with refractory idiopathic generalized epilepsy (IGE) who were submitted to extended one-stage callosal section.

METHODS

Eleven patients with IGE who were submitted to extended one-stage callosal section were studied. Preoperative workup included history and neurologic examination, interictal, and ictal electroencephalography (EEG) recording, high resolution 1.5T magnetic resonance imaging (MRI) and intelligence quotient (IQ) testing. All patients were submitted to extended one-stage microsurgical callosal section, leaving only the splenium intact.

RESULTS

Preoperative ictal patterns included repetitive spike and wave or polyspike and wave discharges or fast epileptic recruiting rhythm. MRI showed no focal lesions. Preoperatively, mean general IQ was 85. Postoperatively, at least a 75% reduction in the frequency of generalized tonic-clonic seizures was noted in all patients. In three patients absences disappeared completely, and the others had at least 90% reduction in seizure frequency. Only one patient had myoclonic seizures preoperatively, and these seizures disappeared after callosal section. After surgery, mean general IQ was 89. A very clear increase in attention level was noted in all patients. Postoperative interictal EEG recordings showed rupture of bilateral synchrony in all patients.

DISCUSSION

This article reports on a large and homogeneous series of patients with refractory IGE submitted for callosal section. There was a marked decrease in generalized seizure frequency and increase in the attention level in this patient population. Our results suggest that corticocortical interaction might have a role in IGE pathogenesis. Callosotomy is a safe, effective, and underused palliative procedure in these well-selected patients with refractory IGE.

Corpus callosotomy

Corpus callosotomy is a palliative surgical procedure that is suitable for some patients with intractable seizures who are not candidates for focal resective surgery. The rationale for this procedure is based on the hypothesis that the corpus callosum is a critical pathway for interhemispheric spread of epileptic activity. Efficacy and relatively low permanent morbidity in corpus callosotomy for medically intractable epilepsy have been demonstrated by more than six decades of experience. Callosotomy best ameliorates drop attacks (tonic and atonic seizures), though tonic-clonic, absence, and frontal lobe complex partial seizures often respond as well. In addition to seizure reduction, behavior and quality of life may improve. Hence, callosotomy is justified as a therapy for appropriate patients with intractable epilepsy.

Outcomes of epilepsy surgery in adults and children

Surgery is widely accepted as an effective therapy for selected individuals with medically refractory epilepsy. Numerous studies in the past 20 years have reported seizure freedom for at least 1 year in 53-84% of patients after anteromesial temporal lobe resections for mesial temporal lobe sclerosis, in 66-100% of patients with dual pathology, in 36-76% of patients with localised neocortical epilepsy, and in 43-79% of patients after hemispherectomies. Reported rates for non-resective surgery have been less impressive in terms of seizure freedom; however, the benefit is more apparent when reported in terms of significant seizure reductions. In this Review, we consider the outcomes of surgery in adults and children with epilepsy and review studies of neurological and cognitive sequelae, psychiatric and behavioural outcomes, and overall health-related quality of life.