Surgical outcome of corpus callosotomy in patients with drop attacks

Reappraisal of corpus callosotomy

PURPOSE OF REVIEW

Corpus callosotomy is a palliative surgical treatment modality that has gone in and out of favor. The purpose of this review is to summarize the studies of callosotomy in the past years as a treatment for severe drug-resistant epilepsy with traumatizing drop attacks, mostly in children and also in some adults. The aim is also to discuss knowledge gaps and suggest how these could be addressed.

RECENT FINDINGS

Lately, a number of callosotomy series, mostly retrospective and single center, have included 289 operated patients. A few series have included nonoperated controls; one prospective long-term series is national and population based. Seizure outcome is shown to be comparable to that earlier reported, with best effect against drop attacks. There is no consensus on whether anterior or complete callosotomy is to be preferred. In a meta-analysis of callosotomy versus vagal nerve stimulation, callosotomy led to better seizure outcome. Diffusion tensor imaging may be a promising tool to analyze the completeness of the procedure.

SUMMARY

Callosotomy remains an effective palliative procedure. Many unresolved issues, such as prognostic indicators, nonseizure-related outcomes, whether to choose anterior or complete callosotomy, and outcomes and adverse effects in adults, need to be studied in prospective, preferably multicenter studies.

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 >90% in 10 patients and >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 < .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.

Corpus callosotomy versus vagus nerve stimulation for atonic seizures and drop attacks: A systematic review

Atonic seizures are debilitating and poorly controlled with antiepileptic medications. Two surgical options are primarily used to treat medically refractory atonic seizures: corpus callosotomy (CC) and vagus nerve stimulation (VNS). However, given the uncertainty regarding relative efficacy and surgical complications, the best approach for affected patients is unclear. The PubMed database was queried for all articles describing the treatment of atonic seizures and drop attacks with either corpus callosotomy or VNS. Rates of seizure freedom, >50% reduction in seizure frequency, and complications were compared across the two patient groups. Patients were significantly more likely to achieve a >50% reduction in seizure frequency with CC versus VNS (85.6% versus 57.6%; RR: 1.5; 95% CI: 1.1-2.1). Adverse events were more common with VNS, though typically mild (e.g., 22% hoarseness and voice changes), compared with CC, where the most common complication was the disconnection syndrome (13.2%). Both CC and VNS are well tolerated for the treatment of refractory atonic seizures. Existing studies suggest that CC is potentially more effective than VNS in reducing seizure frequency, though a direct study comparing these techniques is required before a definitive conclusion can be reached.

Dietary therapy is not the best option for refractory nonsurgical epilepsy

The ketogenic diet (KD) is currently a well-established treatment for patients with medically refractory, nonsurgical epilepsy. However, despite its efficacy, the KD is highly restrictive and constitutes a treatment with serious potential adverse effects, and often with difficulties in its implementation and compliance. Patients on the KD require strict follow-up and constant supervision by a medical team highly experienced in its management in order to prevent complications. Other alternative treatments for patients with refractory epilepsy include vagus nerve stimulation (VNS), new-generation antiepileptic drugs (AEDs), corpus callosotomy (CC), and responsive focal cortical stimulation (RNS). In this review, we explain not only the difficulties of the KD as a therapeutic option for refractory epilepsy but also the benefits of other therapeutic strategies, which, in many cases, have proven to have better efficacy than the KD itself.

Lennox-Gastaut syndrome. Management update

Lennox-Gastaut syndrome (LGS) is a severe pediatric epilepsy syndrome characterized by mixed seizures, cognitive decline, and generalized slow (<3 Hz) spike wave discharges on electroencephalography. Atonic seizures result in dangerous drop attacks with risks of injury and impairment of the quality of life. The seizures are frequently resistant to multiple antiepileptic (AED) drugs. Newer AEDs, such as rufinamide, are now available. When multiple AED trials fail, non-pharmacological treatments such as the ketogenic diet, vagus nerve stimulation, and epilepsy surgery, should be considered. The aim of this review is to present an updated outline of LGS and the available treatments. Although the prognosis for complete seizure control remains poor, the addition of newer therapies provides an improved hope for some of these patients and their families. Further long term randomized controlled trials are required to compare different therapeutic interventions in terms of efficacy and tolerability.

Epilepsy surgery for pediatric epilepsy: optimal timing of surgical intervention

Pediatric epilepsy has a wide variety of etiology and severity. A recent epidemiological study suggested that surgery might be indicated in as many as 5% of the pediatric epilepsy population. Now, we know that effective epilepsy surgery can result in seizure freedom and improvement of psychomotor development. Seizure control is the most effective way to improve patients neurologically and psychologically. In this review, we look over the recent evidence related to pediatric epilepsy surgery, and try to establish the optimal surgical timing for patients with intractable epilepsy. Appropriate surgical timing depends on the etiology and natural history of the epilepsy to be treated. The most common etiology of pediatric intractable epilepsy patients is malformation of cortical development (MCD) and early surgery is recommended for them. Patients operated on earlier than 12 months of age tended to improve their psychomotor development compared to those operated on later. Recent progress in neuroimaging and electrophysiological studies provide the possibility of very early diagnosis and comprehensive surgical management even at an age before 12 months. Epilepsy surgery is the only solution for patients with MCD or other congenital diseases associated with intractable epilepsy, therefore physicians should aim at an early and precise diagnosis and predicting the future damage, consider a surgical solution within an optimal timing.

Pediatric epilepsy surgery

Medically refractory epilepsy is a significant cause of morbidity and mortality in pediatric neurology. Surgical intervention has been well established as a viable treatment option in certain cases. This article reviews the process of selecting appropriate patients using the latest advances in neuroimaging and electrophysiologic techniques. It also discusses the various surgical techniques currently available, including recent advances in minimally invasive approaches.

Carbon dioxide laser for corpus callosotomy in the pediatric population

OBJECT

The authors describe the application of a flexible CO2 laser for corpus callosotomy in children with epilepsy.

METHODS

This retrospective case series reviews all cases in which pediatric patients underwent a corpus callosotomy performed using the CO2 OmniGuide laser between May 2005 and October 2012. Data were collected from 8 corpus callosotomy procedures in 6 pediatric patients presenting with medically refractory epilepsy marked by drop attacks.

RESULTS

Complete corpus callosotomies were performed in 6 patients (3 boys, 3 girls; ages 5-14 years). In 4 patients the complete callosotomy occurred as a single procedure, and in 2 patients an anterior two-thirds callosotomy was performed first. These 2 patients subsequently required a complete callosotomy due to inadequate control of their drop attacks. In all cases there was clean lesioning of the tract with preservation of the ependymal plane and less inadvertent thermal tissue damage due to low penetration of the laser through cerebrospinal fluid. All patients had resolution or improvement of drop attacks after surgery. No complications were encountered, and imaging demonstrated a clean sectioning of callosal fibers with preservation of normal ventricular anatomy.

CONCLUSIONS

These cases illustrate the use of this device in completing corpus callosotomy in pediatric patients. The low-profile laser fiber tip was well suited for working in the depths of the interhemispheric fissure with minimal brain retraction. The flexible CO2 laser allows a precise callosal lesioning through an interhemispheric approach and is a useful adjunct to be employed in these cases.

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.

Corpus callosotomy for childhood-onset drug-resistant epilepsy unresponsive to vagus nerve stimulation

PURPOSE

Corpus callosotomy and vagus nerve stimulation are common palliative options for people with drug-resistant epilepsy when resective epilepsy surgery is not feasible. Because most of the published corpus callosotomy experience comes from a period before vagus nerve stimulation was approved and widely used, there is a paucity of data about efficacy of corpus callosotomy in patients with inadequate response to vagus nerve stimulation.

METHODS

We report seven patients who had complete corpus callosotomy after an inadequate response to vagus nerve stimulation. At the time of surgery, these patients had failed a median of six antiseizure medications, three patients also had failed a trial of ketogenic diet, and all the patients had a vagus nerve stimulation implanted for a mean duration of 2.5 years with maximal tolerated settings.

RESULTS

There was a decrease in total daily seizure frequency of 34.7% (± 94.7; median, 71.4%; interquartile range, 55.3) after corpus callosotomy at a mean follow-up of 2.6 years (± 1.4). One patient achieved complete seizure freedom and five patients had ≥ 50% reduction in seizure frequency. Six patients continued to have partial-onset seizures though the frequency was decreased. Drop attacks and tonic seizures stopped in all the patients.

CONCLUSION

Seizure outcomes after corpus callosotomy in our series are most likely a result of complex dynamic interaction between the natural history of epilepsy, the effect of the surgery, ongoing vagus nerve stimulation modulation, and modification in antiseizure drugs. Our study supports the clinical decision to try corpus callosotomy in patients having nonlateralizing drug-resistant epilepsy with inadequate response to vagus nerve stimulation.

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.

Non-pharmacologic management of epilepsy

Non pharmacological treatment, in addition to pharmacological treatment is indicated in patients with refractory/pharmacoresistant epilepsy and includes ketogenic diet, deep brain stimulator, vagal nerve stimulator, transcranial magnetic stimulation and epilepsy surgery. Ketogenic diet has been recommended since 1921 and has been proved to be a safe and effective treatment for intractable epilepsy. Deep brain stimulator, has been used in the treatment of movement disorders for many years and recently been tried in the treatment of pharmacoresistant epilepsy. Vagus nerve stimulator is increasingly being used as an effective seizure aborting technique in patients not responding to anticonvulsants. Transcranial magnetic stimulation is a noninvasive brain stimulation technique which is being increasingly researched for use in patients with medication-refractory seizures who are not suitable candidates for surgery. Evolution of epilepsy surgery including Vagal nerve stimulator and Deep brain stimulator, as a successful treatment modality for intractable epilepsy has been influenced over the last decade by substantial advancement in imaging and operative/device related technology. The current article reviews the indications, mechanism of action, technological aspects and efficacy of the aforementioned modalities in the treatment of intractable/pharmacoresistant epilepsy in pediatric age group.

Epileptic encephalopathies: new genes and new pathways

Epileptic encephalopathies represent a group of devastating epileptic disorders that occur early in life and are often characterized by pharmaco-resistant epilepsy, persistent severe electroencephalographic abnormalities, and cognitive dysfunction or decline. Next generation sequencing technologies have increased the speed of gene discovery tremendously. Whereas ion channel genes were long considered to be the only significant group of genes implicated in the genetic epilepsies, a growing number of non-ion-channel genes are now being identified. As a subgroup of the genetically mediated epilepsies, epileptic encephalopathies are complex and heterogeneous disorders, making diagnosis and treatment decisions difficult. Recent exome sequencing data suggest that mutations causing epileptic encephalopathies are often sporadic, typically resulting from de novo dominant mutations in a single autosomal gene, although inherited autosomal recessive and X-linked forms also exist. In this review we provide a summary of the key features of several early- and mid-childhood onset epileptic encephalopathies including Ohtahara syndrome, Dravet syndrome, Infantile spasms and Lennox Gastaut syndrome. We review the recent next generation sequencing findings that may impact treatment choices. We also describe the use of conventional and newer anti-epileptic and hormonal medications in the various syndromes based on their genetic profile. At a biological level, developments in cellular reprogramming and genome editing represent a new direction in modeling these pediatric epilepsies and could be used in the development of novel and repurposed therapies.

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.

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.

Combination of corpus callosotomy and vagus nerve stimulation in the treatment of refractory epilepsy

BACKGROUND

Palliative techniques such as partial corpus callosotomy (CC) and vagus nerve stimulation (VNS) may be effective for adequate control of seizures in pharmacoresistant patients who are not candidates for resective surgery.

OBJECTIVE

The objective of this study was to analyze the efficacy of the combination of these two techniques in patients where the first surgery had not achieved adequate control.

MATERIALS AND METHODS

This is a retrospective review of 6 patients with refractory epilepsy in which both types of surgery were performed, CC and VNS. We analyzed variables such as age, sex, age at onset of epilepsy, seizure types, electroencephalogram and magnetic resonance imaging results, and number of pre- and postoperative seizures.

RESULTS

Three patients first underwent VNS and then CC, and 3 patients were treated in reverse order. All patients had some improvement after the first surgery, but they continued to experience persistent falls, so a second palliative technique was used. The mean improvement after both surgeries was 89% (90% in patients first receiving CC and 87% in patients who first underwent VNS).

CONCLUSIONS

In adequately studied patients who are not optimal candidates for resective surgery, palliative surgery is a choice. The combination of VNS and CC shows good results in our series, although the right order to perform both procedures has not been defined. These results should be confirmed in a larger group of patients.

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.

Corpus callosotomy is a valuable therapeutic option for patients with Lennox-Gastaut syndrome and medically refractory seizures

PURPOSE

We present our experience with corpus callosotomy (CC) in a developing country with limited resources in patients with Lennox-Gastaut syndrome (LGS) and medically refractory seizures.

METHODS

All patients with LGS who underwent CC for medically refractory epilepsy at Namazee Hospital, Shiraz University of Medical Sciences, Shiraz, Iran from May 2009 through March 2012 were reviewed in a retrospective study. Presurgical evaluation included clinical history, neurological examination, a 2-hour video-EEG recording, and 1.5-T MRI. Outcome was evaluated at 6, 12, and 24 months postoperatively. We considered the outcome as a success if the patients were either seizure-free or had more than 85% reduction in seizure frequency compared to their preoperative status.

RESULTS

Eighteen patients (14 males and 4 females) had surgery. Overall, seizures in 11 patients (61.1%) responded favorably one year after surgery; this figure was 6 out of 9 patients (66.6%) two years after surgery. Seven patients (38.8%) were free of disabling seizures one year after CC; this figure was three out of nine patients (33.3%) two years after CC. Three patients (16.6%) were free of all seizure types one year after surgery. Ten patients (55.5%) had no postoperative complications of any kind.

CONCLUSION

Corpus callosotomy is an effective palliative surgical procedure for patients with LGS with intractable seizures whose seizures are not amenable to focal resection. This is a feasible treatment option for patients, even for those in developing countries with limited resources.

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.

Seizure Outcomes After Corpus Callosotomy for Drop Attacks

BACKGROUND:

Medically intractable epilepsy involving drop attacks can be difficult to manage and negatively affect quality of life. Most studies investigating the effect of corpus callosotomy (CC) on seizures have been limited, focusing on the pediatric population or drop seizures alone, with little attention to other factors influencing seizure outcome.

OBJECTIVE:

To assess seizure outcomes after CC in adults and children.

METHODS:

Retrospective analysis was performed on all patients who underwent CC (anterior two thirds, 1- or 2-stage complete) at our institution between 1990 and 2011. Change in frequency after CC was assessed for drop seizures and other seizure types. Multiple factors were evaluated for impact on seizure outcome.

RESULTS:

Fifty patients met inclusion criteria. The median age was 1.5 years at seizure onset and 17 years at time of surgery. Anterior two-thirds CC was performed in 28 patients, 1-stage complete in 17, and 2-stage complete in 5. All 3 groups experienced a significant decrease in drop seizures (P &lt; .001, P &lt; .001, and P = .020, respectively), with 40% experiencing complete resolution, and 64% dropping at least 1 frequency category. Other seizure types significantly decreased in anterior two-thirds CC and 1-stage complete (P = .0035, P = .001, respectively). Younger age at surgery correlated with better seizure outcomes (P = .043).

CONCLUSION:

CC for medically refractory generalizing epilepsy is effective for both drop seizures and other seizure types. CC should be considered soon after a patient has been deemed medically refractory because earlier age at surgery results in lower risk and better outcome.

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.

Long-term outcome after callosotomy or vagus nerve stimulation in consecutive prospective cohorts of children with Lennox-Gastaut or Lennox-like syndrome and non-specific MRI findings

PURPOSE

There is currently no resective (potentially curative) surgical option that is useful in patients with Lennox-Gastaut syndrome. Palliative procedures such as callosotomy (Cx), vagus nerve stimulation (VNS) or deep brain stimulation have been offered. We compared the outcomes after Cx or VNS in two consecutive prospective cohorts of patients with generalised epilepsy.

METHODS

Twenty-four patients underwent callosotomy from 2006 to 2007 (Group 1); 20 additional patients were submitted to VNS from 2008 to 2009 (Group 2). They had generalised epilepsy of the Lennox-Gastaut or Lennox-like type. They were submitted to a neurological interview and examination, interictal and ictal video-EEG, high resolution 1.5T MRI, and cognitive and quality of life evaluations. The two-year post-operative follow-up results were evaluated for each patient.

RESULTS

The final mean stimuli intensity was 3.0 mA in the Group 2 patients. Seizure-free patients accounted for 10% in Group 1 and none in Group 2. Ten and sixteen percent of the Group 1 and 2 patients, respectively, were non-responders. Improvements in attention and quality of life were noted in 85% of both Group 1 and 2 patients. Rupture of the secondary bilateral synchrony was noted in 85% of Group 1 patients; there was no EEG modification after VNS in Group 2. Both procedures were effective regarding the control of atypical absences and generalised tonic-clonic seizures. Both procedures were not effective in controlling tonic seizures. Callosotomy was very effective in reducing the frequency of atonic seizures, but VNS was ineffective. In contrast, callosotomy was not effective in reducing myoclonic seizures, whereas VNS was.

DISCUSSION

Callosotomy might be preferred as the primary treatment in children with Lennox-Gastaut syndrome, and no specific findings on MRI if atonic seizures prevail in the patient's clinical picture; when myoclonic seizures prevail, the same might hold true in favour of VNS. When atypical absence or generalised tonic-clonic seizures are the main concern, although both procedures carry similar effectiveness, VNS might be considered a good option as an initial approach, taking into account the adverse event profile. Patients should be advised that both procedures are not very effective in the treatment of tonic seizures.

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.

Update on the management of Lennox-Gastaut syndrome

Lennox-Gastaut syndrome is a severe childhood epilepsy disorder characterized by encephalopathy and multiple, often intractable, seizure types. The drop attack is the most frequently recognizable seizure type in this patient population, and is also the most dangerous physically, thus severely limiting quality of life. The diagnosis is confirmed by electroencephalography, for which the classic pattern is a slow 2.5 Hz generalized spike-and-wave. Newer pharmacologic treatments include rufinimide and clobazam. However, antiepileptic drugs are often exhausted in pursuit of seizure control requiring nonpharmacologic interventions. These include dietary therapies, vagus nerve stimulation, and epilepsy surgery, including corpus callosotomy and focal curative resection. Although large lobar resections are often required, very localized, discrete resections may be possible, as in symptomatic Lennox-Gastaut syndrome (specifically, hypothalamic hamartoma). We review the history of the disease and current management options.

Complete remission of seizures after corpus callosotomy

OBJECT

Corpus callosotomy is usually intended to alleviate-not to achieve total control of-epileptic seizures. A few patients experience complete seizure control after callosotomy, but the associated clinical factors are unknown. The object of this study was to investigate clinical factors associated with long-term seizure remission after total corpus callosotomy in patients with infantile or early childhood onset epilepsy.

METHODS

Thirteen consecutive patients with infantile or early childhood onset epilepsy underwent 1-stage total corpus callosotomy for alleviation of seizures. Their age at surgery ranged from 1 year and 5 months to 24 years (median 7 years). Eleven patients had West syndrome at the onset of disease, and the other 2 had Lennox-Gastaut syndrome. All patients suffered from spasms, axial tonic seizures, or atonic seizures. Six patients had proven etiology of epilepsy, including tuberous sclerosis, polymicrogyria, trauma, and Smith-Magenis syndrome. The association between postoperative seizure freedom and preoperative factors including age at surgery, no MRI abnormalities, proven etiology, and focal electroencephalographic epileptiform discharges was examined.

RESULTS

Postoperative seizure freedom was achieved in 4 of 13 patients for a minimum of 12 months. All 4 patients had no MRI abnormalities and no identified etiology. None of the 8 patients with MRI abnormality, 6 patients with known etiology of epilepsy, or 4 patients aged older than 10 years at surgery achieved seizure freedom. Two of the 7 patients with focal electroencephalographic abnormalities became seizure free. Absence of MRI abnormalities was significantly associated with postoperative seizure freedom (p < 0.01).

CONCLUSIONS

Complete seizure remission is achieved after total corpus callosotomy in a subgroup of patients with intractable epilepsy following West syndrome or Lennox-Gastaut syndrome. One-stage total corpus callosotomy at a young age may provide a higher rate of seizure freedom, especially for patients with no MRI abnormalities and no identified etiology of epilepsy.

Corpus callosotomy for treatment of pediatric refractory status epilepticus

Medically refractory status epilepticus (RSE) causes high morbidity and mortality in children. There are no evidence-based guidelines for treatment. Epilepsy surgery is a treatment option for RSE. We describe a 9-year-old boy treated successfully for RSE with complete corpus callosotomy (CC). Epilepsy surgery should be considered for prolonged RSE. In the absence of evidence of focal epileptogenesis, complete corpus callosotomy may be effective in select cases.

Non-resective surgery and radiosurgery for treatment of drug-resistant epilepsy

Epilepsy surgery is an effective treatment for properly selected patients with intractable seizures. However, many patients with medically intractable epilepsy are not excellent candidates for surgical resection of the epileptogenic zone. Due to recent advances in computer technology and bioengineering, several novel techniques are receiving increasing interest for their role in the care of people with epilepsy. Neuromodulation is an emerging surgical option to be used when conventional resective surgery is not indicated. We review the indications and expected outcomes of neuromodulatory treatments currently available for the treatment of refractory epilepsy, i.e., vagus nerve stimulation, deep brain stimulation, stereotactic radiosurgery, and multiple subpial transections.

Paediatric intractable epilepsy syndromes: changing concepts in diagnosis and management

Epilepsy surgery for drug-resistant childhood epilepsy is not new. However, brain imaging, surgical and anaesthetic techniques have improved to the extent that they are now as much safer and realistic option than they were in the past. Further, the range of surgical candidates is wide, and previous concepts about likely surgical candidates are now challenged as children with previously thought widespread or apparent multifocal disease are evaluated. Outcomes for seizure freedom range from 40 to 80 % depending on the underlying aetiology and the extent of resection. However, the aims of surgery may include seizure reduction in some and improvement in neurodevelopment and behaviour in others, which are less -predictable. Epilepsy surgery in children is no longer a last resort. Children thought to be likely candidates should be evaluated early in their natural history to optimise outcomes in the long term.

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.

Effect of corpus callosotomy on attention deficit and behavioral problems in pediatric patients with intractable epilepsy

To evaluate the effect of corpus callosotomy (CC) on attention deficit and behavioral problems in pediatric patients with intractable epilepsy, we retrospectively investigated sequential patients who had undergone CC to control seizures. Between August 2005 and April 2010, a total of 15 patients aged between 3.1 and 17.9 years underwent CC at our institute. All the patients experienced either drop attacks or head nodding, which were considered to be therapeutic targets of CC. A standardized instrument, the Child Behavior Checklist (CBCL), was used to assess behavioral and emotional problems before and after surgery. On postoperative EEGs, 8 (53%) showed improvement and 7 (47%) showed no change in epileptiform discharges. The Attention Problems scale and total score on the CBCL significantly improved in patients whose postoperative EEGs showed improvement. In addition to amelioration of target seizures, CC can improve attention impairments in association with improvement in the postoperative EEG.

Ethical issues in surgical decision making concerning children with medically intractable epilepsy

The widespread inclusion of surgical strategies in the treatment of medically intractable epilepsy is largely justified by the medical and psychosocial burden of the illness. Performing these procedures in pediatric populations is associated with distinct challenges ranging from unique seizure etiologies to issues surrounding brain development and functional plasticity. As the trend toward more aggressive surgical intervention continues, the ethical foundation of current and emerging practices must be increasingly scrutinized. Here, we present the first article discussing ethical issues in the surgical management of medically intractable epilepsies in children. We discuss principles of informed consent, harm reduction, and justice in this vulnerable patient population. We also highlight the unique ethical challenge of surgical decision making concerning developmentally delayed children. The recognition of these issues is essential to providing patient-centered, responsible, and ethical care.

Management of seizures in Lennox-Gastaut syndrome

Lennox-Gastaut syndrome is an epilepsy syndrome that begins in childhood (between 1 and 8 years of age), worsens during latency and persists frequently into adulthood, is refractory to antiepileptic medications, and results in cognitive decline and behavioral problems in affected individuals. Seizure types consist primarily of axial tonic, atonic, and atypical absence; nocturnal tonic seizures are the most common seizure pattern in this population, but often are not one of the initial seizure patterns. Some patients also have myoclonic seizures; this seizure pattern is less frequent than the three preceding types. Although there are some cases that are cryptogenic, most are symptomatic, arising during prenatal and perinatal periods from intrauterine infections, and vascular insults to the brain. Examples of causes of Lennox-Gastaut syndrome include migrational abnormalities of the brain, late effects of CNS infections, certain genetic disorders such as tuberous sclerosis, and inherited metabolic disorders. The difficulty early in the course of Lennox-Gastaut syndrome is distinguishing this diagnosis from severe myoclonic epilepsy of infancy (Dravet syndrome) or from myoclonic-astatic epilepsy (Doose syndrome), as the seizure patterns in these three syndromes may overlap at the onset. EEG is a helpful diagnostic tool in the diagnosis of Lennox-Gastaut syndrome, usually demonstrating high voltage, bifrontal 1.5-2.5 Hz spike and wave complexes interictally, and attenuation with paroxysmal fast activity (10-13 Hz) during the ictal phase. Treatment options for Lennox-Gastaut syndrome have been less than optimal. In recent years, several drugs have been tested and approved for the treatment of this syndrome; these include felbamate, lamotrigine, topiramate, and rufinamide. The long-term outcome does not appear to be any better with the newer antiepileptic drugs than when using earlier prescribed antiepileptic drugs or polytherapy. Treatment options other than antiepileptic drugs include a ketogenic diet, vagus nerve stimulation, and corpus callosotomy. Long-term outcome of these patients relative to seizure control and cognition is poor. Most develop moderate intellectual disability within a few years of onset of the syndrome. Many develop behavioral problems with inattention, hyperactivity, and aggression.

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.

Complete versus anterior two-thirds corpus callosotomy in children: analysis of outcome

OBJECT

The goal of this study was to evaluate the efficacy of anterior versus complete sectioning of the corpus callosum in children suffering from medically refractory epilepsy. The authors report seizure outcome in patients who underwent anterior two-thirds or complete corpus callosotomy (CC) during the period 1995-2008 at St. Louis Children's Hospital.

METHODS

The medical records of 27 children and adolescents with a minimum follow-up of 6 months were retrospectively evaluated with respect to seizure status, anticonvulsant outcomes, and subjective results. Preoperatively, patients suffered from a variety of seizure types that occurred daily, weekly, or episodically. The male/female ratio was 19:8, and patients ranged in age between 3 and 19 years (mean 9.93 years). Seizure outcome, parental assessment of daily function, and changes in the number of prescribed antiepileptic drugs were all assessed.

RESULTS

Fifteen patients underwent an initial anterior two-thirds CC, and 12 underwent a complete CC. Of the 15 patients who underwent an anterior CC, 7 went on to receive a posterior CC. Seizure control was superior in children undergoing a complete CC (91%, Class I-III) versus an anterior two-thirds CC (75%, Class I-III). Seizure types most affected by CC included atonic, myoclonic, and absence. The number of postoperative antiepileptic drugs did not significantly change following CC in either the anterior only or complete groups. One patient experienced a transient disconnection syndrome that resolved within 4 weeks, and 4 patients experienced mild hemiparesis and speech delays that resolved with therapy. Three patients experienced surgical complications requiring a second operation. The overall daily function and attentiveness of the patients improved.

CONCLUSIONS

A complete CC should be considered as the initial procedure in lower-functioning children afflicted by absence, atonic, or myoclonic seizures. Severely affected higher-functioning children may also benefit from a complete CC, without clinically significant disconnection syndromes. A completion posterior CC may benefit patients in whom a prior anterior CC has failed.

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.

When should corpus callosotomy be offered as palliative therapy?

Long-Term Seizure Outcome after Corpus Callosotomy: A Retrospective Analysis of 95 Patients. Tanriverdi T, Olivier A, Poulin N, Andermann F, Dubeau F. J Neurosurg 2009;110(2):332–342. 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 tonic-clonic 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 (LGS)

Lennox-Gastaut Syndrome (LGS) is a severe form of epilepsy that usually starts in early to mid childhood and is characterized by multiple seizure types, abnormal electroencephalogram with slow spike-and-wave discharges and cognitive problems. Numerous approaches are currently used to treat LGS, including use of conventional antiepileptic drugs (most commonly sodium valproate, lamotrigine and topiramate), other drug interventions (corticosteroids and intravenous immunoglobulin) and nonpharmacologic treatments (ketogenic diet, corpus callosotomy and vagus nerve stimulation). Rufinamide is the most recent antiepileptic drug to have shown efficacy in the treatment of LGS. Despite the variety of therapeutic options, there have been only five double-blind, placebo-controlled clinical trials of antiepileptic drugs in LGS and none of these were head-to-head comparison trials. The evidence supporting the use of available treatments for LGS is, therefore, not robust. Here, we review the evidence supporting the use of specific therapies in LGS and provide recommendations on how to set appropriate treatment goals, select treatments and minimize polypharmacy. A suggested treatment algorithm is presented and discussed. Sodium valproate is recommended for first-line therapy; if seizures persist, alternative interventions should be trialed on an individually tailored basis.

Onset of action and seizure control in Lennox-Gaustaut syndrome: focus on rufinamide

Lennox-Gaustaut syndrome is an electroclinical epilepsy syndrome characterized by the triad of electroencephalogram showing diffuse slow spike-and-wave discharges and paroxysmal fast activity, multiple intractable seizure types, and cognitive impairment. The intractability to seizure medications and cognitive impairment gives rise to eventual institutionalized patient care. Only a small subset of seizure medications has been shown to be helpful in seizure control. Most patients take up to 3 medications at high therapeutic dosing and are susceptible to medication-induced side effects. The lack of medication efficacy in seizure control has led one meta-analysis to conclude that there is no single medication that is highly efficacious in controlling seizures in this syndrome. On this background, a new and structurally novel seizure medication, rufinamide, has been found to be beneficial in the treatment of seizures in this syndrome. In a multicenter, double-blinded, randomized, placebo-controlled study, rufinamide was found to reduce seizures by over 30%. More importantly, it reduced the frequency of the seizure type that induces most of the morbidity of this syndrome, the drop seizure, by over 40%. There were few side effects, the medication was well tolerated, and in the open labeled extension study, tolerance was not found. In this review, we describe the main electroclinical features of Lennox-Gaustaut syndrome and summarize the few controlled studies that have contributed to its rational treatment. Currently, there is no single agent or combination of agents that effectively treat the multiple seizure types and co-morbidities in this syndrome. Our focus will be on the role of the new medication rufinamide in seizure reduction in patients with Lennox-Gaustaut syndrome.

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.