Successful corpus callosotomy for Doose syndrome

Epilepsy Surgery for Cognitive Improvement in Epileptic Encephalopathy

Epileptic encephalopathies are defined by the presence of frequent epileptiform activity that causes neurodevelopmental slowing or regression. Here, we review evidence that epilepsy surgery improves neurodevelopment in children with epileptic encephalopathies. We describe an example patient with epileptic encephalopathy without drug refractory seizures, who underwent successful diagnostic and therapeutic surgeries. In patients with epileptic encephalopathy, cognitive improvement alone is a sufficient indication to recommend surgical intervention in experienced centers.

The role of vagus nerve stimulation in genetic etiologies of drug-resistant epilepsy: a meta-analysis

OBJECTIVE

Drug-resistant epilepsy (DRE) affects many children. Vagus nerve stimulation (VNS) may improve seizure control; however, its role in children with genetic etiologies of epilepsy is not well described. The authors systematically reviewed the literature to examine the effectiveness of VNS in this cohort.

METHODS

In January 2021, the authors performed a systematic review of the PubMed/MEDLINE, SCOPUS/Embase, Cochrane, and Web of Science databases to investigate the impact of VNS on seizure outcomes in children with genetic etiologies of epilepsy. Primary outcomes included seizure freedom rate, ≥ 90% seizure reduction rate, and ≥ 50% seizure reduction rate. Secondary outcomes were seizure severity and quality of life (QOL), including cognitive, functional, and behavioral outcomes. A random-effects meta-analysis was performed.

RESULTS

The authors identified 125 articles, of which 47 with 216 nonduplicate patients were analyzed. Common diagnoses were Dravet syndrome (DS) (92/216 patients [42.6%]) and tuberous sclerosis complex (TSC) (63/216 [29.2%]). Seizure freedom was not reported in any patient with DS; the pooled proportion (95% CI) of patients with ≥ 50% seizure reduction was 41% (21%-58%). Secondary cognitive outcomes of VNS were variable in DS patients, but these patients demonstrated benefits in seizure duration and status epilepticus. In TSC patients, the pooled (95% CI) seizure freedom rate was 40% (12%-71%), ≥ 90% seizure reduction rate was 31% (8%-56%), and ≥ 50% reduction rate was 68% (48%-91%). Regarding the secondary outcomes of VNS in TSC patients, several studies reported decreased seizure severity and improved QOL outcomes. There was limited evidence regarding the use of VNS to treat patients with other genetic etiologies of epilepsy, such as mitochondrial disease, Rett syndrome, Doose syndrome, Landau-Kleffner syndrome, Aicardi syndrome, Angelman syndrome, ring chromosome 20 syndrome, and lissencephaly; variable responses were reported in a limited number of cases.

CONCLUSIONS

The authors conducted a systematic review of VNS outcomes in children with genetic etiologies of DRE. Among the most studied conditions, patients with TSC had substantial seizure reduction and improvements in QOL, whereas those with DS had less robust seizure reduction. Increased testing, diagnosis, and long-term follow-up studies are necessary to better characterize VNS response in these children.

Corpus Callosotomy for Controlling Epileptic Spasms: A Proposal for Surgical Selection

In 1940, van Wagenen and Herren first proposed the corpus callosotomy (CC) as a surgical procedure for epilepsy. CC has been mainly used to treat drop attacks, which are classified as generalized tonic or atonic seizures. Epileptic spasms (ESs) are a type of epileptic seizure characterized as brief muscle contractions with ictal polyphasic slow waves on an electroencephalogram and a main feature of West syndrome. Resection surgeries, including frontal/posterior disconnections and hemispherotomy, have been established for the treatment of medically intractable ES in patients with unilaterally localized epileptogenic regions. However, CC has also been adopted for ES treatment, with studies involving CC to treat ES having increased since 2010. In those studies, patients without lesions observed on magnetic resonance imaging or equally bilateral lesions predominated, in contrast to studies on resection surgeries. Here, we present a review of relevant literature concerning CC and relevant adaptations. We discuss history and adaptations of CC, and patient selection for epilepsy surgeries due to medically intractable ES, and compared resection surgeries with CC. We propose a surgical selection flow involving resection surgery or CC as first-line treatment for patients with ES who have been assessed as suitable candidates for surgery.

Higher intelligence may be a risk factor for postoperative transient disturbance of consciousness after corpus callosotomy

INTRODUCTION

Corpus callosotomy (CC) is an established surgical option for palliative treatment of medically intractable epilepsy, especially for seizures with drop attacks. We postulated that specific risk factors for post-CC transient disturbance of consciousness (pCTDC) are associated with CC. The purpose of this study was to review patients with intractable epilepsy who underwent CC and to statistically analyze risk factors for pCTDC.

METHODS

Inclusion criteria for patients who underwent CC between January 2009 and November 2019 were: (1) ≥2 years old and (2) followed up for more than 8 months. The state of consciousness before and after CC was evaluated with the Glasgow coma scale. We statistically assessed predictors for pCTDC as the primary outcome.

RESULTS

Fifty-six patients (19 females, 37 males) were enrolled, and the age range was 2-57 years old. Thirty-seven (66.1%) patients developed pCTDC. The mean period from the beginning of the state of pCTDC to recovery to their baseline conscious level was 4.9 days (range: 2-25 days). All three (100%) normal intelligence level patients, 13 (81%) of 16 patients with a moderately impaired level of intelligence, and 21 (57%) of 37 patients with a severely impaired level of intelligence exhibited pCTDC. Univariate (p = 0.044) and multivariate (p = 0.006) logistic regression analyses for predictors of pCTDC showed that intellectual function was statistically significant.

CONCLUSION

Two-thirds of patients developed pCTDC. One risk factor for pCTDC may be higher intellectual function.