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

Abstract

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.

<p>Seizure Outcomes in Patients with Complete versus Anterior Corpus Callosotomy: Analysis of Outcome</p>

“…Total callosotomy yields favorable outcome in drop attacks' freedom compared to partial callosotomy. 7 Our observation showed that 5 of 9 patients with total callosotomy achieved complete seizure freedom compared to 1 of 7 partial callosotomy patients. A study in drop attacks patient demonstrated that the seizure-free rate in total and partial callosotomy was 90% and 54% respectively during a 7-year follow-up.…”

Early recovery of interhemispheric functional connectivity after corpus callosotomy

“…1,26 However, the relationship between the location of interhemispheric FC reduction and seizure outcome is rarely studied. Traditionally, callosotomy targets the anterior corpus callosum; complete callosotomy is already known to be more associated with complete seizure freedom and drop attack freedom than partial callosotomy.…”

“…Traditionally, callosotomy targets the anterior corpus callosum; complete callosotomy is already known to be more associated with complete seizure freedom and drop attack freedom than partial callosotomy. 1,26 However, the relationship between the location of interhemispheric FC reduction and seizure outcome is rarely studied. A recent interesting study by Paglioli et al raised the possibility that posterior callosotomy may achieve outcomes in epileptic fall reduction comparable to those of total callosotomy because the crossing fibers from the premotor and primary motor cortex are posteriorly located in the mid to posterior half of corpus callosum.…”

Surgical Treatments of Epilepsy

“…Complete seizure freedom was achieved in 20% of patients. 99 Adverse events were rare, and neurologic deficits including lower-extremity weakness or speech problems occurred in 14.3% of patients. 97…”