Corpus callosotomy for refractory epileptic spasms: Systematic review and meta-analysis

OBJECTIVE: We systematically reviewed the existing literature on the efficacy of corpus callosotomy (CC) in children and adults with refractory epileptic spasms (ES) and analyzed clinical determinants of seizure outcomes. METHODS: The Preferred Report Items for Systematic Reviews and Meta-Analysis Guidelines (PRISMA) were followed. We systematically searched MEDLINE, EMBASE and Cochrane databases up to December 2023 for original research articles on using CC to treat refractory ES. The primary outcome measure was the proportion of study participants who achieved seizure freedom following initial CC at the last follow-up. Meta-regression using mixed-effects models was performed to obtain clinical determinants of seizure outcomes. RESULTS: A total of 12 studies were included (253 individuals). Initial complete total CC was most common (n = 218/253, 86%), followed by anterior CC (n = 29/253, 12%) and other forms of CC (i.e., anterior to posterior, posterior, staged total) (n = 6/253, 2%). The pooled proportion of patients achieving spasm freedom following CC was 0.31 (95% CI: 0.22, 0.42) (mean follow-up 47 months). Meta-regression showed that structural etiology and mean age at the time of CC were significant moderators of the pooled effect. For every 1% increase in the proportion of structural etiology, the proportion of spasm-free outcome was found to reduce by 0.45 (95% CI: -0.86, -0.03, p < 0.0001). In addition, increasing the mean age by 1 month led to a reduction in the proportion of spasms-free patients by 0.003 (95% CI: -0.005, -0.0006, p = 0.01). Sixty-two individuals (24%) from seven studies underwent further surgery for residual ES; 34 became spasm free (55%). CONCLUSIONS: Corpus callosotomy may be an effective treatment option in selected individuals with refractory epileptic spasms. Structural aetiologies and increased age at the time of corpus callosotomy are important clinical determinants. In some cases, CC may lead to further epilepsy surgery.