Association of electrocorticography and seizure outcomes in resective pediatric epilepsy surgery

OBJECTIVE: Up to 30% of children with focal epilepsy have drug-resistant epilepsy and may be candidates for epilepsy surgery. Intraoperative electrocorticography (iECoG) is a method to acutely delineate the epileptogenic zone during epilepsy resections, but its effectiveness is debated. The authors assessed the association between iECoG findings and seizure outcomes in pediatric epilepsy patients undergoing resective epilepsy surgery. METHODS: The authors conducted a retrospective cohort analysis of 115 patients at UPMC Children's Hospital of Pittsburgh who underwent resective epilepsy surgery for focal epilepsy. They assigned patients to subgroups based on the extent of resection in concordance with iECoG findings. Patients in group A had postresection iECoG without epileptiform activity at the margins. Patients in group B had persistent epileptiform activity on postresection iECoG and underwent an extended resection. Patients in group C had persistent epileptiform activity on postresection iECoG, but further resection was contraindicated due to involvement of eloquent cortex. RESULTS: The primary outcome was seizure freedom at 1 year (Engel class I), which was achieved in 64% (n = 74) of all patients; however, there was no statistically significant difference in seizure freedom or antiseizure medication reduction between the three groups. Notably, there was also no significant relationship between patient group and transient or long-term postoperative complications, such as unexpected postoperative deficits, infection, or symptomatic intracranial hemorrhage. CONCLUSIONS: The authors found no statistically significant difference between groups A, B, and C regarding postoperative seizure reduction and freedom. While iECoG provides a biomarker for the purposes of resection, in this cohort, iECoG findings were not associated with postoperative seizure freedom.