Abstracts

Rationale: Malformations of cortical development are a common cause of intractable seizures overall, and the leading cause in the pediatric population. Our aim was to determine the factors associated with long-term seizure control after surgical resection. Methods: We conducted a retrospective review of 104 patients with cortical malformations who underwent surgery for medically refractory epilepsy. Demographic, seizure history, imaging, histopathologic, and surgical variables were collected, and then analyzed for potential association with seizure-freedom. Results: Multivariate logistic regression showed that complete resection of electrocorticographic and/or anatomic imaging abnormalities were two independent predictors strongly associated with complete seizure-freedom (88% for complete resection vs. 16% for incomplete resection; odds ratio=0.089; 95% confidence interval=0.027-0.29, p<0.001). Histopathological features, demographic characteristics, and seizure history were not associated with post-operative seizure control. Imaging features consistent with Barkovich class I lesions related to abnormal proliferation appeared to have slightly better outcome compared to class II (abnormal neuronal migration) or class III (abnormal cortical organization) lesions. Subtotal resection of anatomic or electrocorticographic abnormality was associated with overlapping eloquent cortex and/or widely diffuse areas of epileptiform activity. Long-term follow-up of patients demonstrated sustained overall rates of seizure control (63% at 2 years and 61% at 5 years).