Abstracts

Rationale: Focal cortical dysplasia (FCD) is a common pathology in children with medically refractory epilepsy. Surgical treatment has become an increasingly accepted and advocated approach with reported seizure free outcomes of 60-80%. Few studies have examined the long-term seizure free outcome in patients who have undergone surgical resection of pathology confirmed focal cortical dysplasia during childhood. Our objectives were (1) to assess clinical features associated with sustained seizure freedom in children with pathology confirmed focal cortical dysplasia undergoing surgical resection; (2) To describe the temporal profile of seizure free status among those with early seizure remission. Methods: Single-center, retrospective study of children <18 years who underwent resective surgery between 2000 and 2012 with pathology proven FCD. Surgical outcome was classified as seizure free (Engel's class I) or seizure recurrence (Engel classes II to IV). Fisher exact tests and nonparametric Wilcoxon rank sum test were used as appropriate. Survival analysis is based on seizure-free outcome. Patients were censored at time of seizure recurrence or seizure free at last follow-up. Results: Thirty-eight children with pathology confirmed FCD were identified (male=68%; median age at surgery 6.5 years; median duration of preoperative epilepsy 3 years). At the time of presentation, focal seizures were present in 36 patients (95%), and 2 patients (5%) had epileptic spasms only. All but 3 patients (8%) had structural brain abnormality. Noninvasive video-EEG monitoring showed focal ictal onset in 20 patients (53%). Most patients underwent lesionectomy or lobectomy (87%), and multilobar resection was performed in 5 patients (13%). Twenty-six patients (68%) attained seizure freedom for minimum of 3 months and 20 (53%) patients were seizure free at median follow up of 13.5 months (IQR 7-41). Median time to seizure recurrence was 38 months with cumulative seizure-free outcome at 12 months of 60% (95% CI 43%-77%). Clinical features associated with seizure freedom included older age at seizure onset, age at surgery, and normal cognitive status at baseline. Among those with at least 3 month seizure free outcome, the median time to seizure recurrence is 54 months (95% CI 37-109 months), with seizure freedom in 85% and 79% patients at 12 months and 36 months respectively. Conclusions: About 2/3 of children with pathology confirmed FCD may achieve early seizure free outcome. Favorable clinical features associated with sustained seizure freedom included older age at seizure onset, age at surgery, and normal cognitive status at baseline. Among those patients who achieve early remission, the majority of patients continued to have seizure free control at one and three years from time of surgery.