Predictors of outcome in pediatric epilepsy surgery

OBJECTIVE: To determine the correlation between pre- and perioperative variables on the outcome of children undergoing focal resections for medically intractable partial epilepsy. METHODS: Retrospective analysis of pre- and perioperative variables in a cohort of 75 patients younger than 12 years of age who underwent excisional surgery and had at least 1 year of follow-up. Outcome, measured by postoperative seizure frequency, was analyzed as a function of age at seizure onset, duration of epilepsy, presence of cognitive impairment, lobe of seizure origin, presence of a lesion, histopathology, and completeness of resection. Completeness of resection was defined on the basis of excising both the entire structural lesion if present and the region revealing prominent interictal and ictal abnormalities on intracranial EEG. RESULTS: Seventy-seven percent of patients had good outcomes (class 1 or 2), and 59% were seizure-free. Lesional status, site of resection, and pathologic diagnoses were not significant predictors of outcome except for in multilobar resection, for which overall outcome was relatively poor (44% class 3 or 4; 22% seizure-free). Completeness of resection was the only significant predictor of good outcome (p < 0.001), with 92% of patients who underwent complete resection of the epileptogenic zone achieving good outcome compared with 50% of patients who had incomplete resections. CONCLUSION: In this series of pediatric patients, complete resection of the lesion and the electrographically abnormal region was the main determinant of outcome after focal resections. Except for multilobar resections, other factors examined in this study did not significantly influence postoperative seizure prognosis and should not influence candidate selection for the surgical process.