Postoperative seizures after extratemporal resections and hemispherectomy in pediatric epilepsy

Objectives: To estimate frequency and risk factors for acute postoperative seizures (APOS) within the first week after extratemporal cortical resection (ETR) and hemispherectomy (HS) in children and to assess the predictive value of APOS on long-term seizure outcome in this group. Methods: The authors conducted a retrospective analysis of children (< 18 years), who underwent ETR or HS for intractable epilepsy between 1995 and 2002. APOS features and seizure outcome after ETR or HS were obtained at 6, 12, and 24 months. Univariate logistic regression was used for risk factors of APOS and life table analysis and log rank tests for seizure outcome at 0 to 6, 6 to 12, and 12 to 24 months. Results: Of 132 patients, 34 (26%) had APOS. APOS were more frequent after ETR (26/71) than HS (8/61) (p = 0.01). APOS, irrespective of their timing, number, semiology, or other perioperative complications, were an independent predictor of poor postoperative seizure outcome at 2 years (p = 0.001). The estimated odds of postoperative Engel class I outcome in the APOS vs non-APOS categories was 0.27 (73% less likely) for 0- to 6- month, 0.22 (78% less likely) for 6- to 12- month, and 0.13 (87% less likely) for the 12- to 24- month intervals. Conclusions: Acute postoperative seizures (APOS) occur in 26% children, and the risk is higher after extratemporal cortical resection than hemispherectomy. APOS predict a poor postoperative seizure outcome at 6, 12, and 24 months. This study is useful for counseling families after epilepsy surgery. It also suggests that APOS may not be discounted as "benign" in research studies that evaluate seizure outcomes after epilepsy surgery.