Abstracts

Rationale: Acute postoperative seizures in the immediate and early postoperative period are not infrequent. However, long term inadequate seizure control following hemispherectomy for lateralized hemispheric seizure activity is infrequent. We investigated the causes of failure to obtain good seizure control in our patient populationMethods: A retrospective analysis of the epilepsy surgery database was performed to investigate the causes of inadequate seizure control following hemispherectomy. We then analyzed the preoperative interictal and ictal electroencephalographic data to assess the extent of seizure abnormality. Particular attention was paid to the presence of contralateral abnormalities. Preoperative and postoperative magnetic resonance images were reevaluated to assess the presence of contralateral structural abnormalities and the degree of interhemispheric disconnection.Results: Since 1979, more than 600 children underwent surgery for intractable epilepsy. Eight-two patients underwent hemispherectomy. Inadequate seizure control was possible in 12 patients. We found incomplete interhemispheric disconnection as seen on postoperative MR scans in 3 patients. Contralateral epileptiform activity was present in 6 patients. A detailed analysis of the results will be discussed.Conclusions: Unsuccessful control of seizures following hemispherectomy may be secondary to incomplete hemispheric disconnection, contralateral morphological abnormality and multifocal epileptiform abnormalities and postoperative injury to the contralateral hemisphere.