Preoperative tumor-associated epilepsy in patients with supratentorial meningioma: factors influencing seizure outcome after meningioma surgery

OBJECTIVE: Both pre- and postoperative seizures comprise common side effects that negatively impact patient quality of life in those suffering from intracranial meningioma. Therefore, seizure freedom represents an important outcome measure in meningioma surgery. In the current study the authors analyzed their institutional database to identify risk factors for postoperative seizure occurrence after surgical meningioma therapy in patients with preoperative symptomatic epilepsy. METHODS: Between February 2009 and April 2017, 187 patients with preoperative seizures underwent resection of supratentorial meningioma at the authors' institution. Seizure outcome was assessed retrospectively 12 months after tumor resection according to the International League Against Epilepsy (ILAE) classification and stratified into favorable (ILAE class I) versus unfavorable (ILAE classes II-VI). A univariate and multivariate analysis was performed to identify factors influencing seizure outcome. RESULTS: Overall 169 (90%) of 187 patients with preoperative seizures achieved favorable outcome in terms of seizure freedom after meningioma resection. Multivariate analysis revealed peritumoral edema > 1 cm in maximal diameter and WHO grade II and III tumors, as well as a low extent of resection (Simpson grades III-V) as independent predictors for postoperative unfavorable seizure outcome. CONCLUSIONS: Surgery is highly effective in the treatment of seizures as common side effects of supratentorial meningioma. Furthermore, the present study identified several significant and independent risk factors for postoperative seizure occurrence, enabling one to select for high-risk patients that require special attention in clinical and surgical management.