Reoperative hemispherectomy for intractable epilepsy: a report of 36 patients.

BACKGROUND: In patients with medically intractable epilepsy and diffuse unilateral hemispheric disease, functional or disconnective hemispherectomy is a widely accepted and successful treatment option. If recurrent seizures develop after disconnective hemispherectomy, management options become more complex and include conversion to anatomic hemispherectomy.
OBJECTIVE: To present the outcomes of all patients undergoing reoperative hemispherectomy in 1 institution by 1 surgeon since 1998.
METHODS: The medical records, operative reports, and imaging studies for 36 patients undergoing reoperative hemispherectomy for continuing medically intractable epilepsy from 1998 to 2011 at Cleveland Clinic were reviewed. Patient characteristics, cause of seizure, imaging findings, surgery-related complications, and long-term seizure outcomes were evaluated.
RESULTS: Patients presented with a variety of seizure origins, including Rasmussen encephalitis, perinatal infarction, cortical dysplasia, and hemimegalencephaly. Overall, 19% of patients were seizure free after conversion to anatomic hemispherectomy, and 45% reported a decrease in seizure frequency by ≥ 90%. An additional 36% reported no improvement. Generalized ictal electroencephalography tended to confer a poorer prognosis, as did cortical dysplasia as the underlying diagnosis.
CONCLUSION: The possibility that residual epileptogenic tissue in the operated hemisphere remains connected should be considered after failed functional hemispherectomy because our data suggest that improvement in seizure frequency is possible after reoperative hemispherectomy, although the chance of obtaining seizure freedom is relatively low. The decision to proceed with reoperative hemispherectomy should be made after proper discussion with the patient and family and informed consent is given.