Surgical management and seizure outcome in patients with tuberous sclerosis

The authors report the results obtained in 11 patients with tuberous sclerosis (TS) who underwent cortical resection surgery for medically intractable epilepsy. Patients' ages at time of surgery ranged from 3 to 46 years (mean 19.6 years). Preoperative epileptiform electroencephalographic abnormalities were focal spike wave discharges in six patients (55%), multifocal in four patients (36%), and generalized in one patient (9%). In the multifocal and generalized groups, all patients (45%) were evaluated by means of subdural grid and strip electrode recordings, whereas electrophysiological localization in the remaining patients was derived from ictal and interictal scalp recordings. The seizure loci were found to be extratemporal in six patients (55%) and temporal in five patients (45%). Surgical intervention consisted of craniotomy and seizure loci resection guided by electrocorticographic monitoring and functional mapping in five awake (45%) and six asleep (55%) patients. Neuropathological examination of the reseated seizure foci revealed cortical tubers in eight patients and diffuse gliosis in three patients. Follow up ranged from 8 to 127 months (mean 35 months). Six patients (55%) were seizure free, half of whom were not receiving antiepileptic drugs (AEDs); three patients (27%) had a greater than 70% reduction in seizure frequency, although they required AEDs; one patient (9%) had a 50% temporary reduction in seizure frequency during the initial 6- month postoperative period: and one patient (9%) was lost to follow-up study. From this small but adequately followed patient population with TS, the authors conclude that cortical resection of seizure loci tailored to electrocorticographic findings and functional mapping is encouraging for this difficult to manage patient population with medically intractable epilepsy.