Seizure outcome was studied in 136 children receiving surgery for intractable epilepsy at the Cleveland Clinic between 1990 and 1996. The postoperative follow-up period was 1 to 7.5 years (mean, 3.6 years). Cortical dysplasia and low-grade tumor were the most common causes; hippocampal sclerosis was rare. A seizure-free outcome achieved in 60-69% of patients was more frequent in patients requiring temporal resections (74-80%) than in those with extratemporal or multilobar resection (52-58%), and also among patients with tumor (82%) compared to those with cortical dysplasia (52%). Age was not a factor; the frequency of a seizure-free outcome was similar for infants, children, and adolescents, and comparable to reports of adult series. 
COMMENT. The risk/benefit ratio for surgery of intractable epilepsy varies with the pathology and localization of the lesion. Patients with low-grade tumors and foci located in the temporal lobe have a better outcome than those with cortical dysplasia and extratemporal or hemispheric localization. Outcome is not dependent on age, and delayed surgery may result in psychosocial deterioration.
Etiology as a risk factor for medically refractory epilepsy, and a case for early surgical intervention are presented in a study of 2,200 patients, ages 16 and older, from La Salpetriere Hospital, Paris , and in an editorial . Early surgical intervention is recommended for mesial temporal lobe epilepsy (MTLE), the most common and most medically refractory localization-related epilepsy syndrome. If operation is delayed, MTLE has a progressive course, with more severe seizures over time, and associated cognitive and psychosocial disabilities may become irreversible.
Surgery of epilepsy in tuberous sclerosis is evaluated at the Montreal Neurological Institute . Among 18 patients, 12 having a single tuber or well-localized epileptogenic lesion and treated by lesionectomy or focal resection have the best outcome. Patients without good imaging and EEG correlation respond only partially to corpus callostomy.
Long-term outcome of tuberous sclerosis epilepsy is studied at Okayama University, Japan . Twelve (32%) of 38 patients were seizure-free for >1 year at the mean 14 year follow-up (range, 3 to 30 years). Seizures were generalized in 11, partial and localized in 10, and they changed from generalized to localization-related epilepsies during the clinical course in 17. Neither location nor number of tubers is related to the long-term outcome. Seizure and mental outcomes are least favorable in those with generalized seizures, including West and Lennox-Gastaut syndromes; only 18% seizure free and 9% with a normal mentality.