Factors Predictive of the Outcome of Frontal Lobe Epilepsy Surgery

PURPOSE: To identify factors that predict the outcome in seizure control after frontal lobe epilepsy surgery (FLES). FLES is the second most frequent type of epilepsy surgery, but the results are generally not as good as those after anterior temporal lobectomy. METHODS: Our cohort consisted of 68 consecutive patients whose first epilepsy surgery involving the frontal lobe occurred between 1987 and 1994. Clinical history and results of imaging and electroencephalographic studies were reviewed in detail. Excellent outcome was defined as being seizure free or having only nondisabling seizures at last follow up. RESULTS: Forty of the 68 patients (58.8%) had an excellent outcome; none of the patients with a history of childhood febrile seizures had an excellent outcome, whereas outcome was excellent in 63% of those without that history (p </= 0.01). The other significant presurgical factor was the presence of a potentially epileptogenic lesion in the frontal lobe on neuroimaging (excellent outcome in 72% when present versus 41% when absent, p </= 0.001). The only significant postsurgical factor was early postoperative seizure control in the first year (excellent outcome in 96% with early control versus 25% without, p </= 0.01). CONCLUSIONS: History of childhood febrile seizures is a poor prognostic factor in FLES patients. It may suggest that the structural basis of all or some of the patients' intractable seizures is mesial temporal sclerosis. On the other hand, neuroimaging detection of a potentially epileptogenic frontal lobe lesion and early postoperative seizure control are associated with subsequent excellent outcome.