Objective: To analyze the preoperative and operative factors predictive of outcome in patients undergoing surgery for temporal lobe epilepsy.
Design: From 1984 to 1992, 98 patients with medically refractory temporal lobe epilepsy underwent surgery. Evaluation included the following: video electroencephalography (13 patients had intracranial recordings), head magnetic resonance imaging, interictal and ictal single photon emission computed tomography, psychometric testing, and Wada testing. Seizure-free groups and non-seizure-free groups were analyzed. Follow-up of 1 year to 8 years was available for 89 patients (mean, 3.2 years).
Setting: Indiana University Epilepsy Surgery Program, Indianapolis.
Outcome: Sixty percent (53/89) were seizure free, 16% (14/89) had rare seizures, 13% (12/89) had worthwhile improvement, and 11% (10/89) showed no improvement. Forty-two percent of seizure-free patients had a history of febrile seizures compared with 5% of non-seizure-free patients. Ictal single photon emission computed tomography showed increased flow on the side of seizure onset in 86% of seizure-free patients compared with 62% of non-seizure-free patients. Ninety-seven percent of seizure-free patients had a pathologic diagnosis; mesial temporal structures were identified in 61%. Only 64% of non-seizure-free patients had a pathologic diagnosis, and mesial temporal structures were identified in only 36% of non-seizure-free patients.
Conclusions: Eighty-nine percent (79/89) of our patients benefited from surgery. The following factors were predictive of good outcome: a history of febrile seizures; ictal single photon emission computed tomography showing increased blood flow ipsilateral to the epileptogenic zone; a pathologic diagnosis; and the presence of mesial temporal structures in the resected tissue.