gms | German Medical Science

Objective: To analyze long term results of temporal lobe epilepsy surgery without invasive recording and to evaluate preoperative factors predicting good postoperative outcome.

Methods: Between October 2000 and October 2007, a total of 125 patients underwent resective surgery for pharmacologically intractable epilepsy at the Department of Neurosurgery, University of Damascus. There were 76 male and 49 female patients, ranging in age from 6 to 42 years (mean 19 years). All patients had pharmacologically intractable epilepsy lasting for a minimum of 1 year. For all patients, incomplete seizure control at maximal tolerable serum levels of at least two first-line anticonvulsant agents and one recent antiepileptic drug had to be proven before they were referred for presurgical evaluation. Confirmation of epileptogenicity was done in all patients with interictal and ictal scalp EEG. MRI imaging studies revealed mesiotemporal lesions (hippocampal sclerosis) with or without extrahippocampal structural lesions (neocortical lesions).

Invasive testing is needed if there is evidence of bitemporal mesiotemporal sclerosis on structural imaging and/or EEG-recording (these cases account for 15% of all patients who underwent presurgical evaluation). All patients underwent standard anterior temporal lobectomy (including both lateral temporal resection and amygdalohippocampectomy). In 72 patients (58%) histological examination of the resected tissue showed hippocampal sclerosis, in 53 patients different pathological patterns were found.

Results: With a mean follow up of 38.7 months, 109 patients (87%) were seizure free since the operation (Engel’s classification I), 10 patients (8%) had no more than two seizures per year (Engel II), and 6 patients (5%) showed a reduction in seizure frequency of at least 75% (Engel III). There was no peri- or postoperative mortality.

Conclusions: In intractable epilepsy, structural imaging suggesting unilateral temporal sclerosis as well as concordant interictal and ictal surface EEG recordings and seizure types are predominance factors associated with good postoperative outcome. Outcome at one year postoperatively is highly predictive of long term outcome.