Abstracts

Rationale: Our single center randomized-controlled trial in 80 patients revealed that surgery for temporal lobe epilepsy is superior to medical therapy providing a 58% chance of seizure freedom. In this study, we have looked at our experience over more than 30 years. Methods: The Epilepsy Surgery Database for the London Health Sciences Centre was interrogated for all temporal lobectomies. Consecutive cases, since the inception of the Epilepsy Program until December of 2005, were included. The origin of seizures was determined by interictal and ictal findings on the EEG. If seizure origin was unclear, intracranial EEG was performed with the use of subdural strip electrodes. Patients with poor memory function bilaterally or on the side opposite that of the origin of the seizure underwent bilateral intracarotid amobarbital sodium tests. Patients with adequate memory on the side of the origin of the seizure and poor memory function on the contralateral side did not have surgery. Those with temporal lobe originating seizures consistent with seizure semiology, MRI findings and neuropsychological tests underwent resection of the anterior temporal lobe. A maximum of 6.0 to 6.5 cm of the anterior lateral nondominant temporal lobe or 4.0 to 4.5 cm of the dominant temporal lobe was resected including the amygdala and the anterior 1.0 to 4.0 cm of the hippocampus. Results: 798 patients had temporal lobectomies (402 females). Mean age at seizure onset was 14.5 (SD= 12.52, range: 0-75), mean age at surgery was 30.8 years (SD=12.93, range 1-75). 603 patients were right handed, 116 left handed, and 22 ambidextrous. Standard EEG evaluation revealed 339 cases of right TLE, 381 of left TLE, and 63 with bilateral TLE. 287 patients had placement of intracranial electrodes. The pathology revealed 188 cases with mesial temporal sclerosis and 27 with dual pathology. Since many patients came from a distance, follow-up was variable. At 1 year after surgery, information was available on 507 patients. 307 were seizure free (61.4%); at 2 years 214 patients out of 370 with follow up, were seizure free (57.8%); and, at 3 years 159 out of 263 (60.4%) were seizure free. Conclusions: The retrospective outcome in this larger cohort of patients concurs with the findings, in a much smaller sample, of our previous prospective randomized trial of surgical management of temporal lobe epilepsy.