Abstracts

Rationale: Surgery for refractory temporal lobe epilepsy (TLE) has been well-supported as an effective treatment but remains underutilized in the elderly. There is skepticism about postsurgical outcomes in this group related to the presence of multiple comorbidities, preexisting cognitive dysfunction and longer seizure duration. The goal of this study is to assess the efficacy and tolerability of surgery in patients older than 55 years with a history of treatment resistant TLE. Methods: We reviewed data from all patients who underwent epilepsy surgery from 1998 to 2011. Only 18 met the inclusion criteria for age at surgery (55 or older) and history of TLE. Patients with both lesional and nonlesional imaging characteristics were included. Demographics collected were age at seizure onset, seizure semiology, frequency and duration, number of failed medications, results of standard presurgical workup, type of resection, histopathology and postsurgical seizure reduction over a follow-up period from 1 to 12 years. Fig1. Presurgical data included results of long-term video-EEG monitoring, brain Magnetic resonance imaging (MRI), neuropsychological assessment, speech and language evaluation and Wada test. Selected patients underwent Single Photon Emission Computed Tomography (SPECT) or/and Positron Emission Tomography (PET) scan. Intracranial recording was performed in patients whose noninvasive data was inconclusive. The degree of postsurgical seizure reduction was reported using Engel outcome criteria. We performed a bivariate analysis and found no significant predictors of outcome in type of resection, duration of epilepsy, number of failed medications, or type of MRI lesion. Results: 18 patients aged 55 or older underwent surgery for treatment resistant TLE. All patients had localization-related epilepsy with or without secondarily generalization. The seizure frequency varied from 1-7 per week to 1 per month. The mean number of failed anticonvulsants was 6.6. The mean epilepsy duration was 34 years. 11 patients (61%) had left temporal onset and 7 right temporal onset. 14 patients (78%) had MRI evidence of mesial temporal sclerosis (MTS). One patient had normal MRI. Fig.2 The surgical approach included anterior temporal lobectomy in 8 patients and selective amygdalohippocampectomy in 10. The patients with MRI evidence of MTS showed varying degree of neuronal loss and gliosis. Engel Class I outcome was achieved in 14 patients (78%) during average follow-up of 4.5 years. Conclusions: Our results indicate that the epilepsy surgery is well tolerated and efficacious in patients aged 55 and above who have a longstanding history of treatment resistant TLE. As such our data appear to be in general agreement with previous reports. 78% achieved Engel class I outcome for average of 4.5 years. The long disease duration does not serve as a negative predictor for postsurgical outcome. As such our results are in disagreement with previously suggested observations of higher incidence of seizure recurrence due to long-lasting secondary epileptogenesis and poorer outcomes.