Abstracts

Rationale: Temporal lobectomy is a successful treatment for medically refractory temporal lobe epilepsy. However, there remains a significant percentage who do not benefit from surgery, likely an reflection of disease heterogeneity. Surgery on nonlesional temporal lobe epilepsy patients is generally less successful than on those who have an obvious target on imaging. However, imaging can be open to interpretation and not always reliable. Intracranial EEG can further localize the seizure focus in patients with normal or questionable imaging. In this study we investigate differences between temporal lobectomy patients who required invasive monitoring versus those who did not. Methods: A retrospective review of all patients who underwent a standard anterior temporal lobectomy for epilepsy from 2006 to 2013 at the University of Alabama at Birmingham Hospital was obtained. Patients without 1 year follow up were excluded from analysis. Results: A total of 127 anterior temporal lobectomy patients were included for analysis. Invasive monitoring was performed prior to resection in 58 patients with 69 patients undergoing resection without monitoring. Average seizure free rate was 80% in the nonmonitored group and 66% in the monitored group. Average follow up was 2.37 years. There was a significant difference in the percentage of patients with hippocampal sclerosis on MRI between the two groups (p < 0.0001) however this was not found to be associated with Engel Class (p = 0.35). Pathologic diagnosis of hippocampal sclerosis was also associated with a poorer prognosis than focal cortical dysplasia (p = 0.02). Other significant variables included generalized tonic clonic seizure frequency (p = 0.02) and ICEEG ictal-interictal correlation (p = 0.04). Conclusions: Patients who did not require invasive monitoring had a better seizure free outcome after surgery, however, MRI findings were not found to impact outcome. Generalized tonic clonic seizures are a negative predictor of surgical outcome.