Abstracts

Rationale: To assess the number of distinct anti-epileptic medications patients tried prior to surgical evaluation for refractory epilepsy.Methods: We reviewed presurgical summaries for all patients who underwent surgery for medically refractory epilepsy between 2010 and 2014 at Boston children’s Hospital, and analyzed age of epilepsy onset, age at surgery, surgery type, lesion type and number of anti-epileptic drugs that had been prescribed to the patient from time of epilepsy diagnosis to time of the first presurgical evaluation.Results: 152 unique surgeries were performed on 142 patients. Age range at the time of surgery was 4mo to 22yrs (mean 11yrs). Average time to surgery from seizure onset was 6.7yrs (3mo to 17yrs) with the average age of onset 4.3yrs (1d to 17yrs). Of the 152 surgeries, 135 had MRI-positive lesions. There were 100 resective surgeries, 26 hemispherectomies, 11 corpus callosotomies and 15 laser interstitial thermal ablations. The average number of medications trialed at the time of first epilepsy surgery evaluation was 5.2 (range 1-12). There was no difference in number of medications or time to surgery between lesional and non-lesional cases.Conclusions: Despite an accepted operational definition of medically refractory epilepsy as failing two appropriate anti-epileptic medications, patients undergoing epilepsy surgery at our center typically have tried many more before referral for surgical evaluation.