Abstracts

Rationale: Surgery is a well-established treatment option for medically refractory epilepsy in children. While there are good success rates following initial surgery, some patients may require a second procedure to achieve seizure freedom or significant seizure reduction. The aim of our study is to characterize the patients undergoing repeat surgery and assess their outcomes.Methods: Retrospective observational study of children with refractory epilepsy who underwent repeat epilepsy surgery at Boston Children’s Hospital between January 2005 and December 2014. The surgical techniques evaluated in both the initial and repeat surgeries included focal cortical resection (including lobectomy), hemispherectomy, corpus callosotomy, and Visualase thermal ablation. Data was collected through a chart search reviewing the pre-operative work up as well as clinical follow-up.Results: 25 children were evaluated as part of this study with 9 males and 16 females. The average age of initial surgery was 94 months and the average time until the repeat surgery was 23 months. The initial surgical procedures included 16 resections, 3 hemispherectomies, and 6 Visualase ablations. Out of the 16 patients who underwent focal resections, 13 (82%) went on to have further resections and 3 (18%) had hemispherectomies as the repeat surgical procedure. All 3 of the patients with intial hemispherectomies had completion of their hemispherectomy as their repeat procedure. In the patients who had Visualase as their initial procedure, 1 had a repeat attempt with Visualase ablation and the remaining 5 underwent resection of the region surrounding the previously ablated tissue. Cortical dysplasias were seen 14 patients (56%) and 12 patients (48%) had post surgical scarring from previous resections. Of the remaining etiologies tumor (n=5), neuronal heterotopias, gliosis (n=4), and hippocampal sclerosis (n=3) were the most common. Of the 12 patients with post surgical scarring, 8 had pathology findings consistent with gliosis, 3 had focal cortical dysplasia, 1 had a glioma, and 1 had hippocampal sclerosis. 15 patients (60%) were able to achieve seizure freedom, and overall 19 patients (76%) were able to achieve improved seizure control with an Engel score of 1 or 2. Only 2 patients (8%) still have an Engel score of 4 following the repeat procedure.Conclusions: Epilepsy surgery is a sucessful treatment option for select patients with refractory epilepsy. Despite failure of the first attempt, a repeat surgery should be considered to produce good seizure control. Most repeat surgeries require further resection of previously operated on regions to help remove residual cortical dysplasia or post-surgical scarring.