Authors: Kathryn Wagner, MD; kathryn wagner; Vijay Ravindra, MD; Sandi Lam, MD (Houston, TX)

Introduction: Hemispherectomy has is an effective surgical treatment of intractable epilepsy in appropriately selected patients. Historically an open procedure with significant morbidity, endoscopic approaches to hemispheric disconnection have been pursued in efforts to minimize exposure and associated complications. We have previously described the development and implementation of the endoscopic-assisted hemispherectomy at Texas Children’s Hospital (TCH). Here we present the preliminary results of this technique. Methods: Data was prospectively collected on pediatric patients undergoing hemispherectomy at TCH. Patient candidacy for endoscopic hemispherectomy was the consensus of a multi-disciplinary epilepsy team, and all procedures were performed by the senior faculty who implemented the procedure at TCH. Full disconnection of the hemispheres was performed using the endoscopic-assisted technique previously described. Patient characteristics, perioperative data, clinical course, outcomes, complications, and seizure freedom rates were reviewed. Patient who have a minimum of three months follow up were included in this review. Results: Nine patients aged two months to 16 years underwent endoscopic hemispherotomy from 11/2017-7/2018 with subsequent follow up. Diagnoses included perinatal stroke, intraventricular hemorrhage of prematurity, polymicrogyria, and cortical dysplasia. Estimated blood loss ranged from 30-200cc, and operative time ranged from three to eight hours, with duration correlating with complexity of pathologic anatomy. There were no intraoperative or perioperative complications. All patients remain seizure free at last follow up, and 22% patients have required cerebrospinal fluid shunt to date. When compared to a historical open craniotomy cohort at our institution, endoscopic patients had lower estimated blood loss. Conclusion: Endoscopic hemispherotomy can be safely implemented in clinical practice with early outcomes similar to standard open procedures. Our short-term seizure freedom rate is 100%, and rates of postoperative hydrocephalus requiring shunts are similar to those published regardless of surgical techniqueLarger series and long term data is needed to compare novel endoscopic techniques to current open procedures.