We aim to retrospectively review and characterize clinical outcomes and combination treatment rationale in patients treated concurrently with surgical resection and responsive neurostimulation(RNS).

Medically refractory epilepsy with independent and multi-focal ictal onset can pose a significant challenge to physicians in treating epilepsy. RNS has offered an alternative method to treating ictal onset zones that are otherwise not amenable to surgical resection in refractory epilepsy.² RNS acts like a pacemaker for the brain, it continuously monitors the brain and attempts to stop or shorten seizure duration by delivery of electrical current. RNS has shown promising results in reducing seizure frequency. ³ However, it is limited to placement of only 2 anatomical locations. Hence, certain patients with independent and multiple ictal onset zones remain a great challenge to treat.  

We retrospectively reviewed charts of 63 patients who had RNS implantation at University of California, Irvine (UCI) from 2014-2022. Of which, a subset of 16 patients met inclusion criteria for having both RNS and surgical resection within a 90-day period, and with follow-up of at least 9 months after treatment.

A total of 16 patients met inclusion criteria. The average age was ~35.75 years old. The following formula, ¹Seizure Reduction Formula = 1- (# seizures per month at time of last follow-up divided by number seizures per month at baseline) x 100 was used to calculate seizure reduction. Patients in our cohort had 75.24% reduction in seizures, of which 6/16 (37.5%) patients were seizure free.

This study shows promising results for combination treatment of RNS implantation and surgical resection. It allows for flexibility of treatment options offered to medically and surgically refractory epilepsy patients. It builds on a prior retrospective study of a smaller cohort of patients at UCI that showed similar favorable results of seizure reduction. ¹