Abstracts

Rationale: Responsive neurostimulation (RNS) is a relatively recent addition to the epilepsy surgery armory, gaining FDA approval in 2013 for use in adults with intractable focal epilepsy. Data for the use of RNS system in patients less than 18 years of age is limited. We aim to determine the safety and feasibility of RNS in children with refractory epilepsy.

Methods:
Participants: Consecutive patients receiving RNS implants from October 2018 (the very first implant at our center) to April 2021 at an urban tertiary children’s hospital were included in this study. RNS was chosen for these patients after a robust epilepsy surgery evaluation and interdisciplinary discussion between pediatric epileptologists, pediatric neurosurgeons, and pediatric neuroradiologists.

Measures: Feasibility and safety were determined using information from chart reviews.

Procedure: Demographics of the patients were obtained, including age of implant, seizure onset zone identification, and RNS targets. Feasibility can be determined based on the success of the procedure. To determine safety, perioperative charts were reviewed for any surgical complications such as infection, hemorrhage, or stroke.

Results: Chart review yielded 10 patients, see Table 1. Age at implant ranged from 8 years old to 19 years old. RNS was the first and only epilepsy surgery in 2 of the 10 patients. 3 of the 10 patients had concurrent cortical resections with RNS implant, and the remaining 5 patients had previous epilepsy surgery. One patient had a postoperative complication of infection at the surgical site requiring explantation 2 months after the procedure. This patient had concurrent subdural collection evacuation at the time of RNS implant. One patient had a second RNS canister placed successfully without complication 3 years after the initial RNS single canister implant due to a broad epileptic network and continued seizures. The initial RNS placement done at another center identified seizure onset using strips. At that time, four electrodes were placed and only two were hooked up to the initial canister and the remainder were left intracranial. At our center, the remaining two intracranial electrodes were successfully hooked up to the second canister. Seizure onset zones were identified by stereooelectroencephalography (stereo EEG) using Robotic stereotactic assistance (ROSA^®) in 8 of the 10 patients. RNS was chosen in these patients due to multiple ictal circuits, broad network, and/or refractory epilepsy after previous epilepsy surgery.

Conclusions: In a 16-month time period, 10 RNS systems were implanted at an urban tertiary children’s hospital in patients ranging from 8 years old to 19 years old. Placement of RNS is a feasible, relatively safe option for children as young as eight years with refractory epilepsy. Surgical site infection was a complication observed in one patient in which RNS was placed after undergoing a separate procedure. Two canister RNS placement is feasible for patients with a broad epileptogenic network or multifocal seizure onset zones.

Funding: Please list any funding that was received in support of this abstract.: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.