Abstract, published in Epilepsia
Objective: The RNS System® is a direct brain-responsive neurostimulation system that is approved by the US FDA for adults with drug-resistant seizures that begin in one area of the brain, based on safety and effectiveness data from controlled clinical trials. The purpose of this study was to retrospectively evaluate the real-world safety and effectiveness of the RNS System.
Results: One hundred fifty patients met the criteria for analysis. The average reduction in seizures was 67% at 1 year, 75% at 2 years, 82% at 3 years or more, and 74% at last follow-up (average = 2.3 years). Thirty-five percent of patients had a ?90% seizure frequency reduction, and 18% of patients reported being clinically seizure-free at last follow-up. Seizure frequency reductions were similar regardless of patient age, age at epilepsy onset, duration of epilepsy, location of seizure onset, magnetic resonance imaging findings, prior intracranial monitoring, prior epilepsy surgery, or prior vagus nerve stimulation treatment. The infection rate per procedure was 2.9%; five of the six patients had an implant site infection, and one had a bone infection. Lead revisions were required in 2.7%, and 2.0% of patients had a subdural hemorrhage (a collection of blood outside the brain), none of which had long-lasting neurological consequences.
Significance: In this real-world experience, safety was similar and clinical seizure outcomes exceeded those of the prospective clinical trials, corroborating effectiveness of this therapy and suggesting that clinical experience has informed more effective programming of the RNS device.