The RNS System: responsive cortical stimulation for the treatment of refractory partial epilepsy.

The RNS(®) System is the first commercially available device to provide closed-loop responsive brain stimulation. The system includes a cranially implanted neurostimulator that continually monitors the electrocorticogram through one or two depth and/or subdural cortical strip leads that are placed at the seizure focus. When abnormal electrographic activity is detected, the neurostimulator delivers brief pulses of electrical stimulation to the seizure focus through the implanted leads. In November 2013, the US FDA approved the RNS System as an adjunctive therapy for patients with drug resistant, partial onset seizures who have undergone diagnostic testing that localized no more than 2 epileptogenic foci. Safety and effectiveness of the RNS System for the indicated patient population was demonstrated in a multicenter, randomized, sham-stimulation controlled 2-year pivotal study. An ongoing, prospective, long-term treatment study is currently gathering an additional 7 years of prospective safety and effectiveness data of the RNS System.