Confined Stimulation Using Dual Thalamic Deep Brain Stimulation Leads Rescues Refractory Essential Tremor: Report of Three Cases

BACKGROUND/AIMS: Deep brain stimulation (DBS) of the nucleus ventralis intermedius (VIM) provides a safe and effective therapy for medically refractory essential tremor (ET). However, as many as 9% of VIM DBS patients deteriorate after several years of good tremor control. For these patients, the high voltage needed to adequately control tremor also generates circumferential current spread causing intolerable adverse effects. METHODS: We report 3 ET patients where adding a second parallel thalamic lead anterior-medially to the original and connecting the 2 adjacent leads to a dual-channel pulse generator (Medtronic Synergy, model No. 7427) successfully recaptured tremor control with fewer adverse effects. RESULTS: This approach allowed us to direct the stimulation field away from nearby structures responsible for the adverse effects. Such confined stimulation can be achieved by connecting 2 adjacent DBS leads to a common voltage source, providing current flow between leads. CONCLUSION: This dual lead stimulation method can be used as a reversible rescue therapy in ET patients who require unacceptably high intensity stimulation.