In the first stage, 12 subjects with refractory neuropathic pain will be enrolled to an inpatient clinical trial for insular brain mapping with acute stimulation and neurophysiological brain monitoring. Electrodes for stimulation and recording will be implanted stereotactically along the anterior-posterior axis of the insular cortex. 'Responders' to trial stimulation and the optimal region of the insula for pain relief will be identified during this inpatient stage.~'Responder' subjects who have positive analgesic effects from acute insular stimulation during the first stage will continue to the second stage. The second stage, clinical trial is conducted outpatient and will test chronic deep brain stimulation of the insula. The study design is randomized, sham-stimulation-controlled, double-blinded, and cross-over where subjects receive both active and sham stimulation. Furthermore, neurophysiological biomarkers of pain will be investigated by studying changes in neural activity.
This study will comprehensively investigate the insula as a brain target for neuromodulation to treat chronic neuropathic pain.