Treatment of Poststroke Pain by Epidural Motor Cortex Stimulation With a New Octopolar Lead

Abstract

Chronic, drug-resistant neuropathic pain can be treated by surgically implanted motor cortex stimulation (MCS). The leads used for MCS have not been specifically designed for this application. To study the value of a new 8-contact lead for MCS therapy in a series of 6 patients with refractory central poststroke pain. The study comprised a 1-month randomized phase, starting 1 month after implantation, during which the neurostimulator was switched on in one-half of the patients or remained off in the other half, followed by an open phase of 10 months, during which the stimulator was switched on in all patients. Clinical assessment was performed at baseline and 1, 2, 3, 6, and 12 months after implantation with the following scales: Visual Analog Scale, Verbal Rating Scale, Brief Pain Inventory, McGill Pain Questionnaire, Sickness Impact Profile, and Medication Quantification Scale. In the randomized phase, clinical scores were found to be globally reduced in the on- vs off-stimulation condition. In the open follow-up phase, all clinical scores improved significantly over time. The ratio between affective and sensory McGill Pain Questionnaire subscores decreased, suggesting a preferential effect of MCS on the affective component of pain. Compared with preoperative baseline, 2 patients were totally relieved of central poststroke pain, 3 patients were very much relieved, and 1 patient remained unchanged at the final examination. A good clinical outcome was observed in all patients except 1, suggesting that this new octopolar lead could be used for MCS therapy to treat refractory central poststroke pain.