Occipital Nerve Stimulation with the Bion® Microstimulator for the Treatment of Medically Refractory Chronic Cluster Headache

Abstract

Background: Chronic cluster headache is a severely disabling neurological disorder. Evidence from open-label case series suggest that occipital nerve stimulation may be effective for the treatment of chronic cluster headache. Objective: To evaluate the effectiveness of a microstimulator for chronic cluster headache. Study Design: Prospective, observational feasibility study plus medical record review. Settings: Academic medical center. Methods: Four patients with medically refractory chronic cluster headache underwent implantation of a unilateral bion microstimulator. In-person follow-up was conducted for 12 months after implantation, and a prospective follow-up chart review was carried out to assess long term outcome. Results: Three of the participants returned their headache diaries for evaluation. The mean duration of chronic cluster headache was 14.3 years (range 3 to 29 years). Pain was predominantly or exclusively retroocular/periocular. One participant demonstrated a positive response (> 50% reduction in cluster headache frequency) at 3 months postimplant, while there were 2 responders at 6 months. At least one of the participants continued to show > 60% reduction in headache frequency at 12 months. A chart review showed that at 58-67 months post-implant, all 3 participants reported continued use and benefit from stimulation. No side-shift in attacks was noted in any participant. Adverse events were limited to 2 participants with neck pain and/or cramping with stimulation at high amplitudes; one required revision for a faulty battery. Limitations: Small patient population without control group. Not blinded or randomized. Conclusion: Unilateral occipital nerve stimulation, using a minimally invasive microstimulator, may be effective for the treatment of medically refractory chronic cluster headache. This benefit may occur immediately after implantation, remain sustained up to 5 years after implantation, and occur despite the anterior location of the pain. Prospective, randomized controlled trials of occipital nerve stimulation in chronic cluster headache should proceed. Key words: chronic headache, bion, peripheral nerve stimulation, cluster headache, migraine, occipital