Occipital nerve stimulation with the Bion® microstimulator for the treatment of medically refractory chronic cluster headache.

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 post-implant, 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.