Despite medical advances, it is estimated that five percent of patients with chronic migraine (CM) are refractory to treatment. As some have suggested the feasibility of occipital nerve stimulation (ONS) for the treatment of these headaches, this study examined the long-term outcomes of a single center cohort of patients with CM undergoing ONS.

Patients seen at a headache clinic in London with a diagnosis of CM were treated with implantation of bilateral ONS electrodes, and an implantable pulse generator (IPG). Remote controls were provided to the participants to adjust the stimulation amplitude. The subjects maintained headache diaries and were reviewed in clinic every three months for the first year and 12 months thereafter. The Migraine Disability Assessment Scores (MIDAS) and Headache Impact Test Six (HIT-6) scores were recorded before and after ONS to monitor headache-related disability. The primary outcome measure was improvement in mean monthly, moderate-to-severe headache days compared to baseline. A "responder" was defined as a patient who had a 30% or more reduction in headache days.

Of the 53 patients, the mean duration of CM was 11.77 years, with a mean follow-up of 42 months. At final follow up, 45.3% were "responders" including 34.3% of those with CM alone and 66.7% of those with multiple headache types. Monthly moderate-to-severe headache days fell by 8.51 days (P<0.001). While a significant improvement was noted in the HIT-6 scores, the reduction in MIDAS was not significant. Among responders, improvements in functional outcome related disability were noted.

This study of patients with chronic headaches, including migraine, found that occipital nerve stimulation can significantly reduce the number of headache days, and, among responders, improve functional outcome and disability.