Long-term outcomes of occipital nerve stimulation for chronic migraine: a cohort of 53 patients

Abstract

Background: Chronic migraine affects up to 2 % of the general population and has a substantial impact on sufferers. Occipital nerve stimulation has been investigated as a potentially effective treatment for refractory chronic migraine. Results from randomised controlled trials and open label studies have been inconclusive with little long-term data available.

Methods: The long-term efficacy, functional outcome and safety of occipital nerve stimulation was evaluated in an uncontrolled, open-label, prospective study of 53 intractable chronic migraine patients.

Results: Fifty-three patients were implanted in a single centre between 2007 and 2013. Patients had a mean age of 47.75 years (range 26-70), had suffered chronic migraine for around 12 years and had failed a mean of 9 (range 4-19) preventative treatments prior to implant. Eighteen patients had other chronic headache phenotypes in addition to chronic migraine. After a median follow-up of 42.00 months (range 6-97) monthly moderate-to-severe headache days (i.e. days on which pain was more than 4 on the verbal rating score and lasted at least 4 h) reduced by 8.51 days (p < 0.001) in the whole cohort, 5.80 days (p < 0.01) in those with chronic migraine alone and 12.16 days (p < 0.001) in those with multiple phenotypes including chronic migraine. Response rate of the whole group (defined as a >30 % reduction in monthly moderate-to-severe headache days) was observed in 45.3 % of the whole cohort, 34.3 % of those with chronic migraine alone and 66.7 % in those with multiple headache types. Mean subjective patient estimate of improvement was 31.7 %. Significant reductions were also seen in outcome measures such as pain intensity (1.34 points, p < 0.001), all monthly headache days (5.66 days, p < 0.001) and pain duration (4.54 h, p < 0.001). Responders showed substantial reductions in headache-related disability, affect scores and quality of life measures. Adverse event rates were favourable with no episodes of lead migration and only one minor infection reported.

Conclusions: Occipital nerve stimulation may be a safe and efficacious treatment for highly intractable chronic migraine patients even after relatively prolonged follow up of a median of over 3 years.

Keywords: Chronic migraine; Headache; Neurostimulation; Occipital nerve stimulation.

Fig. 1

Changes in moderate-to-severe headache days following occipital nerve stimulation. a Improvement of moderate-to-severe headache days of whole cohort over follow-up period. b Improvement in moderate-to-severe headache days of those with chronic migraine alone compared to those with multiple phenotypes over follow-up period. Table provides number of subjects included at each time point

Fig. 2

Responder rates of all chronic migraine patients to prolonged occipital nerve stimulation treatment by outcome measure. Various outcome measures have been used across the occipital nerve stimulation literature to measure response in chronic migraine. The response rate of the cohort is shown for each of these outcome measures – headache days, pain intensity and a combination of headache days and/or pain intensity. VRS verbal rating scale