Occipital nerve stimulation for chronic migraine--a systematic review and meta-analysis

Abstract

Background: Chronic migraine is a debilitating headache disorder that has significant impact on quality of life. Stimulation of peripheral nerves is increasingly being used to treat chronic refractory pain including headache disorders. This systematic review examines the effectiveness and adverse effects of occipital nerve stimulation (ONS) for chronic migraine.

Methods: Databases, including the Cochrane Library, MEDLINE, EMBASE, CINAHL and clinical trial registers were searched to September 2014. Randomized controlled trials (RCTs), other controlled and uncontrolled observational studies and case series (n≥ 10) were eligible. RCTs were assessed using the Cochrane risk of bias tool. Meta-analysis was carried out using a random-effects model. Findings are presented in summary tables and forest plots.

Results: Five RCTs (total n=402) and seven case series (total n=115) met the inclusion criteria. Pooled results from three multicenter RCTs show that ONS was associated with a mean reduction of 2.59 days (95% CI 0.91 to 4.27, I2=0%) of prolonged, moderate to severe headache per month at 3 months compared with a sham control. Results for other outcomes generally favour ONS over sham controls but quantitative analysis was hampered by incomplete publication and reporting of trial data. Lead migration and infections are common and often require revision surgery. Open-label follow-up of RCTs and case series suggest long-term effectiveness can be maintained in some patients but evidence is limited.

Conclusions: While the effectiveness of ONS compared to sham control has been shown in multiple RCTs, the average effect size is modest and may be exaggerated by bias as achieving effective blinding remains a methodological challenge. Further measures to reduce the risk of adverse events and revision surgery are needed.

Systematic review registration: this systematic review is an update and expanded work of part of a broader review registered with PROSPERO. Registration No. CRD42012002633.

Fig 1. Flow diagram for study selection.

Fig 2. Results of meta-analysis of RCT data for ONS compared with sham stimulation: days with prolonged (≥4 hours) moderate or severe headache.

Fig 3. Results of meta-analysis of RCT data for ONS compared with sham stimulation: response rate.

Fig 4. Adverse effects associated with implantation and/or use of occipital nerve stimulation: lead migrations.

Fig 5. Adverse effects associated with implantation and/or use of occipital nerve stimulation: infections.

Saper 2011—the number shown was infections at site for lead/extension tract. There were additionally four ‘complications at incision sites’.[17] Silberstein et al. 2012—there were additionally ‘wound site complications’ (four at 3 months;[28] five at 1 year[30]). Lipton et al. described infections being the most frequent device-related adverse events but did not report the numbers in their published abstract.[16] The three cases described by Kiss and colleagues were ‘inflammation at surgical sites’ (3/10, 30%) that were treated with intravenous and oral antibiotics.[33] They stated that ‘neither blood nor wound cultures identified bacterial growth’.