Suboccipital Nerve Blocks for Suppression of Chronic Migraine: Safety, Efficacy, and Predictors of Outcome

Background.- Approximately 1 in 50 Americans is afflicted by chronic migraine (CM). Many patients with CM describe cervicogenic headache. Options for treating CM effectively are at present quite limited. Objective.- To determine the safety and efficacy of occipital nerve blocks (ONBs) used to treat cervicogenic chronic migraine (CCM) and to identify variables predictive of a positive treatment response. Methods.- Using a uniform dose and injection paradigm, we performed ONBs consecutively on a series of patients presenting with CCM. Patients were stratified according to specific findings found to be present or absent on physical examination. A positive treatment outcome was defined as a 50% or greater reduction in headache days per month over the 30 days following treatment relative to the 30-day pre-treatment baseline. We used a 5-point Likert scale as one of the secondary outcome variables. Results.- We treated 150 consecutive patients with unilateral (37) or bilateral (113) ONBs. At the 1-month follow-up visit 78 (52%) exhibited evidence of a positive treatment response according to the primary outcome variable, and 90 (60%) reported their headache disorder to be "better" (44; 29%) or "much better" (46; 30%). A total of 8 (5%) patients reported adverse events within the ensuing 72 hours, and 3 (2%) experienced adverse events that reversed spontaneously but required emergent evaluation and management. Conclusion.- For suppression of CCM, ONBs may offer an attractive alternative to orally administered prophylactic therapy.