Effectiveness of Peripheral Nerve Blocks for the Treatment of Primary Headache Disorders: A Systematic Review and Meta-Analysis.

Study Objective: Primary headache disorders are prevalent and account for 2% of all emergency department visits. Current treatment options are effective; however, time to pain relief is suboptimal. Alternatives such as peripheral nerve blocks have shown promising results. The objective of this systematic review is to examine the effectiveness of peripheral nerve blocks for timely pain relief.

Methods: We searched Ovid MEDLINE, EMBASE, Web of Science Core Collection, and the Cochrane Central Register of Controlled Trials and included randomized controlled trials comparing peripheral nerve blocks to placebo or active therapy. The primary outcome was pain within 120 minutes. Secondary outcomes were pain after 120 minutes, adverse events, need for rescue medications, and relapse of headache. Two reviewers screened and extracted data independently; mean differences (MDs) were calculated, and results were pooled using a random-effects model.

Results: Eleven studies met our eligibility criteria (n=860), of which 9 were included in the meta-analysis. Pain scores were significantly lower in patients treated with peripheral nerve blocks than with placebo at 15 minutes (MD: -1.17; 95% confidence interval: -1.82 to -0.51) and 30 minutes (MD: -0.99; 95% confidence interval: -1.66 to -0.32), and no serious adverse events were reported. Pain scores for peripheral nerve blocks versus active therapy and secondary outcomes were not pooled due to clinical heterogeneity.

Conclusion: Our review shows peripheral nerve blocks are effective as a rapid treatment option when compared to placebo; however, we were unable to assess effectiveness against standard treatment. Emergency physicians should consider peripheral nerve blocks as an adjunct therapy for patients with primary headache disorders.