Greater Occipital Nerve Block for Acute Treatment of Migraine Headache: A Large Retrospective Cohort Study.

INTRODUCTION:Greater occipital nerve (GON) blocks are frequently used to treat migraine headaches, although a paucity of supporting clinical evidence exists. The objective of this study was to assess the efficacy of GON block in acute treatment of migraine headache, with a focus on pain relief. METHODS:This retrospective cohort study was undertaken between January 2009 and August 2014 and included patients who underwent at least 1 GON block and attended at least 1 follow-up appointment. Change in the 11-point numeric pain rating scale (NPRS) was used to assess the response to GON block. Response was defined as "minimal" (<30% NPRS point reduction), "moderate" (31-50% NPRS point reduction), or "significant" (>50% NPRS point reduction). RESULTS:A total of 562 patients met inclusion criteria; 423 were women (75%). Mean age was 58.6 ± 16.7 years. Of these 562, 459 patients (82%) rated their response to GON block as moderate or significant. No statistically significant relationship existed between previous treatment regimens and response to GON block. GON block was equally effective across the different age and sex groups. CONCLUSIONS:Greater occipital block seems to be an effective option for acute management of migraine headache, with promising reductions in pain scores.