The Impact of Spinal Manipulation on Migraine Pain and Disability: A Systematic Review and Meta‐Analysis

Background Several small studies have suggested that spinal manipulation may be an effective treatment for reducing migraine pain and disability. We performed a systematic review and meta‐analysis of published randomized clinical trials (RCTs) to evaluate the evidence regarding spinal manipulation as an alternative or integrative therapy in reducing migraine pain and disability. Methods PubMed and the Cochrane Library databases were searched for clinical trials that evaluated spinal manipulation and migraine‐related outcomes through April 2017. Search terms included: migraine, spinal manipulation, manual therapy, chiropractic, and osteopathic. Meta‐analytic methods were employed to estimate the effect sizes (Hedges’ g ) and heterogeneity ( I 2 ) for migraine days, pain, and disability. The methodological quality of retrieved studies was examined following the Cochrane Risk of Bias Tool. Results Our search identified 6 RCTs (pooled n = 677; range of n = 42‐218) eligible for meta‐analysis. Intervention duration ranged from 2 to 6 months; outcomes included measures of migraine days (primary outcome), migraine pain/intensity, and migraine disability. Methodological quality varied across the studies. For example, some studies received high or unclear bias scores for methodological features such as compliance, blinding, and completeness of outcome data. Due to high levels of heterogeneity when all 6 studies were included in the meta‐analysis, the 1 RCT performed only among chronic migraineurs was excluded. Heterogeneity across the remaining studies was low. We observed that spinal manipulation reduced migraine days with an overall small effect size (Hedges’ g = −0.35, 95% CI: −0.53, −0.16, P < .001) as well as migraine pain/intensity. Conclusions Spinal manipulation may be an effective therapeutic technique to reduce migraine days and pain/intensity. However, given the limitations to studies included in this meta‐analysis, we consider these results to be preliminary. Methodologically rigorous, large‐scale RCTs are warranted to better inform the evidence base for spinal manipulation as a treatment for migraine.