Spinal manipulations for migraine: an updated systematic review and meta-analysis of randomized clinical trials.

The short version

This updated systematic review and meta-analysis examined whether spinal manipulative therapy (SMT), quick thrusts to the spinal joints delivered by chiropractors, osteopaths or physiotherapists, effectively treats migraine. Migraine affects more than one billion people worldwide (about 14% of the population) and is the second most common cause of disability globally. SMT is sometimes used for it, but its biological plausibility and safety have been questioned, and several hundred severe complications after upper-spine manipulation, including arterial dissections, strokes and deaths, have been reported. The review updated a 2011 version with three new trials and searched databases up to September 2023. Six randomized or quasi-randomized trials with 645 people with migraine were included; five tested chiropractic SMT and one osteopathic manipulation, and controls included sham treatment, drug therapy, usual care and mobilization. The studies came from Australia, Norway, Spain and the United States and spanned about 45 years. Outcomes were migraine days, migraine duration, pain intensity, disability, emotional quality of life and adverse effects. One reviewer screened and extracted data and a second validated, results were pooled with random-effects models, and certainty of evidence was graded with GRADE. Pooled results showed small reductions in migraine days (SMD -0.24, 95% CI -0.47 to -0.02; four trials) and disability (SMD -0.27, -0.54 to -0.01; three trials), but no clear effect on pain intensity (SMD -0.22, -0.65 to 0.21; six trials), migraine duration (SMD -0.10, -0.33 to 0.12) or emotional quality of life (two trials). Certainty was very low for every outcome. SMT roughly doubled the risk of adverse effects (risk ratio 2.06, 1.24 to 3.41; number needed to harm 6), for example 83 adverse events in 355 SMT sessions versus 32 in 348 sham sessions in one trial, and 52% versus 34% of participants in another. Only three trials reported adverse effects at all. Only two of the six trials used a sham procedure, and their results were contradictory. The osteopathic trial showed a larger pain effect and lower heterogeneity than the chiropractic trials. The authors conclude that the effectiveness of SMT for migraine remains unproven and that it cannot be considered an evidence-based therapy for this condition, given very low-quality evidence and a twofold higher risk of adverse effects. Limitations include flawed methods in two thirds of trials, small samples, mixed populations and comparators, little long-term safety data, and few comparisons with established migraine treatments. The searches targeted English-language papers, although studies in any language were considered. The authors call for larger, more rigorous and independently conducted trials.

Key findings

• This updated systematic review pooled six trials with 645 people who had migraine to test spinal manipulative therapy (SMT, quick thrusts or mobilization of spinal joints) delivered mostly by chiropractors.
• SMT slightly reduced the number of migraine days (standardized mean difference -0.24) and disability (-0.27), but did not clearly change migraine pain intensity (-0.22, 95% CI -0.65 to 0.21), duration or emotional quality of life.
• People receiving SMT had about twice the risk of adverse effects (risk ratio 2.06, 95% CI 1.24 to 3.41; one extra adverse effect for about every six people treated).
• The certainty of all findings was very low, with flawed methods in two thirds of trials and only two trials using a sham (placebo) procedure.
• The authors conclude that SMT cannot be considered an evidence-based therapy for migraine, and that larger, more rigorous, independent trials are needed.

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