Seven studies (1,046 participants) were included and all were reported as being of fair quality. Six studies were reported as being randomised, but no studies reported on participation rates or withdrawals/drop-outs.
Meta-analysis of vertebral artery blood flow velocity (systolic, diastolic, and average) showed a small effect size (SMD 0.25, 95% CI -0.02 to 0.51; seven studies), but there was statistically significant heterogeneity. For basilar artery blood flow, the corresponding result was a standardised mean difference of -0.05 (95% CI -0.56 to 0.45; seven studies) also with significant heterogeneity. Average vertebral blood flow velocity showed an effect size of 0.25 (95% CI 0.04 to 0.46; three studies) without significant heterogeneity.
Conflicting results for improvement in vertigo were reported, and tuina was found to have no beneficial effect on headache (pooled results were not presented due to statistical heterogeneity).