Benefits and Harms of Spinal Manipulative Therapy for Treating Recent and Persistent Nonspecific Neck Pain: A Systematic Review With Meta-analysis

center dot OBJECTIVE: We aimed to estimate the benefits and harms of cervical spinal manipulative therapy (SMT) for treating neck pain. center dot DESIGN: Intervention systematic review with metaanalysis of randomized controlled trials (RCTs). center dot LITERATURE SEARCH: We searched the MEDLINE, Cochrane CENTRAL, Embase, CINAHL, PEDro, Chiropractic Literature Index bibliographic databases, and grey literature sources, up to June 6, 2022. center dot STUDY SELECTION CRITERIA: RCTs evaluating SMT compared to guideline-recommended and nonrecommended interventions, sham SMT, and no intervention for adults with neck pain were eligible for our systematic review. Prespecified outcomes included pain, range of motion, disability, health-related quality of life. center dot DATA SYNTHESIS: Random-effects meta-analysis for clinically homogenous RCTs at short-term and long-term outcomes. Risk of bias was assessed using the Cochrane Risk of Bias 2.0 Tool. We used the Grading of Recommendations, Assessment, Development, and Evaluations approach to judge the certainty of evidence. center dot RESULTS: We included 28 RCTs. There was very low to low certainty evidence that SMT was more effective than recommended interventions for improving pain at short term (standardized mean difference [SMD], 0.66; 95% confidence interval [CI]: 0.35, 0.97) and long term (SMD, 0.73; 95% CI: 0.31, 1.16), and for reducing disability at short-term (SMD, 0.95; 95% CI: 0.48, 1.42) and long term (SMD, 0.65; 95% CI: 0.23, 1.06). Transient side effects only were found (eg, muscle soreness). center dot CONCLUSION: There was very low certainty evidence supporting cervical SMT as an intervention to reduce pain and improve disability in people with neck pain.