Spinal manipulative therapy for adults with chronic low back pain

RATIONALE: Many therapies exist for the treatment of chronic low back pain (LBP), including spinal manipulative therapy (SMT), which is a worldwide, extensively practised intervention. The effectiveness of SMT for chronic LBP is not without dispute. This Cochrane review is an update of a Cochrane systematic review published in 2011. OBJECTIVES: To evaluate the benefits and harms of SMT compared to (1) sham SMT/placebo intervention, (2) no treatment, and (3) other conservative interventions in people with chronic LBP (18+ years old). SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, two other databases, and two trial registers up to 18 October 2024, unrestricted by language. We also screened the reference lists of all included studies and relevant systematic reviews, and approached content experts to identify potentially missing studies. ELIGIBILITY CRITERIA: We included randomised controlled trials (RCTs) that examined the effect of spinal manipulation or mobilisation in adults with chronic LBP compared to sham SMT/placebo, no treatment, and other conservative interventions. We placed no restrictions on the setting. We excluded studies that exclusively examined sciatica. OUTCOMES: Our critical outcomes were pain, functional status, and adverse events. The primary time point was one month for pain and functional status. We evaluated adverse events at the end of the intervention. RISK OF BIAS: We assessed bias in the included studies using the original Cochrane risk of bias tool (RoB 1). SYNTHESIS METHODS: Where possible, we synthesised results using meta-analysis with a generic inverse-variance approach and random-effects models; otherwise, we used narrative synthesis. We assessed the certainty of evidence using the GRADE approach. Our main comparisons were SMT versus (1) sham SMT/placebo treatment, (2) no treatment, and (3) other conservative interventions at one month. We converted all pain scales to a 100-point scale. INCLUDED STUDIES: Seventy-six RCTs (11,866 participants) met our inclusion criteria, 50 (66%) of which were not included in the previous version of this review. Seventeen trials (2021 participants) compared SMT to sham SMT/placebo, and four trials (435 participants) compared SMT to no treatment. Most trials (43, including 8291 participants) examined the effect of SMT compared to other conservative interventions. The remaining trials examined other comparisons. Treatment allocation was appropriately conducted in just four sham SMT/placebo-controlled trials (24%), while only six trials 'blinded' participants to the intervention (35%), indicating a high risk of selection and performance bias. Similarly, the no-treatment controlled trials were as susceptible to selection bias (50%) and performance bias (75%). All trials were conducted in high-income (n = 53) or middle-income (n = 23) countries. In most studies, the population was middle-aged and included men and women. SYNTHESIS OF RESULTS: = 73%; 28 studies, 3940 participants) compared to other conservative interventions at one month. These effects, however, should be interpreted with caution due to the substantial statistical heterogeneity for which there is no clear explanation. Less than half of the studies (47%) reported on adverse events, of which 12 studies reported these systematically. Adverse events in the SMT group were limited to muscle soreness, stiffness, and/or transient increase in pain. None of the studies registered any serious complications related to either the experimental or control group treatment. The evidence is very uncertain about the adverse effects of SMT. AUTHORS' CONCLUSIONS: When SMT is compared to sham SMT/placebo, it may result in a small improvement in pain and medium improvement in functional status in adults with chronic low back pain. When compared to no treatment, SMT may result in a medium improvement in pain and a large improvement in functional status. When compared to other conservative interventions, SMT may result in little to no difference in pain and a small improvement in functional status. The evidence is of low to very low certainty, largely due to the fact that the effects of SMT were examined in trials conducted in different settings and populations, with different types of SMT technique, dosage, and frequency of treatment. Continuing to conduct RCTs in the same manner will neither strengthen the evidence nor our confidence in it. FUNDING: This Cochrane review had no dedicated funding, only 'in-kind' support from the Department of General Practice, Erasmus Medical Center, Rotterdam, Netherlands, and the Department of Health Sciences, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Science Research Institute, Netherlands. REGISTRATION: Protocol (2009): DOI: 10.1002/14651858.CD008112 Original review (2011): DOI: 10.1002/14651858.CD000447.pub2.