High-quality evidence that spinal manipulative therapy for chronic low back pain has a small, short-term greater effect on pain and functional status compared with other interventions
- Correspondence to Gert Bronfort
Department of Research, Northwestern Health Sciences University, 2501 west 84th street, Bloomington, Minnesota 55431, USA;
Chronic low back pain continues to be a major socioeconomic problem in most parts of the world. Spinal manipulative therapy is one of the several conservative treatment options, which, based on results from numerous randomised clinical trials, has been included as one of the recommended therapies in several national clinical guidelines.
Rubinstein et al systematically evaluated evidence from randomised, placebo or active comparative clinical trials in which spinal manipulative therapy (spinal manipulation and/or spinal mobilisation) was used to treat chronic low back pain in adults. This represents an update from an earlier Cochrane review and the authors identified the latest trials by searching Cochrane CENTRAL, MEDLINE, EMBASE, CINAHL, PEDro and the Index to Chiropractic Literature. The primary outcomes were pain, functional status and perceived recovery. Secondary outcomes were return-to-work and quality of life. Studies with patients of >18 years of age from primary, secondary or tertiary care with non-specific low back pain that had lasted longer than 3 months were included and studies with patients following surgical intervention, studies designed to test the immediate postintervention effect of a single treatment only, with no additional follow-up, as well as studies that solely examined specific pathologies (eg, sciatica) were excluded. Two review authors independently conducted the study selection, risk of bias assessment (study quality) and data extraction. GRADE was used to assess the quality of the evidence of effectiveness.
Of 26 study trials (total participants=6070), nine were of high quality with low risk of bias. Approximately two-thirds of the included studies were not evaluated in the previous review. The reviewers concluded that there is high-quality evidence that spinal manipulative therapy has a small, statistically significant but not clinically relevant, short-term effect on pain relief (mean difference on 0–100 point scale of −4.16, 95% CI −6.97 to −1.36) and functional status (effect size difference of −0.22, 95% CI −0.36 to −0.07) compared with other interventions. Sensitivity analyses confirmed these findings. There were some evidence that spinal manipulative therapy has a short-term effect on pain relief and functional status when added to another intervention. The data for recovery, return-to-work, quality of life and costs of care were sparse. No serious complications from spinal manipulative therapy were observed or reported in the included trials.
This updated Cochrane review, which used the latest methodology for assessing the risk of individual study bias (study validity) and the GRADE system1 (The Grading of Recommendations Assessment, Development and Evaluation) for determining the quality of the evidence of effectiveness, demonstrates that spinal manipulative therapy is as effective as other commonly used therapies like exercise, standard medical care and physical therapy for the management of chronic low back pain. This is consistent with other recent systematic reviews and evidence-based clinical guidelines.2 Based on pooled results from numerous trials, the authors report that spinal manipulative therapy on average has a small advantage compared with other therapies, but that this difference is not clinically important. Unfortunately, there is no standard method for determining what constitutes a clinically important treatment group difference in patient-rated outcomes. It depends on the perspective used. Small group differences may be considered unimportant from the clinician and patient's perspective, but may be important when the proportions of responders are compared and from a societal perspective when cost and risk of adverse events are factored in.3
From other systematic reviews of different treatments for chronic low back pain, it has become evident that anyone of the viable mono-therapeutic options like spinal manipulative therapy offers at best a modest benefit by itself. Given the multi-factorial nature of back pain, it is not likely that a single therapeutic approach will be the best strategy for the majority of patients because of the limited understanding of the underlying aetiology and mediating effects of different bio-psychosocial variables.
So, to improve therapeutic management strategies, research is needed, which goes beyond the evaluation of effectiveness of individual treatment options and focuses more on understanding the biological, psychological as well as pain processing mechanisms associated with chronic low back pain. Given the lack of clear superiority of one treatment over another for chronic low back pain, individual treatment decisions will currently best be made by choosing among or combining established effective treatment options guided by patient preferences and expectations, the clinician's experience and considerations regarding risks and cost.