Friday, March 11, 2011

Manipulative Therapy for Low-Back Pain Reviewed

Research UpdateSpinal manipulative therapy (SMT) is an intervention that is widely practiced by a variety of healthcare professionals, such as chiropractors, osteopaths, and physiotherapists; however, the effectiveness of this form of therapy for the management of chronic low-back pain often has been questioned. Now, an extensive review and analysis of available research evidence has found that SMT appears to be no better or worse than other existing therapies for patients with chronic low-back pain conditions.

Updating an earlier review, Cochrane Collaboration investigators from the Netherlands conducted an extensive literature search (up to June 2009) for all randomized controlled trials (RCTs) that examined the effectiveness of spinal manipulation or mobilization therapies (SMT) in adults with chronic low-back pain [Rubinstein et al. 2011]. No restrictions were placed on the setting or type of pain; however, studies exclusively examining sciatica were excluded. The primary outcome variables of interest were pain, functional status, and perceived recovery. Secondary outcomes included return-to-work and quality of life.

According to the review authors, SMT, also known as "hands-on" treatment of the spine, includes both manipulation and mobilization. In manual mobilizations, the therapist passively moves a patient’s spine within the usual range of motion. Whereas, manipulation uses thrusts applied to joints at or near the end of the physiologic range of motion, which is often accompanied by an audible “crack.” Various practitioners, including chiropractors, physiotherapists or physicians trained in such techniques, and osteopaths use these interventions in their practices — albeit, each discipline may differ somewhat in their diagnostic and therapeutic approaches. Clinical massage therapy, as a hands-on approach, was not mentioned in the review.

For analysis, the investigators included 26 RCTs (total participants = 6,070), 9 of which had a low risk of bias, and 18 of included trials were not evaluated in their earlier Cochrane review on this subject in 2004. Chronic low-back pain was defined as lasting longer than 12 weeks and included cases in which patients’ pain was predominantly in the lower back but also radiated into the buttocks and legs. Cases with a known underlying causative pathology, such as infection, tumor, or fracture were excluded. Other interventions that were compared with SMT included placebo or sham treatment, standard or “best” medical care, exercise, pharmacotherapy, physiotherapy, back school, and myofascial therapy.

In general, there was sufficient high quality evidence to conclude that, compared with other interventions, SMT has small but significantly favorable short-term effects on (1) pain relief ([Mean Difference on 100 point scales] MD = –4.16; 95% CI –6.97 to –1.36) and (2) functional status ([Standardized Mean Difference] SMD = –0.22; 95% CI –0.36 to –0.07). [Negative numbers in this case indicate that SMT was more beneficial; however, the MD and SMD effect sizes are qualitatively small and not clinically relevant.] The authors also conducted a stratified analysis looking at outcomes at various time points, and the mildly positive effects of SMT did not persist long-term.

When combined with another intervention, such as SMT with pharmacotherapy or with exercise, there is a varying quality of evidence (ranging from low to high) that SMT has statistically significant short-term benefits for pain relief and functional status. Compared with inert or sham interventions (eg, placebo condition), the evidence was of low quality and inconclusive as to whether SMT was more beneficial. Data were too sparse to draw any conclusions about back-pain recovery, return-to-work, quality of life, or costs of care. Overall, no serious complications or adverse events were observed as a direct result of SMT.

In sum, the limited high quality evidence available suggests that there is no clinically relevant superiority of SMT compared with other common and generally effective interventions for reducing pain and improving function in patients with chronic low-back pain. SMT appear to be relatively safe and to be as effective as exercise therapy, standard medical care, pharmacotherapy, or physiotherapy. The decision to refer patients for SMT might be based on costs (eg, insurance reimbursement), preferences of patients and healthcare providers, and the relative safety of alternative treatment options considered.

COMMENTARY: Reviews such as this from the Cochrane Collaboration are the most comprehensive, analytical, and insightful investigations of their sort. Usually, when the evidence is of sufficient quality and quantity, meta-analyses performed as a component of the Cochrane review process are invaluable for clinical decision-making. Careful study of Cochrane Reviews, which admittedly can be time consuming (the present review, for example, is 137 pages) can provide an education in how to critically assess medical literature. [Regrettably, full reviews are not accessible for free, but they can be purchased individually online or obtained from a medical library.]

More often than not, the Cochrane review process reveals deficiencies and disarray in the state of research on the particular subject of interest, and this current review by Rubinstein et al. was no exception. Of 55 articles identified as possibly qualifying for inclusion, nearly half had to be excluded due to poor methodology with high risk of bias, inadequate reporting of results, uncontrolled confounding factors, and other inadequacies. At that, only 9 of the qualifying 26 trials examining SMT were considered to have sufficiently low risk of bias that the investigators could have confidence in the trial results. The remaining studies had a higher risk of bias and were included for analysis but could not be completely trusted, according to the authors.

Therefore, while this review represents a summary and analysis of current best evidence demonstrating that SMT is neither superior nor inferior to other therapies for patients with chronic low-back pain, this does not denote that any of the treatments are ineffective. And, the finding of equivalence for SMT could be influenced by the relatively modest amount of high-quality evidence, plus the experience and skills of individual SMT practitioners might play an important role in the effectiveness of this modality. Readers also should note that this present review focuses on SMT for chronic low-back pain, and does not pertain to the effectiveness of SMT or other modalities for acute back-pain conditions (<12 weeks duration).

REFERENCE: Rubinstein SM, van Middelkoop M, Assendelft WJJ, de Boer MR, van Tulder MW. Spinal manipulative therapy for chronic low-back pain. Cochrane Database of Systematic Reviews. 2011(2) [abstract here].