Spinal Manipulation = A Placebo Treatment?

This systematic review was aimed at assessing whether spinal manipulative therapy (SMT) procedures (i.e., target, thrust, and region) impacted on pain and disability for adults with spine pain.

The investigators searched PubMed and Epistemonikos for systematic reviews indexed up to February 2022 and conducted a systematic search of 5 databases (MEDLINE, EMBASE, CENTRAL [Cochrane Central Register of Controlled Trials], PEDro [Physiotherapy Evidence Database], and Index to Chiropractic Literature) from January 1, 2018, to September 12, 2023. They included randomized clinical trials (RCTs) from recent systematic reviews and newly identified RCTs published during the review process and employed artificial intelligence to identify potentially relevant articles not retrieved through our electronic database searches. The authors included RCTs of the effects of high-velocity, low-amplitude SMT, compared to other SMT approaches, interventions, or controls, in adults with spine pain. The outcomes were spinal pain intensity and disability measured at short-term (end of treatment) and long-term (closest to 12 months) follow-ups. Risk of bias (RoB) was assessed using version 2 of the Cochrane RoB tool. Results were presented as network plots, evidence rankings, and league tables.

The researchers included 161 RCTs (11 849 participants). Most SMT procedures were equal to clinical guideline interventions and were slightly more effective than other treatments. When comparing inter-SMT procedures, effects were small and not clinically relevant. A general and nonspecific rather than a specific and targeted SMT approach had the highest probability of achieving the largest effects. Results were based on very low- to low-certainty evidence, mainly downgraded owing to large within-study heterogeneity, high RoB, and an absence of direct comparisons.

The authors concluded that there was low-certainty evidence that clinicians could apply SMT according to their preferences and the patients’ preferences and comfort. Differences between SMT approaches appear small and likely not clinically relevant.

What does that mean?

It means that it is largely irrelevant which form of SMT is being used; the outcomes are more or less independet of the technique that is applied. You don’t need to be particularly skeptical to go one step further and conclude that:

• The percieved effectiveness of SMT compared to other treatments is due to a placebo effect which is likely to be strong with a therapy involving touch, cracking bones, etc.
• The effects of different types of SMT are all similar because these interventions are little more than theatrical placebos.
• Since these placebos can cause consideraable harm, their risk/benefit balance is not positive.
• Because their risk/benefit balance fails to be positive, SMT cannot be recommended as a treatment in routine care.