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Pick a joint, any joint! Study shows no benefit to spinal manipulation based on skilled joint selection

PainSci » bibliography » Nim et al 2021

One article on PainSci cites Nim 2021: Does Spinal Manipulation Work?

PainSci notes on Nim 2021:

This 2021 study shows that it doesn’t much matter which joints are manipulated in spinal manipulative therapy, which is not a great look. More specifically, it showed that there’s no benefit to SMT based on skilled joint selection, which is a nifty angle.

How else would joints be selected? Is there some other kind of joint selection? In theory, all SMT is applied to joints chosen with expertise and skill — especially SMT performed in the context of scientific trials, one would hope. (And yet, ironically, studying only the most mediocre manipulation might actually be more pragmatic: most patients, by definition, can only access average quality care.)

Nim et al. evaluated tests of SMT where adjustment of “clinically relevant joints” was compared to SMT applied “elsewhere” to “non-candidate” joints. Obviously the expertly selected joints should have produced better results. But they didn’t.

That result was based on data from 10 studies “all of acceptable quality” (SMT has been studied quite a bit). Nine of them reported no statistically significant differences. The only paper that did report a difference reported only a small one… and had a high risk of bias (which usually leads inexorably to errors in the researchers’ favour).

If it doesn’t matter what joint you “adjust,” then it doesn’t matter if you adjust joints at all. This data is quite damning to SMT. Obviously.

By focusing on joint selection, this study highlights and reinforces existing knowledge about SMT — that it doesn't work terrible well, if at all — in an interesting new way. Plus, it’s in the freakin' journal Nature! It’s right there on! Right? The ultimate scientific journal! Um… well… so about that…

Plus, it’s in the freakin' journal Nature! It’s right there on! Right? The ultimate scientific journal! Um… well… about that…

Photo of a pair of hands pressing down on a man’s lower back, suggesting chiropractic treatment.

At first glance, this paper might seem to be published in the highly prestigious journal Nature, because of the domain it’s on. But no! It’s from the same publisher, but this is Scientific Reports … which is about as different as it could possibly be: a pay-to-publish open access journal, with much lower average quality and credibility than the journal Nature proper.+

SR is an open-access mega-journal, the largest scientific journal in the world by article count, with a business model that results in some quality control and credibility issues. Contributors literally pay to be published in SR (“article processing fees”).

There are certainly many good papers in SR, and "everyone is doing it" (all the big journals have these open-access versions now). But there is some serious criticism and controversy, there is obviously a lot of junk, too — and they definitely do benefit from the reputation of Nature. Which is a teensy bit gross.

But, welp, this paper confirms my bias against SMT, so it must be a good one despite the source! 🤣

original abstract Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

The concept that spinal manipulation therapy (SMT) outcomes are optimized when the treatment is aimed at a clinically relevant joint is commonly assumed and central to teaching and clinical use (candidate sites). This systematic review investigated whether clinical effects are superior when this is the case compared to SMT applied elsewhere (non-candidate sites). Eligible study designs were randomized controlled trials that investigated the effect of spinal manipulation applied to candidate versus non-candidate sites for spinal pain. We obtained data from four different databases. Risk of bias was assessed using an adjusted Cochrane risk of bias tool, adding four items for study quality. We extracted between-group differences for any reported outcome or, when not reported, calculated effect sizes from the within-group changes. We compared outcomes for SMT applied at a 'relevant' site to SMT applied elsewhere. We prioritized methodologically robust studies when interpreting results. Ten studies, all of acceptable quality, were included that reported 33 between-group differences-five compared treatments within the same spinal region and five at different spinal regions. None of the nine studies with low or moderate risk of bias reported statistically significant between-group differences for any outcome. The tenth study reported a small effect on pain (1.2/10, 95%CI - 1.9 to - 0.5) but had a high risk of bias. None of the nine articles of low or moderate risk of bias and acceptable quality reported that "clinically-relevant" SMT has a superior outcome on any outcome compared to "not clinically-relevant" SMT. This finding contrasts with ideas held in educational programs and clinical practice that emphasize the importance of joint-specific application of SMT.

This page is part of the PainScience BIBLIOGRAPHY, which contains plain language summaries of thousands of scientific papers & others sources. It’s like a highly specialized blog. A few highlights: