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bibliography * The PainScience Bibliography contains plain language summaries of thousands of scientific papers and others sources, like a specialized blog. This page is about a single scientific paper in the bibliography, Ho 2007.

Current evidence does not support Botox for trigger points

updated
Tags: muscle pain, injections, medications, muscle, pain problems, medicine, treatment, self-treatment

PainSci summary of Ho 2007?This page is one of thousands in the PainScience.com bibliography. It is not a general article: it is focused on a single scientific paper, and it may provide only just enough context for the summary to make sense. Links to other papers and more general information are provided at the bottom of the page, as often as possible. ★★★★☆?4-star ratings are for bigger/better studies and reviews published in more prestigious journals, with only quibbles. Ratings are a highly subjective opinion, and subject to revision at any time. If you think this paper has been incorrectly rated, please let me know.

This 2007 review paper shows pretty clearly that “current evidence does not support the use of Botulinum toxin A (BTA) injection in trigger points [muscle knots].” The truth is never bad news, of course, and I’m going to use this as an example of honouring the evidence even when it irritates me. But damn … this study rocked my boat a bit when I found it in Aug 2009.

For years I was under the impression that Botox injection flipped the switch on trigger points, just turned ‘em off completely, zap, done — no more trigger point until the Botox wears off. That didn’t necessarily make it a good treatment option for patients: it’s invasive, there are risks, it’s difficult to reliably inject the actual trigger point, and so on. But the evidence of the effect of Botox on trigger points was terribly important theoretically, because it showed something vital about the physiology of trigger points. (Botox blocks the release of the neurotransmitter acetylcholine, making it impossible for muscle to contract.) If Botox stops a trigger point, it proves that a trigger point is contractile. If you know how to break a trigger point, then you know how it works. It really helped to push back the scientific darkness around muscle pain.

Only I guess it didn’t!

This paper doesn’t necessarily show that Botox doesn’t do anything to trigger points, or that it has no relevance. (For instance, Botox may do exactly what I thought it did, but it’s so difficult for practitioners to reliably inject it into exactly the right place that it is highly unreliable as a treatment.) But it does mean that it’s effectiveness and significance is no longer certain, no longer reliable. It is, at best, debatable.

original abstractAbstracts 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.

Botulinum toxin injection is used to treat various pain conditions including muscle spasticity, dystonia, headache and myofascial pain. Results are conflicting regarding the use of Botulinum toxin for trigger point injection in terms of improvement in pain. The aim of this study was to carry out a systematic review to assess the evidence for efficacy of Botulinum toxin A (BTA) compared with placebo for myofascial trigger point injection. Electronic databases on Medline, Cochrane Library, Scopus, CINAHL were queried using key words such as "botulinum toxin", "myofascial pain", "trigger point", "chronic pain" and "musculoskeletal pain". Relevant published randomized controlled trials that described the use of BTA as injection therapy for trigger points were considered for inclusion. The five-item 0-16 point Oxford Pain Validity Scale (OPVS) was used as a selection criteria for suitable clinical trials. Trials were also assessed based on quality using the Oxford Rating Scale. Data extracted from qualified trials included outcome measures such as pain intensity and pain pressure threshold. All studies were ranked according to the OPVS and the authors' conclusions were compared. Five clinical trials met the inclusion criteria. One trial concluded that BTA was effective, and four concluded that it was not effective for reducing pain arising from trigger points. OPVS scores ranged from 8 to 14 with the negative studies corresponding with higher validity scores. The current evidence does not support the use of BTA injection in trigger points for myofascial pain. The data is limited and clinically heterogeneous.

related content

These two articles on PainScience.com cite Ho 2007 as a source:


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: