Trigger points treated with ultrasound more tolerant of pressure
PainSci summary of Srbely 2008?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. ★★★☆☆?3-star ratings are for typical studies with no more (or less) than the usual common problems. 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.
Canadian researchers treated trigger points in 50 patients with either ultrasound or a sham, and the amount of pressure on the trigger point required to induce pain was measured before and after. Trigger points treated with ultrasound were significantly more tolerant of pressure than those that were not treated, at 1, 3 and 5 minutes after treatment. The improvement was no longer significant just 10 and 15 minutes after treatment, however — so the effect in this case was brief. The authors concluded that “ … low-dose ultrasound evokes short-term segmental antinociceptive effects on trigger points which may have applications in the management of musculoskeletal pain.” They are not necessarily proposing that ultrasound is a useful treatment for myofascial pain syndrome, but producing evidence of an interesting effect that may prove to be clinically significant in time.
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.
Musculoskeletal pain affects a significant proportion of the general population. The myofascial trigger point is recognized as a key factor in the pathophysiology of musculoskeletal pain. Ultrasound is commonly employed in the treatment and management of soft tissue pain and, in this study, we set out to investigate the segmental antinociceptive effect of ultrasound. Subjects (n=50) with identifiable myofascial trigger points in the supraspinatus, infraspinatus and gluteus medius muscles were selected from an outpatient rehabilitation clinic and randomly assigned to test or control groups. Test subjects received a therapeutic dose of ultrasound to the right supraspinatus trigger point while control groups received a sham (null) exposure. Baseline pain pressure threshold (PPT) readings were recorded at the ipsilateral infraspinatus and gluteus medius trigger-point sites prior to ultrasound exposure. The infraspinatus point was chosen due to its segmental neurologic link with the supraspinatus point; the gluteus medius acted as a segmental control point. Following the ultrasound intervention, PPT readings were recorded at 1, 3, 5, 10 and 15min intervals at both infraspinatus and gluteus medius trigger points; the difference between infraspinatus and gluteus medius PPT values, PPT(seg), represents the segmental influence on the PPT. The ultrasound test group demonstrated statistically significant increases in PPT(seg) (decreased infraspinatus sensitivity) at 1, 3 and 5min, when compared with PPT(seg) in the sham ultrasound group. These results establish that low-dose ultrasound evokes short-term segmental antinociceptive effects on trigger points which may have applications in the management of musculoskeletal pain.
related content
These two articles on PainScience.com cite Srbely 2008 as a source:
- PS Trigger Points & Myofascial Pain Syndrome — A guide to the unfinished science of muscle pain, with reviews of every theory and self-treatment and therapy option
- PS Does Ultrasound Therapy Work? — Many concerns about the widespread usage of therapeutic ultrasound, especially extracorporeal shockwave therapy (ESWT)
