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View Full Version : Re: Placebo effects and surgery for overuse injuries



Van Den Bogert, Ton
06-23-2006, 05:24 AM
David McFarlane brought up a good topic for discussion on Biomch-L. There may be some Biomch-L subscribers who know of controlled trials for surgical treatments for overuse injury. Please contribute what you know.

One reason why there may not be much literature is that (at least in the US) there is no government (FDA) regulation of surgical treatments. Controlled trials are therefore not required to demonstrate efficacy and safety. Regulatory approval is only needed if medication or devices are involved. Someone please correct me if I am wrong.

> it would be interesting to know if the outcomes of surgery for carpal
> tunnel syndrome (i.e. decompression of the carpal tunnel) ever reflect a
> placebo effect (especially if this is merely due to rest after the operation).

Rest is one possible mechanism. I would propose also that a placebo effect for overuse injuries can occur because surgery makes the invisible injury visible.

For example, until the 1980s it was common to treat tendinitis in horses by "firing" the skin over the tendon with a hot iron (Silver et al., 1983). There was no good scientific basis for this and the practice has largely been discontinued. However, one theory is that firing was effective because it created a visible injury. This reminded the horse's owner every day that the horse was injured, thus increasing the likelihood that the horse would get adequate rest, at least until the skin was healed.

The only way to fully measure these placebo effects is by clinical trials in which a sham surgery is done in the control group. There is debate on whether such research is ethically acceptable, but there is potential for great benefit to society (Wolf & Buckwalter, 2006).

References

Silver IA, Brown PN, Goodship AE, Lanyon LE, McCullagh KG, Perry GC, Williams IF (1983) A clinical and experimental study of tendon injury, healing and treatment in the horse. Equine Vet J Suppl. (1):1-43. See also http://en.wikipedia.org/wiki/Bowed_Tendon.

Wolf BR, Buckwalter JA (2006) Randomized surgical trials and "sham" surgery: relevance to modern orthopaedics and minimally invasive surgery. Iowa Orthop J. 26:107-111. http://www.uihealthcare.com/depts/med/orthopaedicsurgery/research/ioj2006.pdf (44 MB download)

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Ton van den Bogert, Biomch-L co-moderator


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