MD, PhD, FMedSci, FRSB, FRCP, FRCPEd.

Many chiropractors claim that spinal manipulation (SM) has an effect on the pain threshold even in asymptomatic subjects, but SM has never been compared in studies to a validated sham procedure. Now a chiropractic research team has published a study investigating the effect of SM on the pressure pain threshold (PPT) when measured in

i) the area of intervention,  

ii) an area remote from the intervention.

In addition, the researchers measured the size and duration of the effect.

In this randomized cross-over trial, 50 asymptomatic chiropractic students had their PPT measured at baseline, immediately after and every 12 min after intervention, over a period of 45 min, comparing values after SM and a previously validated sham. The trial was conducted during two sessions, separated by 48 h. PPT was measured both regionally and remotely from the ‘treated’ thoracic segment. Blinding of study subjects was tested with a post-intervention questionnaire.

The results show that the study subjects had been successfully blinded. No statistically significant differences were found between SM and sham estimates, at any time or anatomical location.

The authors concluded that, when compared to a valid sham procedure and with successfully blinded subjects, there is no regional or remote effect of spinal manipulation of the thoracic spine on the pressure pain threshold in a young pain-free population.

Reduced pain sensitivity following SM (often also called ‘manipulation-induced hypoalgesia’ (MIH)) turns out to be little more than a myth promoted by chiropractors for the obvious reason of boosting their business (6 further myths are summarised in the over-optimistic chiropractic advertisement above).

A recent review of the evidence found that systemic MIH (for pressure pain threshold) does occur in musculoskeletal pain populations, though there was low quality evidence of no significant difference compared to sham manipulation. Future research should focus on the clinical relevance of MIH, and different types of quantitative sensory tests.

16 Responses to Manipulation-induced hypoalgesia: another chiro-myth busted

  • So you congratulate the Chiropractic research team on a well done work regardless of political stance and interests?

  • At the risk of being accused of topic drift I cannot help but notice a very common theme in virtually all alternative treatments, remedies and supplements: Increased energy. I bring this up because of the list of “7 common benefits of chiropractic care” illustrated within the post.

    Take this off-beat supplement made from beets: increased energy. Try this newly rediscovered Ancient Wisdom meditation: increased energy. Wear this copper-infused pair of socks: increased energy. Have your spine bent and prodded and manipulated: increased energy. Drink this concoction made of various plant juices and essential minerals: increased energy. Do all non-mainstream medicine adherents use the same Wall Street ad agency?

    My apologies but I could not resist after seeing that grossly overused mantra. I am sure I am overlooking something, somewhere, but the only counterpart in mainstream pharmacopeia I am aware of off the top of my head is Viagra.

    Thank you for bringing this study to the fore.

    • the only counterpart in mainstream pharmacopeia I am aware of off the top of my head is Viagra

      Amphetamines?

      Also corticosteroids, particularly high doses for short durations such as used in many cancer treatment regimens (though the increased energy is offset by muscular weakness and wasting).

      • Apparently what I offered in semi-jest was taken seriously.

        The tweakers will likely tell you that (meth)amphetamine and Viagra can be interchanged. I guess it depends on one’s worldview, sort of like with the purveyors of CAM. One might excuse them for hoping that a magnetic pole reversal may once more occur and the sun will no longer rise in the historic East and would instead align with their preferred views.

        • Apparently what I offered in semi-jest was taken seriously

          No, not really…

          The tweakers will likely tell you that (meth)amphetamine and Viagra can be interchanged.

          I hope not. They have opposing effects on vascular tone.

          I do get annoyed when these people use the word energy to refer to some mysterious entity which flows through the nervous sytem (chiropractic) or from the healer to the punter (Reiki) or surrounding the body like a smell (biofield tuning, which always reminds me of Terry Pratchet’s character Foul Ol’ Ron) or through mysterious meridians (acupuncture), or all of these at once, since you see all of these treatments and more offered at the same clinics. And then they go on to use the same word to refer to a sense of vigour and well-being; perhaps vim is a better word here. So are these different usages of the word energy actually referring to the same thing? Can the energy that is unblocked by spinal manipulation or needling or waving a tuning fork around be the same energy that you feel when you are in the best of health, or listening to Beethoven’s 5th Symphony (allegro con brio – fast and with spirit)?

          Certainly in Japanese the word 気 (pronounced ki) can be used in both senses; it is the same word as 氣 (traditional) or 气 (simplified) in Chinese (written qi in Roman characters and pronounced something like “tchi-!!” in Mandarin; I put in the exclamation marks to emphasise the falling tone).

          And there does seem to be a feeling in languages that have some basis in Chinese (even if it is only some imported vocabulary) that if two words sound the same their meaning or their reality somehow resonate. So, for instance, eating goldfish might make you rich. Or having four of anything might bring bad luck because four (四 shi in Japanese and si in Mandarin, prounounced something like suh!!) sounds similar to the word for death in both languages. This is the reason why hotels in the Far East don’t have a 4th floor (OK, hotels in the West might be missing the 13th floor), and you can’t buy a set of four teacups.

          Rather than using vague terms that might mean anything, I feel it is important to be as unambiguous as possible in the realm of health care. So as far as I am concerned energy is anything you can measure in joules, unless it involves ionising radiation, in which case you can use also use electron-volts and Grays.

    • @Mike B

      Energy is a SYMPTOM of good health.
      Attempting to obtain the symptom void of good health is the same as trying treat poor health via treating the symptoms of poor health. It’s bass’ackwards.

      Energy is a result of good health, put the body in good health and energy will be the natural result.

  • Perhaps this is more evidence that Ernst doesn’t know how to interpret research on spinal manipulation?

    “The SM was performed on all participants at the level of the fifth thoracic vertebra (with a margin of palpatory error), making sure this was a pain free area on light palpation.”

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