A specific type of needle has been developed by Nobuari Takakura and Hiroyoshi Yajima which allows for the blinding of both the Acupuncturist and the patient (double blinding) in Acupuncture based clinical trials.
The so called ‘active’ version of the needle is 0.16mm in diameter and only penetrates to 5mm in depth. The ‘sham’ version does not penetrate the skin at all - it penetrates some stuffing in the bottom of the guide tube and just touches the skin, enough to give some sensation or the impression of needle penetration.
This needle has been validated such that when subjects were told they would receive either ‘real’ needling or ‘placebo’ needling, they could not tell the difference between the two types of needle and were unable to determine which was which.
So when this needle is put to the test in a clinical trialcomparing ‘active’ and ‘sham’ needling do you think there is likely to be a significant difference in pain outcome measures?
No. Given that we know Acupuncture does exert potent non specific effects, and without a significantly improved pain response in the active group, the clinical effect was considered to be entirely non specific i.e placebo based in both groups.
I think it would be reasonable to assume that in this case, both groups effectively received ‘sham’ Acupuncture given the limited depth of penetration in the active group. Very shallow needling has been shown to be effective, however in laboratory settings, changes in pain thresholds generally occur after 20 minutes of moderately strong stimulation of deep tissue rather than skin. So in order for the more specific physiological effects of Acupuncture to take effect in addition to the non specific placebo effects, deeper needling of the somatic tissues, usually muscle is considered necessary.
What this study does remind us is that needling does evoke strong non specific placebo effects related to patient perceptions and expectations. This is likely to be the case for most forms of therapy, needling or otherwise. It also reminds us that shallow needling does work and may be entirely suitable for certain patients, particularly very sensitive ones.
Trying to tease apart the specific and nonspecific effects in Acupuncture treatment will always be a challenge, particularly in clinical trials depending on the condition being treated. At the end of the day, does it matter? If we can prove that Acupuncture is effective and safe, is it really that important to show efficacy? The answer in a clinical setting is probably not, but key decision makers need to see efficacy and for this reason Acupuncture as a technique will be at a disadvantage.
By Simon.
