It is generally considered that the opioid analgesic response which constitutes part of the extra segmental mechanisms of Acupuncture has an ‘all over body’ effect. This may partly explain why it is possible to suppress pain, regardless of where the needle is inserted. This response is more likely to be triggered by the non specific effects of Acupuncture relating to context and expectation.
However, a very interesting study by Benedetti and his colleagues showed that we can also experience a localised anaesthesia response in response to suggestion.
In the study, localised pain was induced by injecting capsaicin into 4 different parts of the body simultaneously. An inactive placebo cream was then applied to just one of these areas which produced local analgesia ONLY in the area where the cream was applied. Furthermore the analgesic response was blocked by naloxone suggesting the opioid systems were at work.
As Benedetti went on to conclude:
‘’This suggests that a highly organised and somatotopic network of endogenous opioids links expectation, attention and body schema’’
What does this mean?
Well it would seem that as human beings, depending on how we ‘primed’ during treatment, we are capable of creating a very localised, expectation generated pain inhibitory effect completely independant of what is being done by way of treatment.
This is not to suggest that all treatment techniques used to suppress pain have only non specific or placebo type effects, but research like this does remind us that there are many mechanisms at work when we are interacting with our patients.
It could be argued that we should try an augment these non specific effects to get better treatment outcomes. How best to do this is still up for discussion but it would seem that if a patient expects to achieve pain relief in a therapeutic setting, they probably will. We should place a focus on where the pain is being felt by the patient both in discussion, with manual contact if appropriate and possibly with needles - in other words get to the patients (not yours!) perceived source of the problem whenever possible. This is obviously easier when treating more localised pain.
So don't forget its not what we do, but also how we do it and in what context which is likely to have a strong influence on clinical outcomes.