There are five physiological mechanisms which can be used to explain how medical acupuncture works. Each can be used for a different purpose which is why anyone using medical acupuncture must be able to make a conventional medical diagnosis and have an understanding of the underlying pathology to be effective when using a medical approach.

The different mechanisms require variations in the treatment technique and so this needs to be tailored to the individual patient.

Local effects:
This refers to the ability of acupuncture to activate specific sensory nerve fibres in the skin and muscle. Needling near the sensory nerve endings sets off action potentials (nerve impulses) which spread around and along the local network of nerve fibres – this is called an axon reflex. Various substances are released as a result including adenosine and calcitonin gene related peptide (CGRP) both of which cause local blood vessels to dilate causing an increase in local blood flow. The blood flow is also increased in the deeper tissues which encourages tissue healing. Adenosine also has a mild local pain relieving effect effect, while CGRP may also promote healing and repair.

Last Saturday I attended the autumn scientific meeting of the British Medical Acupuncture Society in London, an annual event which usually attracts some top speakers from around the world giving an insight into their areas of clinical interest and research.

This year we got to hear from Vitaly Napadow, a Ukrainian-born American neuroscientist and acupuncturist. He is associate professor at Harvard Medical School and the Martinos Center for Biomedical Imaging. He is also the director of the Center for Integrative Pain NeuroImaging and the co-president of the Society for Acupuncture Research.

Vitaly gave a a very interesting presentation based on his recent pilot study¹ which showed that acupuncture can in effect ‘rewire’ the brain when using the technique to treat carpal tunnel syndrome.

Trigger points are exquisitely tender points within muscles which like to refer pain, usually some distance from where the trigger point is located.¹

For example a trigger point within the upper trapezius muscle which sits on top of the shoulder, between the neck and the shoulder tip, typically refers pain to the side of the neck, the temple and even the jaw. They often contribute to a tension type headache, especially if found on both sides of the neck.²

But how reliably can these trigger points be identified on physical assessment? In other words, if I was to assess you and then another physiotherapist were to assess you afterwards, how likely would we both agree that a trigger point either is or is not present?

Physiotherapist love trends. The current trend which has been around for a good number of years now is that all pain, especially persistent pain is a result of some level of central nervous system (CNS) dysfunction, an output of the brain effectively.

As such it is argued we should now forget about structure and the periphery and simply target the central nervous system when treating clients. This basically means talking therapy and exercise, so vociferously promoted by the biopsychosocial pain model zealots. Hands on treatment is now considered an act of high treason and anyone admitting to doing so risk being shamed and admonished. As for acupuncture or dry needling, such techniques are considered by these folk as being so worthless you’d be better off rolling around in a thorn bush for the good it would do you.

Now of course the CNS plays a role in how we perceive pain, how could it not? Given how inextricably linked the peripheral (which supplies the spinal structuctures and limbs etc) and central nervous systems are both physiologically and anatomically, one will of course influence the other. For some, pain may be due to a combination of both peripheral and central nervous system 'wind up'.

Acupuncture, medical acupuncture, dry needling...call it what you want...has been shown to activate proprioceptive afferent receptors in muscle tissue, in particular the type 11 (flower spray type) which which contribute to numbing feeling associated with the needle sensation or ‘de qi’.^1,2 Given the pain modulatory benefits of acupuncture are mainly attributed to sensory effects, the activation of these proprioceptors may be important from a mechanisms point of view.²

Manual therapy also activates proprioceptors (sometimes referred to as ergo or mechanoreceptors) about the muscle spindles and articular structures.³ When looking at the manual therapy literature and listening to experts⁴ discuss the proposed mechanisms which underpin its benefits, the role of proprioceptor activation is considered not only in terms of contribution to pain modulation, but also from functional point of view. In other words, manual therapy is associated with pain modulation, but can also be used to facilitate movement and exercise, help normalise faulty movement patterns etc.

So, my musing for this morning is should acupuncture research be focussing more on functional effects? i.e to what extent may acupuncture impact on specific functional outcomes which assess mobility, strength and control etc? Is acupuncture when combined with specific exercise more effective than one or the other on it’s own? What happens when manual therapy, exercise and acupuncture are combined?