How Medical Acupuncture works - A Mechanisms Review part 2

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 acupuncture approach.

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

This blog will discuss the second of the four mechanisms, the segmental effects:

shield 1264826 640 1The action potentials which have been generated by the insertion of the needle also travel along the nerve directly to its particular segment (entry point) in the spinal cord where it causes depression in activity at the dorsal horn which reduces its response to painful stimuli. This is called the ‘segmental effect’ of acupuncture and is most likely the main mechanism by which acupuncture is able to relieve pain. 

Acupuncture is capable of inhibiting pain signals arising from any structure which sends sensory nerves to that particular part (segment) of the spinal cord. A good example is a pain arising from an arthritic knee. The nerves which supply the painful knee enter the spinal cord at the same segments in the spinal cord as the nerves which supply the muscles around the knee. As such, by targeting the muscles around the knee it is possible to inhibit pain arising from the knee itself.

In addition to the segmental pain-relieving effects, the insertion of a needle may also reduce muscle tension more generally within the area being needled (mainly within the same spinal segments) which may improve muscle function as well as joint mobility. 

Summary: Inserting a needle near sensitive or painful joints or muscles may bring about strong pain-relieving effects as well as easing muscle tension.

By Simon Coghlan MSc, BScPhysio, DipMedAc

References:

White A, Cummings M. Filshie J. An introduction to western medical acupuncture. Churchill Livingstone; 2008.

Campbell A. Acupuncture in practice: beyond points and meridians. Butterworth-Heinemann, Oxford; 2001.

Baldry PE.  Acupuncture, trigger points and musculoskeletal pain. 3rd ed. Edinburgh: Elsevier Churchill Livingstone; 2005.

Andersson S, Lundeberg T. Acupuncture - from empiricism to science: functional background to acupuncture effects in pain and disease. Medical Hypotheses 1995; 45(3):271-281

Simons DG, Travell JG, Simons PT. Travell & Simons’ myofascial pain & dysfunction. The trigger point manual. Volume 1. Upper Half of Body. 2nd ed. Baltimore: Williams & Wilkins; 1999.

Lund I, Lundeberg T. Are minimal, superficial or sham acupuncture procedures acceptable as inert or placebo controls? Acupunct Med. 2006;24(1):13-15.   

Bowsher D. Mechanisms of acupuncture. In: Filshie J, White A, editors. Medical acupuncture- a western scientific approach. 1st ed. Edinburgh: Churchill Livingstone; 1998.p.69-82.

Staud R, Price DD. Mechanisms of acupuncture analgesia for clinical and experimental pain. Expert Rev Neurother 2006;6:661–7.

Sandberg M, Lundeberg T, Lindberg LG, et al. Effects of acupuncture on skin and muscle blood flow in healthy subjects. Eur J Appl Physiol 2003;90:114–9.

Fernández-de-las-Peñas C, Dommerholt J. International consensus on diagnostic criteria and clinical considerations of myofascial trigger points: a Delphi study. Pain Medicine. 2018 Jan 1;19(1):142-50.

 

Image by kalhh from Pixabay

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