Physiotherapy & Sports Injury Clinic

Acupuncture Effects:

Discuss the significance of known physiological evidence and relate to traditional medicine concept in acupuncture practice. Show how acupuncture has a role in alleviating and/or modulating musculoskeletal complaint.

The pain relieving or analgesic effects of acupuncture is supported in the literature through different models and physiological evidence. According to the TCM concept pathways called meridians lie along the body. These pathways carry Qi or “life energy” from the various organs of the body to the surface of the body and help to regulate yin and yang, the two opposing forces that are believed to keep the body in harmony (Eshkevari 2005). The yin and the yang can be thought of in Western medicine terms as the sympathetic and parasympathetic nervous systems in that they are opposing, yet balancing effects on the human body and maintaining health. If this energy cannot pass or becomes interrupted the yin and yang become unbalanced and illness or pathology may occur. The acupuncture points are specific locations where the meridians come to the surface of the skin. The connections between them ensure that there is an even circulation of Qi and a balance between the yin and Yang. Energy constantly flows up and down these pathways. When pathways become obstructed deficient or unbalanced, pathology can occur. There are many factors in the environment as well as within the body that can cause this obstruction (Eshkevari 2005). The environmental factors that include dampness, cold, heat, and wind whereas internal factors include inactivity or over activity, poor diet, excessive alcohol intake, emotional issues, trauma and stress (Eshkevari 2005). All of these causative agents can drain the body of its reserves and predispose the patient to disease.

 Acupuncture mechanisms of pain relief have been categorized into peripheral effects, spinal mechanisms and supraspinal effects (Bradnam, 2003).

The local effects often termed “the needle effect” produces analgesia of the pain spot. In a study by Lewit et al (1979), when the most painful spot was touched by the needle, the needle effect was observed in 86.8% of cases. It is proposed that the needle excites receptors in the skin, muscle or tendons and stimulates the structure indirectly by reflex mechanisms, or that stimulation involves local immunoinflammatory systems causing vasodilation (Smith 1992).Research has shown that acupuncture increases the blood flow when De-Qi occurs; suggesting that increased blood flow maybe one of the mechanisms accounting for meridian system responses during acupuncture (Tsun-Cheng Kuo,2004). Another factor is that needling can provide long lasting stimulation from the injury it creates. Injury potentials are generated and can persist and provide stimulation days until the miniature wound heels (Gunn C, 1996). This stimulation involves synthesis of prostaglandins which increase vascular permeability and mast cell damage causes the release of histamine and heparin causing vasodilation. Therefore pain is relieved as a result of improved perfusion and relief of muscle spasm causes by local effects of needling and somatoviseral reflexes.

The Gate Theory proposed by Melzack and Wall in 1965 highlights the importance of A delta fibres in pain modulation. This theory explains that acupuncture works though the nervous system to alleviate pain. It suggests that the opening and closing of the gate s dependent on the relative activity of the large diameter A Beta and small diameter a Delta and C fibres. Activity in the large diameter fibres is said to close the gate whilst activity in the small diameter fibres tends to open the gate. These nerve fibres come together in the substantia gelatinosa of the spinal chord. The substantia gelatinosa is responsible or sending pain signals to the brain. Acupuncture is said to stimulate the pain inhibitory nerve fibres which lowers the pain input and therefore lowers the pain. Research by Garrison and Foreman 1994 supports this theory as their study shows that the distal horn neurones which can potentially transmit noxious information to supraspinal levels can have their cell activity decreased during TENS application.

Experimental evidence supports the theory that acupuncture is able to activate endogenous opiate peptides.  It has been long suspected that acupuncture causes the release of neuoendorphins and other chemical mediaters. Studies have shown that acupuncture stimulation causes release of endogenous analgesics in the brain and this effect can be counteracted by naxolone (an opioid antagonist). Eshkevari et al, 2005. Many studies have also demonstrated that the pain threshold is increased upon acupuncture stimulation leading to the conclusion that acupuncture analgesia is induced through highly specific nervous and chemical mechanisms. Abergalaer S in 1994 demonstrated a significant increase in plasma B endorphin concentrations after both manual and EA stimulation of chronic pain patients and correlated with a reduction in the VAS in the EA patients. Further support for the idea that acupuncture may cause the release of endogenous opiates comes from the experiments that have found the transfer of cerebro spinal fluid from one animal under acupuncture analgesia resulted in analgesia of the recipient (Smith F 1992)

 Evidence would suggest that the rostral ventral medulla plays a role in acupuncture, Liu et al 1987 found that electroacupuncture could stimulate the off cells and inhibit the on cells in this area. The rostral ventral medulla and the periaqueductal grey are functionally linked. Research by He in 1987 found that injecting naxolone into rabbits PAG partially reversed EA analgesia. A study by Wu M T et al 1999 used FMRI and supported the findings of previous studies. They found that stimulation of LI4 and ST 36 resulted in activation of the hypothalamus and nucleus accumbens and deactivation of the rostral part of the anterior cingulated cortex, amygdyla formations and hippocampal complex while control stimulation of did not result in such activations or deasctivations. They concluded that by inhibiting the limbic system structures acupuncture appears to cause the negative connotations of the pain is decreased

Some patients may have a centrally evoked type pain resulting from altered CNS circuitry and processing (Bradnam, 2002). The features of this type of pain include on-going pain after the injury has healed that present as unfamiliar anatomic pain patterns with atypical pain behaviours. The patient sometimes exhibits signs in the related segments including swelling and redness but often there maybe no signs. Slow healing musculoskeletal conditions maybe related to inhibition of the SNS leading to trophic changes in the target tissue. Bradnam suggests acupuncture maybe used in this pain mechanism in particular in the early stages of the chronicity when the level of the dysfunction in the CNS is not known and some inhibitory pathways might be patent. 

There is also some evidence to suggest that there maybe Sympathetic changes associated with acupuncture. Nathan 1980 stated that sympathetic fibers release noradrenaline throughout their course and that peripheral nerves accompanied by sympathetic nerves will be bathed in a solution of noradrenaline whenever there is sympathetic activity. Wall stated that the firing of normal peripheral nerve fibres when tissue is injured is influenced by the temperature, the vasculature, sympathetic efferents the chemical environment and previous stimuli. It has been suggested that it is through stimulation of the sympathetic system that clinicians use to solve complex TCA problems. These points often located in the extremities have a strong sympathetic innervations and so maybe more useful in manipulating sympathetic responses. Needling at the spinal level supplying the target tissue or region can stimulate the sympathetic nervous system or by needling a point in the periphery sharing the segment.

A further supraspinal mechanism activated by acupuncture, given time and intensity parameters are correct is a neuron hormonal effect (Bradnam 2005). Beta-endorphin and adreno-corticotrohic hormone are released in equimolar amounts from the pituitary gland into the bloodstream. The ACTH in turn will influence the adrenal gland increasing the production of anti-inflammatory corticosteroids. Research suggests that these effects can be incorporated into a treatment plan to optimize healing effects in slow healing conditions, treat immune deficient people or those with high intensity demands on their bodies (Bradnam). To influence the organs producing T lymphocytes and NK cells the thymus, spleen and lung needle the segments that supply these organs with strong sympathetic points and possible ear acupuncture to influence vagal parsympathetic activity (Bradnam 2005).

Despite its widespread use and effectiveness in treating a variety of conditions, acupuncture is not without its limitations. It seems that it maybe most effective in the treatment of chronic disorders. Direct needling can be limited in acute syndromes due to discomfort and needling around recent areas of oedema can be restricted. Also progress can be slow among patients who have multi pathology, weak constitution or disturbed personality.

REFERENCES

Bradnam L (2002) Western Acupuncture Point election: A Scientific Clinical Reasoning Model.AACP p 21-28

Lewith, GT., Kenyon, JN., (1984) Physiological and psychological explanations for the mechanism of acupuncture as a treatment for chronic pain. Soc. Sci. Med. 19(12):1367-78

Eshkevari L & Heath J(2005) Use of Acupuncture for Chronic pain. Optimising Clinical Practice. Holistic Nursing practice 19(5) 217-221

He L (1987) Involvement of endogenenous opiod peptides in acupuncture analgesia Pain Vol; 31 p 99 – 121

Smith F (1992) Neurophysiologic basis of acupuncture Probl Vet Med. Mar;4(1): p 34-52.

Bradnam L (2001) Western Acupuncture point selection: a scientific clinical reasoning model. Journal of AACP p21-29

Ernst, M., Lee, M. H., (1985) Sympathetic vasomotor changes induced by manual and electrical acupuncture of the Hoku point visualized by thermography. Pain. Jan; 21(1): p 25-33

Gifford, L.S., & Butler, D.S. (1997) The Integration of pain sciences into clinical practice. Journal of Hand therapy, Apr-June 87-95

Green, S. et al (2002) Acupuncture for lateral elbow pain in adults, Cochrane Database Syst Rev 2002; 1: CD003527

Liao, T.J. et al (1998) Transient Decrease in skin resistance Response and level at the Deh-Chi stage caused be manual acupuncture.  Tohoko Journal of Experimental Medicine, 186, 19-25

Lundeburg, T., Hurtig, T., Lundeburg, S., & Thomas, M. (1988) Long term results of acupuncture in chronic head and neck pain. Pain clinic, 2, 15-31

Trunh, K.V., Phillips, E., HO & K. Damsma. (2004) Acupuncture for the alleviation of lateral epicondyle pain: a systematic review. Rheumatology, 43, 1085-1090.

Tsun-Cheng Kuo et al. (2004) The soreness and numbness effect of Acupuncture on skin blood flow.  The American journal of Chinese medicine, vol. 32, No.1, 117-120.