Acupuncture and Chronic Pain
By: Helen C. Ly
What is Acupuncture?
Acupuncture is an ancient art of healing that dates back to at least 2,500 years. It has been widely practiced in China and many other Asian countries. Only recently has acupuncture made its way into the western world. Acupuncture accentuates on the natural healing of the body. It involves stimulating acupuncture points by the insertion of very fine, solid, metallic needles.
Acupuncture is gaining popularity as numerous claims are being made to its validity and effectiveness. Although many studies and experiments regarding acupuncture have been done, the scientific basis of the principles of this alternative approach still remains unclear (http://www.health.org/pubs/acu-nih.htm).
Principles of Acupuncture
The basic principles of acupuncture involve terms such as Yin and Yang, Qi, Meridians and Organ Systems. Acupuncture believes in a continuum of energy that flows in the body between two opposite poles, Yin and Yang. The balance of these two poles constitutes health in the body. Although Yin and Yang are opposites, they are related and inseparable from each other. In other words, they are not absolute terms. Yin contains Yang and Yang contains Yin; they are interdependent and interchangeable. A disturbance in the balance of the Yin and the Yang in the body results in sickness, injury, or illness (http://kizuna.ins.cwru.edu/asia110/projects/Tang2/phil.html).
Qi (pronounced "chee") serves as the life force that circulates throughout the body. It is accumulated, balanced, and enhanced by the dietary intake and air. Disorder and sickness are caused by the unbalanced, obstructed and irregular flow of Qi. Meridians are simply channels that carry Qi throughout the body. They are composed of acupuncture points that form a specific pathway. There are fourteen main meridians in the body. The Organ Systems are energy systems in the body that receive, rebuild, and regulate energy or Qi. Most of the names of the Organ Systems reflect the specific organs that they represent. The Organ Systems not only affect their associated organs, but have an effect on other parts of the body too. The Organ Systems affect the entire human body. Acupuncture, by stimulating specific acupuncture points, is able to regulate the Yin and Yang and Qi in the body and, therefore, treat the sickness or disorder
Chronic pain describes pain that persists over long periods of time. It handicaps the normal lifestyle and quality of one’s life(http://www.asri.edu/neuro/brochure/pain1.htm).
In the United States, over 50 million people suffer from chronic pain. The annual cost of chronic pain is around $100 billion. Moreover, 46% of the people suffering from chronic pain lack adequate pain relief(http://www.painfoundation.org/painful.htm).
Claims of Acupuncture for Chronic Pain
Acupuncture has been claimed as an effective treatment for certain chronic pain. The National Institutes of Health (NIH) Consensus Development Conference Statement stated in November 1997 that that there is "clear evidence for acupuncture’s efficacy for treating postoperative and chemotherapy nausea and vomiting, the nausea of pregnancy, and postoperative dental pain." The NIH panel concludes that acupuncture may be an effective adjunctive therapy for many pain conditions. Acupuncture has been claimed effective for various pain conditions including migraines, back pain, tennis elbow menstrual cramps, fibromyalgia, and carpal tunnel syndrome. (http://www.health.org/pubs/acu-nih.htm). However, there exist studies that have not found acupuncture an effective approach in treating certain other pains like osteoarthritis pain, epicondylalgia, and motion sickness. These studies suggest acupuncture as no more effective than placebo. Acupuncture seems to be a safe and effective therapy for certain health problems, but further more controlled research is needed to establish a firmer ground for the efficacy of acupuncture in treating various chronic pains (Ceniceros & Brown 1998).
How Does Acupuncture Work?
Despite the numerous amount of research done to answer why acupuncture works, a direct answer is yet to be found. However, many theories have been postulated about the biological effects that acupuncture has in treating pain. One of these theories is the Gate Theory of Pain. Introduced in 1965, this theory explains that acupuncture works through the nervous system to alleviate pain. It states that in the nervous system, there exist nerve fibers that both transmit and inhibit pain. These nerve fibers come together in the substancia gelatinosa of the spinal cord. The substancia gelatinosa is then responsible for sending pain signals to the brain, depending on the amount of pain input. Acupuncture stimulates the pain inhibitory nerve fibers, which lowers the pain input and therefore, relieves the pain. This theory, however, faces difficulty in explaining the often long-term effects that acupuncture has in treating pain (http://www.healthy.net/library/books/acupuncture/ACUPUNG.HTM).
Man and Chen (1980) present the Two-Gate Control Theory. In this theory, there exist two main nerve fibers: A-beta and C nerve fibers. A-beta nerve fibers are large, fast conducting, and have a low volt threshold. C nerve fibers are small, slow conducting, and have a high volt threshold. Increased amount of impulses coming from A-beta fibers closes the gate in the substantia gelatinosa, which prevents the passage of painful impulses from the C fibers. Acupuncture acts as a pain-reliever by stimulating the acupuncture points, which affect the A-beta nerve fibers. With the constant twirling of the needle, a steady stream of non-pain impulses is transmitted to the substantia gelatinosa causing the gate to close. Once the gate is closed, subsequent pain impulses coming from the slow conducting C fibers can not pass through. Thus, no pain is felt. The impulses from the A-beta fibers can be relayed to the thalamus, which serves as the final gate. Once the gate in the thalamus is closed, analgesia is produced on the entire body. The gate control theories and modern pain physiology try to provide a scientific ground for the actions of acupuncture.
Another theory explains acupuncture as a counter-pain treatment. It hypothesizes that when pain is inputted on one part of the body, that the pain experienced on another part of the body will be less noticeable. This theory also has trouble explaining the long-term effects of some acupuncture treatments on severe pain, since it would make sense that the counter-pain effect be only short-termed and treat mild pains (http://www.healthy.net/library/books/acupuncture/ACUPUNG.HTM).
The release of endorphins in the body by acupuncture describes yet another theory. Endorphins are natural painkillers found in the central nervous system. Studies have shown that acupuncture releases these morphine-like substances, which prove very effective in relieving pain. Nonetheless, arguments exist that the effects of acupuncture are very quick but the production of pain-killing chemicals appears to be a slower process that doesn’t match up with the swiftness (http://www.healthy.net/library/books/acupuncture/ACUPUNG.HTM).
An interesting study performed in China reveals that in 324 acupuncture points observed, 99% of the points are within 0.5 mm away from nerves, 96% are closely related to superficial nerves in the skin, and 86% are near an artery. This study points to a close correlation between acupuncture points and the nervous system (http://www.chronicpainsolutions.com/acupuncture.htm).
Currently, much research has been done to search for the actual physiological effects acupuncture has on the body. Recent scientific research on acupuncture shows evidence of the neurochemical basis of acupuncture. It has been shown that specific frequencies of electrical stimulation of acupuncture points evoke the gene expression of specific neurohoromones. Clinical reports using this type of neuroelectric acupuncture have shown good results in treating health conditions such as various types of pain, depression, addiction, gastrointestinal disorders, and stroke (Ulett, J Han, & S Han, 1998).
In another recent research, magnetic resonance (MR) imaging is used to map the central nervous system (CNS) pathway in the brain for acupuncture stimulation. MR imaging of the whole brain is done in two groups of nine healthy subjects during four stimulation paradigms of real acupuncture and control stimulations. Acupuncture leads to the activation (signal intensity increased during stimulation as compared with that during rest) and deactivation (signal intensity decreased during stimulation as compared with that during rest) of certain parts of the brain, suggesting the analgesia effects of acupuncture. This research suggests possible links of the mechanisms of acupuncture analgesia to the central nervous system (Wu et al., 1999).
Studies on Acupuncture and Chronic Pain
Numerous studies were done on acupuncture in treating chronic pain in general. Many of these studies were done prior to 1990. Most of these studies lack a well-defined control group and, therefore, were inconclusive about the efficacy of acupuncture in treating chronic pains. The following studies describe older studies done on acupuncture.
In a study by Lee, Modell, Andersen, and Saga (1976), the prolonged pain relief of acupuncture following therapy was studied. For twenty-two months, 533 patients suffering from chronic pain were given a total of 2090 treatments. Of these patients, 52% reported 75% pain relief immediately after the last treatment and 19.3% still reported excellent pain relief four weeks after the therapy.
In another study, 72 patients who had not responded well to conventional medicine were given a total of 606 acupuncture treatments for 12 months. After treatments, 19 patients showed great improvement, 20 showed improvement and 21 showed transient improvement. For long-term results, 11 patients showed marked improvement and 20 others still reflected some improvement 4 months after final therapy. Musculo-skeletal disorders, osteoarthritis and headaches proved to be most effectively treated with acupuncture (Yamauchi, 1976).
Similarly, many other older studies were structured like the two previously mentioned. In one study, after patients completed six or more treatments, 74% reported being helped by acupuncture. After three months, 54% were still benefited and after one year, 24% were still helped by acupuncture (Lewis et al., 1976). In another study, 62.8% of 43 patients reported pain relief right after the final treatment. Seven percent said that the pain was worse while the rest remained unchanged (Levitt & Walker, 1975). Still, another research by Mann in 1973 provided 18 well-documented cases of chronic pain resistant to orthodox procedures. Ten of these cases experienced pain relief from partial to total, while the other 8 cases either showed no improvement or slight improvement. Six successful cases were described in detail in the article.
A few meta-analysis have been done on acupuncture for chronic pain. Meta-analysis is a set of systematic techniques used to define accumulated knowledge by grouping results of different studies. One meta-analysis by Patel, Gutzwiller, Paccaud, and Marazzi in 1989 grouped the results of 14 randomized controlled trials of acupuncture treatments for chronic pain. There were not many individual studies that had statistically significant results, but when the data from all the studies were pooled together, the results show significant results in favor of acupuncture.
In another meta-analysis study, the results of 51 controlled clinical studies were compiled and analyzed. The studies were judged based on four categories: comparability of prognosis, adequate intervention, adequate effect measurement, and data presentation. The resulting qualities of the 51 studies proved disappointing. This showed the inadequacy of research studies in proving the efficacy of acupuncture in treating chronic pain (Riet, Kleijnen, & Knipschild, 1990).
Studies on Acupuncture and Specific Chronic Ailments
More recent studies of acupuncture are geared toward studies on specific chronic illnesses. Since there are numerous studies of acupuncture in treating various chronic illnesses, it will not be possible to cover all of them. Therefore, more recent studies on migraines and headaches are presented as one of the many examples of the effectiveness of acupuncture in treating specific conditions.
Acupuncture and Migraines
Migraines are recurrent headaches that are generally felt on one side of the head. Migraines are caused by the rapid widening and narrowing of blood vessel walls in the head, which irritates the pain fibers in the blood vessel wall (http://www.uiuc.edu/departments/mckinley/health-info/dis-cond/headache/migr-hea.html).
Much research has been done on the efficacy of acupuncture in treating migraines or headaches. One study done in 1985 by Dowson, Lewith, and Machin studied the effects of acupuncture versus a placebo in the treatment of headache. Thirty-nine patients received both placebo treatments (mock transcutaneous nerve stimulation) and acupuncture treatments for 6 weeks. Effectiveness of treatments was evaluated by the use of patient diaries. In the end, acupuncture was about 20% more effective than the placebo in relieving headache.
Another study with a control group researched acupuncture and tension-type headaches. Thirty patients with tension-type headache were randomly chosen to undergo either acupuncture or sham acupuncture. Although frequency of headaches, headache index and analgesic consumption decreased significantly with time after the two treatments, the results show that there were no significant difference between acupuncture and placebo treatments (Tavola, Gala, Conte, & Invernizzi 1992).
In a more recent study done by Baischer in 1995, the long-term effects of acupuncture treatment were studied. A group of 26 patients received acupuncture treatments, and no control group was included. Data revealed that 53.8% of the patients after treatment and 50% of the patients after the three-year follow-up showed improvements greater than 50%. Additionally, the drug intake for the migraine was reduced to 50% at posttreatment.
Still, another study was done on acupuncture in the management of migraines in children. This study researched the efficacy of acupuncture by investigating 22 children with migraine. The children were divided into two groups: an acupuncture group and a placebo group. Ten healthy children served as the control group. Since central pain mechanisms are likely to be related to a dysfunction in the endogenous opioid antinociceptive system, there would be lesser panopioid activity in the patients suffering from migraines. For the acupuncture group, the panopioid activity gradually increased with each progressive treatment, and at posttreatment, the values of the panopioid activity was close to the values of the control group. For the placebo group, there were only insignificant changes in the values of the panopioid activity. Moreover, there was a significant increase in the β-endorphin levels in the patients of the acupuncture group as compared with values before treatment or with values of the placebo group (Pintov et al., 1997).
Other studies researched the effectiveness of acupuncture versus medical treatment for certain conditions. A study done by Loh, Nathan, Schott and Zilkha in 1983 served as an example of such studies. A comparison was made between acupuncture and medical treatment for migraines and muscle tension headaches. Forty-eight patients were randomly allocated to either acupuncture or medical treatment. Of the 48, 23 started with acupuncture and 25 started with medical treatment. After three months, the patients were asked to switch to the other treatment and continue with that treatment for another three months. In this event, 18 patients starting with medical treatment switched to acupuncture and 11 patients switched from acupuncture to medical treatment. The results of the study show that 24 out of 41 (59%) patients showed improvements after acupuncture treatments while only 9 out of 36 (25%) patients showed improvements after the medical treatments. In addition, no major side effects were observed for acupuncture.
In a similar study, acupuncture was compared with the beta-1-selective beta blocker metoprolol (Selo-Zok®; Hässle AB, Mölndal, Sweden), which is a well-known drug. The side effects of both regimens were also compared. After a 4-week run-in period, 77 patients were randomly allocated to one of two groups. Group A received acupuncture plus placebo pills, while group B received 100 mg of metoprolol per day plus placebo stimulation. Treatments for both groups lasted for 17 weeks. The results from the data show that while both groups show significant reduction in migraine attacks at posttreatment, the side effects experienced from acupuncture were considerably lower than side effects from the drug. Fourteen patients in the metoprolol group had side effects while only three patients had side effects in the acupuncture group. The side effects of the drug were mainly fatigue, dizziness, and gastrointestinal discomfort. The side effects of acupuncture consisted of two cases of nausea and one case of euphoria. The study concluded that acupuncture should be considered as an alternative to drug taking (Hesse, Mogelvang & Simonsen, 1994).
Are There Any Side Effects to Acupuncture?
Acupuncture is a relatively safe practice. Like any other therapeutic treatments, it has adverse effects, which are often minimal. Acupuncturists are obligated to use sterile needles for treatments. Common adverse effects found in acupuncture include small bleedings, hematoma, dizziness, and other vegetative symptoms (http://users.med.auth.gr/~karanik/english/articles/adv.html). When performed correctly, acupuncture should be free from adverse and addictive side effects. Moreover, the patient often feels relaxed during and after the treatment (http://www.healthy.net/library/articles/caaom/facts.htm). The studies, mentioned earlier, by Hesse, Mogelvang and Simonsen in 1994 and by Loh, Nathan, Schott and Zilkha in 1983 both support the idea that acupuncture is a relatively safe therapy that has minimal side effects.
Acupuncture seems to be a promising treatment for chronic pain. Since the basis of acupuncture is based on principles, philosophies and thousands of years of accumulated observations, it is difficult for the strictly scientific and methodic Western medical mind to relate to this alternative therapy. Many studies offer their findings of the effectiveness of acupuncture, yet, unfortunately, few of them are well structured. Moreover, the research data on acupuncture has been quite controversial in the varied effectiveness of acupuncture in treating a diversity of chronic conditions. Even studies on a single chronic condition may render inconclusive results due to a placebo effect or biased information. However, numerous claims have been made for the effectiveness of acupuncture treatments. In addition, many studies and research have indeed found acupuncture to be more effective than a placebo and effective in treating chronic conditions. Recent studies have also shed light on possible mechanisms of acupuncture.
This ancient oriental art of healing is gradually working its way into the Western medical system as numerous old and new studies and research provide firmer grounds for its principles, mechanisms, and effectiveness. From reviewing the philosophies of acupuncture to checking the claims of acupuncture to researching both old and new studies, I think that acupuncture definitely has potential for a stand in the Western medical field. Due to the fact that acupuncture is based on the natural healing of the body and has minimal side effects, this therapy seems to provide much good and minimal harm. However, due to the controversial research on the effectiveness of acupuncture on various chronic conditions, well-established scientific studies are needed to provide firmer ground for specific chronic conditions.
Baischer, W. (1995). Acupuncture in Migraine: Long-term Outcome and Predicting
Factors. Headache, 35, 472-474.
Bowsher, D., Mumford, J., Lipton, S., & Miles, J. (1973). Treatment of Intractable Pain By Acupuncture. The Lancet, 2(7820), 57-60.
Ceniceros, S., & Brown, G. R. (1998). Acupuncture: A Review of Its History, Theories, and Indications. Southern Medical Journal, 91(12), 1121-1125.
Dowson, D. I., Lewith, G. T., & Machin, D. (1985). The Effects of Acupuncture versus Placebo in the Treatment of Headache. Pain, 21, 35-42.
Hesse, J., Mogelvang, B., & Simonsen, H. (1994). Acupuncture versus metoprolol in migraine prophylaxis: a randomized trial of trigger point inactivation. Journal of Internal Medicine, 235, 451-456.
Lee, P. K. Y., Modell, J. H., Anderson, T. W., & Saga, S. A. (1976). Incidence of Prolonged Pain Relief Following Acupuncture. Anesthesia and Analgesia, 55(2), 229-231.
Levitt, E. E., & Walker, F.D. (1975). Evaluation of Acupuncture in the treatment of Chronic Pain. Journal of Chronic Diseases, 28, 311-316.
Lewis, C. E., Nadler, M. A., Palmer, B. (1976). The Recipients and Results of Acupuncture. Medical Care, 14(3), 255-262.
Loh, L., Nathan, P. W., Schott, G. D., Zilkha, K. J. (1984). Acupuncture versus medical treatment for migraine and muscle tension headaches. Journal of Neurology, Neurosurgery, and Psychiatry, 47, 333-337.
Man, P. L. & Chen, C. H. (1972). Mechanism of Acupunctural Anesthesia. The Two-Gate Control Theory. Diseases of the Nervous System, 33(11), 730-735.
Patel, M., Gutzwiller, F., Paccaud, F., & Marazzi, A. (1989). A Meta-Analysis of Acupuncture for Chronic Pain. International Journal of Epidemiology, 18(4), 900-906.
Pintov, S., Lahat, E., Alstein, M., Vogel, Z., & Barg, J. (1997). Acupuncture and the Opioid System: Implications in Management of Migraine. Pediatric Neurology, 17(2), 129-133.
Riet, G., Kleijnen, J., & Knipschild, P. (1990). Acupuncture and Chronic Pain: A Criteria-Based Meta-Analysis. Journal of Clinical Epidemiology, 43(11), 1191-1199.
Tavola, T., Gala, C., Conte, G., & Invernizzi, G. (1992). Traditional Chinese acupuncture in tension-type headache: a controlled study. Pain, 48, 325-329.
Ulett, G. A., Han, J. S., Han, S. (1998). Traditional and Evidence-Based Acupuncture: History, Mechanisms, and Present Status. Southern Medical Journal, 91(12), 1115-1120.
Wu, M. T., Hsieh, J. C., Xiong, J., Yang, C. F., Pan, H. B., Chen, Y. C., Tsai, G., Rosen, B. R., & Kwong K. K. (1999). Central nervous pathway for acupuncture stimulation: localization of processing with functional MR imaging of the brain—preliminary experience. Radiology, 212(1), 133-141.
Yamauchi, N. (1976). The Results of Therapeutic Acupuncture in a Pain Clinic. Canadian Anaesthetists Society Journal, 28(5-6), 311-316.
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