Acupuncture in Pain Management
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Acupuncture in pain management Jonathan Wilkinson MB ChB MRCP FRCA Richard Faleiro BSc (Hons) DCH FRCA
Acupuncture is a complementary therapy that is being increasingly used in the day-to-day managemen age mentt of pai pain. n. It ori origin ginat ated ed in Chi China, na, ov over er 3000 yr ago and is pra practi ctised sed wor worldw ldwide ide.. Thi Thiss articl art iclee off offers ers a sum summar mary y of the models models of its suggested sugges ted mecha mechanism nism of acti action, on, the evide evidencencebase ba se fo forr it itss ef effe fect ctiv iven enes esss an and d th thee cl clin inic ical al appl ap plic icat atio ions ns fo forr wh whic ich h ac acup upunc unctu ture re ca can n be considered.
feel ve feel very ry rel relaxe axed d or sle sleepy epy,, and som somee re repor portt increased energy levels afterwards.
Traditional theory of action
Frequency of stimulation
Fine nee Fine needle dless (32– 36 gau gauge) ge) ar aree inse inserte rted d int into o body loc locat ation ionss kno known wn as ac acupoi upoints. nts. Cla Classic ssic texts describe up to 356 mapped points located on meridians or channels of energy flow on the surface of the body. In the traditional Chinese medicine (TCM) system, the body is seen as a delicate delic ate balance of two opposing and insepa inseparrable ab le fo forc rces es:: yi yin n an and d ya yang ng.. Yi Yin n re repr pres esen ents ts the cold, slow, or passive principle, while yang represents the hot, excited, or active principle. A ma majo jorr as assum sumpt ptio ion n in TC TCM M is th that at th thee health is achieved by maintaining the body in a ‘balanced state’ and that disease is as a result of an internal imbalance of yin and yang. This imbalance leads to blockage in the flow of Qi (vitall energy (vita energy)) along pathways pathways known as meridians. It is believed that there are 12 main meridians and 8 secondary meridians and that there are more than 2000 acupuncture points on the human body that connec connectt with them. Whether we be beli liev evee th this is or no not, t, th thee co corr rrel elat atio ions ns ar aree based on close clinical observations observations that have existed for millennia.
Techniques
Electro acupuncture (EA) A tiny focused electric current is applied to the skin at the acupoints or can be applied to the needlee itsel needl itself. f. Ther Theree are various modalities modalities to consider.
Specificc end Specifi endoge ogenous nous opi opiat atee re respon sponses ses hav havee been reported: †
†
†
lo loww-fr freq eque uenc ncy y stim st imul ulat atio ion n (1–2 Hz Hz)) caus ca uses es th thee re rele leas asee of en endo dorp rphi hins ns an and d d media enkeph enk ephali alins ns (A (Ad mediated ted). ). Les Lesss tha than n 1 Hz is ineffectual; mid-range mid-range (12– 15 Hz) stim stimulat ulation ion resul results ts in th thee pr prod oduc ucti tion on of al alll th thre reee op opio ioid id classes; high-frequency high-frequency (100 Hz) results in dynorphin phi n rel releas easee and has no eff effect ect on end endororb -mediated). phin ph inss or en enk kep epha hali lins ns (A (Ab -mediated). There is no further gain in opioid peptide release beyond 200 Hz.
Amplitude of stimulation
One to th One thre reee mi mill llia iamp mper eree is th thee ra rang ngee us used ed most commonly in clinical practice. This intensity produces a non-painful fasciculation of the musc mu scle le in wh whic ich h th thee ne need edle le is em embe bedde dded. d. Higher Hig her amp amplit litude udess cau cause se pai pain n and giv givee ris risee to a stre stress ss respon response. se. Stre Stress-indu ss-induced ced analg analgesia esia depend dep endss in par partt on dif diffus fusee nox noxiou iouss inh inhibi ibitor tory y cont co ntro roll an and d doe doess no nott usu usual ally ly fo form rm a pa part rt of acupuncture analgesia.
Basic needling
Key points
Acupuncture originated 3000 yr ago and has been used as a modality for treatment of acute and chronic pain. There are five main techniques practised. Dry needling is probably the most common, but electro acupuncture (EA) possesses the most promising research resear ch endorsement. Many expert panels have convened worldwide and have found at least 40 different indications for acupuncture. However, further research is needed. Thus far, the use of acupuncture, along with other therapies, has proved to be very promising in osteoarthritis of the knee and in intractable neck pain. Despite minimal contraindications and an excellent safety profile, cynicism still exists, mainly as a result of the evidence-based climate in which we practise today. Jonathan Wilkinson MB ChB MRCP FRCA
Specialist Registrar and Fellow in Thoracic Anaesthesia Nottingham University Hospitals NHS Trust Hucknall Road Nottingham Nottin gham NG5 1PB, UK Richard Faleiro BSc (Hons) DCH FRCA
Needle Need less ar aree in inse sert rted ed to a de dept pth h of 4– 25 mm and left in place for a period of time (from a few seconds to many minutes). There are often
Duration of stimulation
6–12 needles (and sometimes more) inserted at different acupoints at the same time. The sensation sat ion is oft often en des descri cribed bed as a tin tingli gling ng or dul dulll ache at the entry point. Many people say they
20 min. When stimulation is prolonged beyond 1 h, or if th thee st stim imul ulat atio ion n is re repe peat ated ed (e (e.g .g.. 30 min bursts repeated after a 1 h interval), the analgesic effect is attenuated.
At least 10 min is required required for the production production of the endorphins, with maximal release after
doi:10.1093/bjaceaccp/mkm021 Continuing Education in Anaesthesia, Critical Care & Pain | Volume 7 Number 4 2007 & The Board of Management and Trustees of the British Journal of Anaesthesia [2007]. All rights reserved. For Permissions, please email: [email protected]
Consultant in Anaesthesia and Pain Management Derby Hospitals NHS Foundation Trust London Road Derby DE1 2QY, UK Tel: þ Tel: þ 0133 225 4747 Fax: þ Fax: þ0133 0133 225 4963 E-mail: [email protected] (for correspondence)
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Acupuncture in pain management
Moxibustion A stimulating stimulating heat may be applied onto the needle over the acupoints. Traditionally, this was a smouldering herb.
Laser acupunctu acupuncture re In laser acupuncture, a fine low-energy laser beam is directed onto the acupoint.
Acupressure Here, pressure is used to stimulate the acupoints. This can be in the form of a bracelet or strap. This method is commonly used to alleviate motion sickness.
Acupoints and their locations The Standard Acupuncture Nomenclature published by the World Health Healt h Organ Organizat ization ion (WHO) listed about 400 acupu acupunctur ncturee points and 20 meridians connecting most of the points. The exact anatomical locations of these points are beyond the scope of this article. There are 12 meridians on the arms and the legs. Meridians are divided into Yin and Yang groups. The Yin meridians of the arm are: ar e: hea heart, rt, lun lung, g, and per perica icardi rdium. um. The Ya Yang ng mer meridi idians ans of the arm are: small intestine, intestine, large intes intestine, tine, and tripl triplee warm warmer. er. The Yin meridians of the leg are: kidney, spleen, and liver. The Yang meridians of the leg are: stomach, bladder, and gall bladder.
Mechanisms of action How can unm unmedi edica cated ted nee needle dles, s, ins insert erted ed at sit sites es so dis distan tantt fro from m their desired application, work? Why does placing a needle on the lower leg, for example, affect gastric function? Many maintain that this is a placebo effect, as these meridians and their Qi cannot be measur mea sured, ed, diss dissect ected, ed, or obse observe rved d usi using ng sta standa ndard rd ana anatom tomica icall or physiologic physi ological al techn techniques. iques. The acup acupoints oints are loca located ted at sites that have a high density of neurovascular structures and are generally between or at the edges of muscle groups. A study demonstrating the map of a meridian pathway, involved the injection injection of tec techne hnetiu tium m 99 into both tru truee and sham (min (minima imalldepth dept h nee needle dle inse insertio rtion n at site sitess aw away ay fro from m tra tradit ditiona ionall ac acupun upunctu cture re points) acupoints. acupoints. The scans demonstrated demonstrated random diffusion of the tracer around sham points, but rapid progression of the tracer along the meri meridian dian at a ra rate te tha thatt was inc inconsi onsiste stent nt wit with h eit either her lym lympha phatic tic/ / 1 vascula vasc ularr flow or nerv nervee cond conduct uction ion at the true acupoint. acupoint. Another demons dem onstra trated ted tha thatt need needling ling a poin pointt on the low lower er leg tra tradit ditiona ionally lly associated with the eye, activated the occipital cortex of the brain, as detected by the detected by functional magnetic resonance imaging. There are several postulated mechanisms of action.
Natural opioid substances Needling affects the cerebrospinal fluid (CSF) concentrations of the natura nat urally lly occ occurri urring ng opia opiate te subs substanc tances: es: dyno dynorphi rphin n (ac (actin ting g at spin spinal al
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level), endorphin (acting within the brain) brain),, and encephalin (acting both in the brain and at a spinal level). Endorphins and enkephalins are potent blockers or modulators of pain arising from the musculoskele losk eletal tal sys system tem.. Dyno Dynorphi rphin n is a pow powerfu erfull modu modula lator tor of visc viscera erall pain; it has a weaker effect on musculoskeletal pain modulation. The above notions wer weree support supported ed by cross cross-perfus -perfusion ion experiments in which an acupuncture-induced analgesic effect was transferred from the donor rabbit to the recipient rabbit when the CSF was transferred.2 The prevention of acupuncture-induced analgesia by nal naloxo oxone ne and by ant antise iserum rum aga agains instt end endorp orphin hinss off offers ers fur furthe therr support the involvement of endorphins.
The neurogate theory Similarr to the mechanis Simila mechanism m of the action action of wid widely ely used tr trans ans-cutane cut aneous ous ele electr ctrica icall ner nerve ve sti stimul mulat ation ion (TE (TENS) NS),, the neu neurog rogat atee theory has also been offered as an explanation to the blockade of pain. The close correlation correlation between local acup acupunctur uncturee point pointss for 3 pain and trigger points as noted by Melzack , co-author of the gate theory the ory of pai pain, n, re repre presen sents ts a maj major or con conve verge rgence nce of We Weste stern rn and Eastern knowledge.
Endogenous corticosteroid release The presence of a foreign body (needle) may act to stimulate vascular and immuno-modulatory factors, including those of local inflammatio ma tion. n. Adr Adreno enoco corti rtico cotr troph ophic ic hor hormon monee ha hass be been en sho shown wn to be elevated elevate d after acupuncture acupuncture trea treatments, tments, suggesting that adrenal activation and the release of endogenous corticosteroids may also result.
Myofibrillary Myofibrilla ry entanglement Acupuncturee may induce rela Acupunctur relaxati xation on of ‘stuc ‘stuck’ k’ myofi myofibrils brils within tissue planes. This is thought to have a similar effect to the injection of painful trigger points (a common procedure undertaken in pain clinics).
Local blood flow In cau causin sing g min minor or tra trauma uma to an are areaa of the body, it is pos postul tulat ated ed that acupuncture may increase local blood flow to the surrounding area. This may initiate or catalyze the healing process.4
Mesolimbic loop of analgesia The mesolimbic pathway is one of the neural pathways the brain that link the ventral tegmentum area in the midbrain to the nucleus accumbens in the limbic system. It is one of the four major pathways where the neurotransmitter dopamine is found and produces a pleasurable feeling when stimulated. It is postu postulate lated d that that,, in chron chronic-pa ic-pain in pati patients, ents, the mesoli mesolimbic mbic loop loo p is in a st stat atee of imb imbala alance nce.. Aft After er a rel relat ative ively ly bri brief ef (30 min min)) period of stim stimulat ulation ion with TENS or EA, a self-su self-sustai staining ning reverberat ber ation ion is set up, cau causin sing g a re re-set -settin ting g of the pai pain-m n-modu odula latio tion n
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Acupuncture in pain management
pathways. This theory may well account for the long-term analge5 sic effects seen frequently in clinical practice.
Evidence for efficacy The National Institute of Health (NIH) in the USA has convened a consensus panel to review the available literature concerning acupuncture.6 The quality of many studies has been poor; enthusiastic practitioners, rather than trained researchers, have performed most studies. studi es. The panel concluded concluded that there were only two evide evidencencebase ba sed d in indi dica cati tions ons fo forr ac acup upun unct ctur ure: e: de dent ntal al pa pain in an and d na naus usea ea (postoperative, chemotherapy-induced and pregnancy-related). The panel also concluded that it was time to take acupuncture more seriously and their systemati systematicc revi review ew of the literature literature indicated cate d that there may, may, in fact, be far more indications, indications, but bette betterr designed studies were needed to confirm its utility in these areas. These include investigation into the basic science of acupuncture and appropriate sham needle approaches to the placebo arm. The WHO has identified over 40 medical conditions that may be effectively tive ly trea treated ted with acup acupunctur uncture. e. Those rela relating ting to pain alone are shown in Table 1. Research into acupuncture has to contend with the concept of a contr con trol ol gro group. up. If, in cont control rol gr groups oups,, non non-a -acup cupoin ointt nee needli dling ng is performed,, physio formed physiologica logicall acup acupunctur uncturee effec effects ts are implie implied. d. There Therefore, fore, the effects shown in this group are often close to those shown in the acupun ac upunctu cture re gr group. oup. In oth other er tri trials als,, con contr trol ol gro groups ups ha have ve re recei ceived ved obviously obvious ly diffe different rent treatments, treatments, such as TENS or TENS-l TENS-laser aser treatment; it is not clear if the effects of acupuncture are as a result of only the psychological effects of the treatment. A placebo acupuncture needle has now been developed, with which it should be possible to simulate an acupuncture procedure without penetrating the skin.
Clinical applications The most common indication is for chronic pain unresponsive to standard stan dard therapy, therapy, wher wheree other options have been exha exhausted usted.. It is often seen as a last resort for pain relief, as a result of the inconclusive clusi ve evidence base thus far. This creates creates an adve adverse rse selection bias, leaving acupuncture as an option only for those patients who faill to res fai respond pond to all other met methods hods and can cre creat atee unr unreal ealist istic ic expectations from patients.
Osteoarthritis of the knee A major study involving 570 patients looking at the effect of acupunctur punc turee on ost osteoa eoarth rthriti ritiss of the knee has found tha thatt it can both 7 relieve relie ve pain and impro improve ve mov movement. ement. A US NIH study concluded that acupuncture is an effective complement to standard care. Patients who took part in the study received acupuncture, sham acupuncture, or guidance on self-help, alongside standard drug treatment. Previous studies of acupuncture for osteoarthritis have had conflicting results. This may have occurred because most studies have included small samples, a limited number of treatment sessions, or other oth er lim limita itatio tions. ns. Imp Impro rove vemen mentt in a st stand andard ard pai pain n and func functio tion n score was more like likely ly in the traditionaltraditional- and sham-a sham-acupunc cupuncture ture groups than in the standard-treatment group (53 and 51% vs vs 29%, respectively). However, the placebo effect could be operating here, because similar improvements were observed regardless of whether or not the needles were inserted into defined acup acupunctur uncturee points points.. Commentators have questioned the use of sham acupuncture as a contr con trol ol in thi thiss stu study dy and oth others ers,, arg arguin uing g tha thatt sham ac acupun upunctu cture re may ma y be to too o si simi mila larr to re real al ac acup upun unct ctur uree to be a va vali lid d co cont ntro rol, l, thereby skewing results towards showing a relative lack of efficacy. Others questioned the success of blinding, because the study plan was published published on the Inter Internet net before the study ended. ended.
Table 1 Conditions that may be amenable to acupuncture identified by the WHO U pp pp er er re sp sp ir ir at ato ry ry t ra rac t di so sor de de rs rs
Gastrointestinal disorders
Neurological disorders
Musculo-skeletal disorders
Other
Chronic neck pain
A cu cu te te si nu nus it iti s Acute rhinitis Acute tonsillitis Acute /c /chronic gastritis Chronic duodenal ulcer (pain) Chronic colitis Pelvic pain Headache Migraine Trigeminal neuralgia Post-herpetic neuralgia Peripheral neuropathies Intercostal neuralgia Tennis elbow Frozen shoulder Cervico-brachial syndrome Sciatica Low back pain Osteoarthritis Phantom limb pain Fibromyalgia Dysmenorrhoea Atypical chest pain Labour pain/stimulation of labour Dental pain
Researchers Researche rs at the Univ University ersity of Southa Southampton mpton compared genuine and sham treatments from the same therapist on 124 patients with chro ch roni nicc ne neck ck pa pain in ag aged ed be betw twee een n 18 an and d 80 80..8 Ov Over er 12 we weeks eks,, patie pa tients nts fro from m bot both h gro groups ups rep report orted ed a dec decre rease ase in pai pain n lev levels els of moree tha mor than n 60% 60%.. Thi Thiss may imply that mos mostt of the improvem improvement ent gained from acupuncture is not as a result of the needling process itself, but predominantly as a result of the non-specific yet powerful effects which are probably part of the treatment process.
Low back pain 9
For low back pain, a Cochrane review stated: Thirty-fiv Thir ty-five e RCTs covering covering 2861 patients patients wer were e incl included uded in this systematic review. There is insufficient evidence to make any recommend omm endat ation ionss ab about out ac acup upunc unctur ture e or dr dry-n y-need eedlin ling g for ac acute ute low-back pain. For chronic low-back pain, results show that acu puncture punctur e is more effective for pain relief than no treatmen treatmentt or sham treatment treatment,, in meas measure urement mentss tak taken en up to thr three ee mont months. hs. The results res ults also sho show w tha thatt for chronic chronic low low-ba -back ck pain pain,, acu acupun punctur cture e is
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more effe more effectiv ctive e for impr improvi oving ng func function tion than no tre treatm atment, ent, in the short-ter shor t-term. m. Acup Acupunct uncture ure is not mor more e effe effectiv ctive e than other conv convenentional and ‘alternative’ treatments. When acupuncture is added to other conventional conventional therapies, it relieve relievess pain and improves function better than the conventional therapies alone. However, effects are only small. Dry-needlin Dry-needling g app appears ears to be a usef useful ul adjunct to
Table 3 Adverse effects of acupuncture
other therapies for chronic low-back pain.
Metal allergy Local pain Bruising Bleeding Haematoma formation
Contraindications and adverse effects The abs absolu olute te and rel relat ativ ivee con contra traind indica icatio tions ns to ac acupu upunct ncture ure are listed in Table 2. Acupuncture is technically an invasive procedure and has rare associated risks (Table 3). Serious injury is extremely raree give rar given n the millions of needl needles es plac placed ed annual annually ly worldw worldwide. ide. A well-trained practitioner can prevent most of these problems. The introduction of single-use disposable needles has eliminated cross infect inf ection ion.. The mos mostt com common mon com compli plica catio tion n is syn syncop copee or pr preesyncop syn copee (th (thee so-c so-call alled ed nee needle dle sho shock ck re reac actio tion). n). In mos mostt cas cases, es, remo re mova vall of th thee ne need edle le an and d pe perf rfor ormi ming ng th thee te tech chni nique que in th thee recumbent rather than the sitting position is enough to prevent this.
Conclusion Acupunctu Acupun cture re ma may y wor work k via the sam samee mec mechan hanism ismss oth other er com compplementary therapies work namely: † † † † †
†
†
Placebo. Diversion. Cyclical nature of the illness—it went away by itself anyway. Incorrect diagnosis. Mo Mood od im impr prov ovem emen entt du duee to th thee in inti tima mate te na natu turre of th thee treatment. Psychological investment of the patient in the success of the therapy. Other medications the patient may be taking.
Table 2 Contraindications to the use of acupuncture Abso Ab solu lute te co cont ntra rain indi dica cati tion onss
Rela Re lati tive ve co cont ntra rain indi dica cati tion onss
Needle phobia
Pregnancy—avoid any points known to stimulate uterine contractility Poin Po ints ts ov over er ni nipp pple les, s, um umbi bili licu cus, s, an and d ma majo jorr vessels are forbidden by conventional texts Pointt ove Poin overr infant fonta fontanel nel Application during menses (less effective) If patient is on corticosteroids, benzodiazepines, or narcotics (less effective) Anticoagulant drugs
Seve Se vere re bl blee eedi ding ng di diat athe hesi siss
Inability to rema Inability remain in stil stilll for treat treatment ment Systemic sepsis Unco-operative—hallucinating, delusions, etc. Cellulitis Burns Ulceration EA—do not apply over heart or brain. Do not apply in region of pacemaker or implanted medical pump
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Adverse effects of acupuncture Pneumothorax Cardiac tamponade Neurovascular damage Infection
Whenever the conventional standard of care is not effective, acceptable to the patient or has intolerable side effects, acupuncture can 10 be consi consider dered ed with within in an inte integra grated ted car caree plan plan.. Al Altho though ugh no nott a panacea, it is often an option considered too late. It must be noted that delaying conventional proven therapy in order to use acupuncture as the initial treatment modality for a condition, may be unwise. This is particularly true if there is insufficient validation from scientific studies for that condition. Explanations Explanations offered by tradit traditional ional Chinese medicine are admittedly rich in metaphor and allegory and results res ults of stu studie diess are often confl conflict icting; ing; however however,, doct doctors ors hat hatee to admit that acupuncture can work. Why? They find it hard to believe what they can’t see. Now there’s something to look at.
References 1. Vernejo ernejoul ul P, Albar Albarede ede P, Darras JC. Nuclea Nuclearr medic medicine ine and acup acupunct uncture ure message transmission. J Nucl Med 1992; 1992; 33 : 409–12 2. Hans JS, Xie GX, Zhou ZF, ZF, Folkesson R, Terenius Terenius L. Acupuncture mechanisms ani sms in rab rabbit bitss st studi udied ed wit with h mic micro roinj inject ection ion of ant antibo ibodie diess agai agains nstt -endorphin, enkephalin, and substance P. P. Neuropharmacology 1984; 23: b -endorphin, 1– 5 3. Melzack Melzack R. Acupu Acupunctu ncture re and pain mechanisms. mechanisms. Anaesthesist 1976; 25: 204–7 4. Kapthuk TJ. Acupuncture: theory, efficacy, efficacy, and practice. Ann Intern Med 2002; 136: 374–83 5. Takes akeshige hige C, Oka K, Mizuno T et al. The acupunctu acupuncture re point and its connecting central pathway for producing acupuncture analgesia. Brain Res Bull 1993; 1993; 30 : 53–67 6. NIH. NIH. NI NIH H co cons nsen ensu suss st stat atem emen entt Acupuncture 1997; 15 : 1–34
onli on line ne 3–5
Novvem No embe berr
1997 19 97..
7. Scharf Scharf H, Man Mansma smann nn U, Str Streit eitber berger ger K et al. Acu Acupun punctu cture re and kne knee e osteoarth oste oarthritis ritis:: a thre three-armed e-armed rando randomized mized trial. Ann Intern Med 2006; 145: 12–20 8. White P, P, Lew Lewith ith G, Pres Prescott cott P, P, Conw Conway ay J. Acupu Acupunctu ncture re versus versus plac placebo ebo for the tr treat eatmen mentt of chr chroni onicc mec mechan hanica icall nec neck k pai pain: n: a ran random domiz ized, ed, controlled trial. Ann Intern Med 2004; 2004; 141: 911–9 9. Furlan Furlan AD AD,, van Tulder Tulder MW, MW, Cherki Cherkin n DC et al. Acupuncture Acupuncture and dryneedli nee dling ng for lo low w ba back ck pai pain n (C (Coch ochran rane e rev revie iew). w). Cochrane Cochrane Database Syst Sy st Re Rev v 2005 2005.. Is Issu sue e 1. Art Art.. No No.: .: CD CD00 0013 1351 51.. DO DOI: I: 10 10.1 .100 002/ 2/ 14651858.CD001351.pub2 10. Zhang X. Acupuncture: Review and Analysis of Reports on Controlled Clinical Trials. Geneva: World Health Organization, 2002
Please see multiple choice questions 22–26
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