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Acupuncture Analgesia: II. Clinical Considerations

Wang, Shu-Ming MD*; Kain, Zeev N. MD, MBA*†; White, Paul F. PhD, MD, FANZCA

doi: 10.1213/ane.0b013e318160644d
Analgesia: Pain Medicine: Review Article

BACKGROUND: Acupuncture and related percutaneous neuromodulation therapies can be used to treat patients with both acute and chronic pain. In this review, we critically examined peer-reviewed clinical studies evaluating the analgesic properties of acupuncture modalities.

METHODS: Using Ovid© and published medical databases, we examined prospective, randomized, sham-controlled clinical investigations involving the use of acupuncture and related forms of acustimulation for the management of pain. Case reports, case series, and cohort studies were not included in this analysis.

RESULTS: Peer-reviewed literature suggests that acupuncture and other forms of acustimulation are effective in the short-term management of low back pain, neck pain, and osteoarthritis involving the knee. However, the literature also suggests that short-term treatment with acupuncture does not result in long-term benefits. Data regarding the efficacy of acupuncture for dental pain, colonoscopy pain, and intraoperative analgesia are inconclusive. Studies describing the use of acupuncture during labor suggest that it may be useful during the early stages, but not throughout the entire course of labor. Finally, the effects of acupuncture on postoperative pain are inconclusive and are dependent on the timing of the intervention and the patient's level of consciousness.

CONCLUSIONS: Current data regarding the clinical efficacy of acupuncture and related techniques suggest that the benefits are short-lasting. There remains a need for well designed, sham-controlled clinical trials to evaluate the effect of these modalities on clinically relevant outcome measures such as resumption of daily normal activities when used in the management of acute and chronic pain syndromes.

IMPLICATIONS: The peer-reviewed literature suggests that acupuncture and related forms of acustimulation provide temporary pain relief in patients with a wide variety of acute and chronic pain syndromes. There is minimal evidence, however, that these nonpharmacologic treatments provide longer-term benefits unless the treatments are administered on a continuing basis.

From the The Center for Advancement of Perioperative Health©, Departments of *Anesthesiology, and †Pediatrics, and Child and Adolescent Psychiatry, Yale University School of Medicine, New Haven, Connecticut; and ‡Department of Anesthesiology and Pain Management, University of Texas Southwestern Medical Center at Dallas, Texas.

Accepted for publication October 15, 2007.

Supported by National Institutes of Health (NCCAM, R21AT001613-02 to S.M.W.; NICHD, R01HD37007-02 to Z.N.K.), Bethesda, MD, and by funds from the McDermott Chair of Anesthesiology and the White Mountain Institute (to P.F.W.), a non-for profit private foundation.

Dr. Paul F. White, Section Editor for Special Projects, was recused from all editorial decisions related to this manuscript.

Address correspondence and reprint requests to Shu-Ming Wang, MD, Department of Anesthesiology, Yale School of Medicine, 333 Cedar St., New Haven, CT 06510. Address e-mail to shu-ming.wang@yale.edu.

Acupuncture and related techniques are nonpharmacologic modalities that are based on classical teachings in Chinese medicine and can be used for the management of pain. Although a National Institute of Health consensus statement published in 19981 indicated that acupuncture might be useful for the treatment of certain pain conditions, the recent scientific evidence supporting the use of acupuncture and related forms of acustimulation for the relief of acute and chronic pain has not been critically reviewed. Although many early clinical studies describing the potential clinical usefulness of acupuncture were poorly controlled,1 more recent studies2–4 suggest that acupuncture analgesia can be used as an adjuvant in the treatment of conditions such as low back pain (LBP), osteoarthritis (OA) of the knee and neck pain.

In the first review article in this series, we addressed the issue of underlying mechanisms of acupuncture analgesia.5 In this article, we critically evaluate the clinical evidence regarding the use of acupuncture and its variants in both the short- and long-term management of specific pain syndromes. The focus of this article is on prospectively randomized, sham-controlled clinical trials published in the peer-reviewed medical literature after the consensus panel review of 1998.1 Anecdotal case reports, case-series, and cohort studies were excluded from this review. We have chosen to focus on sham-controlled trials because of the potential bias for patients and investigators in uncontrolled clinical trials. Indeed, sham-control design is mandatory in acupuncture research to prevent the introduction of reporting bias. This calls for the introduction of an acupuncture-like intervention (e.g., needling to a nonacupuncture point, or a spurious stimulation at established acupuncture points).

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METHODS

We evaluated studies involving clinical analgesic effects of specific forms of acustimulation that include not only traditional Chinese manual acupuncture, acupressure, and electroacupuncture (EA), but also auricular acupuncture and related electrical nerve stimulation techniques such as transcutaneous electrical acupoint stimulation (TEAS), percutaneous electrical nerve stimulation (PENS), percutaneous neuromodulation therapy (PNT), and transcutaneous electrical nerve stimulation (TENS). In reviewing the peer-reviewed literature, all these forms of acustimulation appear to have very similar clinical outcomes. Classic manual acupuncture consists of inserting and manipulating needles into the various acupuncture points whereas acupressure is a technique that uses pressure to stimulate these same acupuncture points. EA is a technique that applies small electrical currents to needles inserted at acupuncture points, whereas TEAS consists of applying an electrical current to cutaneous electrodes that have been placed at acupuncture points. Auricular acupuncture is based on the concept that different ear points represent different organs of the body and includes administration of pressure, needle, or electrical stimulation to specific points on the ear. In contrast, TENS and PENS are based on sending an electrical current either through cutaneous electrode patches (TENS) or acupuncture-like needles to the nerve serving the painful area (PENS). Finally, PNT is a variant of PENS that differs only with respect to the length of needle.

The oldest acustimulation, traditional Chinese manual acupuncture, consists of inserting acupuncture needles into acupuncture points along traditional acupuncture meridians and applying manipulations, e.g., twist, thrust, push and pull until the patient and acupuncturist both experience the “De Qi” sensation. This sensation is frequently described by patients as soreness, numbness, ache, fullness, or warm sensation and by acupuncturists as the feeling of the needle getting caught. Wang et al. suggest that manipulation of the acupuncture needle activates various afferent fibers (type II, III, and IV) and that this activation results in the De Qi sensation.6 For example, type II afferent fibers (A-β fibers) are responsible for the sensation of numbness/pressure, type III fibers (A-δ fibers) are responsible for a stinging sensation, and type IV fibers (C-fibers) are responsible for a slow diffusion, and aching/nagging sensation. Studies by Langevin et al. indicate that the “needle grasp” sensation experienced by acupuncturists during manipulation is due to the mechanical coupling between the needle and the connective tissue with winding of tissue around the needle during needle rotation.7,8 In contrast, electrical acupuncture modalities consist of applying different frequencies of electrical stimulation to acupuncture needles inserted at the traditional acupuncture points. Interestingly, a study has shown that 70% of local trigger points correspond to the traditional acupuncture points9 and that the analgesic effect through electrical acupuncture point stimulation is similar to the electrical stimulation at the corresponding dermatomal levels or peripheral nerve.10,11 Alternative medical therapies, such as acupuncture and related forms of acustimulation, will likely assume an increasing role in western medicine as scientific evidence supporting these therapies becomes available to practitioners.12

In this article, we will discuss evidence supporting the use of acustimulation in chronic LB and neck pain, OA involving the knees, dental pain, surgical and procedure-related pain, acute postoperative pain, and labor pain.

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Chronic LBP

Early clinical studies and meta-analysis indicating that acupuncture was not effective for the treatment for chronic LBP13–15 suffered from methodologic limitations such as inadequate sample sizes, problematic study designs, and the use of invalid outcome measures. In 2001, Carlsson and Sjolund conducted a sham randomized controlled trial (RCT) study among men and women suffering from chronic LBP and found that both manual and EA were superior to sham electrical stimulation in reducing pain and improving sleep patterns, activity repertoire, and analgesic consumption at 4–6 mo postintervention.16 Interestingly, these positive findings were limited to women subjects. In 2002, Leibing et al. published a RCT involving 131 patients who suffered from LBP and who had normal neurologic examinations for at least 6 mo before their enrollment in the study.17 These investigators found that an intervention consisting of 26 sessions of combined ear and body manual acupuncture and physical therapy was superior to an intervention that consisted of 26 sessions of standard physical therapy alone for reducing pain, disability, and psychological distress for the first 3 mo of treatment. The beneficial effects of acupuncture were not lasting and at 9 mo after the last intervention there were no differences between the two study groups. A more recent RCT found that the combination of true acupuncture with conservative orthopedic treatment was superior to sham acupuncture combined with conservative orthopedic treatment or conservative orthopedic treatment alone.18 However, the beneficial effects lasted only 3 mo.

Several studies have also compared the efficacy of alternative electrostimulation techniques (e.g., PENS, PNT) for the treatment of LBP. For example, Ghoname et al.19 found that PENS was more effective than TENS or exercise therapy in providing short-term pain relief and improved physical function in patients with LBP caused by degenerative disk disease. In a follow-up study, these investigators reported that PENS analgesic effects resulting from alternating electrical stimulation at frequencies of 15 and 30 Hz were superior to analgesic effects resulting from isolated lower (4 Hz) or higher (100 Hz) frequency stimulation.20 These investigators also studied the effect of the duration of alternating 15 Hz/30 Hz PENS stimulation. They found that analgesic effects resulting from 30 min of stimulation were superior to analgesic effects obtained after 15 min stimulation. However, prolonging the stimulation to 45 min failed to improve the analgesic response. The investigators concluded that there is no additional prolongation of the analgesic effect once the alternated 15 Hz/30 Hz PENS was given for longer than 30 min.21

Yokoyama et al.22 performed a RCT to compare the effects of 8 wk of PENS and TENS therapy for the treatment of long-term pain relief in patients with chronic LBP. They found that, although PENS is more effective than TENS for chronic LBP, the analgesic effect was only sustained for 1 mo posttreatment. The investigators concluded that to sustain the analgesic effect PENS therapy should be continued. Sator-Katzenschlager et al.23 explored the effectiveness of semi-permanent press needle auricular acupuncture compared with electrical auricular acupuncture as a treatment for LBP. The investigators found that electrical auricular acupuncture is superior to semipermanent press needle acupuncture in decreasing the severity of LBP and improving psychological well being, activity, and sleep at 3 mo after treatment. Similarly, Meng et al. found that EA is superior to standard therapy such as nonsteroidal antiinflammatory drug, muscle relaxants, paracetamol, and back exercises in elderly patients who suffer from LBP.24 Since the above long-term acupuncture studies did not have a sham-control group, one can only conclude that there are some differences in the effect of analgesia among various stimulation techniques and treatment modalities.

In conclusion, although data from sham-controlled clinical studies indicate that acupuncture and alternative forms of electrostimulations (PENS and PNT) can serve as a short-term adjunct treatment for LBP management, no study has proven any long-term benefit of acupuncture and/or any other related interventions as a treatment for LBP.22–26 This lack of long-term benefit may be related to quick degradation of acupuncture-induced endogenous endorphins.5 Future studies should include sham-control groups and focus on specific target patient population, types and location of LBP. These studies should also focus on clinically relevant outcome measures such as activity of daily living and functionality (e.g., return to work).

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Chronic Neck Pain

The design of many of the clinical studies focusing on the therapeutic effect of acupuncture and other forms of acustimulation on chronic neck pain is similar to that of LBP. Irnich et al. conducted a sham-controlled RCT that compared acupuncture with massage therapy for treatment of chronic neck pain.27 The investigators found that although true acupuncture was superior to massage therapy it was not superior to sham acupuncture. After the publication of this study in the British Medical Journal, a letter to the editor by Vickers suggested that data analysis of the study was not acceptable and that the original data had to be reanalyzed.28 Indeed, after reanalysis of the data, Vickers suggested that acupuncture was superior as compared to massage and sham therapies as a short-term treatment for chronic neck pain. Vickers and Irnich next collaborated in a sham-RCT study that compared acupuncture needle placement at acupuncture points to local trigger points and to sham laser acupuncture. They found that stimulation at acupuncture points is superior to both direct needling of local trigger points and laser sham acupuncture for improving motion-related pain and range of movement in chronic neck pain patients.29 This study examined, however, only the immediate effects of acupuncture on neck pain (15–30 min). A similar study was conducted using true and sham acupuncture needling applied directly to local trigger points in patients who suffered from chronic neck and shoulder pain.30 The investigators found that although acupuncture provided greater immediate relief for the neck and shoulder pain there were no long-term benefits.30 White et al.31 conducted a sham-controlled crossover study to explore whether the location of the PNT has an effect on the immediate analgesic responses in patients who suffer from chronic neck pain. These investigators found that local (versus remote) dermatomal needling produced greater improvement in the analgesic response, as well as both physical and mental performance, as assessed by a well-validated functional inventory, the SF-36.

Sator-Katzenschlager et al.32 compared the efficacy of six weekly treatments of manual and auricular EA for the treatment of chronic neck pain (Fig. 1). The investigators found that auricular EA is superior to manual auricular acupuncture in reducing the severity of pain, analgesic consumption, and return to full-time employment. In a large-scale trial that was conducted in the United Kingdom, patients were randomized to receive either TEAS or sham-TEAS. Eight treatments were administered over a 4-wk period and outcome assessments included neck pain, the neck disability index, the SF-36, and analgesic consumption. This study found that patients in the TEAS group reported significantly less pain when compared with patients in the sham-TEAS group.33 However, neck disability index and SF-36 scores did not differ significantly between groups. Finally, a small-scale sham-RCT was conducted with 24 subjects who suffered from chronic neck and shoulder pain.34 Subjects were randomized to receive either 10 acupuncture or sham-acupuncture treatments combined with daily acupressure at acupuncture points or at sham points over a 3–4 wk period. After this very intensive regimen, the investigators found that at the 6 mo and 3 yr follow-up evaluations patients in the acupuncture group had better sleep quality, less anxiety and pain, less depression, and a higher satisfaction with life when compared with patients in the sham group.34 In contrast to the above studies, a crossover study by Zhu and Polus indicated that there are no differences in either subjective or objective measures between true and sham acupuncture treatments for chronic neck pain.35 Analogous to the studies in patients with chronic LBP, studies indicate that PENS and PNT are effective short-term treatments for chronic neck pain. Preliminary data suggest that acustimulation may establish the efficacy of acupuncture as a long-term treatment for chronic neck pain. We submit that additional studies are needed to determine the duration and strength of pain relief compared with established therapies and the underlying physiologic mechanism of acupuncture-induced analgesia in chronic neck pain.

Figure 1

Figure 1

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OA of the Knee

Although acupuncture is commonly used as a treatment for OA of the knee,36 a systematic review published in 2001 found inconsistent results and insufficient evidence to determine whether acupuncture is superior to sham treatment.37 However, Berman et al.38 investigated the efficacy of acupuncture as an adjunctive therapy in elderly patients suffering from OA of the knee using a randomized crossover study design. These investigators found that patients randomized to acupuncture treatments had improved on both McMaster University's OA index and Lequesne's indices at 4 and 8 wk. The same research team then conducted a large-scale sham-controlled RCT that included 570 patients that were randomized to receive acupuncture treatment, sham treatment, or an educational intervention over a 6-mo period.39 The research team found that patients in the acupuncture group experienced significantly greater improvement than the sham group in both McMaster University's OA index function and pain scores. A sham-controlled RCT published in Lancet randomized patients with OA of the knee to receive 8 wk of acupuncture, sham, or waiting list control. The study found that patients in the acupuncture group experienced improved joint movement and significantly less pain. However, a follow-up at 1 yr revealed no differences among the various study groups.40

We conclude that the use of acupuncture stimulation is an effective short-term treatment of OA of the knee. Unfortunately, long-term benefits from acupuncture treatment have not been demonstrated.

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Dental-Related Pain

A systemic review published in 1998 in the British Dental Journal suggested that acupuncture could alleviate pain after dental procedures.41 In 1999, a randomized, double-blind, placebo-controlled trial conducted by Lao et al. reported that the average pain-free postoperative time and time to requested pain medication was longer in patients who received true versus sham acupuncture during wisdom tooth extraction.42 Kitade and Ohyabu43 performed a study to examine patients who underwent mandibular wisdom tooth extraction using local anesthesia versus a combination of local anesthesia and low-frequency electrical acupuncture at bilateral LI4 (“He Gu” the 4th acupuncture point along the large intestine meridian), unilateral at ST6 (“Jia Che” the 6th acupuncture point along the stomach meridian) and ST7 (Xia Guan the 7th acupuncture point along the stomach meridian) acupoints (ipsilateral to the surgical side). The investigators found that EA significantly decreased the magnitude of postoperative pain. A large-scale study by Bausell et al.44 was designed to explore the effect of “expectancy” in acupuncture analgesia on postprocedural dental pain. The investigators found that, although there was no statistically significant analgesic effect between the acupuncture and placebo groups, participants who believed they received “real” acupuncture reported significantly less pain than those who believed they had received a placebo.

We conclude that data regarding the use of acupuncture analgesia for the management of acute dental pain is inconclusive and that future studies should consider the issue of “expectancy effect.”

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Procedural Analgesia

Acupuncture and related techniques have been used during medical procedures, such as colonoscopy. Wang et al.45 demonstrated that pain, serum β-endorphins, epinephrine, norepinephrine, and dopamine levels were similar between patients who received EA (ST36-Zusanli, ST37-Shangjuxu; the 36th and 37th acupuncture points along the stomach meridian, auricular Shenmen point) and patients who received meperidine during colonoscopy procedures. These investigators also found that patients receiving EA had fewer side effects such as dizziness. Since these investigators did not include a sham-control group, their findings should be interpreted cautiously. Fanti et al.46 conducted a sham-RCT to evaluate the analgesic effects of EA in a group of patients who were undergoing colonoscopy procedures. Patients in both the acupuncture and sham groups received the same frequency (100 Hz) of stimulation for the 20 min before the procedure and throughout the duration of the procedure. The investigators found that patients in the acupuncture group reported nonsignificantly reduced pain during the procedures.

Therefore, currently available data do not support the use of acupuncture as an analgesic adjuvant during colonoscopy.

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Surgical Anesthetic and Anecdotal Analgesic—Sparing Effects

Anecdotal reports from China indicate that acupuncture can be used successfully as a sole anesthetic in a variety of surgical procedures such as open-heart surgery.47 However, whether acupuncture can be used as a sole anesthetic or as an adjunct to local and general anesthesia in the Western world remains to be determined. Schaer48 conducted a study in which women undergoing gynecological procedures that required general anesthesia were randomized to receive either fentanyl or EA for intraoperative analgesia. The investigator found that EA was as effective as 0.27 μg/kg of fentanyl given IV every 10 min. Greif et al.49 performed electrical stimulation at the lateralization-control point near the ear tragus and reported that this intervention significantly decreased the desflurane anesthetic requirements (approximately 25%). Similarly, Taguchi et al.50 who applied auricular acupuncture stimulation at Shenmen, thalamus, tranquilizer, and master cerebral points also observed a similar anesthetic-sparing effect.

In contrast, Sim et al.51 conducted a sham-controlled RCT study of EA in a group of women scheduled for lower abdominal surgery. The women were randomized to receive preoperative EA or sham EA, or postoperative EA at ST36 and PC6. The investigators found no difference when preoperative EA was compared with preoperative sham EA; more importantly, postoperative patient-controlled analgesia morphine consumption was not different among the three treatment groups. Similarly, Morioka et al.52 found that EA failed to decrease desflurane anesthetic requirements, and Kvorning et al.53 found that EA actually increased sevoflurane anesthetic requirements.

Based on these contradictory data, it is reasonable to conclude that the effect of intraoperative acupuncture analgesia remains controversial. In future studies, it is also necessary to standardize the type and depth of anesthesia and opioid analgesic usage, as well as the duration of stimulation. These conflicting results can be partially explained by suppression of acupuncture-induced blood oxygen level-dependent (BOLD) signals observed under general anesthesia.54 Acupuncture-induced BOLD signals are the magnetic signals generated by the ratio of oxyhemoglobin and deoxyhemoglobin in the areas of the brain where there are hemodynamic changes related to acupuncture stimulation. In other words, acupuncture-induced BOLD signals are an indirect measure of neuronal activities at the regions of the brain affected by the acupuncture stimulation.

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Acute Postoperative Pain

Manual Acupuncture Techniques

In a sham-controlled RCT, Kotani et al. applied intradermal needles to “Back Shu” acupoints in a group of patients who were scheduled to undergo major abdominal procedures.55 These acupuncture needles were inserted 2 h before induction of anesthesia and retained in place for 48 h postoperatively. The investigators found that patients in the acupuncture group reported a significant reduction in postoperative pain and analgesic requirements and postoperative nausea and vomiting compared to the sham group. Usichenko et al.56 examined the analgesic effects of auricular acupuncture in a group of patients who underwent total hip arthroplasty. Sixty-one patients, who were scheduled to have total hip arthroplasty, were randomized to receive either auricular acupuncture or sham (auricular) acupuncture perioperatively. The acupuncture semipermanent press needles were placed the evening before surgery and retained for 36 h postoperatively. The investigators found that analgesic consumption during the first 36 h postoperatively was lower in the auricular acupuncture when compared with the sham group. In contrast to the above positive studies, Gupta et al.57 conducted a sham-controlled RCT to evaluate the effect of intraoperative acupuncture intervention on the analgesic requirement after knee arthroscopy. The investigators were not able to demonstrate a reduction of postoperative analgesic effect in the acupuncture treatment group. In examining these and other studies, one can conclude that acupuncture is effective in decreasing the severity of postoperative pain, only when the acupuncture stimulation was performed before induction of anesthesia and/or during the postoperative period.56,58–61 In contrast, acupuncture administered while the patient was under general anesthesia was found to be ineffective in decreasing postoperative analgesic requirement.57,62

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Electroacustimulation

In 1989, Christensen et al.58 conducted a RCT involving 20 healthy women who underwent gynecological surgery and received either EA or no treatment (control). The intervention was administrated while these women were emerging from general (volatile) anesthesia but received 70% nitrous oxide to block recall of the intervention. Postoperatively, the investigators found that patients who received EA consumed significantly less (40%) pethidine in the postanesthesia care unit when compared with the control group. In a follow-up RCT, these researchers administered continuous EA from the preoperative period throughout the intraoperative period.61 In contrast to their previous findings, the investigators found no differences in the postoperative analgesic consumption between the acupuncture and control groups.61 This reported inconsistency may have been a result of the development of tolerance to prolonged acupuncture stimulation62 and/or a direct suppression of acupuncture-related BOLD signals by general anesthesia.54 These data are consistent with studies examining the efficacy of acupoint stimulation for the prevention of postoperative nausea and vomiting. For example, White et al.63 found that acupoint stimulation was only effective when administered after surgery.

In 1997, Wang et al.59 conducted a sham-controlled RCT evaluating the analgesic effect of postoperative TEAS in patients undergoing lower abdominal surgery (Fig. 2). Following a standardized anesthetic protocol, TEAS was applied either to acupuncture points or the para-incisional dermatomes, with the intensity of the electrical stimulation delivered high (9–12 mA) or low (4–5 mA) level. The investigators found that TEAS treatment of these locations resulted in a 30%–35% reduction in the postoperative opioid analgesic requirements. They also found that high-intensity TEAS was more effective in decreasing postoperative analgesic requirement than low-intensity TEAS. Chen et al.11 conducted a similar study with surgical patients randomized to receive TENS at one of three locations: an acupuncture point, a nonacupuncture point, or at the dermatome corresponding to the surgical incision (Fig. 3). They found that both TENS at the acupuncture point and TENS at para-incisional dermatomes were effective in producing a similar analgesic-sparing effect after surgery. Importantly, simultaneous stimulation at both acupoints and dermatomes resulted in additive opioid-sparing effects. Lin et al.60 performed a large scale RCT to examine the effects of various frequencies of preoperative EA on postoperative pain and opioid-related side effects. Analogous to previous investigations,11,60 They found that the postoperative analgesic effect is positively correlated to the frequency of the electrical stimulation. That is, 100 Hz of EA resulted in less analgesic consumption in the first 24 h postoperatively.

Figure 2

Figure 2

Figure 3

Figure 3

In conclusion, acupuncture is effective as an adjunctive treatment for acute postoperative analgesia if administered to surgical patients in the postoperative period. Future studies should examine whether the efficacy of EA and related forms of acustimulation is influenced by the depth of anesthesia, types of anesthetics (i.e., IV versus volatile), and different states of anesthesia or types of anesthetics. It also seems that the analgesic effect of electro-analgesia is affected by the duration, amplitude, and frequencies of stimulation. Location of electrode placement plays a less significant role in the analgesic effect as long as the placement of electrodes is either at an appropriate acupuncture point or at the peripheral nerves corresponding to the surgical incision.11

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Labor Analgesia

Ramnero et al.64 conducted a nonblinded RCT study to evaluate the efficacy of acupuncture as an analgesic adjuvant during labor. These investigators found a decreased requirement for meperidine in the acupuncture group compared with a control group with the same parity. Chung et al.65 conducted a sham-controlled RCT study to determine the effect of acupressure on labor pain and uterine contractions during the first stage of labor (Fig. 4). These investigators found that during the first stage of labor the patients who received acupressure reported significantly less labor pain compared to patients who received sham or no treatment. Moreover, there was no significant difference in uterine contractions during the first stage of labor among the three groups. Finally, Lee et al.66 performed a sham-controlled RCT to evaluate the analgesic effects of acupressure on labor pain and time to delivery. These investigators reported that labor pain score during the first hour after the intervention was lower and the total labor time (i.e., delivery time) was significantly shorter in the acupressure versus sham-control group. Therefore, available data indicate that acupuncture and related techniques may be effective for the early stage of labor. However, more data are needed to establish the effectiveness of acustimulation techniques during the entire labor process.

Figure 4

Figure 4

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SUMMARY

This article summarizes the current peer-reviewed literature related to the analgesic effect of various forms of acustimulation. Indeed, acupuncture appears to be most effective for short-term management of back pain, neck pain and OA involving the knee. Data regarding the efficacy of acupuncture for dental pain, perioperative pain and colonoscopy pain are inconclusive. Although there are only a few studies examining the efficacy of acupuncture during labor, it seems that acupuncture and related techniques are effective only for stage I labor.*

Any discussion that involves acupuncture-related research is not complete without addressing some of the methodologic issues in this area. Similar to other clinical studies, some acupuncture studies are hindered by inappropriate sample size, confounding variables, poorly defined outcomes, invalidated outcome measures, and inadequate follow-up. Acupuncture research does, however, present additional hinderances such as acupuncturist positive expectancy bias. Although the use of sham is widely recommended in the literature, this technique is not without problems. Insertion of a needle in a nonacupuncture point may result in unexpected physiological results, such as changes in pain thresholds and unintended release of endorphins. The development of a sham-needle may be a solution to the above issue; however, it is difficult to blind the patient and acupuncturist because the presentation of how an acupuncture needle is secured into the acupuncture point and sensation of acupuncture stimulations are different from true acupuncture stimulation. The quest for a matching sham control, one that is inert and identical in appearance and sensation is continuing. Also, the use of subjective De Qi sensation experienced by acupuncturists and patients poses a significant challenge for researchers. There remains a need for well-designed, sham-controlled clinical trials to evaluate the role of acupuncture and related acustimulation analgesic techniques in the management of acute and chronic pain syndromes. These future studies should also include outcome measures such as patient well-being and resumption of normal activities.

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*We refer the reader to www.yinyanghouse.com for an anatomical drawing of the locations of specific acupuncture points. The reader should note that acupuncture points used in the different studies described in this review appear in Table 1 and therapeutic effects of acupuncture analgesia for various acute and chronic clinical entities discussed in this paper are summarized in Tables 2 and 3.
Cited Here...

Table 1

Table 1

Table 1

Table 1

Table 2

Table 2

Table 3

Table 3

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