Electroacupuncture: mechanisms and clinical application

Acupuncture is an ancient Chinese method to treat diseases and relieve pain. We have conducted a series of studies to examine the mechanisms of this ancient method for pain relief. This article reviews some of our major findings. Our studies showed that acupuncture produces analgesic effect and that electroacupuncture (EA) is more effective than manual acupuncture. Furthermore, electrical stimulation via skin patch electrodes is as effective as EA. The induction and recovering profiles of acupuncture analgesia suggest the involvement of humoral factors. This notion was supported by cross-perfusion experiments in which acupuncture-induced analgesic effect was transferred from the donor rabbit to the recipient rabbit when the cerebrospinal fluid (CSF) was transferred. The prevention of EA-induced analgesia by naloxone and by antiserum against endorphins suggests that endorphins are involved. More recent work demonstrated the release of endorphins into CSF following EA. In addition, low frequency (2 Hz) and high frequency (100 Hz) of EA selectively induces the release of enkephalins and dynorphins in both experimental animals and humans. Clinical studies suggesting its effectiveness for the treatment of various types of pain, depression, anxiety, spinally induced muscle spasm, stroke, gastrointestinal disorders, and drug addiction were also discussed.

Acupuncture treatment for pain: systematic review of randomised clinical trials with acupuncture, placebo acupuncture, and no acupuncture groups

OBJECTIVES

To study the analgesic effect of acupuncture and placebo acupuncture and to explore whether the type of the placebo acupuncture is associated with the estimated effect of acupuncture.

DESIGN

Systematic review and meta-analysis of three armed randomised clinical trials.

DATA SOURCES

Cochrane Library, Medline, Embase, Biological Abstracts, and PsycLIT. Data extraction and analysis Standardised mean differences from each trial were used to estimate the effect of acupuncture and placebo acupuncture. The different types of placebo acupuncture were ranked from 1 to 5 according to assessment of the possibility of a physiological effect, and this ranking was meta-regressed with the effect of acupuncture.

DATA SYNTHESIS

Thirteen trials (3025 patients) involving a variety of pain conditions were eligible. The allocation of patients was adequately concealed in eight trials. The clinicians managing the acupuncture and placebo acupuncture treatments were not blinded in any of the trials. One clearly outlying trial (70 patients) was excluded. A small difference was found between acupuncture and placebo acupuncture: standardised mean difference -0.17 (95% confidence interval -0.26 to -0.08), corresponding to 4 mm (2 mm to 6 mm) on a 100 mm visual analogue scale. No statistically significant heterogeneity was present (P=0.10, I(2)=36%). A moderate difference was found between placebo acupuncture and no acupuncture: standardised mean difference -0.42 (-0.60 to -0.23). However, considerable heterogeneity (P<0.001, I(2)=66%) was also found, as large trials reported both small and large effects of placebo. No association was detected between the type of placebo acupuncture and the effect of acupuncture (P=0.60).

CONCLUSIONS

A small analgesic effect of acupuncture was found, which seems to lack clinical relevance and cannot be clearly distinguished from bias. Whether needling at acupuncture points, or at any site, reduces pain independently of the psychological impact of the treatment ritual is unclear.

The effect of high and low frequency electroacupuncture in pain after lower abdominal surgery

In the present study, we examined the effects of preoperative electroacupuncture (EA) at classical bilateral acupuncture points (Zusanli, also known as ST-36) on postoperative pain and opioid-related side effects. One hundred healthy consenting women undergoing lower abdominal surgery were randomly assigned to four treatment regimens: Group I (n=25), control; Group II (n=25), sham-EA (needle insertion without electrical stimulation); Group III (n=25), low-EA (2 Hz of electrical stimulation); and Group IV (n=25), high-EA (100 Hz of electrical stimulation). EA groups received needle insertion with or without electrical stimulation 20 min prior to anesthesia. All patients received patient-controlled analgesia (PCA) of morphine postoperation. Postoperative pain was evaluated by recording (1). the time of the first required analgesic, (2). the number of PCA demands, (3). the total amount of morphine required by PCA, and (4) patients' VAS pain score. We found that the time of first analgesic requested was 10, 18, 28, and 28 min in the control, sham-, low-, and high-EA groups, respectively. During the first 24h, the total amount of morphine required was decreased by 21, 43 and 61% in the sham-, low- and high-EA groups, respectively. The incidence of nausea and dizziness during the first 24h after surgery was significantly reduced in both the low-EA and high-EA groups compared with the control and sham-EA groups. We also found that sham-EA exerts a beneficial effect with respect to its pain relieving quality but not the side effect profiles. Our findings demonstrates that preoperative treatment with low-EA and high-EA can reduce postoperative analgesic requirements and associated side effects in patients undergoing lower abdominal surgery.

Activation of the hypothalamus characterizes the acupuncture stimulation at the analgesic point in human: a positron emission tomography study

We performed a positron emission tomography study, using regional cerebral blood flow as the index of brain activity, to address the specificity of brain activation pattern by acupuncture stimulation of short duration at the classical analgesic point. Needling manipulation at 2 Hz was performed at a classical point of prominent analgesic efficacy (Li 4, Heku) and a near-by non-classical/non-analgesic point, respectively, in normal subjects. Regions activated by acupuncture stimulation at Li 4 included the hypothalamus with an extension to midbrain, the insula, the anterior cingulate cortex, and the cerebellum. Of note, it was only the stimulation at Li 4 that activated the hypothalamus under the similar psychophysical ratings of acupuncture sensation (deqi) as elicited by the stimulation at the two points, respectively. The data suggested that the hypothalamus might characterize the central expression of acupuncture stimulation at the classical analgesic point and serve as one key element in mediating analgesic efficacy of acupuncture stimulation.

Acupuncture mechanisms for clinically relevant long-term effects--reconsideration and a hypothesis

From the author's direct involvement in clinical research, the conclusion has been drawn that clinically relevant long-term pain relieving effects of acupuncture (>6 months) can be seen in a proportion of patients with nociceptive pain. The mechanisms behind such effects are considered in this paper. From the existing experimental data some important conclusions can be drawn: 1. Much of the animal research only represents short-term hypoalgesia probably induced by the mechanisms behind stress-induced analgesia (SIA) and the activation of diffuse noxious inhibitory control (DNIC). 2. Almost all experimental acupuncture research has been performed with electro-acupuncture (EA) even though therapeutic acupuncture is mostly gentle manual acupuncture (MA). 3. Most of the experimental human acupuncture pain threshold (PT) research shows only fast and very short-term hypoalgesia, and, importantly, PT elevation in humans does not predict the clinical outcome. 4. The effects of acupuncture may be divided into two main components--acupuncture analgesia and therapeutic acupuncture. A hypothesis on the mechanisms of therapeutic acupuncture will include: 1. Peripheral events that might improve tissue healing and give rise to local pain relief through axon reflexes, the release of neuropeptides with trophic effects, dichotomising nerve fibres and local endorphins. 2. Spinal mechanisms, for example, gate-control, long-term depression, propriospinal inhibition and the balance between long-term depression and long-term potentiation. 3. Supraspinal mechanisms through the descending pain inhibitory system, DNIC, the sympathetic nervous system and the HPA-axis. Is oxytocin also involved in the long-term effects? 4. Cortical, psychological, "placebo" mechanisms from counselling, reassurance and anxiety reduction.

A systematic review of randomized controlled trials of acupuncture for neck pain

OBJECTIVE

To establish whether there is evidence for or against the efficacy of acupuncture in the treatment of neck pain.

METHODS

A systematic literature review was undertaken of studies that compared needle or laser acupuncture with a control procedure for the treatment of neck pain. Two reviewers independently extracted data concerning study methods, quality and outcome.

RESULTS

Overall, the outcomes of 14 randomized controlled trials were equally balanced between positive and negative. Acupuncture was superior to waiting-list in one study, and either equal or superior to physiotherapy in three studies. Needle acupuncture was not superior to indistinguishable sham control in four out of five studies. Of the eight high-quality trials, five were negative.

CONCLUSIONS

In conclusion, the hypothesis that acupuncture is efficacious in the treatment of neck pain is not based on the available evidence from sound clinical trials. Further studies are justified.

Relations between brain network activation and analgesic effect induced by low vs. high frequency electrical acupoint stimulation in different subjects: a functional magnetic resonance imaging study

Two- or 100-Hz electrical acupoint stimulation (EAS) can induce analgesia via distinct central mechanisms. It has long been known that the extent of EAS analgesia showed tremendous difference among subjects. Functional MRI (fMRI) studies were performed to allocate the possible mechanisms underlying the frequency specificity as well as individual variability of EAS analgesia. In either frequencies, the averaged fMRI activation levels of bilateral secondary somatosensory area and insula, contralateral anterior cingulate cortex and thalamus were positively correlated with the EAS-induced analgesic effect across the subjects. In 2-Hz EAS group, positive correlations were observed in contralateral primary motor area, supplementary motor area, and ipsilateral superior temporal gyrus, while negative correlations were found in bilateral hippocampus. In 100-Hz EAS group, positive correlations were observed in contralateral inferior parietal lobule, ipsilateral anterior cingulate cortex, nucleus accumbens, and pons, while negative correlation was detected in contralateral amygdala. These results suggest that functional activities of certain brain areas might be correlated with the effect of EAS-induced analgesia, in a frequency-dependent dynamic. EAS-induced analgesia with low and high frequencies seems to be mediated by different, though overlapped, brain networks. The differential activations/de-activations in brain networks across subjects may provide a neurobiological explanation for the mechanisms of the induction and the individual variability of analgesic effect induced by EAS, or that of manual acupuncture as well.

Superficial Dry Needling and Active Stretching in the Treatment of Myofascial Pain – a Randomised Controlled Trial

A pragmatic, single blind, randomised, controlled trial was conducted to test the hypothesis that superficial dry needling (SDN) together with active stretching is more effective than stretching alone, or no treatment, in deactivating trigger points (TrPs) and reducing myofascial pain.

Forty patients with musculoskeletal pain, referred by GPs for physiotherapy, fulfilled inclusion / exclusion criteria for active TrPs. Subjects were randomised into three groups: group 1 (n=14) received superficial dry needling (SDN) and active stretching exercises (G1); group 2 (n=13) received stretching exercises alone (G2); and group 3 (n=13) were no treatment controls (G3). During the three-week intervention period for G1 and G2, the number of treatments varied according to the severity of the condition and subject/clinician availability. Assessment was carried out pre-intervention (M1), post-intervention (M2), and at a three-week follow up (M3). Outcome measures were the Short Form McGill Pain Questionnaire (SFMPQ) and Pressure Pain Threshold (PPT) of the primary TrP, using a Fischer algometer. Ninety-one per cent of assessments were blind to grouping.

At M2 there were no significant inter-group differences, but at M3, G1 demonstrated significantly improved SFMPQ versus G3 (p=0.043) and significantly improved PPT versus G2 (p=0.011). There were no differences between G2 and G3. The mean PPT and SFMPQ scores correlated significantly in G1 only, though no significant inter-group differences were demonstrated. Numbers of patients requiring further treatment following the trial were: 6 (G1); 12 (G2); 9 (G3). Conclusion: SDN followed by active stretching is more effective than stretching alone in deactivating TrPs (reducing their sensitivity to pressure), and more effective than no treatment in reducing subjective pain. Stretching without prior deactivation may increase TrP sensitivity.

Auricular acupuncture for pain relief after total hip arthroplasty – a randomized controlled study

Auricular acupuncture (AA) is known to be effective in treatment of various pain conditions, but still there have been no randomized controlled studies of AA for treatment of acute postoperative pain. Therefore we tested whether AA of specific points is superior to sham acupuncture for complementary analgesia after total hip arthroplasty in a patient-anesthesiologist-evaluator-analyst blinded study. The patients were randomly allocated to receive true AA (lung, shenmen, thalamus and hip points) or sham procedure (4 non-acupuncture points on the auricular helix). Permanent press AA needles were retained in situ 3 days after surgery. Postoperative pain was treated with intravenous piritramide (opioid receptor agonist with analgesic potency of 0.7 compared with morphine) using a patient-controlled analgesia (PCA) pump. The time to the first analgesic request, the amount of postoperative piritramide via PCA and pain intensity on a 100-mm visual analogue scale (VAS-100) were used to evaluate postoperative analgesia. Intraoperative anesthetic requirement, incidence of analgesia-related side effects, inflammation parameters and success of patients' blinding were also recorded. Fifty-four patients (29 AA and 25 controls) completed the study. Piritramide requirement during 36 h after surgery in AA group was lower than in control: 37+/-18 vs. 54+/-21 mg; mean+/-SD; P=0.004. Pain intensity on VAS-100 and incidence of analgesia-related side effects were similar in both groups. The differences between the groups as regard patients' opinions concerning success of blinding were not significant. Findings from our study demonstrate that AA could be used to reduce postoperative analgesic requirement.

Effect of acupuncture in patients with angina pectoris

Twenty-one patients with stable effort angina pectoris were randomized in a crossover study to 4 weeks traditional Chinese acupuncture or placebo tablet treatment. The patients had at least five anginal attacks per week in spite of intensive treatment. Acupuncture was given three times per week at main points Neiguan (Pericardium 6), Tongli (Heart 5), Xinshu (Urinary Bladder 15), Pishu (Urinary Bladder 20) and Zusanli (Stomach 36). Previous antianginal treatment remained unchanged during the whole study. During the acupuncture period, the number of anginal attacks per week was reduced from 10.6 to 6.1 compared with placebo (P less than 0.01). Accordingly, the performance before onset of pain during exercise test increased from 82 W to 94 W (P less than 0.05). However, maximal performance did not increase after acupuncture. Intensity of pain at maximal workload decreased from 1.4 to 0.8 (scale 0-4, P less than 0.01). Further, ST-segment depressions at maximal comparable load decreased from 1.03 to 0.71 mm after acupuncture (P less than 0.01). A life quality questionnaire confirmed improved feeling of well-being. Thus, acupuncture showed an additional beneficial effect in patients with severe, intensively treated angina pectoris.

Treatment of Fibromyalgia with Formula Acupuncture: Investigation of Needle Placement, Needle Stimulation, and Treatment Frequency

OBJECTIVES

The objective of this study was to investigate whether typical acupuncture methods such as needle placement, needle stimulation, and treatment frequency were important factors in fibromyalgia symptom improvement. DESIGN/SETTINGS/SUBJECTS: A single-site, single-blind, randomized trial of 114 participants diagnosed with fibromyalgia for at least 1 year was performed.

INTERVENTION

Participants were randomized to one of four treatment groups: (1) T/S needles placed in traditional sites with manual needle stimulation (n = 29): (2) T/0 traditional needle location without stimulation (n = 30); (3) N/S needles inserted in nontraditional locations that were not thought to be acupuncture sites, with stimulation (n = 28); and (4) N/0 nontraditional needle location without stimulation (n = 2 7). All groups received treatment once weekly, followed by twice weekly, and finally three times weekly, for a total of 18 treatments. Each increase in frequency was separated by a 2-week washout period.

OUTCOME MEASURES

Pain was assessed by a numerical rating scale, fatigue by the Multi-dimensional Fatigue Inventory, and physical function by the Short Form-36.

RESULTS

Overall pain improvement was noted with 25%-35% of subjects having a clinically significant decrease in pain; however this was not dependent upon "correct" needle stimulation (t = 1.03; p = 0.307) or location (t = 0.76; p = 0.450). An overall dose effect of treatment was observed, with three sessions weekly providing more analgesia than sessions once weekly (t = 2.10; p = 0.039). Among treatment responders, improvements in pain, fatigue, and physical function were highly codependent (all p < or = 0.002).

CONCLUSIONS

Although needle insertion led to analgesia and improvement in other somatic symptoms, correct needle location and stimulation were not crucial.

Trigger point acupuncture treatment of chronic low back pain in elderly patients--a blinded RCT

OBJECTIVE

There is some evidence for the efficacy of acupuncture in chronic low back pain, but it remains unclear which acupuncture modes are most effective. Our objective was to evaluate the effects of two different modes of trigger point acupuncture on pain and quality of life in chronic low back pain patients compared to standard acupuncture treatment.

METHODS

Thirty five consecutive out-patients (25 women, 10 men; age range: 65-81 years) from the Department of Orthopaedic Surgery, Meiji University of Oriental Medicine, with non-radiating low back pain for at least six months and normal neurological examination, were randomised to one of three groups over 12 weeks. Each group received two phases of acupuncture treatment with an interval between them. Nine patients dropped out during the course of the study. The standard acupuncture group (n=9) received treatment at traditional acupuncture points for low back pain, while the other acupuncture groups received superficial (n=9) or deep (n=9) treatments on trigger points. Outcome measures were VAS pain intensity and Roland Morris Questionnaire.

RESULTS

After treatment, the group that received deep needling to trigger points reported less pain intensity and improved quality of life compared to the standard acupuncture group or the group that received superficial needling to trigger points, but the differences were not statistically significant. There was a significant reduction in pain intensity between the treatment and interval in the group that received deep needling to trigger points (P<0.01), but not in the standard acupuncture group or the group that received superficial needling to trigger points.

CONCLUSION

These results suggest that deep needling to trigger points may be more effective in the treatment of low back pain in elderly patients than either standard acupuncture therapy, or superficial needling to trigger points.

Pain relief by applying transcutaneous electrical nerve stimulation (TENS) on acupuncture points during the first stage of labor: a randomized double-blind placebo-controlled trial

Transcutaneous electrical nerve stimulation (TENS) is one of the non-pharmacological means of pain relief for labor and delivery. We aimed to investigate the efficacy and safety of TENS on specific acupuncture points for reducing pain in the first stage of labor. In this double-blind, placebo-controlled trial, we randomly assigned healthy full-term parturients in active phase of first-stage labor to either TENS on four acupuncture points (Hegu [Li 4] and Sanyinjiao [Sp 6]) (n=52) or the TENS placebo (n=53). Visual analogue scale (VAS) was used to assess pain before and 30 and 60 min after treatment. The primary outcome was the rate of VAS score decrease 3 in each group. A questionnaire was given at 24h post-partum to evaluate the satisfaction of pain relieving method and the willingness to have the same treatment again. Mode of delivery and neonatal effect were measured as secondary outcome. One hundred women were eligible for analysis. TENS group experienced VAS score reduction 3 significantly more common than the TENS placebo group (31/50 [62%] vs 7/50 [14%], P<0.001). Willingness of using the same analgesic method for a future childbirth was also significantly different (TENS: 48/50 [96%] vs TENS placebo: 33/50 [66%], P<0.001). Operative delivery was increased in the TENS group (12/50 [24%] vs 4/50 [8%], P=0.05), but the neonatal outcomes were not different. The application of TENS on specific acupuncture points could be a non-invasive adjunct for pain relief in the first stage of labor.

A comparative study of diazepam and acupuncture in patients with osteoarthritis pain: a placebo controlled study

Forty-four patients with chronic cervical osteoarthritis took part in this study. Patients were treated with acupuncture, sham-acupuncture, diazepam or placebo-diazepam in randomized order. Pain was rated on visual analogue scales before, during, and after treatment. Two scales were separately used to rate the intensity (sensory component) and the unpleasantness (affective component) of pain. The results analyzed from these trials show that diazepam, placebo-diazepam, acupuncture and sham-acupuncture have a more pronounced effect on the affective than on the sensory component of pain. Acupuncture was significantly more effective than placebo-diazepam (p less than 0.05), but not significantly more effective than diazepam or sham-acupuncture.

Acupuncture analgesia in a new rat model of ankle sprain pain

The lack of suitable experimental animal models for persistent pain showing clear acupuncture analgesia, has been the major stumbling block in the investigation of the physiological mechanisms of acupuncture analgesia. The present study developed a new rat model of ankle sprain pain and the effect of electroacupuncture (EA) on this model was examined. A common source of persistent pain in humans is the lateral ankle sprain. To model this condition, the rat's right ankle was bent repeatedly, overextending lateral ligaments, for 4 min under halothane anesthesia. The rat subsequently showed swelling of the ankle and a reduced stepping force of the affected limb for the next several days. The reduced stepping force of the limb was presumably due to a painful ankle since systemic injection of morphine produced temporary improvement of weight bearing. EA was applied to the SI-6 acupuncture point on the contralateral forelimb for 30 min under halothane anesthesia. After the termination of EA, behavioral tests measuring stepping force were periodically conducted during the next 4h. EA produced a 40% recovery in the stepping force of the sprained foot lasting for at least 2h. The magnitude of this improvement was equivalent to that obtained after a systemic injection of 2mg/kg of morphine and this improvement of stepping pressure was interpreted as an analgesic effect. The analgesic effect was specific to the acupuncture point since (1). the analgesic effect on the ankle sprain pain model could not be mimicked by EA applied to a nearby point, LI-4 and (2). EA applied to the SI-6 point was not effective in the knee arthritis pain model. The analgesic effect could not be blocked by systemic injection of opioid antagonists naloxone or naltrexone. These data suggest that EA produces a potent analgesic effect on the ankle sprain pain model in the rat. This analgesic effect is produced by applying EA to a site remote from the painful area in a stimulus point-specific way. The present study provides a powerful experimental animal model that can be used for investigating the unique physiological mechanisms involved in acupuncture analgesia.

Acupuncture for chronic low back pain in older patients: a randomized, controlled trial

OBJECTIVE

To determine if acupuncture is an effective, safe adjunctive treatment to standard therapy for chronic low back pain (LBP) in older patients.

METHODS

The inclusion criteria for subjects were: (i) LBP > or =12 weeks and (ii) age > or =60 yr; the exclusion criteria were (i) spinal tumour, infection or fracture and (ii) associated neurological symptoms. The subjects were randomized to two groups. The control group of subjects continued their usual care as directed by their physicians, i.e. NSAIDs, muscle relaxants, paracetamol and back exercises. Subjects in the acupuncture group in addition received biweekly acupuncture with electrical stimulation for 5 weeks. Outcome was measured by the modified Roland Disability Questionnaire (RDQ) at weeks 0, 2, 6 and 9. The primary outcome measure was change in RDQ score between weeks 0 and 6.

RESULTS

Fifty-five patients were enrolled, with eight drop-outs. Twenty-four subjects were randomized to the acupuncture group and 23 were randomized to the control group. Acupuncture subjects had a significant decrease in RDQ score of 4.1 +/- 3.9 at week 6, compared with a mean decrease of 0.7 +/- 2.8 in the control group (P = 0.001). This effect was maintained for up to 4 weeks after treatment at week 9, with a decrease in RDQ of 3.5 +/- 4.4 from baseline, compared with 0.43 +/- 2.7 in the control group (P = 0.007). The mean global transition score was higher in the acupuncture group, 3.7 +/- 1.2, indicating greater improvement, compared with the score in the control group, 2.5 +/- 0.9 (P < 0.001). Fewer acupuncture subjects had medication-related side-effects compared with the control group.

CONCLUSIONS

Acupuncture is an effective, safe adjunctive treatment for chronic LBP in older patients.

Dry Needling of Trigger Points with and Without Paraspinal Needling in Myofascial Pain Syndromes in Elderly Patients

OBJECTIVES

To compare the efficacies of dry needling of trigger points (TrPs) with and without paraspinal needling in myofascial pain syndrome of elderly patients.

DESIGN

Single-blinded, randomized controlled trial.

SUBJECTS

Forty (40) subjects, between the ages of 63 and 90 with myofascial pain syndrome of the upper trapezius muscle.

INTERVENTIONS

Eighteen (18) subjects were treated with dry needling of all the TrPs only and another 22 with additional paraspinal needling on days 0, 7, and 14.

RESULTS

At 4-week follow-up the results were as follows: (1) TrP and paraspinal dry needling resulted in more continuous subjective pain reduction than TrP dry needling only; (2) TrP and paraspinal dry needling resulted in significant improvements on the geriatric depression scale but TrP dry needling only did not; (3) TrP and paraspinal dry needling resulted in improvements of all the cervical range of motions but TrP dry needling only did not in extensional cervical range of motion; and (4) no cases of gross hemorrhage were noted.

CONCLUSIONS

TrP and paraspinal dry needling is suggested to be a better method than TrP dry needling only for treating myofascial pain syndrome in elderly patients.

A combined [11C]diprenorphine PET study and fMRI study of acupuncture analgesia

Functional neuroimaging studies suggest that a lateral network in the brain is associated with the sensory aspects of pain perception while a medial network is associated with affective aspects. The highest concentration of opioid receptors is in the medial network. There is significant evidence that endogenous opioids are central to the experience of pain and analgesia. We applied an integrative multimodal imaging approach during acupuncture. We found functional magnetic resonance imaging signal changes in the orbitofrontal cortex, insula, and pons and [11C]diprenorphine positron emission tomography signal changes in the orbitofrontal cortex, medial prefrontal cortex, insula, thalamus, and anterior cingulate cortex. These findings include brain regions within both the lateral and medial pain networks.

Acupuncture in the management of pain in labor

BACKGROUND

To assess if acupuncture could be a reasonable option for pain relief in labor and to look at possible effects of acupuncture on the progress of labor.

METHODS

In a controlled, single blind study, 210 healthy parturients in spontaneous, active labor at term were randomly assigned to receive either real acupuncture or false acupuncture. Visual analog scale assessments were used to evaluate subjective effect on pain. The objective parameter of outcome was the need for analgesic medication in each group.

RESULTS

There were significantly lower mean pain scores and significantly less need for pharmacological analgesia in the study group compared with the control group. The women given real acupuncture spent less time in active labor and needed less augmentation than the control group.

CONCLUSION

The results indicate that acupuncture reduces the experience of pain in labor. A secondary outcome of acupuncture was a shorter delivery time, which mainly, if not exclusively, can be explained by the reduced need for epidural analgesia. Acupuncture may be useful for parturients who wish a nonpharmacological analgesia without side-effects. For others it could be the analgesic method of choice, with pharmacological analgesics as supplements.

Research on the neurophysiological mechanisms of acupuncture: review of selected studies and methodological issues

This presentation reviews studies that contribute to an understanding of the neurophysiological mechanisms of acupuncture. A 1973 study, using volunteer medical students, looked into acupuncture's analgesic effect on experimentally induced pain and suggests that humoral factors may mediate acupuncture-induced analgesia. In a study of the possible role of the cerebrospinal fluid transmission of pain suppression effects of acupuncture, cerebrospinal fluid from acupuncture-treated rabbits was infused into recipient rabbits. The analgesic effect was observed in the recipient rabbits, suggesting that acupuncture-induced analgesia may be mediated by substances released in the cerebrospinal fluid. Studies of electroacupuncture in rats revealed that both low-frequency and high-frequency stimulation could induce analgesia, but that there are differential effects of low- and high-frequency acupuncture on the types of endorphins released. In another study, low-frequency electroacupuncture, given as median nerve stimulation in cats, was shown to protect the myocardium by inhibiting sympathetic pressor response and increasing myocardial oxygen demand. The development of neuroimaging tools, such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), make noninvasive studies of acupuncture's effects on human brain activity possible. Studies using PET have shown that thalamic asymmetry present among patients suffering from chronic pain was reduced after the patients underwent acupuncture treatment. Other studies, using fMRI, have pointed to relationships between particular acupoints and visual-cortex activation. These powerful new tools open the possibility to new scientific studies of this ancient therapy.

[Neurobiological mechanisms of acupuncture analgesia]

AIM

The aim of this review is to present the findings of basic research about mechanism of acupuncture-induced analgesia (AA) on the basis of the relevant literature. The transferability of the results into practice and theory of traditional acupuncture are critically discussed.

METHOD

Extensive literature research was used to identify and summarize relevant studies.

RESULTS

AA has been proven by biochemical, immunohistochemical, molecular biological and neurophysiological investigations. It has been shown that short term AA is mediated by an activation of endogenous antinociceptive systems and descending inhibitory systems. Long term effects cannot be explained sufficiently by experimental results; however, they suggest an involvement of long term inhibitory synaptic modification at spinal cord neurons and clinical and radiological findings indicate limbic system modulation.

CONCLUSION

Regarding the complexity of endogenous pain-inhibitory systems and the methodological shortcomings many questions remain unanswered. Further research activities are necessary in this field.

The effectiveness of relaxation acupoint stimulation and acupressure with aromatic lavender essential oil for non-specific low back pain in Hong Kong: a randomised controlled trial

OBJECTIVES

To assess the effect of acupoint stimulation with electrodes combined with acupressure using an aromatic essential oil (lavender) as an add-on-treatment on pain relief and enhancing the physical functional activities among adults with sub-acute or chronic non-specific low back pain.

DESIGN

Randomised controlled trial.

SETTING

The community centre, Old-Aged Home and Women Workers Association, Hong Kong.

INTERVENTION

8-session relaxation acupoint stimulation followed by acupressure with lavender oil over a 3-week period. The control group received usual care only.

OUTCOME MEASURES

Changes from baseline to the end of treatment were assessed in pain intensity (by Visual Analogue Scale) and duration; lateral fingertip-to-ground distance in centimetres; walking time and interference on daily activities.

RESULTS

The baseline VAS scores for the intervention and control groups were 6.38 (S.E.M. = 0.22) and 5.70 (S.E.M. = 0.37) out of 10, respectively ( P=0.24 ). One week after the end of treatment, the intervention group had 39% greater reduction in VAS pain intensity than the control group ( P=0.0001 ), improved walking time ( P=0.05 ) and greater lateral spine flexion range ( P=0.01 ).

CONCLUSIONS

Our results show that 8-sessions of acupoint stimulation followed by acupressure with aromatic lavender oil were an effective method for short-term LBP relief. No adverse effects were reported. To complement mainstream medical treatment for sub-acute LBP, the combined therapy of acupoint stimulation followed by acupressure with aromatic lavender oil may be one of the choices as an add-on therapy for short-term reduction of LBP.

Comparison between superficial and deep acupuncture in the treatment of the shoulder's myofascial pain: a randomized and controlled study

The principle aim of the present work is the evaluation of the importance of the variable "depth" of needle insertion in the determination of acupuncture's therapeutic results. A randomized clinical trial carried out on 44 patients belonging to two groups of 22 each, suffering from shoulder myofascial pain: group A: superficial acupuncture; group B: deep acupuncture. All of them subjected to the same model of treatment with 13 needles and the treatment of the most painful 4 trigger points (TP) found in the shoulder's area. In the group A patients, the needles were introduced in the skin at a depth of 2 mm, on the TP. In the group B patients, the needles were placed deeply both in the muscular acupuncture points and in the TP. The treatment was planned for a cycle of 8 sessions, the first 4 to be performed twice a week, the last 4 weekly. The intensity of pain was evaluated with the McGill Pain Questionnaire before beginning the therapy, at the end of the therapy, and at the follow-up after 1 and 3 months. Both techniques had efficacy in controlling pain. A statistically significant difference rose between the two needling techniques at the end of the treatment and at the follow up after one and three months. Deep acupuncture shows to be better at all times and this underlines the importance of the muscular afferences in acupunctural stimulation in the control of pain.

Laser acupuncture in patients with temporomandibular dysfunction: a randomized controlled trial

A prospective, double-blind, randomized, and placebo-controlled trial was conducted in patients with chronic temporomandibular disorder (TMD) to check the analgesic efficacy of infrared low-power GaAlAs diode laser applied to acupuncture points. Forty female subjects, ranging in age from 20 to 40 years, with diagnoses of chronic myofascial pain and arthralgia were randomly allocated to two groups: an experimental group (EG) who received the laser acupuncture as adjunct to reversible occlusal splint therapy and a control group (CG) who received a placebo laser associated with occlusal splint therapy. Both approaches were applied once a week for 3 months. Laser acupuncture was defined by the following parameters: 50-mW continuous radiation for 90 s to acupoints ST6, SI19, GB20, GB43, LI4, LR3, NT3, and EX-HN3; defining 4.5-J energy; 1250-W/cm(2) density point; and 112.5-J/cm(2) total density. The outcome measurements included a symptom evolution assessment carried out by checking spontaneous and palpation pain intensity, which was indicated on a visual analog scale (VAS). All evaluations were made by an assessor who was blind to the treatment. The symptom reduction was significant in both groups (EG: VAS = 0, n = 20; CG: VAS between 2 and 4, n = 18). The measurements showed significantly faster and lower pain intensity values in the EG (p ≤ 0.002), where there was a higher proportion of patients with remission of symptoms related to the action of laser acupuncture. For patients in whom conservative treatment was adopted, the laser acupuncture is a secure, noninvasive, and effective treatment modality because it improves the chronic pain associated with TMD and has no side effects.