Introduction

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Neck pain is a common complaint with a point prevalence from 10% to 18% and lifetime prevalence from 30% to 50%. In many cases symptoms persist, causing severe discomfort and inability to work. ^{1 2} Neck pain is associated with limited cervical spine mobility.³ Frequent concomitant symptoms are headache, vertigo, visual disorders, tinnitus, and vegetative symptoms (sweating, dizziness, nausea). ^{4 5} Common treatment consists of drugs, massage and other manual treatments, physiotherapy and exercise, local and epidural injections, and patient education. ^{6 7} Systematic reviews have shown that the efficacy of these interventions remains questionable. ^{7 8} Current treatment increasingly includes complementary methods, of which acupuncture is one of the most common.⁹ There is, however, a lack of evidence to support acupuncture as an effective treatment for chronic neck pain.^10-12

We compared the efficacy of acupuncture with conventional massage and "sham" laser acupuncture for the treatment of neck pain.

	Methods

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Study design
The study was a randomised, placebo and alternative treatment controlled clinical trial performed at three outpatient departments at the universities in Munich and Würzburg, Germany, from 1996 to 1999.

Participants
Patients were consecutively preselected by the doctors of the three outpatient departments, who were informed about the inclusion and exclusion criteria. Patients who were eligible and willing to participate in the study were then assessed by an independent examiner. This assessment included a detailed physical examination and collection of baseline data. The main inclusion criteria were that patients had had a painful restriction of cervical spine mobility for longer than one month and that they had not received any treatment in the two weeks before entering the study. Patients who had undergone surgery or those with dislocation, fracture, neurological deficits, systemic disorders, or contraindications to treatment were excluded.

Randomisation
Participants were randomly allocated to acupuncture or massage or sham laser acupuncture. A block randomisation stratified for two centres was performed by using a validated software program (PC Random, Biometric Center for Therapeutic Studies, Munich). Patients were told before randomisation that one of the three treatments might be a sham procedure.

Treatment protocols
Patients were treated five times over three weeks. Each treatment lasted 30 minutes. Acupuncture and sham laser acupuncture were performed by four experienced, licensed medical acupuncturists. Massages were performed by five experienced physiotherapists. Patients took no concomitant analgesics. Patients who rated their pain as over 20 on the visual analogue scale (0-100) or who had an inconvenient restriction of mobility at the primary study end point were referred for physiotherapy during follow up.

Assessments
Assessments were performed by a blinded observer before the intervention (M1), immediately after (M2) and three days after (M3) the first treatment, and immediately after (M4) and one week after (M5, primary end point) the last treatment. Follow up included an assessment at three months (M6, secondary end point). Patients were requested not to reveal any information about their treatment during assessment.

Outcome measures
Primary outcome measure The primary outcome measure was the change in the maximum pain related to motion, irrespective of the direction of movement, evaluated before (M1) and one week after (M5) intervention. Patients were asked to move their head in the most affected direction and to score the intensity of pain on a 100 point visual analogue scale.

Statistical analyses
Our intention was to analyse 52 patients per group, which, given a standard deviation of 18, would have provided 80% power at the 5% significance level to detect a 10 point difference in the mean change of motion related pain. This calculation was based on a pilot study that compared acupuncture with sham laser on immediate changes of motion related pain after a single treatment. We estimated a drop out rate of 20% and therefore aimed to recruit 200 patients. However, the study was terminated after we recruited 177 patients because the study period was over and the drop out rate was mostly below 20%, leading to a sufficient number of eligible patients for analyses.

	Results

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Randomisation and progress through the trial
Of 182 patients referred for the first assessment, five did not meet entry criteria; 177 patients were included in the trial. Baseline characteristics of the study sample were equally balanced between groups for most variables, but there was some difference with regard to myofascial pain (table 1). In all three groups most patients believed in the potential benefit of the treatments. The figure shows the progress of patients through the trial and withdrawal from study.

View larger version (23K): [in this window] [in a new window]   Participants' progress through trial and withdrawals

Main outcome measure
The results of the baseline measurements are shown in table 2. The mean improvement one week after intervention is shown in table 3. The reduction in pain related to motion was significantly greater in the acupuncture group compared with the massage group (P=0.0052) but not compared with sham laser (P=0.327). Differences between acupuncture and massage or sham laser were more distinct in the subgroup who had had pain for longer than five years and in patients with the myofascial pain syndrome (table 3).

Secondary outcome measures
Table 4 shows mean changes in secondary outcome measures and comparisons between treatment groups. The results for secondary outcome measures were similar to those for the primary outcome measure. The acupuncture group achieved the best results in most of the secondary outcome measures, including significant differences compared with massage in pain related to motion and direction immediately and one week after treatment. Three months after treatment these differences were comparatively small and no longer significant. However, significantly more patients in the acupuncture group considered their pain (spontaneous, motion related) and global complaints improved three months after treatment compared with patients in the massage group (² tests). We found no significant differences between groups in pressure pain threshold.

Side effects
Seventeen (33%) participants reported mild reactions after needle insertion during acupuncture, mainly slight pain or vegetative reactions (sweating, low blood pressure). After a short rest they agreed to continue the treatment. Similar mild reactions were seen in four (7%) in the massage group and 12 (21%) in the sham laser group. No serious adverse reactions were observed.

	Discussion

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Our results show that acupuncture is a safe form of treatment for people with chronic neck pain and offers clear clinical advantages over conventional massage in the reduction of pain and improvement of mobility. Acupuncture was most effective in people who had had pain for over five years and in those with the myofascial pain syndrome. Such patients can be identified from their case histories and a detailed physical examination.

Our study population generally had "non-specific neck pain," which includes most patients suffering from chronic neck pain. ^{23 24} Between 55% and 90% of patients with chronic neck pain have the myofascial pain syndrome ^{4 14} and 20% to 50% have suffered a whiplash injury.⁵ There were no significant differences between groups in the primary outcome measure (pain related to motion) and most of the secondary outcome measures three months after treatment. This is consistent with the results of recent systematic reviews that show that a single treatment approach in chronic pain does not result in long term effects. ^{7 8} However, results of the qualitative verbal rating scales, which express a more subjective change of pain and global complaints, might indicate longer lasting benefits of acupuncture. Conventional massage had only a weak effect on chronic neck pain. This is in agreement with recent reviews indicating a lack of evidence for the efficacy of massage, although it is one of the most common forms of treatment. ^{2 18}

Previous trials of acupuncture for neck pain have had contradictory results. In a systematic review of 14 acupuncture trials, White and Ernst found no evidence for efficacy, with outcomes equally balanced between positive and negative.¹⁰ The authors judged methodological quality of the studies as disappointing. In a more recent review, Smith et al assessed the analgesic efficacy of acupuncture for neck and back pain. Using a newly developed tool to measure validity of findings of randomised clinical trials, they found no convincing evidence for the analgesic efficacy of acupuncture, and, again, the quality of most trials was poor.¹² In contrast with previous studies our trial had a large sample size, adequate measures evaluated by blinded observers, blinded patients for placebo control, individual acupuncture treatment by more than one licensed acupuncturist, data analyses by an independent institution, follow up assessments, and documentation of drop outs and adverse events.

We chose sham laser acupuncture because it does not activate somatosensory receptors and laser acupuncture is a well known method. We were surprised by the results of sham laser acupuncture compared with massage. They could be explained by an enhanced placebo effect, but the assessment of credibility showed no differences between therapies before treatment. Sham laser acupuncture, however, does not really resemble needle acupuncture. Consequently, non-specific acupuncture effects can only be estimated. Also, sham laser was probably not an inert control because participants might have benefited from palpation of acupuncture points, performed before treatment to select acupuncture points.

Participants received only five treatments because we did not want to treat patients with chronic pain with placebo for longer for ethical reasons. According to traditional Chinese medicine about 10 sessions would be more appropriate.¹⁵ Future research is necessary to evaluate the optimum number of treatments.

It has become clear from our results that placebo controlled studies should include a third group with alternative treatment or without treatment for improved classification of the effects of acupuncture because a true placebo procedure, including blinding of acupuncturists, does not exist for needle acupuncture studies. ^{11 25} The results do not elicit the specificity of acupuncture points or physiological mechanisms.

Conclusion
We conclude that acupuncture can be a safe form of treatment for patients with chronic neck pain if the objective is to obtain relief from pain related to motion and to improve cervical mobility. As neck pain may be a chronic condition with considerable socioeconomic impact single forms of treatment may be inadequate, and acupuncture merits consideration.

	Acknowledgments

We thank K Gleditsch, Dr R Pfeiffer, Dr M Haase, H Arndt, C Müller, D Drexler, and P Köllges for their work in data collection, and all participating colleagues and physiotherapists in the department of physical medicine and rehabilitation, University of Munich, the pain unit, University of Munich, and the department of orthopaedics, University of Würzburg. We also thank the patients who made the project possible.

Contributors: DI coordinated the study, wrote the case report form, analysed the data, and wrote the paper. NB had the original idea, prepared the grant application, and coordinated the study in the first phase until 1997. HM contributed to the coordination and running of the study in Würzburg. AK coordinated the study in Würzburg and contributed to the data analysis and writing of the paper. MN contributed to the original idea and the grant application and coordinated the study in Würzburg. MK had the main responsibility for the data analyses and contributed to writing the paper. JG, AB, ES, and PS supported and contributed to the planning of the project, the grant application, the study running, and the publication. DI and MK and guarantors for the study.

	Footnotes

Funding: German Ministry for Education and Research (BMBF, formerly BMFT) (Project 01 KT 9406/1). Preparation of the manuscript was supported by the German Medical Acupuncture Association (DÄGfA).

Competing interests: None declared.

	References

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(Accepted 15 March 2001)

Commentary: Controls for acupuncturecan we finally see the light?

Mike Cummings, medical director. 

British Medical Acupuncture Society, Royal London Homoeopathic Hospital, London WC1N 3HR

DoE{at}medical-acupuncture.org.uk

Irnich et al are to be congratulated for performing this rigorous trial. Funding is not easy to obtain for trials of acupuncture, so a sample size of 177 is considered large in this specialty. The result is hard to interpret. Advocates of acupuncture will call it a "positive" result. Opponents will argue that acupuncture is no better than placebo and that a similar trial on low back pain gave the opposite result.¹ We are left to speculate on whether acupuncture has specific efficacy in neck pain. A response rate of 57% would certainly be typical of an effective treatment in acute and chronic pain,² but even if this trial had shown a significant effect of acupuncture over sham laser acupuncture, we would still be unsure of the size of the non-specific component related to the needle.

Sham laser acupuncture was a good choice of control when this trial was designed. It can be considered inert, and it controls for the concept of having "acupuncture" in the mind of a participant who recognises it as a valid form of treatment. We cannot be sure, however, that this would equate to controlling for the concept of needle insertion. In the past, researchers have focused on the concept of acupuncture points, and, ironically, controls were often chosen simply by missing the real pointthat is, inserting needles at sites not classically described as acupuncture points. The pressure stimulus applied to the nervous system from a solid needle, however, in the absence of direct impingement on a nerve bundle, is likely to be comparable at any soft tissue site within the same region, so the stimulus applied in such trials was virtually identical in the real and control groups. The response rate seen with such controls often reaches 50%. Reviews that fail to take this into account, by assuming that penetrating sham controls represent inert placebos, are open to criticism.³

Within the past three years the "placebo" needle has been developed. Such a device aims for credible simulation of needle penetration with minimal sensory stimulus. Rather like a stage dagger, the shaft of the placebo needle disappears into its own handle as the blunted tip presses on to the skin at the site of simulated insertion. The remaining challenge is in supporting the needle if it is to be left in place for any length of time. The first randomised controlled trial to use such a device yielded positive results for acupuncture in the treatment of supraspinatus tendonitis.⁴ Further trials with a similar type of needle are underway at the department of complementary medicine in Exeter University.

In the light of these methodological developments, the suggestion from Irnich et al that acupuncture is likely to be more effective in the myofascial pain syndrome, and the considerable empirical support for this suggestion, we can be confident that future studies of sufficient size will determine whether or not the acupuncture needle has efficacy beyond placebo. Musculoskeletal pain has such an important impact on the community⁵ that we must find funding for large scale, methodologically sound trials of this simple, relatively safe, and potentially efficacious technique.

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