Acupuncture versus Placebo for the Treatment of Chronic Mechanical Neck Pain

Context Chronic neck pain is a common, disabling condition and is difficult to treat. Because traditional therapies, such as physical therapy and nonsteroidal anti-inflammatory drugs, have limited effectiveness and can have adverse effects, many patients seek alternative therapies, such as acupuncture. Contribution This randomized, controlled trial of acupuncture versus sham transcutaneous electrical stimulation for patients with chronic mechanical neck pain identified no clinically significant benefit of acupuncture over placebo with respect to pain, function, or analgesic use. Implications Acupuncture did not lead to clinically significant improvement in chronic mechanical neck pain when compared with placebo. The Editors Chronic mechanical neck pain can be caused by dysfunction of a variety of structures within the neck (1-3) but specifically excludes systemic problems such as rheumatoid arthritis. It is usually associated with unspecified degenerative changes (cervical spondylosis) that include osteoarthritis. Neck pain presents a substantial problem and may be responsible for as many days of work absenteeism as low back pain (4). Osteoarthritis is the most common of the chronic diseases and affects most people older than 65 years of age (5). It is degenerative and progressive in nature (1-3, 6). Because there is no cure for cervical spondylosis, treatment tends to center on symptom relief (7, 8). If the condition is symptomatic and symptoms are left untreated, this manifests as increasing episodic pain, stiffness, or both, and patients may then experience a spiral of increasing dysfunction (9). Two systematic reviews of conventional conservative physical therapy suggest that little evidence supports the efficacy of such intervention (8, 10). Nonsteroidal anti-inflammatory drugs, the mainstay of pharmacologic treatment, are associated with a wide spectrum of serious and well-documented adverse reactions (5). There has been a huge increase in the use of complementary and alternative medicine in both the United States and the United Kingdom (11, 12). Acupuncture is the most frequently used type of complementary and alternative medicine therapy for the treatment of osteoarthritis (13). Despite little sound evidence of efficacy (14), approximately 1 million people seek complementary and alternative medicine treatment annually in the United States (15). Two systematic reviews of acupuncture in neck pain (4, 16) suggest that there has been insufficient research in this area and that the published studies are of poor quality. Therefore, we conducted a rigorous evaluation to test whether western-style acupuncture performs better than placebo for treatment of chronic mechanical neck pain. We defined western acupuncture as a conventional diagnosis followed by individualized acupuncture treatment using a combination of prescriptive tender, local, and distal points. This is in contrast to a traditional Chinese approach, which would formulate an individualized diagnosis based on traditional Chinese theories of meridians and energy (or qi). Methods Study Design and Patient Selection We designed a randomized, single-blind, placebo-controlled trial using a pragmatic treatment regimen. The study was conducted in the outpatient departments of Southampton General Hospital and Salisbury District Hospital in the United Kingdom. Between 1999 and 2001, patients were referred by rheumatologists or family physicians or from physiotherapy waiting lists. Appropriate ethical approval was obtained from the Southampton and South West Hampshire Joint Research Ethics Committee. Patients were 18 to 80 years of age, had chronic (>2 months) mechanical neck pain, and had a pain score of more than 30 mm on a visual analogue scale (VAS) for 5 of 7 pretreatment days (possible score on this VAS ranges from 0 to 100 mm). We excluded pregnant patients; those with a history of fracture or surgery to the neck, cervical congenital abnormality, uncontrolled low back pain, contraindication to acetaminophen, systemic illness (for example, rheumatoid arthritis), or ongoing neck-related litigation or disability claims; and those with current or recent manual neck treatment or steroid use (oral or local injection). Sample Size Previous studies suggested a 50% to 75% improvement using acupuncture for patients with chronic pain, compared with 30% for placebo treatment (17). We used these findings as the basis for our power calculation. At 5% significance and 90% power, 53 patients were required in each group to detect a 30% difference in response between active and placebo treatments. Interventions Informed consent was obtained along with a full medical history, neurologic examination, cervical radiography, and laboratory investigations (full blood count, erythrocyte sedimentation rate, and liver function tests). We told patients that we were comparing 2 types of intervention: 1) acupuncture with needles and 2) treatment with a machine designed to stimulate acupuncture points through skin electrodes. The patients were informed that the treatment might or might not prove to be effective and that there was a 50% chance that they would be assigned to a placebo but were not told what the placebo was. Blinding was not broken until 1 year after treatment. One practitioner performed all interventions. Acupuncture We used single-use, sterile, silver-handle, prepacked needles without guide tubes. Sizes used were 13 mm 0.25 mm, 25 mm 0.25 mm, and 40 mm 0.25 mm. We based point selection on individualized western acupuncture techniques by using a list of points previously reported as being effective in neck pain (18, 19) and by reaching a consensus according to our own clinical and teaching practice (Appendix Table). The specific points for each individual were defined at each treatment session, depending on the patient's pain distribution and palpation of the neck and thorax to determine ah-shi points, or local tender points, for acupuncture. At least 1 distal point was used. Point location and depth of insertion were as described in traditional texts (19). Six points on average, per side if pain was bilateral, were used on each patient, and deqi (a term used to describe acupuncture needle sensation) was obtained on each needle. Twenty-minute treatment sessions were given. The patient was checked every 6 or 7 minutes to ascertain whether deqi was still present, and needles were manipulated again if required. Placebo There is considerable debate about the ideal placebo for acupuncture studies (20). To enhance the rigor of our study, we chose to use a previously well-validated placebo (17, 21-23) that could not have a specific physiologic effect. The Noma FM-4 electroacupuncture stimulator (Noma Ltd., Southampton, United Kingdom) was used. It has 4 channels, allowing pseudostimulation of up to 8 acupuncture points simultaneously, and emits visual and audio signals. Reusable electrodes (Body Clock Health Care Ltd., London, United Kingdom) were fixed to the surface of the patient's skin and were connected to the stimulator through decommissioned cables. The cables were severed inside the output plug, so that no current could reach the patient. Examination and point selection were the same as with real acupuncture for each treatment. Point location and treatment variables were changed during subsequent treatment sessions if patients felt they were not progressing. Patients were told that the machine could stimulate acupuncture points through high-frequency, low-intensity stimulation and therefore would not produce any sensation. If patients reported sensation, the therapist adjusted the unit for comfort (although since this was a sham procedure, such adjustment made no real difference). Patients in both groups were instructed to use acetaminophen alone for pain relief and were not given or permitted any other form of treatment, including exercises or stretches, during the study and for 2 months after treatment ended. Patients were treated twice per week for 4 weeks. The therapist had taken an Acupuncture Association of Chartered Physiotherapists accredited course on western acupuncture techniques and had 7 years of experience practicing acupuncture. Randomization Randomization lists for Southampton General Hospital and Salisbury District Hospital were generated by using a computer program, Randomlogue, produced by Southampton University Department of Medical Statistics, Southampton, United Kingdom. Sealed envelopes containing the individual randomization codes, numbered consecutively with sex and age strata, were then prepared (sex strata were male and female, and age strata were 18 to 49 years and 50 to 80 years) Patients were strictly allocated across 4 strata for either of the study hospitals according to the next available envelope number. Data Collection Before randomization, patients were instructed to use a daily pain diary (on a VAS) to record pain and acetaminophen use for 7 consecutive days. After a week, the pain diaries were examined, and if the inclusion criteria (which were unknown to the patients) were satisfied, randomization occurred. Patients completed the various questionnaires before treatment and at 1 and 8 weeks after treatment. Pain continued to be recorded either weekly or daily throughout treatment and up to 8 weeks after treatment. Additional questionnaires and pain evaluation were also completed at 6 and 12 months after treatment. Figure 1 shows a flow chart of the trial. Figure 1. Study flow with outcome assessments. Outcomes The VAS score for pain 1 week after treatment, recorded daily for 7 consecutive days, was the primary outcome. Pain was recorded on a scale of 0 mm (indicating no pain) to 100 mm (indicating worst pain imaginable). A significant outcome for acupuncture was considered to be a 30% difference in VAS score between groups 5 weeks after randomization (1 week after treatment), taking into account baseline pain. Secondary Outcomes