Acupuncture: An Update
As a licensed acupuncturist, I am often asked by both medical professionals and laypersons whether acupuncture actually “works” and whether it should really be considered part of a belief system rather than science.
Fortunately, when responding to these questions, I am able to draw on a growing body of literature that supports the use of acupuncture for a variety of painful conditions. Nevertheless, there is still controversy about how it works and how to identify those patients who will most benefit from it.
Primarily because of difficulties in obtaining funding to perform substantive studies and in designing studies that accurately compare real and sham acupuncture, there are still a relatively limited number of well-designed, published studies on acupuncture. However, several recent studies, which I will describe next, do provide useful information on its potential benefits and mechanisms of action.
One of the questions that has perplexed researchers is how acupuncture can continue to provide benefits for long periods after the treatment is performed. A recent article has suggested a possible explanation for this phenomenon. Using functional MRI, Dhond and colleagues compared the resting-state brain activity of 15 healthy patients who received acupuncture that consisted of needling at a single traditional acupuncture point and sham acupuncture that involved simulated needling but no actual insertion.
The researchers found that, unlike sham therapy, acupuncture treatment produced multiple changes, including enhanced resting default mode network (DMN) connectivity with several areas of the brain, such as the anterior cingulate cortex, periaqueductal gray, amygdala, and hippocampus. The DMN is one of the resting state networks in the brain that is deactivated during the performance of a task. The authors theorized that these changes involved in a variety of functions, including memory and the perception of pain, may explain at least some of the lasting effects of acupuncture. This study also found evidence that acupuncture may induce changes in the sympathetic nervous system.
Issues in studies
The problems that are encountered in studying acupuncture are highlighted in 2 articles that sought to determine its efficacy based on earlier studies. Manheimer and colleagues performed a meta-analysis of studies on acupuncture for osteoarthritis of the knee. They were able to find only 11 studies that were randomized and controlled; 5 of those studies included 50 or fewer participants. Furthermore, there was a substantial degree of heterogeneity in results from study to study. Pooled results indicated that acupuncture was no more effective than sham acupuncture in decreasing pain in the short term or at 6-month follow-up. However, patients who received acupuncture had clinically relevant short- and long-term improvements compared with patients who received either treatment as usual or who were kept on a waiting list for treatment.
A significant problem identified by this meta-analysis was the variability as to what constituted sham acupuncture. Some studies used no needling; others employed needling at nontraditional points. This is important because it is still unclear whether needling the traditional points provides more analgesia.
Mayhew and Ernst performed a similar meta-analysis on studies of acupuncture to treat fibromyalgia. Only 5 studies fit their inclusion criteria, and all had 100 or fewer participants. These authors also found variable results. Three of the studies reported that acupuncture was beneficial while 2 reported negative results. However, in 1 of the negative studies, there was at least a short-term reduction in the number of tender points among patients who received acupuncture.
Because I virtually always use electrical stimulation when I perform acupuncture, I found one finding in this meta-analysis to be especially interesting. The 2 negative studies used traditional Chinese acupuncture, which consists of manual manipulation of the needles. In contrast, the 3 studies that found acupuncture to be beneficial employed electrical stimulation.
This stimulation appears to play a significant role in the effectiveness of acupuncture. Needles are usually inserted for 15 to 30 minutes during treatment, and the provision of a consistent level of stimulation during this period appears to be important. Obviously, it would be difficult if not impossible for a practitioner using manual manipulation to provide this over the course of a single treatment much less to provide anything close to consistency when treating multiple patients during the day.
Acupuncture for chronic pain
Several recent studies of large numbers of subjects indicate that acupuncture has beneficial effects for some of the most common pain conditions beyond those that are provided by standard treatments.
As I noted in a recent column (“Update on Treatment of Low Back Pain: Part 2,” Psychiatric Times, July 2008, page 13), the American Pain Society/American College of Physicians clinical practice guideline on chronic low back pain (CLBP) reported that there was a fair level of evidence for the use of acupuncture for this problem. A more recent observational study of 2564 patients with CLBP found that those who received acupuncture reported significantly diminished pain and number of days lost from work.
Witt and colleagues compared 1880 patients with chronic neck pain who received acupuncture with an equal number of controls. Those who received acupuncture and routine care had statistically significant improvements in both pain and disability status at 3-month follow-up compared with those in the control group who received only routine care.
Taken overall, these studies indicate that acupuncture continues to be a useful treatment but that more and better studies on both its clinical efficacy and underlying mechanisms of action are needed.