Chronic nonspecific Low Back Pain (LBP) is defined as pain occurring for more than three months that is not attributable to an identifiable disease. It is very common and a major cause of disability, absenteeism, and high medical costs. People with chronic LBP often need long-term treatment, but conventional therapies like physiotherapy, exercise, or mild analgesics are not always effective. Acupuncture originated in China 4,000 years ago and is based on traditional Chinese medicine, which claims that the body’s vital energy flows through 12 primary and eight secondary meridians. Needles are inserted at specific points along these meridians, with or without manipulation, and as a consequence, the proper vital energy flow is considered to be restored. The mechanism of acupuncture has not yet been clarified; one of the most accredited hypotheses, based on the gate control theory, states that one type of sensory input such as pain can be suppressed in the central nervous system by another type of stimulus like the insertion of the needle. Acupuncture has been shown to produce both central effects (such as the release of endogenous opioids) and local effects (such as locally increasing blood flow).

This review investigated the effects of acupuncture compared to sham intervention, no treatment, and usual care for chronic nonspecific LBP. This is an update of a Cochrane Systematic Review (CSR) published in 2005. The outcomes analyzed were related to pain, function, quality of life, and adverse events. This review included only randomized controlled trials (RCTs) conducted on adults with chronic LBP (lasting more than three months) without a specific etiology, that were randomly assigned to either acupuncture or sham, no treatment, or usual care.

The CSR included 33 trials published and/or registered up to August 29, 2019, with 8,270 participants. Current evidence shows that, compared to sham therapy, acupuncture may relieve pain in the immediate term (up to seven days). However, the magnitude of pain relief was on average lower than what has been reported as being clinically meaningful by patients with chronic pain. Furthermore, the authors were uncertain whether acupuncture improves back function in the immediate term compared to sham intervention, as the quality of evidence was assessed as very low. On the other hand, current evidence shows that, compared to no treatment, acupuncture probably produced a clinically relevant improvement in pain and back function in the immediate term. Finally, compared with usual care, acupuncture may make little or no difference in reducing pain clinically, as the quality of evidence was low, but it may improve function immediately after sessions, and it probably improves physical quality of life in the short term. Additionally, acupuncture was compared to other treatments (e.g., TENS, baclofen, pulsed radiofrequency therapy) obtaining no further clinical benefit. The certainty of this evidence was low to very low. Furthermore, no acupuncture technique was found to be appreciably better than another. As to safety, low-certainty evidence suggested a similar incidence of adverse events immediately after treatment between acupuncture, sham intervention, or usual care groups.

In conclusion, current evidence suggests some possible small benefits of acupuncture compared to sham or no treatment and to usual care, particularly in the immediate (up to seven days) term. However, even though the quality of included studies has substantially improved over the past years, moderate- to high-quality evidence is still lacking. In conclusion, the authors suggest that acupuncture might be a safe treatment for people with chronic LBP, and that the adoption of such treatment might be based on availability, cost, and patient preferences.

Comment by Francesca Cecchi