Low-dose laser acupuncture for non-specific chronic low back pain: a double-blind randomised controlled trial

Chronic low back pain is a condition that affects approximately 23% of the adult population, representing a significant public health problem because of the limitations it causes in daily life, the high medical costs, and lost work productivity. Traditionally treated with medications, physical therapy, and invasive procedures, this condition has led researchers to investigate non-pharmacologic therapeutic alternatives such as laser acupuncture. This technique combines the principles of traditional acupuncture with the application of low-intensity laser light at specific points, offering a non-invasive approach that does not involve needles. Despite the growing use of this modality, scientific questions remained about its actual efficacy, especially when compared with simulated treatments.

This Australian study was designed as a randomized, double-blind clinical trial — considered the gold standard in medical research — involving 144 adults with chronic non-specific low back pain. The term "double-blind" means that neither the participants nor the therapists knew which treatment was being applied, eliminating psychological influences on the results. The investigators used specially modified equipment to ensure this blinding. Participants were divided into three groups: a control group that received simulated treatment (no laser emission), a group that received low-dose laser (0.2 joules per point), and another that received a higher dose (0.8 joules per point).

All received eight weekly sessions of 15 minutes each, with individualized acupuncture point selection according to each patient's needs. The investigators followed participants for up to one year after treatment, evaluating mainly pain intensity and the level of functional disability.

The results revealed a surprising and clinically important finding: there was no significant difference among the three groups at any time point during follow-up. All participants, including those who received only simulated treatment, showed considerable improvement in pain and function. The mean pain reduction was approximately 28% immediately after treatment, holding at 26% one year later. This finding suggests that the benefits observed cannot be specifically attributed to the biological effect of the laser at the doses studied, but rather to other non-specific factors of treatment.

The improvement in functional disability was more modest, with a reduction of only 4% in daily activities, which probably does not represent a clinically meaningful change for most patients.

For patients suffering from chronic low back pain, these results offer valuable insight into laser acupuncture treatment. Although the study did not demonstrate a specific effect of the laser at the doses tested, the improvement seen across all groups suggests that factors such as individualized attention, the development of a therapeutic relationship, the expectation of improvement, and other positive psychological influences may contribute significantly to symptom relief. For health professionals, these findings indicate that, if they choose to offer laser acupuncture, they should be transparent about the limited evidence for specific efficacy of the laser at low doses, although they may still consider the non-specific benefits of treatment within a broader therapeutic approach. Importantly, the study does not entirely rule out laser acupuncture but specifically questions the low doses traditionally used.

Several important limitations should be considered when interpreting these results. The study excluded patients with more complex conditions, such as those on regular opioid use, recipients of disability pension for back pain, or with a history of lumbar surgery, which may limit the applicability of the results to patients with more severe conditions. In addition, the laser equipment showed variation in actual emitted power over time, and therapists tended to use more acupuncture points in the groups that received shorter-duration stimulation, factors that may have influenced the results. The study also tested only relatively low laser doses at a specific infrared wavelength, leaving open the possibility that higher doses or different types of laser could have distinct effects.

The investigators acknowledge that international guidelines suggest much higher doses for lumbar laser therapy, indicating the need for future research investigating these higher doses before reaching definitive conclusions about the lack of efficacy of laser acupuncture as a whole.