[Note: to read the full text of this article free, click here. LLLT is also known as ‘cold laser therapy’ or ‘laser biostimulation’.
Background: Neck pain is a common and costly condition for which pharmacological management has limited evidence of efficacy and side-effects. Low-level laser therapy (LLLT) is a relatively uncommon, non-invasive treatment for neck pain, in which non-thermal laser irradiation is applied to sites of pain.
We did a systematic review and meta-analysis of randomized controlled trials to assess the efficacy of LLLT in neck pain.
Methods: We searched computerized databases comparing efficacy of LLLT using any wavelength with placebo or with active control in acute or chronic neck pain. Effect size for the primary outcome, pain intensity, was defined as a pooled estimate of mean difference in change in mm on 100 mm visual analogue scale.
Findings: We identified 16 randomized controlled trials including a total of 820 patients.
• In acute neck pain, results of two trials showed a relative risk (RR) of 1.69 (95% CI 1.22 - 2.33) for pain improvement of LLLT versus placebo. [Note: an RR of 1.0 would indicate no difference in odds of reduced pain intensity vs placebo. The RR of 1.69 would indicate a 69% greater liklihood of reduced pain in the patients receiving LLLT.]
• Five trials of chronic neck pain reporting categorical data showed an RR for pain improvement of 4.05 (2.74 - 5.98) of LLLT. [That is, 305% greater likelihood of reduced pain than with placebo, on average.]
• Patients in 11 trials reporting changes in visual analogue scale had pain intensity reduced by 19.86 mm (10.04 - 29.68). [An average improvement of nearly 20 points on a 100-point pain scale.]
• Seven trials provided follow-up data for 1 to 22 weeks after completion of treatment, with short-term pain relief persisting in the medium term with a reduction of 22.07 mm (17.42 - 26.72).
• Side-effects from LLLT were mild and not different from those of placebo.
Interpretation: We show that LLLT reduces pain:
• Immediately after treatment in acute neck pain,
• And up to 22 weeks after completion of treatment in patients with chronic neck pain.
Source: The Lancet, Dec 5, 2009. 374(9705) pp1897-1908. Chow RT, Johnson MI, Lopes-Martins RAB, Bjordal JM. Nerve Research Foundation, Brain and Mind Research Institute, University of Sydney, NSW, Australia; Faculty of Health, Leeds Metropolitan University, UK; Institute of Biomedical Sciences, Pharmacology Department, University of São Paulo, Brazil; Faculty of Health and Social Science, Institute of Physiotherapy, Bergen University College, Norway; Section of Physiotherapy Science, Institute of Public Health and Primary Health Care, University of Bergen, Norway. [E-mail: firstname.lastname@example.org]