What does the Evidence Say about LLLT?
Several studies have been completed where LLLT was found to reduce lower back pain in the short-term, and intermediate-term, more effectively than sham laser treatment (Basford, 1999, Yousefi-Nooraie, 2008). Other studies have found that reduction in disability was higher in the treatment group versus the placebo group in the short-term (Yousefi-Nooraie, 2008), although the same review noted that LLLT performed the same, or worse, compared to exercise intervention (with or without sham laser therapy) in relieving short-term pain. A problem with these studies could be that the inclusion criteria is for non-specific lower-back pain, meaning that it may not in all cases be a musculoskeletal problem or damaged disc at the root of the pain, and therefore the body may not respond the the LLLT. In a study of those with lumbar pain due to disc herniation LLLT was found to an effective treatment when assessed using clinical evaluation and objective MRI analysis (Unlu, 2008). However, another study of both acute and chronic lumbar disc herniation using LLLT vs. placebo in each case found that pain was significantly reduced in all groups but did not vary between placebo and LLLT (Ay, 2010). Unfortunately this trial made use of heat-packs in every treatment group, thereby adding an extra, uncontrolled for, variable and making analysis difficult.
There is strong evidence that LLLT can lead to a reduction in osteoarthritis pain (Brosseau, 2007) and this appears to be particularly true in cases of pain-relief in those with temporomandibular joint osteoarthritis. Iimproved range of motion in those with osteoarthritis of the knee, has also been noted with implications for LLLT treatment in other stenotic conditions such as back pain from spinal stenosis (Brosseau, 2007). Those with neck pain who underwent LLLT were found by Chow (2009) to achieve significant pain relief for up to twenty-two weeks after treatment.
Problems with the Evidence Regarding LLLT
An issue with all of the evidence presented so far in these reviews is the lack of ability to assess the consistency between trials in terms of the strength of the lasers used, the duration of treatment, and the specific conditions in the population groups. Many researchers have called for higher standards in the investigation of this treatment and clear reports on methodology used in trials so that, as with any quality trial, they are able to be replicated and verified by others.
The evidence for the efficacy of LLLT in spinal stenosis appears inconclusive due to failures in the standardization of evidence from research trials. Specific conditions, such as disc herniation appear to respond well to the treatment, whereas generalized lower-back pain has a variety of results associated with LLLT. Neck pain may be helped by the laser therapy, but again, it appears to depend on the cause of the condition, and the specifications of treatment. In the ‘journal’ Dynamic Chiropractic, which does not appear to be peer-reviewed and is instead a media and marketing-oriented online magazine, the authors of ‘Laser Therapy for Disc Herniation’ claim that over 85% of patients with back problems and severe pain are successfully treated at their clinic by LLLT. No proof of this is given, which does not necessarily invalidate the claim, but should make one curious as to why the clinical trials provide, as yet, no such evidence. Unfortunately a lot of the research also takes place in the context of donations of equipment, resources and funding from manufacturers of LLLT products and are published in relatively unknown journals such as Laser Therapy which may cast doubt on the veracity of the science contained therein.