Authors' objectives:

To determine the effectiveness of low level laser therapy (LLLT) for: carpal tunnel syndrome, tendinopathies, osteoarthritis, low back pain ankle sprain and wound healing.

Authors' results and conclusions: Carpal tunnel syndrome (CTS): One laser manufacturer provided information concerning two randomized controlled trials of LLLT to treat CTS. While the studies suggest that active LLLT resulted in improvement more often than placebo, the effect was moderate. In addition, improvement did not extend to all measure outcomes. Loss to follow-up may have affected results, but the studies do not address attrition in their analyses. Naersers crossover trial of TENS and LLLT found improvement following active laser. However, the study population was small (n=11), and some key measurements were based on the results of only 8 patients. Therefore, the results of the study may not be generalizable to a larger population. Two case series studies suggest that LLLT may be associated to improved pain and function. However, without a control or comparison group, the studies do not prove that LLLT directly results in improvement. Due to the lack of published trials, LLLT for CTS is considered investigational. Unspecified musculoskeletal disorders and tendinopathies: One meta-analysis on LLLTs effect on musculoskeletal pain found no effect of LLLT on pain compared to placebo. A second meta-analysis on LLLTs effect on tendinopathies found a pooled effect of 32% improvement in pain in favor of LLLT. A third metaanalysis on LLLT for chronic joint disorders showed a pooled improvement of approximately 30% in favor of active LLLT. However, the heterogeneity of the studies included in these meta-analyses substantially limits their findings. The included studies had varied treatment parameters, indications, and patient populations. One randomized trial examined LLLT for soft tissue conditions. The study found greater improvement among placebo group patients. However, the number of indications included for treatment in the study limits the ability to draw conclusions from the results. A recent trial on lateral epicondylitis was not included in any of the meta-analyses. The small trial (n=30) showed marginal benefit of active laser over placebo for patient perception of benefit and improved lifting ability. While the pooled analyses concerning tendinopathy suggest a possible 30% effect, the heterogeneity of included studies limits these findings. Therefore, there is not substantial evidence to draw firm conclusions concerning the effectiveness of LLLT for general musculoskeletal disorders and tendinopathies. Osteoarthritis: A meta-analysis of osteoarthritis was conducted of trials published through 2002. The trials were of moderate quality and did not find any treatment effect following LLLT compared to placebo. Therefore, the evidence does not substantially show LLLT effectiveness for osteoarthritis. Low Back Pain: One double-blind trial showed that active laser resulted in greater perception of treatment benefit. While pain and function improved, the modest improvement lessened over time. The study did not detect differences in mobility or pain with movement. One observer-blinded study showed that laser did not add benefit to exercise in the treatment of chronic low back pain. Due to the moderate and inconsistent nature of the results, the evidence has not substantially shown LLLTs effectiveness for low back pain. Ankle Sprains: One double-blind study did not find improvement on pain or function following active high or low dose laser compared to placebo. The researchers conclude that LLLT is not effective for ankle sprains. Wound Healing: A meta-analysis included studies of LLLT for venous leg ulcers published through 1998. After pooling results, the analysis did not detect differences between active and sham laser in the treatment of venous leg ulcers. Two recent double-blind trials not included in the meta-analysis compared standard therapy with active laser to standard therapy with sham laser. The studies did not detect differences in improvement between the treatment groups. Pooled analyses concerning wound healing have not detected any improvement of active laser compared to placebo. The evidence has not shown LLLT to be effective in the treatment of venous wounds.

Authors' recommendations: Low level laser therapy is a noninvasive treatment that has been used for many conditions. While researchers have published extensively on LLLT, the trials have generally been small, do not compare LLLT to alternative therapies, and apply a range of treatment parameters. In several trials, the placebo control groups have improved as much as active laser groups. Therefore, the evidence has not substantially shown the effectiveness of LLLT.

Authors' methods: Systematic review

Project Status: Completed

URL for project: http://www.lni.wa.gov/ClaimsIns/Files/OMD/LLLTTechAssessMay032004.pdf

Year Published: 2004

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: United States

Organisation Name: Washington State Department of Labor and Industries (WSDLI)

Contact Address: Box 44321, 7273 Linderson Way SW, Olympia, WA, USA 98504-4321. Tel: 1(360)902-5227

Contact Name: mojo235@LNI.wa.gov

Contact Email: mojo235@LNI.wa.gov

Copyright: Washington State Department of Labor and Industries