Evidence

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Depending on which source one refers to, cold laser therapy is most effective when used on traditional acupuncture points or biomeridians, or is most effective when used on injured tissue, or is equally effective in all tissues (injured and uninjured), or does not work at all. The fact that cold laser therapy has such diverse support makes it difficult to determine what the actual efficacy of the treatment is.

The initial research into laser therapy began in 1967 with Endre Mester researching applications in relation to skin cancer. Since then, research into therapeutic lasers has continued in both western medicine and more alternative/complimentary medical approaches. Western Medicine has embraced several lasers, all of which are of the high energy output type, utilized primarily in surgical and cosmetic applications. The three most utilized are:

1. CO2 Laser- medium energy laser in mid-infrared region (wavelength 10,600nm), used mostly for ENT surgery.

2. Argon Ion Laser-488-514nm wavelength, used for photocoagulation in dermatology and ophthalmology.

3. Nd:YAG Laser-wavelength 1064-1320nm, used in bronchoscopy and for deep tissue photocoagulation.

Research continues on the interactions of lasers and living tissue. With low-level laser therapy, pain management and improved tissue regeneration seem to show the most promise. The Cochran Review Database has 5 meta-analyses regarding low-level laser therapy (LLLT):

1. Low Level Laser Therapy for Nonspecific Low-Back Pain 2007

9 separate trials (total n=416) tested low-level laser therapy vs placebo, with and without exercise in the treatment of nonspecific low-back pain. Conclusion: Based on the heterogeneity of the populations, interventions and comparison groups, we conclude that there are insufficient data to draw firm conclusions on the clinical effect of Low-Level Laser Therapy for low-back pain.

2. Laser Therapy for Venous Leg Ulcers 1999

4 Trials were identified. Two randomized controlled trials (RCTs) of laser therapy vs sham. One of laser therapy vs ultra-violet light and one of laser therapy vs unpolarized red light (total n=88.). Conclusion: We have found no evidence of any benefit associated with low level laser therapy on venous leg ulcer healing. One small study suggests that a combination of laser and infrared light may promote the healing of venous ulcers, however more research is needed.

3. Low Level Laser Therapy (Classes I, II and III) for Treating Rheumatoid Arthritis 2000

5 RCTs were found (n=222) all compared laser therapy to placebo. Conclusion: LLLT could be considered for short-term treatment for relief of pain and morning stiffness for RA patients, particularly since it has few side-effects. Clinicians and researchers should consistently report the characteristics of the LLLT device and the application techniques used. New trials on LLLT should make use of standardized, validated outcomes. Despite some positive findings, this meta-analysis lacked data on how LLLT effectiveness is affected by four important factors: wavelength, treatment duration of LLLT, dosage and site of application over nerves instead of joints. There is clearly a need to investigate the effects of these factors on LLLT effectiveness for RA in randomized controlled clinical trials.

4. Low Level Laser Therapy for Treating Tuberculosis 2002

One RCT was found (n=130) from India with poorly reported information regarding study set up and patient allocation. Conclusion: The use of low level laser therapy for treating tuberculosis is still not supported by reliable evidence. Researchers need to focus on conducting well-designed randomized controlled trials to justify the continued participation of volunteers for studies of this experimental intervention.

5. Low Level Laser Therapy (Classes III) for Treating Osteoarthritis 2008

Review was withdrawn

In addition to The Cochran Database analyses, researchers at the Medical College of Wisconsin published findings on Therapeutic Photobiomodulation for Methanol-Induced Retinal Toxicity in 2003. The study concluded, "The results of this study and others suggest that photobiomodulation with red to near-IR light augments recovery pathways promoting neuronal viability and restoring neuronal function after injury." For the full article: click here.

In March 2006, William Posten, MD, et al. published a paper in Dermatologic Surgery entitled Low-Level Laser Therapy for Wound Healing: Mechanism and Efficacy. They conducted an extensive literature review on LLLT therapy from 1965-2003. In their search, they found that there were no well designed, credible studies supporting the use of LLLT. Furthermore, articles which claimed to enhance wound healing were conducted on animal models vastly different from humans. The abstract conclusion of Posten, et al reads:

To better understand the utility of LLLT in cutaneous wound healing, good clinical studies that correlate cellular effects and biologic processes are needed. Future studies should be well-controlled investigations with rational selection of lasers and treatment parameters. In the absence of such studies, the literature does not appear to support widespread use of LLLT in wound healing at this time. Although applications of high-energy (10–100 W) lasers are well established with significant supportive literature and widespread use, conflicting studies in the literature have limited low-level laser therapy (LLLT) use in the United States to investigational use only. Yet LLLT is used clinically in many other areas, including Canada, Europe, and Asia, for the treatment of various neurologic, chiropractic, dental, and dermatologic disorders. To understand this discrepancy, it is useful to review the studies on LLLT that have, to date, precluded Food and Drug Administration approval of many such technologies in the United States. The fundamental question is whether there is sufficient evidence to support the use of LLLT.

Finally, according to Stein et al, LLLT promotes osteoblast proliferation and differentiation in vitro in a paper published in 2005. Stein et al used a He-Ne laser (632nm 10mW) to irradiate osteoblasts in vitro and noticed a 31-58% increase in cell proliferation in the irradiated osteoblasts.

There are many more papers regarding LLLT available, which were not covered here. For more, please see Resources

Generally, there is insufficient data to determine whether or not LLLT is an effective therapy. The only real certainty with LLLT is that more research is needed.

Currently the FDA has approved several LLLT devices as "experimental" for use in clinical trials. Despite the lack of supporting evidence and the "experimental" classification of the lasers themselves, there are many who tout LLLT as next-generation medicine to cure anything that ails you. As such, LLLT are available for purchase if one is willing to pay for them. It is vital to know what you are buying as some commercially available LLLT devices are actual lasers with the appropriate wavelengths and power output, while others are nothing more than LEDs or red light bulbs in a fancy housing.