Low-level laser therapy (LLLT) is a form of laser medicine used in medical and veterinary treatment that uses low-level (low-power) lasers or light-emitting diodes to alter cellular function. Other names for the therapy include low-power laser, soft laser, cold laser, biostimulation laser, therapeutic laser, and laser acupuncture. Whereas high-power lasers ablate tissue, low-power lasers may stimulate it, encouraging the cells to function.
LLLT is controversial in mainstream medicine with ongoing research to determine whether there is a demonstrable effect. Also disputed are the ideal location of treatment (specifically whether LLLT is more appropriately used over nerves versus joints), dose, wavelength, timing, pulsing and duration. The effects of LLLT appear to be limited to a specified set of wavelengths of laser, and administering LLLT below the dose range does not appear to be effective.
In 1967 a few years after the first working laser was invented, Endre Mester in Semmelweis University in Budapest, Hungary experimented with the effects of lasers on skin cancer. While applying lasers to the backs of shaven mice, he noticed that the shaved hair grew back more quickly on the treated group than the untreated group.
LLLT has primarily been shown useful in the short-term treatment of acute pain caused by rheumatoid arthritis, osteoarthritis,tendinopathy, and possibly chronic joint disorders. LLLT has also been useful in the treatment of both acute and chronic neck pain. A Cochrane Library review concluded that low level laser therapy (LLLT) has insufficient evidence for treatment of nonspecific low back pain, a finding echoed in a later review of treatments for chronic low back pain. Though it has been suggested for decades that LLLT could be useful in speeding wound healing, the appropriate parameters (dose, type of laser, materials, wavelength, etc.) have not been identified. Similarly, the use of lasers to treat chronic periodontitis and to speed healing of infections around dental implants is suggested, but there is insufficient evidence to indicate a use superior to traditional practices.
Stephen Barrett, writing for Quackwatch, concluded there was evidence to support LLLT use for temporary pain relief, but "there's no reason to believe that they will influence the course of any ailment or are more effective than other forms of heat delivery."
The insurance company, Cigna, has reviewed the evidence for LLLT and concluded that it is still considered an experimental treatment. Therefore, Cigna does not provide coverage for it.
The effects of LLLT appear to be limited to a specified set of wavelengths of laser, and though more research is required to determine the ideal wavelengths, durations of treatment, dose and location of treatment (specifically whether LLLT is more appropriately used over nerves versus joints). Administering LLLT below the dose range does not appear to be effective. The factors of wavelength, effective dose, dose-rate effects, beam penetration, the role of coherence, and pulses (peak power and repetition rates) are still poorly understood in the clinical setting. The typical laser average power is in the range of 1-500 mW; some high-peak-power, short-pulse-width devices are in the range of 1-100 W with typical pulse-widths of 200 ns. The typical average beam irradiance then is 10 mW/cm2 - 5 W/cm2. The typical wavelength is in the range 600-1000 nm (red to near infrared), but some research has been done and products outside of this range are available.
^ abcdBrosseau, L.; Welch, V.; Wells, G. A.; de Bie, R.; Gam, A.; Harman, K.; Morin, M.; Shea, B.; Tugwell, P. (2005). "Low level laser therapy (Classes I, II and III) for treating rheumatoid arthritis". In Brosseau, Lucie. Cochrane Database of Systematic Reviews (4): CD002049. doi:10.1002/14651858.CD002049.pub2. PMID16235295. edit
^ abcdBjordal, JM; Couppé, C; Chow, RT; Tunér, J; Ljunggren, EA (2003). "A systematic review of low level laser therapy with location-specific doses for pain from chronic joint disorders". The Australian journal of physiotherapy49 (2): 107–16. PMID12775206. edit
^ abJamtvedt, G.; Dahm, K. T.; Christie, A.; Moe, R. H.; Haavardsholm, E.; Holm, I.; Hagen, K. B. (2007). "Physical Therapy Interventions for Patients with Osteoarthritis of the Knee: an Overview of Systematic Reviews". Physical Therapy88 (1): 123–136. doi:10.2522/ptj.20070043. PMID17986496. edit
^ abChow, R.; Johnson, M.; Lopes-Martins, R.; Bjordal, J. (Nov 2009). "Efficacy of low-level laser therapy in the management of neck pain: a systematic review and meta-analysis of randomised placebo or active-treatment controlled trials.". Lancet374 (9705): 1897–1908. doi:10.1016/S0140-6736(09)61522-1. PMID19913903. edit
^ abTumilty, S. .; Munn, J. .; McDonough, S. .; Hurley, D. A.; Basford, J. R.; Baxter, G. D. (2010). "Low Level Laser Treatment of Tendinopathy: A Systematic Review with Meta-analysis". Photomedicine and Laser Surgery28 (1): 3. doi:10.1089/pho.2008.2470. PMID19708800. edit
^ abYousefi-Nooraie, R.; Schonstein, E.; Heidari, K.; Rashidian, A.; Pennick, V.; Akbari-Kamrani, M.; Irani, S.; Shakiba, B.; Mortaz Hejri, S.; Mortaz Hejri, S. O.; Jonaidi, A. (2008). "Low level laser therapy for nonspecific low-back pain". In Yousefi-Nooraie, Reza. Cochrane database of systematic reviews (Online) (2): CD005107. doi:10.1002/14651858.CD005107.pub4. PMID18425909. edit
^ abSculean, A.; Schwarz, F.; Becker, J. (2005). "Anti-infective therapy with an Er:YAG laser: influence on peri-implant healing". Expert Review of Medical Devices2 (3): 267. doi:10.1586/174344220.127.116.117. PMID16288590. edit
^ abDa Silva, J. P.; Da Silva, M. A.; Almeida, A. P. F.; Junior, I. L.; Matos, A. P. (2010). "Laser Therapy in the Tissue Repair Process: A Literature Review". Photomedicine and Laser Surgery28 (1): 17. doi:10.1089/pho.2008.2372. PMID19764898. edit
^Mester, E.; Szende, B.; Tota, J.G. (1967). "Effect of laser on hair growth of mice". Kiserl Orvostud19: 628–631.
^Karlsson, M. R.; Diogo Löfgren, C. I.; Jansson, H. M. (2008). "The Effect of Laser Therapy as an Adjunct to Non-Surgical Periodontal Treatment in Subjects with Chronic Periodontitis: A Systematic Review". Journal of Periodontology79 (11): 2021–2028. doi:10.1902/jop.2008.080197. PMID18980508. edit
^Bjordal, J. M.; Johnson, M. I.; Iversen, V.; Aimbire, F.; Lopes-Martins, R. A. B. (2006). "Low-Level Laser Therapy in Acute Pain: A Systematic Review of Possible Mechanisms of Action and Clinical Effects in Randomized Placebo-Controlled Trials". Photomedicine and Laser Surgery24 (2): 158. doi:10.1089/pho.2006.24.158. PMID16706694. edit