Low level laser therapy
|Low level laser therapy|
Low-level laser therapy (LLLT) is a form of laser medicine used in physical therapy 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 are claimed to stimulate it and to encourage the cells to function.
LLLT is integrated with mainstream medicine with ongoing research to determine where there is a demonstrable effect. Areas of dispute include 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.
Despite a lack of consensus over its scientific validity, specific test and protocols for LLLT suggest it may be mildly effective, but in most cases no better than placebo, in relieving short-term pain for rheumatoid arthritis, osteoarthritis, acute and chronic neck pain, tendinopathy, and possibly chronic joint disorders. The evidence for LLLT being useful in the treatment of low back pain, dentistry and wound healing is dubious.
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 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."
It is unclear how LLLT works. LLLT may reduce pain related to inflammation by lowering, in a dose-dependent manner, levels of prostaglandin E2, prostaglandin-endoperoxide synthase 2, interleukin 1-beta, tumor necrosis factor-alpha, the cellular influx of neutrophil granulocytes, oxidative stress, edema, and bleeding. The appropriate dose appears to be between 0.3 and 19 joules per square centimetre. Another mechanism may be related to stimulation of mitochondrion to increase the production of adenosine triphosphate resulting in an increase in reactive oxygen species, which influences redox signalling, affecting intracellular homeostasis or the proliferation of cells. The final enzyme in the production of ATP by the mitochondria, cytochrome c oxidase, does appear to accept energy from laser-level lights, making it a possible candidate for mediating the properties of laser therapy.
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.
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.
Society and culture
At least one LLLT practitioner, Robert Lytle DDS, has been cited by the FDA for promoting non-FDA approved treatments on company websites.
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- Jamtvedt, 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 Therapy 88 (1): 123–136. doi:10.2522/ptj.20070043. PMID 17986496.
- Chow, 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.". Lancet 374 (9705): 1897–1908. doi:10.1016/S0140-6736(09)61522-1. PMID 19913903.
- Tumilty, 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 Surgery 28 (1): 3–16. doi:10.1089/pho.2008.2470. PMID 19708800.
- Yousefi-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). Yousefi-Nooraie, Reza, ed. "Low level laser therapy for nonspecific low-back pain". Cochrane database of systematic reviews (Online) (2): CD005107. doi:10.1002/14651858.CD005107.pub4. PMID 18425909.
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- Cobb, C. M. (2006). "Lasers in Periodontics: A Review of the Literature". Journal of Periodontology 77 (4): 545–564. doi:10.1902/jop.2006.050417. PMID 16584335.
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- 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 Periodontology 79 (11): 2021–2028. doi:10.1902/jop.2008.080197. PMID 18980508.
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- Barrett, S (2009-07-17). "A Skeptical Look at Low Level Laser Therapy". Quackwatch. Retrieved 2010-07-23.
- Rogers, NE; Avram, MR (October 2008). "Medical treatments for male and female pattern hair loss.". Journal of the American Academy of Dermatology 59 (4): 547–66; quiz 567–8. PMID 18793935.
- Rangwala, Sophia; Rashid, Rashid M. (Feb 2012). "Alopecia: a review of laser and light therapies". Dermatology Online Journal 18 (2): 3. ISSN 1087-2108. PMID 22398224.
Since then, a number of studies have suggested the use of lasers as an effective way to treat alopecia, particularly androgenetic alopecia and alopecia areata, but there is still a paucity of independent, peer-reviewed blinded clinical trials.
- Avci, Pinar; Gupta, Gaurav K.; Clark, Jason; Wikonkal, Norbert; Hamblin, Michael R. (2014-2). "Low-Level Laser (Light) Therapy (LLLT) for Treatment of Hair Loss". Lasers in surgery and medicine 46 (2): 144–151. doi:10.1002/lsm.22170. ISSN 0196-8092. PMC 3944668. PMID 23970445. Check date values in:
- Gupta, AK; Daigle, D (April 2014). "The use of low-level light therapy in the treatment of androgenetic alopecia and female pattern hair loss.". The Journal of dermatological treatment 25 (2): 162–3. PMID 23924031.
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- Tafur, J. .; Mills, P. J. (2008). "Low-Intensity Light Therapy: Exploring the Role of Redox Mechanisms". Photomedicine and Laser Surgery 26 (4): 323–8. doi:10.1089/pho.2007.2184. PMC 2996814. PMID 18665762.
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- Mester, E.; Szende, B.; Tota, J.G. (1967). "Effect of laser on hair growth of mice". Kiserl Orvostud 19: 628–631.
- "Cigna Medical Coverage Policy - Subject: Low Level Laser Therapy" (pdf). Cigna. 2010-07-15. Retrieved 2010-08-06.