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{{for|more general use of light in therapy|Light therapy}}
{{for|more general use of light in therapy|Light therapy}}
<gallery>
File:Laser-LLLT-treatment-neck-pain.png|Laser LLLT treatment for neck pain
File:LED-LLLT-treatment-osteoarthritis-knee.png|LED treatment for osteoarthritis of the knee
</gallery>
'''Low-level laser therapy''' ('''LLLT''') is a [[medicine|medical]] and [[Veterinary medicine|veterinary]] treatment that uses low-level [[laser]]s or [[light-emitting diode]]s to alter cellular function. LLLT is controversial in mainstream medicine with ongoing research to determine the ideal location of treatment (specifically whether LLLT is more appropriately used over [[nerve]]s versus [[joint]]s<ref name = Brosseau/>), dose, wavelength, timing, pulsing and duration.<ref name = Huang>{{cite pmid | 20011653 }}</ref> The effects of LLLT appear to be limited to a specified set of wavelengths of laser,<ref name = Bjordal2008/> and administering LLLT below the dose range does not appear to be effective.<ref name = Bjordal2003/>
'''Low-level laser therapy''' ('''LLLT''') is a [[medicine|medical]] and [[Veterinary medicine|veterinary]] treatment that uses low-level [[laser]]s or [[light-emitting diode]]s to alter cellular function. LLLT is controversial in mainstream medicine with ongoing research to determine the ideal location of treatment (specifically whether LLLT is more appropriately used over [[nerve]]s versus [[joint]]s<ref name = Brosseau/>), dose, wavelength, timing, pulsing and duration.<ref name = Huang>{{cite pmid | 20011653 }}</ref> The effects of LLLT appear to be limited to a specified set of wavelengths of laser,<ref name = Bjordal2008/> and administering LLLT below the dose range does not appear to be effective.<ref name = Bjordal2003/>


Revision as of 22:14, 29 August 2010

For more general use of light in therapy, see Light therapy.

Low-level laser therapy (LLLT) is a medical and veterinary treatment that uses low-level lasers or light-emitting diodes to alter cellular function. LLLT is controversial in mainstream medicine with ongoing research to determine the ideal location of treatment (specifically whether LLLT is more appropriately used over nerves versus joints[1]), dose, wavelength, timing, pulsing and duration.[2] The effects of LLLT appear to be limited to a specified set of wavelengths of laser,[3] and administering LLLT below the dose range does not appear to be effective.[4]

Despite a lack of consensus over its ideal use, specific test and protocols for LLLT suggest it is effective in relieving short-term pain for rheumatoid arthritis,[1] osteoarthritis,[5] acute and chronic neck pain,[6] tendinopathy,[7][3] and possibly chronic joint disorders.[4] The evidence for LLLT being useful in the treatment of low back pain,[8][9] dentistry[10][11] and wound healing is equivocal.[12]

History

In 1967 a few years after the first working laser was invented, Endre Mester in Semmelweis University 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.[13]

Clinical applications

LLLT has primarily been shown useful in the short-term treatment of acute pain caused by rheumatoid arthritis,[1] , osteoarthritis,[5] tendinopathy,[7][3] and possibly chronic joint disorders.[4] LLLT has also been useful in the treatment of both acute and chronic neck pain.[6] A Cochrane Library review concluded that there is insufficient data to draw a firm conclusion on the clinical effectiveness of low-level laser therapy for low back pain,[8] a finding echoed in a later review of treatments for chronic low back pain.[9] 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.[12] Similarly, the use of lasers to treat chronic periodontitis[10] and to speed healing of infections around dental implants[11] 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."[14]

Insurance company Cigna has reviewed the evidence for LLLT and concluded that it is still considered an experimental treatment therefore does not provide coverage for it.[15]

Mechanism

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.[16] 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.[17] 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.[18]

The effects of LLLT appear to be limited to a specified set of wavelengths of laser,[3] 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.[1] Administering LLLT below the dose range does not appear to be effective.[4] 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 are available outside this range.[19]

See also

References

  1. ^ a b c d Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 16235295 , please use {{cite journal}} with |pmid= 16235295 instead.
  2. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 20011653 , please use {{cite journal}} with |pmid= 20011653 instead.
  3. ^ a b c d Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 18510742 , please use {{cite journal}} with |pmid= 18510742 instead.
  4. ^ a b c d Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 12775206 , please use {{cite journal}} with |pmid= 12775206 instead.
  5. ^ a b Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 17986496 , please use {{cite journal}} with |pmid= 17986496 instead.
  6. ^ a b Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 19913903 , please use {{cite journal}} with |pmid= 19913903 instead.
  7. ^ a b Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 19708800 , please use {{cite journal}} with |pmid= 19708800 instead.
  8. ^ a b Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 18425909 , please use {{cite journal}} with |pmid= 18425909 instead.
  9. ^ a b Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 20640863 , please use {{cite journal}} with |pmid= 20640863 instead.
  10. ^ a b Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 16584335 , please use {{cite journal}} with |pmid= 16584335 instead.
  11. ^ a b Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 16288590 , please use {{cite journal}} with |pmid= 16288590 instead.
  12. ^ a b Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 19764898 , please use {{cite journal}} with |pmid= 19764898 instead.
  13. ^ Mester, E. (1967). "Effect of laser on hair growth of mice". Kiserl Orvostud. 19: 628–631. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  14. ^ Barrett, S (2009-07-17). "A Skeptical Look at Low Level Laser Therapy". Quackwatch. Retrieved 2010-07-23.
  15. ^ "Cigna Medical Coverage Policy - Subject: Low Level Laser Therapy" (pdf). Cigna. 2010-07-15. Retrieved 2010-08-06.
  16. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 16706694 , please use {{cite journal}} with |pmid= 16706694 instead.
  17. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 18665762 , please use {{cite journal}} with |pmid= 18665762 instead.
  18. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 18651871 , please use {{cite journal}} with |pmid= 18651871 instead.
  19. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 20011653 , please use {{cite journal}} with |pmid= 20011653 instead.
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