Laser is a therapy characterized by the use of a monochromatic light beam. This beam is unidirectional (unlike the multidirectional beam used for conventional light), coherent, and contains only one wavelength. The laser energy source has long been used in industry and military. It is also used in several areas of medicine such as surgery and dentistry, the reflex or local therapy.
Compared to lasers used in other areas, those used in reflex or local therapy are of low intensity. Around the world, researchers are working to design and develop low-power laser instruments of more accurate and efficient use in diagnosis and therapy.
When penetrating into the skin, the photons emitted by the laser interact with the electrons of the molecules composing the tissues, resulting therapeutic physiologic responses.
Acceleration of collagen synthesis, increased levels of serotonin (pain reduction), opening of the cell membrane (decrease of edema), acceleration of the healing process.
Periarticular pains or other chronic conditions, when patients do not respond to other modality treatments, some patients respond well to laser.
A study was made in 2007 on 61 patients suffering with low back pain for at least 12 weeks.
One group received laser therapy alone, one received laser therapy and exercise, and the third group received placebo laser therapy and exercise. Laser therapy was performed twice a week for 6 weeks.
Outcomes were pain severity, lumbar range of motion, and disability on admission to the study, after 6 weeks of intervention, and after another 6 weeks of no intervention.
There was no greater effect of laser therapy compared with exercise for any outcome, at either 6 or 12 weeks. There was also no greater effect of laser therapy plus exercise compared with exercise for any outcome at 6 weeks. However, in the laser therapy plus exercise group pain had reduced, lumbar range of movement increased by 15 degrees of active flexion, and disability reduced by 9.4 points more than in the exercise group at 12 weeks.
In chronic low back pain low level laser therapy combined with exercise is more beneficial than exercise alone in the long term.
Another randomised trial tempted to assess the effectiveness of low-intensity laser therapy in the treatment of musculoskeletal low back pain.
This experiment divided into 2 groups 63 ambulatory men and women between the ages of 18 and 70years with symptomatic nonradiating low back pain of more than 30 days' duration and normal neurologic examination results.
All underwent irradiation for 90 seconds at eight symmetric points along the lumbosacral spine three times a week for 4 weeks by a masked therapist. The sole difference between the groups was that the probes of a 1.06Î¼m neodymium: yttrium-aluminum-garnet laser emitted 542mW/cm2 for the treated subjects and were inactive for the control subjects.
The treated group had a time-dependent improvement in two of the three outcome measures : perception of benefit and level of function.
These results were most marked at the midpoint evaluation and end of treatment but tended to lessen at the 1-month follow-up.
Lumbar mobility did not differ between the groups at any time. All tests were two-sample t tests with unequal variances.
Conclusion : Treatment with low-intensity laser irradiation produced a moderate reduction in pain and improvement in function in patients with musculoskeletal low back pain. Benefits, however, were limited and decreased with time. Further research is warranted.
In total, over 20 studies were made on the subject, leading to a meta-analysis on the effects of low-level laser therapy on muskuloskeletal pain.
A meta-analysis refers to methods focused on contrasting and combining results from different studies, in the hope of identifying patterns among study results, sources of disagreement or other interesting relationships that may come to light in the context of multiple studies.
A literature search revealed 23 low-level laser therapy trials and of these 17 were controlled trials. 10 were double blind and 7 were insufficiently blinded. Within the studies identified pain was assessed by visual analogue scale or by â€œsome other indices of painâ€. 9 double-blind trials and 4 controlled trials presented results in a form which allowed pooling of data. In the double-blind trials, the mean difference in pain between low-level laser therapy and placebo was 0.3%. In the insufficiently blinded trials the mean difference in pain was 9.5%.
The conclusion of this meta-analysis is thatlow-level laser therapy has no effect on pain in musculoskeletal syndromes.
Back pain treatment in Hong-Kong
December 8th, 2013