Laser Therapy: A Randomized, Controlled Trial of the Effects of Low-Intensity Nd:YAG Laser Irradiation on Musculoskeletal Back Pain
ABSTRACT. Basford JR, Sheffield CG, Harmsen WS. Laser therapy: a randomized, controlled trial of the effects of lowintensity Nd:YAG laser irradiation on musculoskeletal back pain. Arch Phys Med Rehabil 1999;80:647-652.
Objective: To assess the effectiveness of low-intensity laser therapy in the treatment of musculoskeletal low back pain.
Design: A double-masked, placebo-controlled, randomized clinical trial.
Setting: A physical medicine and rehabilitation clinic.
Participants: Sixty-three ambulatory men and women between the ages of 18 and 70yrs with symptomatic nonradiating low back pain of more than 30 days’ duration and normal neurologic examination results.
Intervention: Subjects were bloc randomized into two groups with a computer-generated schedule. 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 1.06unr neodymium:yttrium-aluminum-garnet laser emitted 542mW/cm2 for the treated subjects and were inactive for the control subjects.
Main Outcome Measures: Subject’s perception of benefit, level of function as assessed by the Oswestry Disability Questionnaire, and lumbar mobility.
Results: 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 (p < ,005, p < .Ol) and end of treatment (p < ,017, p < .OOl) but tended to lessen at the l-month follow-up @ < .lO, p < .004). Lumbar mobility did not differ between the groups at any time. All tests were two-sample t tests with unequal variances.
Conclusions: Treatment with low-intensity 1.06ym laser irradiation produced a moderate reduction in pain and improvement in function in patients with musculoskeletal low back vain. Benefits, however, were limited and decreased with time.