title: Laser therapy: a randomized, controlled trial of the effects of low-intensity Nd:YAG laser irradiation on musculoskeletal back pain.
abstract: OBJECTIVE
  To assess the effectiveness of low-intensity laser therapy in the treatment of musculoskeletal low back pain.
  
  
  METHODS
  A double-masked, placebo-controlled, randomized clinical trial.
  
  
  METHODS
  A physical medicine and rehabilitation clinic.
  
  
  METHODS
  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.
  
  
  METHODS
  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 1.06 microm neodymium:yttrium-aluminum-garnet laser emitted 542mW/cm2 for the treated subjects and were inactive for the control subjects.
  
  
  METHODS
  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 < .01) and end of treatment (p < .017, p < .001) but tended to lessen at the 1-month follow-up (p < .10, 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 1.06 microm 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.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Mayo Clinic and Foundation, Rochester, MN 55902, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Basford
authors.forename: C G
authors.initials: CG
authors.lastname: Sheffield
authors.forename: W S
authors.initials: WS
authors.lastname: Harmsen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001416:Back Pain / Q000532:radiotherapy*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D053685:Laser Therapy; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome