1: Physiotherapy Department, Royal Brisbane Hospital, Brisbane;
2: Physiotherapy Department, University of Queensland, Brisbane;
3: Pain Clinic, Royal Brisbane Hospital, Brisbane, Queensland, Australia.

Clinically, Low Level Laser Therapy - LLLT has been used successfully in the treatment of chronic pain but many have questioned the scientific basis for its use. Many studies have been poorly designed or poorly controlled. A double-blind, placebo-controlled, random allocation study was designed to analyze the effect of second daily infrared (JR) laser (820 nm, 25mW) and visible red laser (670 nm, 10 mW) at 1 J/cm2 and 5 J/cm2 on chronic pain. Forty-one consenting subjects with chronic pain conditions exhibiting myofascial trigger points in the neck and upper trunk region underwent five treatment sessions over a two-week period. To assess the progress, pain scores were measured using visual analogue scales before and after each treatment. The incidence of side effects was recorded. All groups demonstrated significant reductions in pain over the duration of the study with those groups which received infrared (820nm) laser a 1 J/cm2 and 5 J/cm2 demonstrating the most significant effects (p< 0.001). Only those subjects who had active laser treatment experienced side effects. Results indicated that responses to LLLT at the parameters used in this study are subject to placebo and may be dependent on power output, dose and/or wavelength.