The effect of 300 mW, 830 nm laser on chronic neck pain

Abstract

Does 300 mW, 830 nm low-level laser therapy (LLLT) improve pain, disability and quality of life in people with chronic neck pain? Randomised controlled trial. Primary care (medical centre of 17 general practitioners). Ninety subjects with chronic neck pain (mean duration 15.1 ± 12.6 years). The intervention group received twice-weekly treatments of LLLT (830 nm, 300 mW, at a power density of 0.67 W/ cm 2 ) applied to tender points in the neck, for 7 weeks. The control group received sham laser treatment. The primary outcome was pain intensity (10 cm VAS scale). Other outcomes were quality of life (Short Form- 36, consisting of a Physical Component Summary and a Mental Component Summary, each scored from 0 to 100); perceived disability (Northwick Park Neck Pain Questionnaire, NPNPQ, measured on a scale of 0 to 36); neck pain intensity and interference with living (Neck Pain and Disability Scale, NPAD, measured on a scale of 0 to 100); pain (Short-Form McGill Pain Questionnaire, MPQ) and a participant rating of global assessment (self-assessed improvement, SAI, expressed as percentage change). Outcomes were measured 1 month after completion of the treatment (approximately 12 weeks from baseline). The between-group difference in VAS pain score at 12 weeks was –3.0 cm (95% CI –2.1 to –3.8). Measured on the McGill VAS Pain Scale, the reduction in pain intensity was –2.2 cm (95% CI –0.9 to –3.5). Self-assessed improvement (SAI) scores favoured the active LLLT group, with between group differences of 41% (95% CI 27.7 to 55.8). The NPAD disability score was reduced by a mean of –12.1 (95% CI –19.3 to –4.8). The mean change in NPNPQ score was –3.0 (95% CI –5.0 to –9.0). Negligible changes (3% to 5%) were reported in the SF-36 and MPQ (sensory and affective) scores. LLLT, as implemented in this study, was effective in providing pain relief for patients with chronic neck pain.