Abstract
BACKGROUND: Multi-wave locked system (MLS) laser therapy has shown efficacy in reducing pain in various musculoskeletal conditions. However, its standalone effects on pain and function in patients with chronic non-specific neck pain (CNNP) remain unclear. AIM: The aim of this study was to evaluate the effects of MLS laser therapy on pain, function, and disability in patients with CNNP compared to a placebo treatment. DESIGN: Randomized controlled study. SETTING: Outpatient. POPULATION: Patients aged 20-65 years with CNNP and a neck pain score between 4 and 7 on a Visual Analogue Scale. METHODS: Forty-seven patients were randomized into two groups: MLS Laser and Sham Laser, receiving 8 sessions of their respective treatments. Assessments were conducted at baseline (T0), end of therapy (T1), and one month post-therapy (T2) for neck pain (VAS), function (kinematics and electromyography of head movements), and disability (Neck Disability Index, NDI). Within- and between-group differences were analyzed across these time points. RESULTS: The MLS Laser group showed significant improvements (P<0.05) in the range of motion for head lateral bending and rotation compared to the Sham Laser group, which exhibited no changes. Both groups demonstrated increased movement velocity (P<0.05) and reduced pain and disability scores (P<0.05). However, either VAS and NDI did not reach the thresholds for minimal clinically important differences (MCID). At T2, a trend towards greater pain reduction was observed in the MLS Laser group (P=0.05). CONCLUSIONS: Both MLS Laser and Sham Laser therapies resulted in statistically significant improvements in pain, disability, and movement velocity. However, these changes were not clinically meaningful. MLS Laser therapy provided more pronounced and sustained pain relief and improved range of motion in head movements. CLINICAL REHABILITATION IMPACT: MLS Laser therapy improves neck range of motion as a standalone treatment for chronic non-specific neck pain, despite similar effects on pain and disability reduction with placebo.