Efficacy of low-level laser therapy on pain, disability, pressure pain threshold, and range of motion in patients with myofascial neck pain syndrome: a systematic review and meta-analysis of randomized controlled trials.

Low-level laser therapy (LLLT) is one of recent modalities for treatment of myofascial neck pain (MNP). Several RCTs have been conducted on its effectiveness. The aim of this comprehensive meta-analysis was to evaluate the effectiveness of LLLT on MNP. Electronic databases were searched for identifying eligible studies comparing the effectiveness of LLLT using any wavelength with placebo or active control in myofascial neck pain up to June 2022. Data related to pain intensity, pain pressure threshold (PPT), range of motion (ROM), and disability was analyzed as a pooled estimate of mean difference or standard mean difference (SMD) with 95% confidence intervals (CIs) using random/fixed-effect model. Funnel plot and Egger's linear regression test were also conducted to examine the risk of publication bias. A total of 13 randomized controlled trials were included in this systematic review and meta-analysis. The data assessing laser effectiveness on different outcomes of 556 patients were considered for meta-analysis. Pooled results revealed that LLLT was significantly effective in pain reduction (MD =  - 1.29, 95% CI =  - 2.36; - 0.23, P < 0.001). Also, secondary outcomes including PPT (SMD of 2.63, 95% CI = 0.96; 4.30, P < 0.01) and right bending ROM (SMD of 3.44, 95% CI = 0.64; 6.24, P < 0.01) were improved, while disability (MD of - 7.83, 95% CI =  - 17.1; 0.08, P = 1.34) did not improve significantly after LLLT. Our meta-data revealed that LLLT may reduce myofascial neck pain and its related outcomes. LLLT is suggested to be used by clinicians along with other therapies such as manual and exercise therapy.