Efficacy of low-level laser therapy in carpal tunnel syndrome management: a systematic review and meta-analysis

We performed this meta-analysis to investigate the efficacy of low-level laser therapy (LLLT), a physiotherapy modality with anti-inflammatory and analgesic effects, in the management of mild-to-moderate carpal tunnel syndrome (CTS). We searched PubMed, Web of Knowledge, Scopus, Cochrane Central, and Virtual Health Library for randomized controlled trials (RCTs) that compared the effects of LLLT with or without splinting versus placebo on functional and electromyographic outcomes in CTS. All outcomes were pooled as mean differences (MD) under the inverse variance or random effects model, using the statistical add-in (MetaXL, version 5.0). Eight RCTs (473 patients/631 wrists) were eligible for the final analysis. The overall effect estimates did not favor LLLT therapy group over placebo in all primary outcomes: visual analogue scale (MD −1.11, 95% CI [−2.58, 0.35]), symptom severity scale score (MD −1.41, 95% CI [−5.12, 2.29]), and functional status scale score (MD −1.33, 95% CI [−3.27, 0.61]). However, LLLT was superior to placebo in terms of grip strength (MD 2.19, 95% CI [1.63, 2.76]) and inferior to placebo in terms of sensory nerve action potential (MD −2.74, 95% CI [−3.66, −1.82]). Laser therapy is superior to placebo in terms of improving the grip strength; however, no significant difference was found between both groups in terms of functional status improvement, pain reduction, or motor electrodiagnostic evaluations. Further high-quality trials with longer follow-up periods are required to establish the efficacy of LLLT for CTS treatment.