Placebo-controlled investigation of low-level laser therapy to treat carpal tunnel syndrome.

Abstract

This study investigated the short-term efficacy of low-level laser therapy (LLLT) in patients with mild to moderate carpal tunnel syndrome (CTS), lasting for <1 year. Seventy-nine patients with CTS were included in this double-blind, placebo-controlled study, and randomly divided in two treatment groups: Experimental group (EG), active laser group (40 patients); and control group (CG), placebo (sham) laser group (39 patients). A GaAlAs diode laser [780 nm, 30 mW continuous wave (CW), 0.785 cm(2), 38.2 mW/cm(2)] was applied in contact with four points perpendicularly to the skin over the carpal tunnel area for 90 sec per point (2.7 J, 3.4 J/cm(2)/point). Both groups were treated five times per week, once a day over 2 weeks, followed by 10 treatments every other day for 3 weeks, that is, for a total of 20 treatments. Clinical assessment, including visual analogue scale (VAS) pain rating, Tinel's sign, and median nerve conduction studies (NCSs) were evaluated before, and 3 weeks after, the last LLLT treatment. Significant reduction in pain, reduction in the percentage of patients with a positive Tinel's sign, and shortening of sensory and motor latency time in the NCS examination was observed in the experimental LLLT group (but not in the control group). This study has observed and documented the statistically significant short-term effects of LLLT on CTS patients in comparison with a placebo group. The results support this conclusion, especially if the LLLT is applied in the earlier stages of CTS, and with mild to moderate cases.