Efficacy of low-level laser therapy on management of Bell's palsy: a systematic review.

The aim of this study is to evaluate the efficacy of low-level laser therapy (LLLT) in patients with Bell's palsy (BP) through a systematic review method. We systematically searched international databases including PubMed, Scopus, and Web of Science to find eligible articles without language limitation. All relevant randomized controlled trials (RCTs) that compared the efficacy of the LLLT with placebo laser, exercise, massage, or no intervention on BP patients were included. Four studies (out of 259) had met our inclusion criteria involving 171 patients and were entered to the systematic review. Full texts of the selected studies were retrieved and critically appraised using Physiotherapy Evidence Database (PEDro) scale. The patients of all trials were in sub-acute (less than 1 week) stage. Both of LLLT and control groups showed significant improvement after trials. Two authors reported significant differences between the groups after 6 weeks of laser application (830 nm, 100 mW). In converse, two other authors did not identify any effectiveness following 4 weeks and 15 days of LLLT application with 670 and 830 nm wavelength, sequentially. There is clear lack of information lead to get and evidence-based suggestion for the LLLT application on Bells' palsy; however, the LLLT irradiation with 830 nm and 100 mW power for a period of 6 weeks might be beneficial on recovery for the patients with sub-acute Bell's palsy. There were no reported adverse effects during treatment and/or follow-up sessions.