Photobiomodulation for spinal cord injury: A systematic review and meta-analysis.

In recent years, photobiomodulation therapy (PBMT) has found many applications in various medical fields. Studies of PBMT on spinal cord injury (SCI) have mostly used laser sources in experimental animal models. The purpose of this study was to summarize studies that have employed PBMT for various kinds of SCI in animals. A thorough search in databases including MEDLINE, EMBASE, SCOPUS, and Web of Science, with the removal of unrelated articles, yielded 16 relevant articles. The meta-analysis showed that PBMT was effective in improving post-SCI movement in the first 14 days (MD = 1.593 (95% CI: 1.110 to 2.075; p <0.001, I2 = 51.9%) and this improvement became even greater thereafter (MD = 2.086 (95% CI: 1.570 to 2.603; p = <0.001. I2= 90.3%). Time of irradiation (<300 sec or >300 sec), gender (male or female), injury model (contusion or compression, radiation protocol (<14 days or ≥14days), laser wavelength (<800nm or >800nm) and injury severity (moderate or severe) were found to be factors that can affect PBM efficacy for SCI treatment. PBMT has an anti-inflammatory effect, is effective in reducing the size of spinal cord lesions and helps to absorb administrated proteins and stem cells to the lesion site.