Optimization of photobiomodulation therapy for spinal cord injury: A review

Interrelated secondary events occur within days and weeks following a spinal cord injury (SCI), constituting a major hurdle in providing both an effective and affordable treatment for spinal cord repair in that it requires a multifaceted approach. Photobiomodulation (PBM) therapy in the red/near-infrared spectrum holds promising reparative potential; however, there are no consistent or defined parameters for PBM delivery, which may explain the limited number of ongoing clinical trials and less-than-optimal reported outcomes. This review outlines the associated complexities of the secondary cascade after SCI, with insights on how and when red/near-infrared irradiation may alleviate these issues. The primary focus is to discuss limitations within the field that may be inhibiting our ability to characterize optimal guidelines and specifications. Ultimately, this review provides a call for action, as there is an urgent need for consensus and standardization of therapeutic preclinical methodologies if we hope to develop treatment protocols that provide a first-line minimally invasive therapy to (i) minimize injury sequelae and (ii) facilitate spinal cord repair. We recommend establishing a universal method to measure the therapeutic dose of light delivered to an injury site and employing standardized methodologies across all studies to assess the benefits of PBM therapy.