Extracorporeal shockwave therapy in spinal cord injury, early to advance to clinical trials? A systematic review and meta-analysis on animal studies:

Background As there is no consensus over the efficacy of extracorporeal shockwave therapy in the management of spinal cord injury complications, the current meta-analysis aims to investigate preclinical evidence on the matter. Methods The search strategy was developed based on keywords related to 'spinal cord injury' and 'extracorporeal shockwave therapy'. A primary search was conducted in Medline, Embase, Scopus and Web of Science until the end of 2020. Studies which administered extracorporeal shockwave therapy on spinal cord injury animal models and evaluated motor function and/or histological findings were included. The standardised mean difference with a 95% confidence interval (CI) were calculated. Results Seven articles were included. Locomotion was significantly improved in the extracorporeal shockwave therapy treated group (standardised mean difference 1.68, 95% CI 1.05-2.31, P=0.032). It seems that the efficacy of extracorporeal shockwave therapy with an energy flux density of 0.1 mJ/mm2 is higher than 0.04 mJ/mm2 (P=0.044). Shockwave therapy was found to increase axonal sprouting (standardised mean difference 1.31, 95% CI 0.65, 1.96), vascular endothelial growth factor tissue levels (standardised mean difference 1.36, 95% CI 0.54, 2.18) and cell survival (standardised mean difference 2.49, 95% CI 0.93, 4.04). It also significantly prevents axonal degeneration (standardised mean difference 2.25, 95% CI 1.47, 3.02). Conclusion Extracorporeal shockwave therapy significantly improves locomotor recovery in spinal cord injury animal models through neural tissue regeneration. Nonetheless, in spite of the promising results and clinical application of extracorporeal shockwave therapy in various conditions, current evidence implies that designing clinical trials on extracorporeal shockwave therapy in the management of spinal cord injury may not be soon. Hence, further preclinical studies with the effort to reach the safest and the most efficient treatment protocol are needed.