"Low-intensity focused ultrasound therapy for sciatic nerve traumatic injury rehabilitation: preliminary results of a scoping review.

Abstract

Background. Sciatic nerve traumatic injury represents a significant challenge for rehabilitation due to motor and sensory loss, prolonged muscle denervation, incomplete remyelination, and limited functional recovery even after surgical repair. Although the peripheral nervous system retains regenerative capacity, axonal growth is usually slow and may not translate into adequate functional reinnervation. Low-intensity pulsed ultrasound has emerged as a non-invasive physical strategy with the potential to modulate cellular and molecular processes related to nerve regeneration, including Schwann cell activation, increased neurotrophic factors, remyelination, axonal sprouting, and regulation of the inflammatory response, which could contribute to the comprehensive rehabilitation of the sciatic nerve. Objective. To describe the impact of low-intensity ultrasound therapy on the comprehensive rehabilitation of sciatic nerve traumatic injury. Materials and methods. A literature search was conducted in PubMed and Google Scholar using algorithms based on the following Medical Subject Headings (MeSH) and search terms: ( ). In vivo preclinical studies, in vitro studies, reviews, and meta-analyses evaluating the effect of low-intensity ultrasound on peripheral nerve regeneration were included, with an emphasis on models of sciatic nerve traumatic injury, autograft, neurotomy, crush injury, or conduit repair. Selection was performed in two stages (title/abstract and full text) in duplicate. Finally, a narrative synthesis was reported under PRISMA guidelines based on the following variables: study type, experimental model, ultrasound parameters, intervention duration, functional outcomes, electrophysiological outcomes, histomorphometric findings, and associated cellular or molecular mechanisms. Results. A total of 101 articles were found and 11 were included. The evidence was mainly preclinical and included murine models of sciatic nerve injury, Schwann cell studies, and experimental reviews. Overall, low-intensity ultrasound was associated with better functional recovery, electrophysiological parameters, and histomorphometric indicators of regeneration. Its effects appear to depend on application parameters, with more consistent benefits between 140 and 250 mW/cm². Mechanistically, it was related to Schwann cell activation, neurotrophic modulation, and a reduction in pro-inflammatory mediators and axonal growth inhibitors. However, motor recovery was variable, and clinical evidence in humans remains limited. Conclusions. In conclusion, low-intensity pulsed ultrasound represents a promising adjuvant strategy to promote sciatic nerve regeneration following traumatic injury. However, the evidence remains mainly in the preclinical stage, with heterogeneity in application parameters and variable motor outcomes; therefore, translational and clinical studies are required to define its efficacy, safety, and an optimal therapeutic protocol.