A review of mechanism of actions of ultrasound waves for treatment of soft tissue injuries

Abstract

Objective: Ultrasound (US) waves have unique characteristics that making them promising option for treatment of different soft tissue injuries particularly wounds. The mechanisms of actions of this technique in the treatment of soft tissue are not fully understood. This paper aimed to comprehensively review the biological interactions and mechanism of action of US waves in the treatment of chronic wounds. Methods: The databases of PubMed (1990-2016), EMBASE (1990-2016), Web of Sciences (1990-2016), and Google Scholar (1980-2016) were searched using the set terms “US waves†and “wound treatment,†“mechanism of action†and “soft tissue injuries,†and “biologi8cal interaction.†The title and abstract of the collected results were reviewed by two authors, and the relevant papers were selected for further evaluations. Results: The mechanisms of action depend on the US physical parameters as well as exposure factors including duration and injury type. The main mechanisms of US waves for wound healing are enhancing the rate of inflammatory phase, stimulating fibroblasts to secrete collagen, enhancing extensibility of collagen, circulation, pain threshold, enzymatic activity, permeability of cell membrane, and accelerating nerve conduction. Conclusion: The therapeutic effects of US depend on dose (W/cm2) and dosage (frequency of application). Low US frequencies show more therapeutic efficiency in wound healing compared with high frequencies