Penetration Depth and Tissue Interaction of Focused Extracorporeal Shock Waves: An In-vitro Investigation

Introduction: Extracorporeal shock wave therapy (ESWT) is a non-invasive therapeutic approach with minimal consequences, extensively utilized for the management of musculoskeletal problems. Focused ESWT (f-ESWT) is known to have regenerative effects on muscle and bone tissues; however, little is known about its penetration and propagation in different tissues. Objective: To assess the reach of f-ESWT in soft tissues and bone tissues. Methods: An in-vitro observational study was conducted. A piezoelectric shock wave device was used to evaluate the penetration and visual propagation of shock waves in an aquarium with water in muscle tissues (ham) of different thicknesses, and bone tissues (scapula and femur). High-resolution images and videos were captured to observe the penetration of mechanical waves into the different tissues. Results: Light beams and air bubbles were observed, consistent with the propagation of f-ESWT through different tissues. The f-ESWT was able to penetrate wide bones such as the femur and thin bones such as the scapula. Conclusion: F-ESWT is capable of penetrating soft tissues and bone tissues depending on the depth. This is an important study for the safe application of f-ESWT by a healthcare professional with prior anatomical knowledge.