Structural design sensitivity analysis of an ultrasonically activated scalpel to improve contact pressure distribution

Ultrasonically activated scalpels (UAS) have excellent hemostatic effects with minimal tissue damage while dissecting tissue. However, inhomogeneous contact pressure (CP) distribution at the sealing site can decrease the quality of sealing strength and cutting. In this study, we evaluated the contact mechanics of UAS using 3D finite element analysis (FEA) simulations, and examined the effects of structural design parameters on the contact mechanics (average CP, standard deviation of CP, maximum CP, and contact area) using experiment-based sensitivity analysis. The largest positive and negative response of the average CP and standard deviation of CP were 0.68-0.85 MPa and 0.81-0.44 MPa, respectively (r = 0.32 and r = -0.73, P < 0.05) when the handle length, jaw cave, and tissue pad height were increased. In conclusion, design parameters (tissue pad height, jaw cave height, jaw cave length, and handle length) of UAS demonstrating high correlation with average CP, standard deviation of CP, maximum CP, and contact area should be considered to attain evenly distributed CP for improved structural optimization of UAS.