Finite element analysis for evaluating liver tissue damage due to mechanical compression.
The development of robotic-assisted minimally invasive surgery (RMIS) has resulted in increased research to improve surgeon training, proficiency and patient safety. Minimizing tissue damage is an essential consideration in RMIS. Various studies have reported the quantified tissue damage resulting from mechanical compression; however, most of them require bench work analysis, which limits their application in clinical conditions of RMIS. We present a new methodology based on nonlinear finite element (FE) analysis that can predict damage degree inside tissue. The effects of the boundary conditions and material property of the FE model on the simulated von Mises stress value and tissue damage were investigated. Four FE models were analyzed: two-dimensional (2D) plane strain model, 2D plane stress model, full three-dimensional (3D) model, and 3D thin membrane model. Nonlinear material properties of liver tissue used in the FEA were derived from previously reported in vivo and in vitro experiments. Our study showed that for integrated von Mises stress and tissue damage computations, the 3D thin membrane model yielded results closest to the full 3D analysis and required only 0.2% of the compute time. The results from 3D thin membrane and the full 3D models fell below plane-strain model and above the plane-stress model. Both stress and necrosis distributions were impacted by the material property of FE models. This study can guide engineers to design surgical instruments to improve patient safety. Additionally it is useful for improving the surgical simulator performance by reflecting more realistic tissue material property and displaying tissue damage severity.
Department of Mechanical Engineering, University of Washington, Box 352600, Seattle, WA 98195, United States. Electronic address: leicheng@u.washington.edu.
Lei
L
Cheng
Department of Electrical Engineering, University of Washington, Box 352500, Seattle, WA 98195, United States.
Blake
B
Hannaford
D000818:Animals; D020342:Finite Element Analysis; D008099:Liver / Q000293:injuries / Q000473:pathology / Q000502:physiology / Q000601:surgery; D019060:Minimally Invasive Surgical Procedures; D008962:Models, Theoretical; D013314:Stress, Mechanical; D013552:Swine
Finite Element Analysis (FEA); Geometrical boundary; Liver; Material characterization; Minimally invasive surgery; Tissue damage