Nonlinear Finite Element-based Modeling of Soft-Tissue Cutting

This paper concerns with nonlinear modeling of biological soft-tissue cutting for simulation and planning of medical procedures. The complicated mechanical behavior of soft-tissue is modeled by considering both geometrical and material nonlinearities using an Ogden-based constitutive equation. The incompressible property of soft-tissue material during deformation is enforced and the Finite Element Method is utilized to discretize the deformable object model in the spatial domain. Element separation and node snapping are used to create a cut in the mesh that is as close as possible to the tool trajectory while preserving the mass of the object and the number of elements in the mesh. In addition, an algorithm is proposed to ensure that the cutting technique guarantees a minimum mesh quality and hence simulation stability by remeshing few elements in the cut area only when needed. Numerical simulations have been carried out in order to evaluate the effectiveness of the proposed modeling techniques.