A new approach to cutting into finite element models

Abstract

Virtual reality based surgical simulators offer a very elegant approach to enhancing traditional training in endoscopic surgery. In this context a realistic soft tissue model is of central importance. The most accurate procedures for modeling elastic deformations of tissue use the Finite Element Method to solve the governing mechanical equations. Therapeutic interventions (e.g. cutting) require topological changes of the Finite Element mesh, thus making a non-trivial remeshing step necessary. This paper describes a new approach to cutting in Finite Element models. The central idea is not to introduce new nodes/elements but to displace the existing ones to account for the topological changes introduced by a cut. After the displacement of the nodes/elements the mesh is homogenized to avoid tiny elements which destabilize the explicit time integration necessary for solving the equations of motion.