Non-linear and Anisotropic Elastic Soft Tissue Models for Medical Simulation

In this article we describe the latest developments of the minimally invasive hepatic surgery simulator pro totype developed at INRIA A key problem with such a simulator is the physical modeling of soft tissues We propose a new deformable model based on non linear elasticity and the nite element method This model is valid for large displacements which means in particu lar that it is invariant with respect to rotations This property improves the realism of the deformations and solves the problems related to the shortcomings of linear elasticity which is only valid for small displacements We also address the problem of anisotropic behavior and volume variations by adding to our model incom pressibility constraints Finally we demonstrate the relevance of this approach for the real time simulation of laparoscopic surgical gestures on the liver