Toward realistic soft-tissue modeling in medical simulation

Most of today's medical simulation systems are based on geometric representations of anatomical structures that take no account of their physical nature. Representing physical phenomena and, more specifically, the realistic modeling of soft tissue will not only improve current medical simulation systems but will considerably enlarge the set of applications and the credibility of medical simulation, from neurosurgery planning to laparoscopic-surgery simulation. To achieve realistic tissue deformation, it is necessary to combine deformation accuracy with computer efficiency. On the one hand, biomechanics has studied complex mathematical models and produced a large amount of experimental data for accurately representing the deformation of soft tissue. On the other hand, computer graphics has proposed many algorithms for the real-time computation of deformable bodies, often at the cost of ignoring the physics principles. In this paper, we survey existing models of deformation in medical simulation and analyze the impediments to combining computer-graphics representations with biomechanical models. In particular, the different geometric representations of deformable tissue are compared in relation to the tasks of real-time deformation, tissue cutting, and force-feedback interaction. Last, we inspect the potential of medical simulation under the development of this key technology.