Deformable Modeling of Facial Tissue for Craniofacial Surgery Simulation

While deformable object modeling has been studied in computer graphics for more than two decades, only a few applications in surgical simulation have been developed which provide both real-time and physically realistic modeling of complex, non-linear, tissue deformations. Especially in craniofacial surgery the prediction of soft tissue changes- which are the result of the alteration of the underlying bone structure-is critical to the surgical outcome. Up until today the prediction of these tissue changes, and therefore the prognosis of the postoperative appearance of the patient, is still based on empirical studies of the relationship between bone and tissue movements: There exist no physical model, which takes into account the individual patient anatomy in order to simulate the resulting tissue changes during craniofacial surgery. In this article we present two different deformable tissue models, which are integrated in an interactive surgical simulation testbed. Both techniques allow the precise preoperative simulation of the resulting soft tissue changes during craniofacial surgery and the visualization of the patient’s postoperative appearance. The different deformable models are described in detail and both are applied to the same craniofacial case study. The simulation results are shown and compared with regard to the speed and accuracy of the prediction of the patient’s postoperative appearance