Fast Finite Element Modeling for Surgical Simulation

Deformation of complex geometric structures is computationally intensive if based on continuum mechanics. Virtual Reality (VR) application typically require haptic updates at 1000 Hz and visual updates at 30 Hz. Because of this need for speed, many have used simpler methodologies that are not reality based for achieving real-time deformation in VR.

Since the graphical interpolations and simple spring models commonly used in these applications are not based on the mechanical properties of the simulated material, these "quick and dirty" methods typically do not accurately represent the complex deformations and force-feedback interactions that can take place. Finite element (FE) analysis, which is based on continuum mechanics, is widely regarded as the most appropriate alternative to these methods. However, because of the highly computational nature of the FE method, its direct application to real-time force-feedback and visualization of structure deformation has not been practical for most applications.

This limitation is primarily due to the overabundance of information provided by the standard FE approaches. If the mathematics are optimized through pre-processing to yield only the information essential for a task, computation time can be drastically reduced at run-time. Such methodologies are being developed in a combined effort between the Human Interface Technology Laboratory (HITLab), the Department of Civil and Environmental Engineering and the Mechanical Engineering Department of the University of Washington. We have created computer demonstrations which support real-time interaction with fast finite element models.

One example is a fast finite element analysis package that can be used for engineering design. This package allows implicit models to be meshed and then analyzed in real time. Effort has also been dedicated to creating implicit models from medical images. This will allow for the creation of patient specific models that can be used in surgery simulation.

In collaboration with the Division of Dermatology, our current focus is the development of a real-time skin surgery simulator that will allow user to perform soft-tissue deformation, soft-tissue cutting, skin undermining and suture placement. The goal is to develop a suturing simulator that accurately portrays surgical suturing such that a user can easily learn the basic techniques of suturing.

Sponsoring Agencies

The current funding is coming from the Department of Energy`s Computational Science Graduate Fellowship who is funding the student (Alex Lindblad).

Contacts

Suzanne Weghorst <weghorstu.washington.edu>, Alex Lindblad <alexhitl.washington.edu>, George Turkiyyah <georgece.washington.edu>, Jeff Berkley <jberkleyhitl.washington.edu>, Dan Berg