Health Sciences

Virtual surgery is an active research subject. Such systems allow physicians to practice and improve their skills in a virtual environment, performing surgery on virtual patients, before entering the operating room (OR). Studies have shown that using VR surgical simulation can significantly improve the performance in the OR [282], in particular for endoscopic and laparoscopic procedures.

Surgery simulation requires real-time computer graphics and haptic interfaces. The main objective of a virtual surgery system is to accurately simulate the behavior of tissues (skin, muscles, internal organs, bones) under cutting operations.

Realistic collisions should be computed to simulate the interaction of surgical instruments with different kinds of tissue. Simulating cutting operations requires surface deformation and other geometric operations. The topology of the 3D shapes representing tissues suffers changes; new geometry should be created during the simulation. The behavior of the tissue should be accurately reproduced. This requires the use of finite element models (FEM) and other free-form surface deformation algorithms [283]. Besides FEM, other methods like the boundary element method (BEM) are used as alternative computational mechanics techniques. BEM differs from FEM in that only the surface is discretized in order to apply boundary conditions to the equations defining the behavior of the body whose surface is being discretized. This reduces the size of the system of equations to be solved and allows for faster calculations. Together with haptic and visual feedback, BEM has been applied to simulate three basic actions performed on virtual deformable objects: prodding, pinching, and cutting. This research is targeted at the development of a neurosurgery simulator [284].

The user interface is a very important element; haptic interfaces, in particular single-point force-feedback devices like the PHANTOM®, are commonly used, as in VR training in gynecologic laparoscopy [285]. Special-purpose haptic interfaces have been developed to simulate the complex interaction involved in endoscopy [286].