A model for virtual suturing in vascular surgery

Vascular surgery is a technically demanding surgical speciality, one component of which is the accurate placement of sutures through a diseased vessel wall. Minor errors can result in thrombosis and failure of the procedure. To develop the necessary skills takes many hours of practice, which, in the past, have been acquired at the operating table. Recreating a surgical environment using virtual tools presents a number of research challenges. Conventional collision detection methods fail for deformable bodies and do not provide a mechanism to scale the response over different regions at the same time. We have developed a threaded collision test allowing the mesh to be updated whilst guaranteeing a smooth force response for haptic devices. The finite element method (FEM) is adapted to allow multiple points of contact and the validity of this model is discussed with respect to known tissue behaviour. Following a preliminary examination by clinicians, a novel scheme is introduced for simulating more realistic force responses