Haptic surgical simulation: An application to virtual suture

Abstract

Virtual surgical planning and training require high fidelity not only in visual modeling, but also in haptic modeling. As a fundamental and typical application of surgical simulation, virtual suturing deals with technical problems such as soft tissue modeling, collision detection, and force modeling. In this paper, a haptic system of virtual suture is developed for surgical training. A realistic tissue modeling method based on either MRI or CT images is proposed. Given a CT or MRI file, an STL file is constructed. The STL file is voxelized to generate a regular spatial lattice that provides the basis for constructing the mass-spring system (MSS). Surface textures are mapped to this MSS for better visual effect of human tissues. Haptic interaction between the tissue model and a haptic device is rendered on a piecewise linear stress-strain model. A prototype system based on the proposed method is implemented. When using this system, a user can feel the force change at different stage of the suturing process. A force bar recording and showing the changing force in the suturing process provides an intuitive way of force magnitude display.