Virtual Laparoscopic Cholecystectomy Simulator Using Force-Feedback Device

Lee, Tae Soo; Kim, Cheong; Choi, Jae Woon

Abstract

For the minimally invasive surgery, endoscopic surgery has been being a useful technique in diagnosis and treatment of many kind of human diseases and injuries. But, performing endoscopic operations demand expert skills which allow surgeon to learn navigating complex organs in the body through limited view of endoscope as well as manipulating surgical instruments. So the virtual reality based endoscopic surgery simulator has been great increasingly developed with improvements in computing power, graphic hardware, and haptic device in the recent few years. A good balance between surgical realism and real-time interactive rates of simulation is one of most challenging problems in surgical simulation. And when coupled with precise computations of the forces and deformation of organs, it may be possible for the surgeon to feel haptic sensations close to reality. We describe the virtual laparoscopic cholecystectomy simulator using force-feedback device. A goal of this paper is to improve the realism of simulator through real-time interaction between force-feedback and visual-feedback. To calculate deformation of virtual objects separately from the force-feedback, because the latter must be updated much more frequently, the two feedbacks are implemented in each processor. And pre-calculated data set which used for reducing amount of calculation about deformation results in improvement of the real-time interactive rates between the two feedbacks. When virtual surgical tool, manipulated by the user, was collided with isosurface based organ, the surface was deformed in real-time and the graphics, including tissue deformation, performed at 20~30 frames per second. Simultaneously, force-feedback was transmitted to the user at about 500 times per second, therefore we could implement real-time interactive virtual laparoscopic surgery simulator.