Haptic feedback for minimally invasive surgery simulation

Amsterdam, 11 November 97 At the University of Hull in the United Kingdom, James Ward is one of the researchers occupied with a five year program on virtual knee arthroscopy. Just like the Fraunhofer Institute in Darmstadt, the Hull team has developed a Virtual Environment Simulator to realise a spectacular breakthrough in the traditional approaches of knee examination. One of the great advantages of working with a VE Simulator lies in the sensitive feedback the physician is getting through the instruments during the arthroscopy. This haptic experience is leading to more reliable results.

The existing training systems for arthroscopy are all using knee joints in rubber. Medical students have to exercise themselves by means of hands-on clinical experience on plastic models. This kind of didactic method presents the problem of difficult coordination resulting in various distortions, as Ward explains. In the case of knee arthroscopy, the surgeon operates through a small incision so he has to display an extraordinary dexterity in the coordination of his delicate movements.

The development of the Virtual Environment Simulator therefore pays large services to such minimally invasive surgery because this device is highly reusable and configurable. Moreover, it can handle a wide range of knee problems and means a great support for an objective scoring system. In the long run, it even turns out to be a cost reducing tool in comparison to the conventional tackling of the knee examination.

Trainees of course are enthusiastic about the enormous progress the haptic control is meaning to them. Via this feedback which is still being refined, it is possible for them to become more involved in the operation they are executing. Technically, the PC haptic controller can be steered via a workstation outside the hospital. We like to refer here to the role of the meta-centres Andy Marsh has been stipulating in his Euromed project.

It goes without saying that the Virtual Environment Simulator is confronting both user and researcher with tremendous challenges. Visual realism constitutes one of the capital concerns together with precise collision detection. To achieve this amount of reality needs the creation of a high resolution model and working up to an adjustable point. A precalculated collision depth map is no luxury as well as force calculations are. Essential for the training is also the validity of the process. The model has to be correct before you can work on it.

The Virtual Environment Simulator

At present, Ward's team is ardently working on the measurement of operational forces as well as on the development of a biomechanical model. After this, they will be focusing on how to obtain objective scoring methods and have further investigation of arthroscope distortion. If you are curious to know more about the VE Simulator project Ward and his colleagues are dealing with, don't hesitate to see what the University of Hull has in store for you.

Leslie Versweyveld