The Newsletter of a Medical
Robotics project of the
Institute of Robotics and
Intelligent Systems, a
Federally Funded Network
of the Centres of Excellence

An image tracking system has been developed to integrate with the existing 2D imaging system for laparoscopic surgery. Tracking hardware follows specially designed markers located at the tips of the laparoscopic tools. The system identifies the allowable four-degrees of freedom of motion for the laparoscopic tool.

The system will initially be applied in the LaparoRobot--a mechanism which holds the laparoscope (see endoSCOPE No. 4, 1999)--to position the tool within the desired field of view specified by the surgeon.

  Haptic Feedback Mechanism

We have developed a device similar to a conventional joystick that allows a surgeon to feel the sensation of force in his hands. The device gives force feedback for all four-degrees of freedom available in actual surgery. It's being integrated with our Laparoscopic Training Environment to give the surgeon the sensations of the virtual tools touching, pulling, and tearing their environment.

  Haptic Rendering

Just as computer graphics render the visual environment, similar tools are required to render the sense of touch. One of the main challenges in developing a Laparoscopic Training Environment is modelling the way compliant tissues and organs feel when they are touched. A major requirement is for the model to be computationally fast to increase the degree of realism. A framework has been identified and extended using a surface mesh with added physical attributes such as a mass-spring-damper. This approach can be used to model various 3D shapes and contours used in our Laparoscopic Training Environment. The model can create both the reaction force at the contact points and the proper graphical representation of the deformation.

  Volume Estimating System

A system was developed which can be used in estimating the volume of the abdominal cavity during surgery. The system consists of a specially designed sensor and the required graphical interface. It was evaluated using an emulated environment consisting of an artificial cavity made of real tissue.

  Laparoscopic Training Environment

A virtual training environment under development can help surgeons improve hand-eye coordination and dexterity needed for laparoscopic surgery. The theme of the initial phase focuses on hand-eye coordination. The surgeon is required to make contact with a landmark on a compliant object from various initial starting positions of the tool. Completion times for such actions are recorded for further evaluation and comparison. The user can view sites similar to real laparoscopic operations with spotlight illumination. All the objects are compliant and users will eventually be able to feel the force of interactions through specially designed joysticks.