Year

2006

Degree Name

Doctor of Philosophy

Department

School of Electrical, Computer and Telecommunications Engineering - Faculty of Informatics

Abstract

Cochlear implantation is a maximally invasive surgical procedure aimed at overcoming human inaudibility and providing the sensation of sound to thousands of severely deaf recipients worldwide. Specialists require extensive training to perform the surgery, yet traditional approaches such as cadaver dissection and device insertion can prove costly. Alternative training schemes have not been developed, however surgical simulators that offer force feedback during anatomical model manipulation may provide the answer. In the work, a novel approach to medical education is presented. It combines haptic technology and computer visualisation to recreate cochlear implantation in a virtual environment. The surgical simulator provides visual and haptic rendering during cochlear implant insertion into a virtual model of the human Scala Tympani. As the user inserts the sub-sampled array into a three-dimensional, reproducible representation of the Scala Tympani, collisions between the electrode and Scala Tympani walls are detected. In response, real-time forces are delivered back through the haptic device in a closed loop control system. Insertion studies are performed to evaluate the cochlear implant insertion process. Electrode array trajectories and output forces are monitored during device insertion into a synthetic model of the Scala Tympani. The force, torque and position data produced from the experiments are used in the final stage of work for simulator validation. A three-dimensional, surface description of the human Scala Tympani is derived from measured data and parameterised for future reproduction. It is visualised in a virtual environment, the Reachin Application Programming Interface, where visual and haptic rendering is implemented to make the insertion process interactive. Algorithms are produced and program optimisations performed to enable real-time, dynamic manipulation of the environment. Real world physical attributes are added to the Scala Tympani surfaces and electrode carrier to make the scene more realistic. System validation is performed by statistical and qualitative comparisons between the force profiles produced from the simulation and experimentation. The results are presented and evaluated in terms of overall system performance. The thesis offers unique approaches for simulator design, development and validation. The significant contributions of the work are reported, as are the benefits, with recommendations for future system enhancements.

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Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.