Virtual Reality Simulation of Hip Surgery

Abstract

This thesis describes the design and application of a virtual reality simulator for orthopaedic surgeryof the proximal femur. The aim of the research was to create a simulator with the followingattributes; could be used within the current public hospital setting, reflected the perceived needs ofthe local orthopaedic community, provided surgically relevant feedback about aspects of technicalability to orthopaedic surgical trainees and the training committee, allowed practice of operativetasks which for reasons of radiation exposure could otherwise not occur, was validated, and couldbe developed further for other operations. The ultimate aim of the simulator is to allow trainees topractice aspects of surgical treatment such that their care of real patients is improved. The novel aspect of this work has been the development of a simulator which allows the trainee toperform all the steps required for two surgical procedures; namely hip fracture fixation and pinningof slipped femoral capital epiphyses. The simulator runs on the computers found within the publichospital as it does not require expensive hardware such as haptic (force feedback) devices. Resultsfrom the simulator mimic real world measurements which are seldom available to trainees asfeedback to enable them to practice their craft. A survey of the New Zealand orthopaedic surgeons and advanced trainees showed this communitywas generally supportive of simulation, though only 4 respondents had previous experience with asurgical simulator. The task of practicing angulation/spatial orientation was thought most suitablefor simulation, which is the task which the simulator specifically allows trainees to practice. Morerecently qualified surgeons were more likely to agree that simulation was an effective way topractice surgical procedures. Validation of the simulator was tested in two experiments. The simulator was shown to have facevalidity; i.e. a realistic representation of the operating room. This result was obtained by surveyingusers who had completed a number of virtual operations. Construct validity was assessed by thesimulator’s ability to identify between groups of users with differing levels of real surgicalexperience. The simulator was able to discriminate medical students from orthopaedic trainees,despite the medical students’ greater ability in computer-gaming. Advanced trainees generallyperformed better than basic trainees, though in the limited number of trainees available significancewas not reached. Finally the simulator was developed further to allow all advanced trainees within New Zealand tocomplete virtual pin placement of a slipped capital femoral epiphysis. This demonstrated thefeasibility of using the simulator for assessment of trainees within their normal training weekend. Italso revealed different operating styles, and showed how these differing styles do not correlate withthe accuracy with which the final screw is placed.