A task analysis of laparoscopic surgery : requirements for remote manipulation and endoscopic tool design

Minimally invasive surgery, or endoscopic surgery is an alternate surgical technique to the conventional open technique in general surgery, such as for gall bladder removal, hernia repair, and appendectomy. It requires surgeons to operate using an endoscope and specially designed endoscopic tools. The instrumentation for this technique imposes additional visual, spatial, tactual and motoric constraints on the surgeons. This exploratory study, examining three laparoscopic procedures, Cholecystectomy, Appendectomy, and Fundoplication, is based on a human-centred, information processing approach. The task analysis included an analysis of selected surgical tasks, and the endoscopic manipulators used, as well as a survey of the surgeons' views about the tasks and tools. Dissecting, suturing, knotting, and cutting tasks were decomposed into subtasks and analyzed by timeline and motion analysis. Scissors, graspers and needle drivers/holders were analyzed and evaluated for their usability. User feedback on all three aspects of the study (user, task, and tool) were obtained through personal interviews, and a questionnaire survey of registered general surgeons in British Columbia, Canada. Task analysis results and user feedback agreed that suturing and knotting are the most difficult tasks in laparoscopic surgery. Surgeons require more time and movements to suture and tie knots than other tasks. Surgeons also considered the needle drivers/holders that were used for these tasks to be more difficult than other tools to use. As tools were evaluated with respect to the task requirements, the perceived difficulty in using the tools was associated with both the physical and information processing constraints arising from performing the tasks. Surgeons' performance of basic surgical skills reflect these constraints. Remote manipulation in laparoscopic surgery exhibits the characteristic motions of natural human prehension, such as reaching and grasping. However, contrary to the parallel arrangement of transport and grasp components in direct manipulation, the results of motion analysis suggest that these reaching and grasping components are organized serially for remote manipulation in endoscopic surgery. ACKNOWLEDGEMENTS The completion of this thesis would not have been possible without the support and encouragement of many people. For all their patience and understanding throughout my endeavour, I thank them. I thank my family for the love and emotional support I needed to achieve my goal, feeding me when I was hungry, entertaining me when I needed a distraction from my video analysis, and keeping me on track when I strayed. I thank my good friends, for humoring me by listening to my monologues when I demanded their attention and participation as a naive audience to my research, and I thank my not-so-good friends for adding to my determination to work hard, as well as for strengthening my character. Most importantly, I thank my senior supervisor/mentor, Dr. Christine MacKenzie, for opening the door, for me, to the wonderful world of motor control research. I am eternally indebted to her for her enthusiastic guidance and mentorship. I especially thank my supervisory committee members: Dr. Shahram Payandeh for introducing me to this area of research and for his constant support and encouragement thereafter; and, Dr. Ron Marteniuk for his expert advice and keeping things in perspective. My external examiner, Dr. Barry Wills from the Department of Systems Engineering at the University of Waterloo, deserves special thanks for his thorough examination of my thesis and insightful feedback. To my friends in the Human Motor Systems Lab, who were the most likely recipients of my free-flowing emotions through the most intensive periods of my research, I extend my most sincere appreciation for their help and support. Many thanks to the Kinesiology office staff for always having an answer to my questions. Lastly, I thank Dr. A. Nagy for helpful discussion and for permitting me to videotape his laparoscopic training workshops at the Jack Bell Research Centre in Vancouver, and Matt Hanley of Ethicon for providing us with the endoscopic tools. This research was supported by IRIS-PRECARN (through Dr. S. Payandeh) and the Natural Sciences and Engineering Research Council of Canada (through Dr. C. MacKenzie). Table of