DEVELOPMENT OF ELECTRONIC INSTRUMENTATION FOR COMPUTER-ASSISTED SURGERY by Kaci Carter A thesis submitted to the Department of Electrical and Computer Engineering In conformity with the requirements for the degree of Master of Applied Science Queen’s University Kingston, Ontario, Canada (August, 2015) Copyright ©Kaci Carter, 2015 Abstract In the operating room, feedback, such as instrument positioning guidance provided by surgical navigation systems is typically displayed on an external computer monitor. The surgeon’s attention is usually focused on the surgical tool and the surgical site, so the display is typically out of the direct line of sight. A simple visual feedback mechanism was developed to be mounted on the surgical tool. This feedback is within the surgeon’s direct line of sight and alerts the surgeon when it is necessary to look at the monitor for detailed navigation information. The combination of visual feedback with the surgical navigation system is designed to aid the surgeon in cutting around a tumor, maintaining negative margins, while reducing the amount of healthy tissue contained within the cut. The tool- mounted visual feedback device was designed to be light-weight, compatible with electromagnetic (EM) tracking, and pose no risk of galvanic connection to the patient. The device was tested through the resection of multiple tumor contour models using computer navigation screen only, and computer navigation screen with visual feedback mounted on the surgical tool. Use of the device was shown to decrease the amount of healthy tissue contained within the surgical cut, and to increase the subjects’ confidence in their ability to follow acceptable margins. The second objective of this work is to develop a system to both spatially and temporally track electrosurgical instruments, within the surgical navigation system. In order to temporally track the tools, it is important to know when the electrosurgical unit is powered on. However, electrosurgical instruments are FDA and Health Canada approved and therefore cannot be interfered with. Thus, a non-invasive method of sensing when the tool is powered on is required. Two AC current sensors, two peak detector circuits, and one voltage comparator circuit were used to detect when an electromagnetically tracked electrosurgical cauterizer is being powered on and differentiate between the cut and coagulation modes when cauterizing different substances. This can be integrated into the existing surgical navigation system through the use of an Arduino Uno microcontroller. ii Acknowledgements I would like to thank my supervisors Dr. Fichtinger and Dr. Morin for their support and guidance throughout this year. My work at the Laboratory for Percutaneous Surgery has been full of many wonderful opportunities that have helped me to further develop my academic and research skills. I would also like to thank my colleagues in the Perk Lab who always made the environment welcoming and friendly. I would also like to thank Ryan Anderson, Matthew Holden, Thomas Vaughan, Dr. Padina Pezeshki, Dr. Tamas Ungi, and Dr. Andras Lasso for their help with various aspects of this thesis. I was supported financially by NSERC Canada Graduate Scholarship (2014-2015) and Dr. Fichtinger was supported as a Cancer Care Ontario Research Chair in Cancer Imaging. Finally, I would like to thank my parents and my sister for their constant encouragement throughout this thesis work and for always being so supportive of my dreams. You are always there when I need your guidance and encouragement. iii Table of Contents Abstract ......................................................................................................................................................... ii List of Figures .............................................................................................................................................. vi List of Tables ............................................................................................................................................... ix List of Abbreviations .................................................................................................................................... x Chapter 1 Introduction .................................................................................................................................. 1 1.1 Motivation ........................................................................................................................................... 1 1.2 Research Objectives ............................................................................................................................ 1 1.3 Thesis Outline ..................................................................................................................................... 2 1.4 Thesis Contributions ........................................................................................................................... 3 Chapter 2 Literature Review ......................................................................................................................... 5 2.1 Surgical Navigation ............................................................................................................................ 5 2.1.1 Tracking/registration .................................................................................................................... 5 2.1.2 SlicerIGT Surgical Navigation using PLUS Toolkit ................................................................... 8 2.1.3 Augmented Reality Surgical Navigation ..................................................................................... 8 2.1.4 Video Based Surgical Navigation ................................................................................................ 9 2.2 Real Time Feedback Methods for Surgical Navigation ...................................................................... 9 2.2.1 Auditory Feedback ..................................................................................................................... 10 2.2.2 Visual Feedback ......................................................................................................................... 11 2.2.3 Vibrotactile Feedback ................................................................................................................ 12 2.3 Electrosurgical Devices .................................................................................................................... 13 2.4 Current sensing ................................................................................................................................. 15 2.5 Surgical Margins ............................................................................................................................... 17 2.6 Breast Conserving Surgery ............................................................................................................... 18 Chapter 3 Visual feedback mounted on surgical tool ................................................................................. 19 3.1 Objectives ......................................................................................................................................... 19 3.2 Device Design ................................................................................................................................... 20 3.3 Light Pattern Exploration .................................................................................................................. 21 3.4 Prototype ........................................................................................................................................... 23 3.5 Methods............................................................................................................................................. 26 3.6 Results ............................................................................................................................................... 28 3.7 Discussion ......................................................................................................................................... 46 3.8 Conclusion ........................................................................................................................................ 49 iv Chapter 4 Current sensing for electrosurgical devices ................................................................................ 50 4.1 Objective ........................................................................................................................................... 50 4.1.1 Initial Exploration ...................................................................................................................... 51 4.1.2 Current Sensor Prototype ........................................................................................................... 52 4.1.3 System Integration ..................................................................................................................... 52 4.2 Results ............................................................................................................................................... 54 4.3 Discussion ......................................................................................................................................... 63 4.4 Conclusion ........................................................................................................................................ 66