Design and Simulation of a Nerve Tracer System for Vagotomy Surgery

................................................................................................................ ii List of Figures ..................................................................................................... viii List of Tables ....................................................................................................... xi CHAPTER 1: INTRODUCTION ............................................................................ 1 1.1 Gastric Ulcers ................................................................................................. 1 1.2 Nerve Cells and Behavior ............................................................................... 2 1.3 Stimulation of Nerves and Neurons ................................................................ 7 1.4 Vagus Nerve ................................................................................................... 8 1.5 Vagotomy ...................................................................................................... 10 1.6 Surgical Complications of Vagotomy: Project Motivation .............................. 12 1.7 Vagus Nerve Stimulation (VNS) – An Existing System ................................. 13 1.8 Overview of Proposed Vagus Nerve Tracing System ................................... 14 References ......................................................................................................... 17 CHAPTER 2: DESIGN OF THE TRACER SIGNAL AND TRACER EXCITATION CUFF .................................................................................................................. 19 2.1 3D Modeling of a Human Vagus Nerve Test Bed ......................................... 19 2.1.1 COMSOL 4.3b Multiphysics Simulation .................................................. 19 2.1.2 Vagus Nerve Test Bed Geometry ........................................................... 20 2.1.3 Material ................................................................................................... 21 2.1.4 Subdomain Settings ................................................................................ 22 2.1.5 Boundary Conditions .............................................................................. 28 2.1.6 Meshing .................................................................................................. 30 2.1.7 Solver Configuration ............................................................................... 32 2.1.8 Running the Simulation ........................................................................... 32 2.1.9 Test Bed Simulation Results and Discussions ........................................ 34 2.1.9.1 Action Potential (AP) Propagation through the Vagus Nerve ........... 34 2.1.9.2 A Check to Ensure that the Action Potential is Generated by the External Applied Potential ............................................................................ 35 2.1.9.3 Action Potential (AP) at the Beginning & at the End of the Vagus Nerve ............................................................................................................ 36