A Device to Measure Tensile Forces in the Deep Fascia of the Human Abdominal Wall Sponsored by Dr. Raymond Dunn of the University of Massachusetts Medical School A Major Qualifying Report Submitted to the Faculty Of the WORCESTER POLYTECHNIC INSTITUTE In partial fulfillment of the requirements for the Degree of Bachelor of Science By Olivia Doane _______________________ Claudia Lee _______________________ Meredith Saucier _______________________ April 18, 2013 Advisor: Professor Kristen Billiar _______________________ Co-Advisor: Dr. Raymond Dunn _______________________ Table of Contents Table of Figures ............................................................................................................................. iv List of Tables ................................................................................................................................. vi Authorship Page ............................................................................................................................ vii Acknowledgements ...................................................................................................................... viii Abstract .......................................................................................................................................... ix Chapter 1: Introduction ................................................................................................................... 1 Chapter 2: Literature Review .......................................................................................................... 2 2.1 Anatomy ................................................................................................................................ 2 2.1.1 The Skin ......................................................................................................................... 2 2.1.2 The Fascia ...................................................................................................................... 2 2.1.3 Biomechanics of the Fascia ........................................................................................... 4 2.1.4 Muscles of the Abdomen ............................................................................................... 6 2.2 Laparotomies......................................................................................................................... 7 2.2.1 Muscles and Fascia in Closure ....................................................................................... 8 2.3 Closure Methods & Complications ....................................................................................... 9 2.3.1 Consequences of Abnormal Closures ............................................................................ 9 2.3.2 Ventral Hernias ............................................................................................................ 10 2.4 Temporary and Gradual Closures ....................................................................................... 11 2.4.1 Temporary Closures ..................................................................................................... 11 2.4.2 Gradual Closures .......................................................................................................... 12 2.5 Gap in Research .................................................................................................................. 15 2.6 Current Devices for Tensile Force Measurements .............................................................. 15 Chapter 3: Project Strategy ........................................................................................................... 19 3.1 Initial Client Statement ....................................................................................................... 19 3.2 Objectives ........................................................................................................................... 19 3.3 Constraints .......................................................................................................................... 20 3.4 Revised Client Statement .................................................................................................... 21 3.5 Project Approach ................................................................................................................ 21 3.6 Testing Protocols ................................................................................................................ 22 3.6.1 Swine Weight Testing .................................................................................................. 22 i 3.6.2 Swine Prototype Testing .............................................................................................. 23 Chapter 4: Design Alternatives ..................................................................................................... 24 4.1 Needs Analysis.................................................................................................................... 24 4.2 Functions and Specifications .............................................................................................. 25 4.2.1 Functions ...................................................................................................................... 25 4.2.2 Specifications ............................................................................................................... 25 4.2.3 Functions and Means ................................................................................................... 25 4.3 Design Alternatives ............................................................................................................. 27 4.3.1 Design 1: L-Shaped Handle Clamp ............................................................................. 28 4.3.2 Design 2: Force Sensor ................................................................................................ 28 4.3.3 Design 3: Instrumented Forceps and Hemostats Variations ........................................ 30 4.4 Final Selection Matrix......................................................................................................... 34 4.5 Conceptual Design .............................................................................................................. 35 4.6 Feasibility Study ................................................................................................................. 36 4.6.1 Design Calculations ..................................................................................................... 37 4.6.2 Strain Gage Selection and Data Collection .................................................................. 39 4.7 Preliminary Data ................................................................................................................. 40 4.7.1 Factor of Safety ............................................................................................................ 40 4.7.2 Analytical Strain Calculations ..................................................................................... 41 Chapter 5: Design Verification ..................................................................................................... 43 5.1 Finite Element Analysis Validation .................................................................................... 43 5.1.1 Analytical Model ......................................................................................................... 43 5.1.2 FEA Model................................................................................................................... 44 5.2 Rapid Prototype .................................................................................................................. 47 5.3 Initial Prototype .................................................................................................................. 48 5.3.1 Calibration.................................................................................................................... 49 5.3.2 Swine Testing............................................................................................................... 49 5.4 Final Prototype .................................................................................................................... 50 5.4.1 Calibration.................................................................................................................... 50 5.4.2 Design Modifications ................................................................................................... 50 Chapter 6: Results & Discussion .................................................................................................. 52 ii 6.1 Fish Scale Weight Testing .................................................................................................. 52 6.2 Swine Trial Testing ............................................................................................................. 52 6.3 Design Modifications .......................................................................................................... 54 6.4 Human Testing .................................................................................................................... 55 Chapter 7: Final Design and Validation........................................................................................ 56 7.1 Final Device Design ............................................................................................................ 56 7.2 Finite Element