Design and Evaluation of Novel Devices to Facilitate Long Bone Fracture Reconstruction by Hamid Ebrahimi A thesis submitted in conformity with the requirements for the degree of Doctor of Philosophy Institute of Biomaterials and Biomedical Engineering University of Toronto © Copyright by Hamid Ebrahimi 2017 Design and Evaluation of Novel Devices to Facilitate Long Bone Fracture Reconstruction Hamid Ebrahimi Doctor of Philosophy Institute of Biomaterials and Biomedical Engineering University of Toronto 2016 Abstract Intramedullary (IM) nailing is the standard of care for adult lower extremity long bone fracture stabilization. In IM nailing, obtaining the correct entry point for nail insertion has been identified as the most important technical aspect of the operation [1]. Upon accurate entry point selection and opening the intramedullary canal, intra-operative reduction is necessary to insert a long guide wire through the proximal and distal fragments to enable subsequent IM reaming and nail insertion. Despite widespread usage of IM nailing, significant surgical challenges arise in accurate entry point selection and obtaining adequate provisional reduction to allow conventional intramedullary guide wire insertion. Such challenges can significantly impede the surgical workflow, introduce surgical complications, requiring additional operative time and radiation exposure to both patients and medical staff, as well as elevating surgical frustration levels. This thesis focuses on analyzing the IM nailing surgical process and the development and evaluation of two novel surgical tools, FAST, to facilitate entry point selection and FLEX FiRST ii wire, to aid long bone fracture reduction. FAST (Femoral Antegrade Starting Tool) is a surgical tool that enables maintenance of Kirschner (K) wire anteroposterior (AP) alignment when lateral images are acquired to obtain accurate K-wire positioning in the sagittal plane. FLEX FiRST (FLEXible Fracture Reduction Steerable Telescoping) Wire is a flexible endoscopic device whose insertion is guided by a proximal joy-stick like controller which enables navigation of the device tip through a malreduced fracture site under standard intra-operative fluoroscopy. Ultimately, the design of these novel tools can address the lack of connectivity in utilizing sequential 2D fluoroscopic images to achieve 3D alignment and may facilitate the overall surgical workflow in IM nailing of femoral shaft fractures. iii Acknowledgments First and foremost, I would like to thank the people of Canada for their contributions toward my OGS and CIHR scholarships in my entire graduate studies. I have always tried to find a way to pay back to the society by teaching and helping the undergraduate students across three universities of Toronto, Ryerson, and McMaster. I hope the devices I have designed and tested, would be utilized in the operating rooms and help the patients undergo surgery in a more efficient way. I would like to specially acknowledge the help, support, and guidance of my supervisors, Dr. Cari Whyne and Dr. Albert Yee. Dr. Whyne, has always been an inspiration for all her students. Her trust on my project allowed me to fully enjoy taking responsibility for my Ph.D. project. She has been extremely supportive and helped me flourish an idea to a working prototype in my Ph.D. project. Dr. Albert Yee, my co-supervisor, truly facilitated my understanding of the clinical needs in my project and also provided financial support for me to attend different scientific conferences. I am grateful for the guidance and invaluable comments from my doctoral committee members Dr. Emil Schemitsch and Dr. Emily Seto. In addition, I would like to extend my gratitude to my external examiners Dr. Paul Kuzyk and Dr. James Johnson for their constructive feedback. I also want to thank Mr. Mohammad Kazem and Mr. Michael Pozzobon in the device development laboratory at the Sunnybrook Research Institute. Thank you for teaching me machining and helping me optimize my designs. My words of gratitude also go to my undergraduate supervisor at Ryerson University, Dr. Marcello Papini, who gave me an opportunity to explore the world of biomedical engineering for the first time. I wanted to thank my fantastic team of five engineers during my eighteen-month internship at Celestica, who taught me the fundamentals of industrial design, Mr. Dale Warner, Mr. Warner Wong, Mr. Andrew Smith, and Mr. David Lekx. The internship definitely helped me become a better designer and apply the experience to my Ph.D. project. iv I wanted to thank my lab members at Orthopaedic Biomechanics Lab for their help, support and great memories. My special thanks go to Dr. David Burns, Dr. Ayelet Atkin, Dr. Patrick Henry and Dr. Normand Robert for their help and consultations in my cadaveric testing. Last but not least, I wanted to thank my parents for providing me with an opportunity to study at a world - class University, and supporting me throughout my entire life and being a motivation to conquer new opportunities in my life. I would like to dedicate this thesis to my parents. May this serve as a small thank - you for their sacrifices they made throughout their lives for me. v Contents Acknowledgments.......................................................................................................................... iv List of Tables ...................................................................................................................................x List of Figures ................................................................................................................................ xi Chapter 1: Introduction ...................................................................................................................1 1.1 Anatomy of Femur ...............................................................................................................1 1.2 Proximal Femur ...................................................................................................................1 1.3 Femoral Shaft .......................................................................................................................2 1.4 Distal Femur.........................................................................................................................3 1.5 Femoral Fractures ................................................................................................................4 1.5.1 Fracture Types .........................................................................................................4 1.5.2 Standard of Care for the Treatment of Diaphyseal Femoral Fractures ....................7 1.5.3 IM nailing, External Fixation and Plating..............................................................16 1.6 Methodology ......................................................................................................................17 1.6.1 Introduction ............................................................................................................17 1.6.2 User-centered Design .............................................................................................17 1.6.3 CAD and FEA ........................................................................................................18 1.6.4 Experimental Design ..............................................................................................18 1.6.5 Performance Evaluation .........................................................................................19 1.7 Motivation and Objectives .................................................................................................19 1.8 Thesis Organization ...........................................................................................................20 Chapter 2: Surgical Process Analysis ...........................................................................................21 2.1 Abstract ..............................................................................................................................21 2.2 Introduction ........................................................................................................................22 vi 2.3 Research Design and Methods ...........................................................................................23 2.3.1 Semi-structured interviews ....................................................................................23 2.3.2 Surgical observations .............................................................................................24 2.4 Results ................................................................................................................................24 2.4.1 Semi-structured interviews ....................................................................................24 2.4.2 Surgical observations .............................................................................................26 2.5 Discussion ..........................................................................................................................32 2.5.1 Entry point selection analysis ................................................................................32 2.5.2 Reduction analysis .................................................................................................35 2.5.3 Common challenges and limitations ......................................................................37 2.6 Conclusion .........................................................................................................................37