FEA simulation of hip fracture treated with rod-screw fixation and design of robotic surgery

• Κύριος συγγραφέας: Μπέκας, Ανδρέας
• Άλλοι συγγραφείς: Bekas, Andreas
• Γλώσσα: English
• Έκδοση: 2022
• Θέματα: Computer-assisted surgery; Dynamic hip screw; Ansys mechanical; Finite element analysis; Manipulators; Simulink; Force-motion hybrid control; Kuka IIWA; Χειρουργική ρομποτική; Μέθοδος πεπερασμένων στοιχείων; Ρομποτικοί βραχίονες; Υβριδικός έλεγχος θέσης-δύναμης

It is an indisputable fact that surgical operations have evolved over the last years, though hip fracture rehabilitation is not always successful; many individuals experience pain, disability, and reduced quality of life afterward[1]. So, continuous emphasis should be placed on optimizing the surgical procedure and minimizing the risk of complications. Furthermore, Computer-Assisted Surgery (CAS) is an evolving method of integrating robotic technologies in the operating room, improving the operation's accuracy and efficiency[2]. So, this thesis is oriented towards evaluating a new way of Dynamic Hip Screw (DHS) insertion through the Ansys Finite Element Analysis (FEA) Software and then designing a manipulator’s control system for its prosecution. Rotation of femoral head fracture during the operation of DHS insertion due to screw’s frictional forces is a subject of interest for surgeons because it leads to fault attachment of the two fragments. In the first part of this thesis, a new approach to surgical operation was proposed and studied through Ansys FEA software. Compared with the conventional way, this method's distinguishing feature is applying a traction force to the screw before its rotation, which causes the bone fractures to come in contact and develop frictional forces. Finally, the method’s validity is evaluated based on the Ansys results, namely the sliding distance between the two fragments and the internal stresses of the bone. The next step was to simulate the surgical operation utilizing a KUKA IIWA manipulator imported into Simulink, a block diagram environment software. The controller’s development was based on kinematic and dynamic principles. Upon completion of the screw’s finite element analysis, obtained values of forces and velocities, along with the screw’s reaction forces during tightening, were used for a more realistic simulation of Kuka’s operation. Finally, the applied joints' torque and end-effector's position and forces were assessed, confirming the system's validity, and highlighting its future perspectives to be integrated into an actual surgery room.