Design and Analysis of a Compliant Mechanism Spinal Implant

• Main Author: Stratton, Eric M.
• Format: Others
• Published: BYU ScholarsArchive 2010
• Subjects: FlexSuRe; spine; implant; virtual work; compliant; Mechanical Engineering
• Online Access: https://scholarsarchive.byu.edu/etd/2441; https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=3440&context=etd

This thesis introduces and presents the modeling of a novel compliant spinal implant designed to reduce back pain and restore function to degenerate spinal disc tissues as well as provide a mechanical environment conducive to healing the tissues. The initial objectives for this device development and the focus of this work are modeling and validation of the force-deflection relationships and stress analysis. Modeling was done using the pseudo-rigid-body model to create a 3 degree of freedom mechanism for flexion-extension (forward-backward bending) and a 5 degree of freedom mechanism for lateral bending (side-to-side). These models were analyzed using the principle of virtual work to obtain the force-deflection response of the device. The model showed good correlation to finite element analysis and experimental results. Also, described in this thesis is a model that incorporates an estimate of the combined stiffness of the biologic structures. This combined model is confirmed by cadaveric testing. A stress analysis of the implant for combined loading conditions is also presented. This work introduces and provides a foundation for the FlexSuRe™ spinal implant.