Numerical Size Optimization of Cervical Spine Disc Prosthesis Mobi-C Using Design of Experiment Technics

The cervical spine is a structure subject to various vertebral injuries, namely, herniation of intervertebral discs and osteoporosis. Nowadays, several segments of society are vulnerable to these diseases that affect spine motion especially elderly people and women. Hence, various designs of cervical artificial discs are in use or under investigation claiming to restore the normal kinematics of the cervical spine. In this work, it is proposed to minimize the stress level by numerical size optimization in the Mobi-C cervical spine prosthesis to improve their biomechanical performances. For this aim, design of experiment (DoE) is employed as an optimization technique to investigate three geometrical parameters of the prosthesis design. Accordingly, DoE optimization allowed to minimize the equivalent stress value on Mobi-C from 20.3 MPa to 17.856 MPa corresponding to a percentage decrease of 12% from the original geometry. This provides an advantage for the durability of the prosthesis and also for the bone by reducing stress concentration.