Analysis of Influence Location of Intervertebral Implant on the Lower Cervical Spine Loading and Stability

摘要

Because nerve/spinal cord impingement (decompression surgery) and spinal instability (fusion surgery) of the cervical spine are worldwide problems, biomechanics research is very important for developing new treatment methods. Spinal instrumentation (such as a small plate, artificial intervertebral replacement or fusion) can also be used to help increase stability to the spine column. A disadvantage of the fusion is a decrease of mobility in dependence on the increasing of adjacent vertebrae and discs loads. The aim of presented study was an analysis of influence location of intervertebral implant on the lower cervical spine loading and stability. A three-dimensional finite element (FE) model of the multi-level cervical spine C3-C6 has been developed using computed tomography (CT) data, and applied to determination of movement of the implanted mobile artificial discs prosthesis on the biomechanical behavior of the lower cervical spine in this directions (flexion-extension, axial rotation, and lateral bending moments). Models accuracy was validated by comparing with previously published experimental and numerical results for flexion-extension, axial rotation, and lateral bending moments. The influence of the various surgical techniques on the cervical spine stiffness was compared at the same time. The intact spinal segment and the implanted spine was compared using artificial disc replacement Prodisc-C made by Synthes. The different types of artificial disc are going to be compare between each other. The technology of discs share similar goals of replacing the original disc, but differ in their designs and materials. By the definition of the optimal position range of replacements investigated (neutral zone of spine) would be minimized overloading of the soft tissue components (ligaments, adjacent discs) and instability of the spine as well. The output data was used for effective treatment of the patients. The results achieved have a large medical gain in neurology and spine surgery.