Influence of Connecting Plate on Construct Stiffness of Spinal Implants and Motion of Adjacent Segments
Resource
JOURNAL OF THE CHINESE INSTITUTE OF ENGINEERS v.26 n.6 pp.809-816
Journal
JOURNAL OF THE CHINESE INSTITUTE OF ENGINEERS
Journal Volume
v.26
Journal Issue
n.6
Pages
809-816
Date Issued
2003
Date
2003
Author(s)
Lin, Son‐Jyh
Chen, Po‐Quang
Wu, Shing‐Sheng
So, Hon
Abstract
An in vitro biomechanical study compared the influence of connecting plates on construct stiffness and motion of adjacent segments. Twelve porcine lumbar spines were destabilized by laminectomy and instrumented at the L3 and L 4 vertebrae by one of three transpedicular screw fixation systems: Cotrel-Dubousset, Diapason, and a newly designed implant (FPI). The current study demonstrated that connecting plates significantly increased the construct compression and flexion stiffness and added resistance to axial rotation. The upper intact disc had greater rotational displacement than the unfixed intact spine, but the lower intact disc had more anterior translational displacement. When the construct was flexed with a I-second period, the upper intact disc (L2/L3) flexed much more than with a 5- second period (P<0.05). This study also showed a significant correlation between flexion stiffness and compensatory rotational displacement at the upper intact disc.
Subjects
spinal implant
cross-linkage
loading rate
adjacent segment
stiffness