Abstract:
"Analysis of Compression Behavior on Intervertebral Disc L4-5 in Pedicle Screw System Instrumented Lumbar Spine Under Follower Load"
This biomechanical study investigates the compression behavior of the L4-5 intervertebral disc in a lumbar spine instrumented with a pedicle screw system, using a finite element analysis (FEA) model. The research simulates the mechanical response of the implanted spine under a "follower load," which mimics the physiological loading conditions of the human body more accurately than simple compressive loads. The main objective is to analyze the effects of instrumentation on the nucleus pulposus pressure (NPP), the flexibility of the spinal segment, and the von Mises stress distribution in both the pedicle screws and the intervertebral disc itself. The study's findings indicate that the pedicle screw system significantly reduces the flexibility of the L4-5 spinal segment, thereby altering the natural biomechanics. Furthermore, the analysis reveals that the presence of the pedicle screws leads to a decrease in the NPP, suggesting that the load is being shared and redistributed through the instrumentation. The pedicle screws also showed a concentration of von Mises stress, particularly at the screw-bone interface, which is a critical area for potential implant failure. The detailed biomechanical insights from this FEA model provide a better understanding of the mechanical environment of an instrumented lumbar spine, which is crucial for improving surgical techniques and implant design.
