Comparison of the biomechanical performance of three spinal implants for treating the wedge-shaped burst fractures

Abstract

Spinal fracture is a serious problem impairing life quality, associating with low back pain and many other chronic diseases. Among all the spinal fractures, the rate of thoracolumbar fractures is the highest and accounts for approximately 90%. Although surgical treatment is an effective approach, it is still unclear which treatment method performs the best. The aim of the present study was to investigate the biomechanical performance of three spinal implants for treating the thoracolumbar wedge-shaped burst fractures using the finite element (FE) method. FE model of the T12/L1/L2 spinal segment was created from CT images and the thoracolumbar wedge-shaped burst fractures were created by removing some elements in the anterior part of L1. The FE models of the traditional system, the universal spine system (USS) and the cortical bone trajectory (CBT) system were created and their biomechanical performances were evaluated. The results revealed that among the three fixation systems, the highest von-Mises stress occurred in the CBT system. Under all the loading scenarios except for the lateral bending, the maximal von-Mises stress was higher when the USS system rather than the traditional system was applied. The average displacement around the fracture site was the highest in the CBT system. Except for the lateral bending, the average displacement around the fracture site was higher when the USS system rather than the traditional system was applied. For all the fixation approaches, the highest von-Mises stress always occurred at the screw junctions. The present study provided important data for the treatment of thoracolumbar wedge-shaped burst fractures. For example, the traditional spinal system is preferentially selected for the thoracolumbar wedge-shaped burst fracture of L1.

Keywords

• Spinal fracture
• Fixation implant
• Finite element
• Biomechanical performance
• Stress analysis