Zhang Dong-Xiang, Guo Li-Xin
School of Mechanical Engineering and Automation, Northeastern University, Shenyang 110819, China.
School of Mechanical Engineering and Automation, Northeastern University, Shenyang 110819, China.
Clin Biomech (Bristol). 2023 Jan;101:105864. doi: 10.1016/j.clinbiomech.2022.105864. Epub 2022 Dec 16.
The main purpose of this study was to examine the effect of different fixation methods (anterior fixation, self-stabilizing fixation and anterior-posterior fixation) on biomechanical property of vertebral body replacement and fusion.
Three finite element models of cervical vertebral body replacement and fusion were established. The implanted models included artificial vertebral body and fixation system, and the loads imposed on the models included 75 N compression load and 1 Nm moment load.
For anterior-posterior fixation, the cervical load was mainly transmitted by the posterior pedicle screw and rod (more than 50%), and the stress shielding problem was the most significant than the self-stabilizing and anterior fixation. Self-stabilizing fixation was more helpful to the fusion of implant and vertebrae, but the higher risk of vertebral body collapse was worthy of attention if the cervical spine with osteoporosis. The stress of bone was mainly concentrated around the screw hole. The maximum stress (20.03 MPa) was lower than the yield stress of cortical bone and the possibility of fracture around the fixation device of cervical spine was low. The anterior fixation could meet the requirement of vertebral body replacement and fusion, and the addition of posterior pedicle screws and rods might obtain better treatment in cases of severe spine injury or osteoporosis.
The findings of this study may provide guidance on clinical treatments for choosing more appropriate fixation methods for different patients.
本研究的主要目的是探讨不同固定方法（前路固定、自稳定固定和前后路固定）对椎体置换与融合生物力学性能的影响。
建立了三个颈椎椎体置换与融合的有限元模型。植入模型包括人工椎体和固定系统，施加在模型上的载荷包括75N压缩载荷和1Nm弯矩载荷。
对于前后路固定，颈椎载荷主要通过后路椎弓根螺钉和棒传递（超过50%），应力遮挡问题比自稳定固定和前路固定更为显著。自稳定固定对植入物与椎体的融合更有帮助，但对于骨质疏松的颈椎，椎体塌陷风险较高值得关注。骨应力主要集中在螺钉孔周围。最大应力（20.03MPa）低于皮质骨的屈服应力，颈椎固定装置周围骨折的可能性较低。前路固定可满足椎体置换与融合的要求，对于严重脊柱损伤或骨质疏松病例，增加后路椎弓根螺钉和棒可能获得更好的治疗效果。
本研究结果可为临床治疗中针对不同患者选择更合适的固定方法提供指导。
