Department of Orthopedics surgery, Ningbo Medical Center Li Huili Hospital, Affiliated to Ningbo University, Ningbo 315040, Zhejiang, China.
Department of Orthopedics, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, Zhejiang, China.
Medicine (Baltimore). 2022 Jul 22;101(29):e29316. doi: 10.1097/MD.0000000000029316.
Multilevel cervical corpectomy has raised the concern among surgeons that reconstruction with the anterior cervical screw plate system (ACSPS) alone may fail eventually. As an alternative, the anterior cervical transpedicular screw (ACTPS) has been adopted in clinical practice. We used the finite element analysis to investigate whether ACTPS is a more reasonable choice, in comparison with ACSPS, after a 2-level corpectomy in the subaxial cervical spine. These 2 types of implantation models with the applied 75 N axial pressure and 1 N • m pure moment of the couple were evaluated. Compared with the intact model, the range of motion (ROM) at the operative segments (C4-C7) decreased by 97.5% in flexion-extension, 91.3% in axial rotation, and 99.3% in lateral bending in the ACTPS model, whereas it decreased by 95.1%, 73.4%, 96.9% in the ACSPS model respectively. The ROM at the adjacent segment (C3/4) in the ACTPS model decreased in all motions, while that of the ACSPS model increased in axial rotation and flexion-extension compared with the intact model. Compared to the ACSPS model, whose stress concentrated on the interface between the screws and the titanium plate, the stress of the ACTPS model was well-distributed. There was also a significant difference between the maximum stress value of the 2 models. ACTPS and ACSPS are biomechanically favorable. The stability in reducing ROM of ACTPS may be better and the risk of failure for internal fixator is relatively low compared with ACSPS fixation except for under lateral bending in reconstruction the stability of the subaxial cervical spine after 2-level corpectomy.
多节段颈椎椎体切除术引起了外科医生的关注，即单独使用前路颈椎螺钉板系统（ACSPS）重建最终可能会失败。作为替代方法，临床实践中采用了前路颈椎经椎弓根螺钉（ACTPS）。我们使用有限元分析来研究在亚下颈椎 2 节段椎体切除术后，与 ACSPS 相比，ACTPS 是否是更合理的选择。评估了这两种植入模型，施加了 75N 的轴向压力和 1N·m 的纯扭矩偶。与完整模型相比，ACTPS 模型中手术节段（C4-C7）的活动度（ROM）在前屈-后伸方向减少了 97.5%，在轴向旋转方向减少了 91.3%，在侧屈方向减少了 99.3%；而在 ACSPS 模型中，ROM 在前屈-后伸方向减少了 95.1%，在轴向旋转方向减少了 73.4%，在侧屈方向减少了 96.9%。在 ACTPS 模型中，相邻节段（C3/4）的 ROM 在所有运动中均减小，而在 ACSPS 模型中，ROM 在轴向旋转和前屈-后伸方向上与完整模型相比增加。与 ACSPS 模型相比，ACTPS 模型的应力分布更均匀，其应力集中在螺钉和钛板之间的界面上。两种模型的最大应力值也存在显著差异。ACTPS 和 ACSPS 在生物力学上都有优势。与 ACSPS 固定相比，ACTPS 可能在减少 ROM 方面具有更好的稳定性，并且内固定器失效的风险相对较低，除了在重建下颈椎后路 2 节段椎体切除术后的稳定性时，在侧屈方向。
