Nishida Norihiro, Tripathi Sudharshan, Mumtaz Muzammil, Kelkar Amey, Kumaran Yogesh, Sakai Takashi, Goel Vijay K
Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan.
Engineering Center for Orthopaedic Research Excellence, Departments of Bioengineering and Orthopaedics, University of Toledo, Toledo, Ohio, USA.
World Neurosurg. 2023 Mar;171:e777-e786. doi: 10.1016/j.wneu.2022.12.105. Epub 2022 Dec 27.
This finite element analysis aimed to investigate the effects of surgical procedures for cervical spine injury.
A three-dimensional finite element model of the cervical spine (C2-C7) was created from computed tomography. This model contained vertebrae, intervertebral discs, anterior longitudinal ligament, and posterior ligament complex. To create the cervical spine injury model, posterior ligament complex and anterior longitudinal ligament at C3-C4 were resected and the center of the intervertebral disc was resected. We created posterior-only fixation (PF), anterior-only fixation (AF), and combined anterior-posterior fixation (APF) models. A pure moment with a compressive follower load was applied, and range of motion, annular/nucleus stress, instrument stress, and facet forces were analyzed.
In all motion except for flexion, range of motion of PF, AF, and APF models decreased by 80%-95%, 85%-93%, and 97%-99% compared with the intact model. C3-C4 annulus stress of PF, AF, and APF models decreased by 28%-72%, 96%-100%, and 99%-100% compared with the intact model. Facet contact forces of PF, AF, and APF models decreased by 77%-79%, 97%-99%, and 77%-86% at C3-C4 compared with the intact model. Screw stress in the PF model was higher than in the APF model, and plate stress in the AF model was lower than in the APF model, but bone graft stress in the AF model was higher than in the APF model.
Cervical stabilization was preserved by the APF model. Regarding range of motion, the PF model had an advantage compared with the AF model except for flexion. An understanding of biomechanics provides useful information for the clinician.
本有限元分析旨在研究颈椎损伤手术方法的效果。
根据计算机断层扫描创建颈椎（C2 - C7）的三维有限元模型。该模型包含椎体、椎间盘、前纵韧带和后韧带复合体。为创建颈椎损伤模型，切除C3 - C4的后韧带复合体和前纵韧带，并切除椎间盘中心。我们创建了单纯后路固定（PF）、单纯前路固定（AF）和前后联合固定（APF）模型。施加带有压缩随动载荷的纯力矩，并分析活动度、纤维环/髓核应力、器械应力和小关节力。
在除屈曲外的所有运动中，与完整模型相比，PF、AF和APF模型的活动度分别降低了80% - 95%、85% - 93%和97% - 99%。与完整模型相比，PF、AF和APF模型在C3 - C4处的纤维环应力分别降低了28% - 72%、96% - 100%和99% - 100%。与完整模型相比，PF、AF和APF模型在C3 - C4处的小关节接触力分别降低了77% - 79%、97% - 99%和77% - 86%。PF模型中的螺钉应力高于APF模型，AF模型中的钢板应力低于APF模型，但AF模型中的植骨应力高于APF模型。
APF模型可保持颈椎稳定性。在活动度方面，除屈曲外，PF模型比AF模型具有优势。对生物力学的理解为临床医生提供了有用的信息。
