Guo Zhiyuan, Liu Guangfei, Wang Lu, Zhao Yuejiang, Zhao Ye, Lu Shouliang, Cheng Cai
Department of Orthopedics, Cangzhou Central Hospital Cangzhou, Hebei, China.
Am J Transl Res. 2022 Jul 15;14(7):5155-5163. eCollection 2022.
To explore the biomechanical differences between Coflex and X-STOP devices by finite element analysis.
Based on the normal lumbar CT images from a healthy adult volunteer, four finite element models including the healthy lumbar segment model, the mild degenerated lumbar segment model, a Coflex fixed lumbar segment model and X-STOP fixed lumbar segment model were constructed. A simulation analysis under the conditions of flexion, extension, lateral bending, and rotation was performed to compare range of motion (ROM), intradiscal pressure, the facet joint force, the maximum Von Mises stress and the peak facet contact forces, between Coflex and X-STOP devices.
Compared to the mild degenerated lumbar segment model at surgical level L4-L5, Coflex and X-STOP could reduce ROM in extension by 98.34% and 95.86%, respectively, decrease peak stress of intervertebral discs in extension by 59.4% and 66.17%, respectively, and release peak force of facet joint in extension by 97.09% and 95.42%, respectively. Both devices had no significant impact on adjacent levels. The maximum Von Mises stress in Coflex device was 637.56 Mpa in flexion, 528.86 Mpa in extension, while the maximum Von Mises stress in X-STOP device was 476.65 Mpa at extension position. The peak facet contact forces of Coflex and X-STOP devices appeared in extension and were 19.76 Mpa and 49.28 Mpa, respectively.
Coflex and X-STOP devices can effectively decrease the ROM and intradiscal pressure in extension, without affecting the adjacent levels.
通过有限元分析探讨Coflex和X-STOP装置之间的生物力学差异。
基于一名健康成年志愿者的正常腰椎CT图像，构建了四个有限元模型，包括健康腰椎节段模型、轻度退变腰椎节段模型、Coflex固定腰椎节段模型和X-STOP固定腰椎节段模型。进行了前屈、后伸、侧屈和旋转条件下的模拟分析，以比较Coflex和X-STOP装置之间的活动范围（ROM）、椎间盘内压力、小关节力、最大冯·米塞斯应力和小关节峰值接触力。
与手术节段L4-L5的轻度退变腰椎节段模型相比，Coflex和X-STOP分别可使后伸时的ROM降低98.34%和95.86%，后伸时椎间盘的峰值应力分别降低59.4%和66.17%，后伸时小关节的峰值力分别释放97.09%和95.42%。两种装置对相邻节段均无显著影响。Coflex装置在前屈时的最大冯·米塞斯应力为637.56 Mpa，后伸时为528.86 Mpa，而X-STOP装置在后伸位置的最大冯·米塞斯应力为476.65 Mpa。Coflex和X-STOP装置的小关节峰值接触力出现在后伸时，分别为19.76 Mpa和49.28 Mpa。
Coflex和X-STOP装置可有效降低后伸时的ROM和椎间盘内压力，且不影响相邻节段。
