Zhao Liujun, Chen Jianqing, Liu Jiayong, Elsamaloty Lina, Liu Xiaochen, Li Jie, Elgafy Hossein, Zhang Jihui, Wang Leining
Ningbo No.6 Hospital, 1059#, Zhongshan Dong Road, Ningbo City, Zhejiang Province, PR China.
Jinhua people's Hospital, 228#, Xinhua Road, Jinhua City, Zhejiang Province, PR China.
Clin Biomech (Bristol). 2018 Dec;60:76-82. doi: 10.1016/j.clinbiomech.2018.09.008. Epub 2018 Oct 11.
Anterior cervical trans-pedicle screw fixation was introduced to overcome some of the disadvantages associated with anterior cervical corpectomy and fusion. In vitro biomechanical studies on the trans-pedicle screw fixation have shown excellent pull-out strength and favorable stability. Comprehensive biomechanical performance studies on the trans-pedicle screw fixation, however, are lacking.
The control computed tomography images (C2-T2) were obtained from a 22-year-old male volunteer. A three dimensional computational model of lower cervical spine (C3-T1) was developed using computed tomography scans from a 22 year old human subject. The models of intact C3-T1 (intact group), anterior cervical trans-pedicle screw fixation (trans-pedicle group), and anterior cervical corpectomy and fusion (traditional group) were analyzed with using a finite element software. A moment of 1 N·m and a compressive load of 73.6 N were loaded on the upper surface and upper facet joint surfaces of C3. Under six conditions, four parameters such as the range of motion, titanium mesh plant stress, end-plate stress, and bone-screw stress were measured and compared on two treatment groups.
Compared with the intact model, the range of motions for treatment groups were decreased. Compared with cervical corpectomy and fusion, the titanium plant, C4 upper end-plate and C7 lower end-plate stresses in trans-pedicle group were reduced. No significant difference was discovered on bone-screw stress between the two groups for lateral flexion and rotation, but bone-screw stress is smaller in trans-pedicle group when compared with traditional group. With exception of individual difference, trans-pedicle group had better biomechanical results than traditional group in range of motions, titanium mesh plant stress, end-plate stress and bone-screw stress.
The trans-pedicle method has better biomechanical properties than the anterior cervical corpectomy and fusion making it a viable alternative for cervical fixations.
颈椎经椎弓根螺钉固定术被引入以克服与颈椎椎体次全切除融合术相关的一些缺点。经椎弓根螺钉固定术的体外生物力学研究显示出优异的拔出强度和良好的稳定性。然而，关于经椎弓根螺钉固定术的综合生物力学性能研究尚缺乏。
从一名22岁男性志愿者获取对照计算机断层扫描图像（C2 - T2）。利用一名22岁人类受试者的计算机断层扫描构建下颈椎（C3 - T1）的三维计算模型。使用有限元软件分析完整C3 - T1模型（完整组）、颈椎经椎弓根螺钉固定模型（经椎弓根组）和颈椎椎体次全切除融合模型（传统组）。在C3的上表面和上关节突关节面施加1 N·m的力矩和73.6 N的压缩载荷。在六种条件下，测量并比较两个治疗组的四个参数，如活动度、钛网植入物应力、终板应力和骨 - 螺钉应力。
与完整模型相比，治疗组的活动度降低。与颈椎椎体次全切除融合术相比，经椎弓根组的钛网植入物、C4上终板和C7下终板应力降低。两组在侧屈和旋转时骨 - 螺钉应力无显著差异，但与传统组相比，经椎弓根组的骨 - 螺钉应力较小。除个体差异外，经椎弓根组在活动度、钛网植入物应力、终板应力和骨 - 螺钉应力方面的生物力学结果优于传统组。
经椎弓根方法比颈椎椎体次全切除融合术具有更好的生物力学性能，使其成为颈椎固定的一种可行替代方法。
