颈椎后路单开门椎管扩大成形术联合侧块螺钉固定稳定性的有限元分析

A finite element analysis of the stability of posterior open door extended laminoplasty in cervical spine combined with lateral mass screw fixation

中文关键词:  单开门椎管扩大成形术  侧块螺钉  有限元分析

英文关键词:Open door extended laminoplasty  Lateral mass screw  Finite element analysis

中文摘要:

  【摘要】 目的：应用有限元技术建立颈椎多节段椎管狭窄伴不稳模型，分析并比较后路单开门椎管扩大成形术联合单侧或双侧侧块螺钉固定时的稳定性区别。方法：基于宁波市第六医院2023年1月就诊的1例成年男性志愿者颈椎CT扫描数据，构建C0~T1带肌肉的颈椎有限元模型。该模型在屈伸、侧屈及旋转方向活动度（range of motion，ROM）与以往文献结果相近，应力分布合理，有较高可信度。在完整模型基础上通过有限元技术，分别生成颈椎多节段椎管狭窄及多节段椎管狭窄伴不稳的有限元模型。将上述两个模型左侧作为开门侧，删除全层椎板，并采用钛板固定，右侧为门轴侧做V形槽，分别建立多节段椎管狭窄开门模型（经典开门组）和多节段椎管狭窄伴不稳的开门模型（不稳开门组）。在不稳开门组基础上，于C3~C7节段置入单侧或双侧侧块螺钉，分别生成单侧侧块螺钉固定模型（单侧螺钉组）和双侧侧块螺钉固定模型（双侧螺钉组），计算各组模型在屈伸、侧屈和旋转方向的ROM及应力分布情况。采用独立样本F检验对比各组的ROM，两组间比较采用SNK q检验。结果：单侧螺钉组和双侧螺钉组在C3~C7节段各运动方向ROM均低于不稳开门组（P＜0.05），双侧螺钉组在C3~C7节段屈伸和侧屈方向ROM低于单侧螺钉组（P＜0.05）。单侧螺钉组中螺钉的应力峰值在左侧屈和左旋转方向较大，分别为402.9MPa和450.2MPa；双侧螺钉组中螺钉在前屈和后伸方向的应力峰值明显高于其余方向，分别为409.8MPa和651.0MPa。结论：与单纯行单开门椎管扩大成形术相比，联合单侧侧块螺钉固定或双侧侧块螺钉固定均显示出良好的力学稳定性。

英文摘要:

  【Abstract】 Objectives: To construct a multi-segment cervical spinal stenosis with instability model through finite element technology, and to analyze and compare the stability difference of posterior open door laminoplasty combined with unilateral or bilateral lateral mass screw fixations. Methods: A C0-T1 muscular finite element model of the cervical spine was constructed based on the cervical computed tomography(CT) data of an adult healthy male volunteer who visited Ningbo No.6 Hospital in January 2023. The model′s range of motion(ROM) in flexion and extension, lateral bending, and rotation aligned closely with the ROM results reported in relevant literature, showing reasonable stress distribution and high reliability. And based on the complete model, models of cervical multi-segment spinal stenosis and multi-segment spinal stenosis combined with instability were generated using finite element technology. After setting the left side of the two models as the door opening side, removing the full layer of vertebral lamina and fixing with titanium plate, and making a V-shaped groove on the right side as the door axis, an open-door model of multi-segment spinal stenosis (classical open-door group) and an open-door model of multi-segment spinal stenosis combined with instability (unstable open-door group) were established, respectively. On the basis of model of unstable open-door group, unilateral or bilateral lateral mass screws were implanted in C3-C7 segments, generating a unilateral lateral mass screw fixation model(unilateral screw group) and a bilateral lateral mass screw fixation model(bilateral screw group). The ROM and stress distribution in flexion extension, lateral bending, and rotation directions of each group of models were calculated. The ROM results of the unstable open-door group, unilateral screw group, and bilateral screw group were tested using independent sample F, and comparison between groups was made with SNK′s q test. Results: The ROMs in all motion directions of the C3-C7 segment in unilateral screw group and bilateral screw group were smaller than unstable open-door group (P<0.05); The ROMs in flexion, extension, and lateral bending directions at the C3-C7 segments in the bilateral screw group was also smaller than those in the unilateral screw group(P<0.05). The peak stress of the screws in the unilateral screw group was relatively high in the left bending and left rotation directions, with values of 402.9MPa and 450.2MPa, respectively; In the bilateral screw group, the stress peaks of the screw in flexion and extension directions were significantly higher than those in the other directions, at 409.8MPa and 651MPa, respectively. Conclusions: Compared to the open door extended laminoplasty, both unilateral lateral mass screw fixation and bilateral lateral mass screw fixation demonstrate good mechanical stability.