横连接在经骨折椎骨置椎弓根钉固定治疗胸腰椎爆裂骨折中作用的有限元分析

The Role of Cross-Link in the Treatment of Thoracolumbar Burst Fractures with Pedicle Screw Fixation at Fracture Vertebrae—A Finite Element Analysis

摘要: 目的：研究横连在经骨折椎体置椎弓根钉固定治疗胸腰椎爆裂骨折中的作用，研究最佳的横连的放置方式。方法：运用有限元分析，构建健康志愿者胸腰椎脊柱模型，运用截骨术创建胸腰椎爆裂骨折模型，给予经骨折椎体椎弓根钉固定，构建经棘突放置横连内固定、切除棘突放置横连内固定和无横连的内固定方式，以及术后去除内固定后三种脊柱模型，通过模拟日常的活动，测量6种模型的位移和活动度、椎弓根钉和纵棒的等效应力，运用两独立样本t检验比较三种内固定之间的位移和活动度的差异，评价横连对内固定稳定性和安全性的作用。结果：经棘突放置横连内固定的位移和活动度最小，切除棘突放置横连内固定的次之，无横连内固定最大。经棘突放置横连内固定较无横连内固定在不同运动中的位移和活动度有20%~30%的减低，切除棘突放置横连较无横连在不同运动中的位移和活动度有10%~20%的减低，经棘突放置横连后较无横连内固定降低了骨折临近椎体椎弓根钉的等效应力，增加了横连的应力。切除棘突脊柱在前屈和后伸的位移和活动度大于完整棘突脊柱。结论：经棘突放置横连具有更高的稳定性和安全性，应该在经骨折椎体置椎弓根钉治疗胸腰椎爆裂骨折中使用。

Abstract: Objective: To study the role of cross-link in the treatment of thoracolumbar burst fractures (TLBF) with pedicle screw fixation at fracture vertebrae (PFFV), and to study the optimal placement of cross-link. Methods: The thoracolumbar model of healthy volunteers was constructed by finite element analysis (FEA), and the TLBF model was established by osteotomy. The internal fixation methods of Through spinous process cross-link (ESPC), Excision spinous process cross-link (TSPC), and No cross-link (NC) were constructed, and three spinal models after internal fixation were removed after recovery also established. The displacement and range of motion (ROM) and the equivalent stress of pedicle screw and connecting rod were measured by simulating daily motions. Two independent sample t-test was used to compare the difference in displacement and ROM. Results: The displacement and ROM of TSPC were the smallest, followed by ESPC, and NC was the largest. The displacement and ROM of TSPC were 20%~30% lower than NC in different motions, and those of ESPC were 10%~20% lower than NC in different motions. ESPC reduced the equivalent stress of pedicle screw of the vertebrae adjacent to the fracture vertebrae and increased the stress of connecting rod. After internal fixation was removed, the displacement and ROM of the excision spinous process spine in flexion and extension were greater than those of the intact spine. Conclusion: Internal fixation with TSPC had higher stability and safety, and should be used in the treatment of TLBF with pedicle screw fixed at fracture vertebrae.