三种骶髂螺钉多模式固定骶骨骨折的离体与计算生物力学研究

The sacroiliac screw technique has nearly become the gold standard for treatment of posterior pelvic ring injury. However, in the management of vertical sacral fractures (Tile C) whose stability is the poorest in posterior pelvic ring injuries, conventional sacroiliac screws' fixation failure rate is higher. Our previous study (Injury, 2012; 43: 490-494.) has shown that different sacroiliac screws and their respective combinations result in different fixation effects. Based on our research findings, we intends to found the pelvic specimens and finite element models of various subtypes of Tile C sacral fractures and find out the fractures' pathological mechanical characteristics of three dimensional stability by using the method of combination of in vitro biomechanical investigation and finite-element analysis. Then based on our radiological anatomy study on lengthened sacroiliac screw fixation (Eur Spine J, 2012; 21:1807-1814.) , we design a variety of fixation models of lengthened sacroiliac screws, longer sacroiliac screws, conventional sacroiliac screws and their respective combinations. Furthermore, we appraise the effectiveness and safety of the three kinds of sacroiliac screws' multi-mode fixations via comparison and analysis of the stress of multiple sites (such as screws and interfaces between screws and bones) and the three dimensional stability and stress distribution of the complex of pelvis and screw, which will help to provide biomechanical support and specific fixation modes for realizing optimization of the fixation effects and to provide biomechanical foundation for maximizing three kinds of sacroiliac screws' respective advantages and for treating this kind of injury securely, minimally invasively, standardly, and individually.

骶髂螺钉技术几近成为治疗骨盆后环损伤的金标准，然而对于该类损伤中稳定性最差的Tile C型骶骨骨折，常规骶髂螺钉固定仍存在较高的失效率。我们的前期研究(Injury,2012;43:490-494.)显示，不同的骶髂螺钉及其各自组合的固定方式的固定效果各不相同。基于此，本研究拟运用离体和计算生物力学相结合的方法，建立Tile C型骶骨骨折各亚型的离体和三维有限元模型，探明骨折三维稳定性的病理力学特征，然后基于我们针对加长骶髂螺钉固定的放射解剖学研究(Eur Spine J,2012;21:1807-1814.)，设计加长骶髂螺钉、长骶髂螺钉、普通骶髂螺钉及其各自组合的多种固定模式，通过对骨盆-螺钉复合体的三维稳定性、应力分布、螺钉及钉-骨交界面等多部位的应力等指标进行比较分析，对三种骶髂螺钉多模式固定的有效性、安全性进行评估，为实现固定效果的最优化提供生物力学支持及具体固定模式的技术参考。

骶髂螺钉几近成为骨盆后环微创内固定的金标准，但并不总能达到稳定性固定。不同长度的骶髂螺钉及其各自组合的安全性和力学特征各不相同，具有各自利弊。为了在尽量规避螺钉置入风险的同时将三种骶髂螺钉的固定效果最大化，我们进行了以下研究。本项目使用CT测量的方法，对骶1、骶2加长骶髂螺钉置入的骨性安全区进行了应用解剖学研究，确定了水平方向骶髂螺钉的安全范围及其特征；然后使用CTA测量的方法，分别对骶1、骶2水平方向骶髂螺钉进钉点与毗邻血管结构的关系进行了应用解剖学测量和总结，为水平方向骶髂螺钉在骶1、骶2两个层面的进钉提供了毗邻血管结构的应用解剖学资料；在前述研究所得结论的基础上，本项目使用离体生物力学和计算生物力学相结合的方法，对三种不同长度骶髂螺钉固定各型Tile C型骶骨骨折进行横向和纵向的生物力学比较研究，为骶1、骶2不同长度骶髂螺钉固定的有效性、安全性进行了详细的生物力学评估，并为实现三种骶髂螺钉固定效果的最优化，提供了具体的生物力学技术支持，并做出了骶1、骶2单双层面多种固定模式的优劣排序。上述研究为安全、快速、有效、微创、规范化、个体化地治疗骨盆后环稳定性最差的Tile C型骶骨骨折探索出了一条新路。