椎间盘置换联合节段融合治疗多节段颈椎病的有限元法生物力学研究

发布时间：2018-09-13 11:17

【摘要】：背景:多节段颈椎病的术式选择一直存在争议。选择多节段融合术不可避免的造成融合节段活动度的丢失,生物力学已证实其对邻近节段的影响比单节段融合更大。选择多节段人工颈椎间盘置换术理论上是更好的选择。但是人工颈椎间盘置换的手术指针非常严格,多节段颈椎病中的某一节段可能不适合置换。另外,多节段置换手术操作难度增加、时间延长,其可能的并发症还未知。鉴于这种权衡,联合椎间盘置换与节段融合(Hybrid手术)治疗多节段颈椎病既是一个折中的方案,又可能是一个很有希望的手术。目前有少数学者的临床研究报道了Hybrid手术的近期效果至少不差于传统的多节段融合术。详细比较两节段置换、两节段融合、Hybrid手术的生物力学特性的研究还比较缺乏,且结论还不一致;关于Hybrid手术本身因位置组合方式的不同造成生物力学差异的研究还未见报道。有鉴于此,我们设计本课题。目的:一、以有限元法分析两节段置换、两节段融合、Hybrid手术的生物力学特性,比较三种术式在手术节段、邻近节段的生物力学差异,为临床术式选择提供生物力学基础。二、在连续两节段颈椎中通过融合与置换互换位置构建相互对应的两种Hybrid手术,比较相互对应的两种Hybrid手术之间的生物力学差异,进而探讨这种生物力学差异的根源,为临床实施Hybrid手术时选择怎样的置换与融合的位置组合方式提供力学参考。方法:1.C2-T1颈椎有限元模型的建立和验证以健康志愿者薄层CT扫描图像为数据源,利用Mimics 10.1软件、Rapidform 2006软件、Abaqus 6.11软件构建C2-T1有限元模型,进而加载运算。将实验结果与既往文献对比验证。当验证有效后用于后续实验。2.C4-C6两节段置换、两节段融合、Hybrid手术的有限元法生物力学对比分析以Prestige-LP假体模拟置换,以颈椎前路钢板系统加松质骨植骨模拟节段融合。根据实验设计构建C4-C6双节段融合组、C4-C6双节段置换组、C4-C6 Hybrid手术组(C4-C5置换联合C5-C6融合,Hybrid-M1组),以位移控制为加载条件,计算各组模型的整体刚度、节段活动度、椎间盘压力、小关节Von Mises应力。以正常对照组为参照,对比分析各组之间的力学参数。3.连续两节段颈椎中互换位置的hybrid手术的有限元法生物力学对比分析同上述方法构建c3-c4置换联合c4-c5融合的hybrid-s1组、c3-c4融合联合c4-c5置换的hybrid-s2组,c5-c6置换联合c6-c7融合的hybrid-u1组、c5-c6融合联合c6-c7置换的hybrid-u2组。c4-c5融合联合c5-c6置换的hybrid-m2组。以位移控制为加载条件,计算各组模型的整体刚度、节段活动度、椎间盘压力、小关节vonmises应力。以正常对照组为参照,hybrid-s1与hybrid-s2进行力学参数比较,hybrid-u1与hybrid-u2进行力学参数比较,hybrid-m1与hybrid-m2进行力学参数比较。结果:1.c2-t1颈椎有限元模型的建立和验证c2-t1几何模型的成功构建,包括椎体骨性结构,小关节突上覆盖软骨,椎间盘包括髓核和纤维环,纤维环分成纤维环基质和纤维环纤维,韧带包括前纵韧带、后纵韧带、黄韧带、棘间韧带、小关节突关节囊韧带。c2-t1有限元模型节点78631,单元数190608。c2-t1三维有限元模型施加前负荷75n,再施加1.0n*m驱动力矩,得到前屈、后伸、左轴转、右侧弯四种工况的活动度,模型整体活动度分别为35.24°、17.22°、17.14°、14.29°。与既往体外实验数据基本一致。即本有限元模型验证有效。2.c4-c6两节段置换、两节段融合、hybrid手术的有限元法生物力学对比分析双节段置换组整体刚度均低于正常对照组。hybrid手术组除前屈外整体刚度均低于正常对照组。双节段融合组整体刚度均高于正常对照组。以正常对照组为参照,双节段置换组的rom在置换节段均有增加,在邻近节段则降低。双节段融合组的rom在融合节段极度降低,在邻近节段则均有增加。hybrid-m1的rom在置换节段增加、融合节段降低,除前屈外其邻近节段均降低。以正常对照组为参照,双节段置换组的邻近节段idp降低。双节段融合组的邻近节段idp增加。hybrid-m1除前屈外邻近节段idp降低。以正常对照组为参照,双节段置换组的置换节段的小关节vonmises应力仅在后伸和左轴转时增加,其邻近节段均降低。双节段融合组的小关节vonmises应力在融合节段极度降低,其邻近节段则都有增加。hybrid-m1的小关节vonmises应力在置换节段增加,在邻近节段除前屈外均降低。3.连续两节段颈椎中互换位置的hybrid手术的有限元法生物力学对比分析各hybrid手术组在前屈时c2-t1整体刚度均大于正常对照组,而在后伸、左轴转、右侧弯时c2-t1整体刚度均小于正常对照组。(1)c3-c5hybrid手术:屈伸、左轴转、右侧弯时置换节段的ROM增加,C3-C4置换分别增加146.5%、207.9%、172.7%;C4-C5置换分别增加193.0%、251.4%、163.6%。后伸、左轴转、右侧弯时置换节段小关节Von Mises应力增加,C3-C4置换分别增加256.5%、186.9%、185.1%;C4-C5置换分别增加50.1%、54.1%、124.4%。前屈时邻近节段IDP增加,C3-C4置换导致C2-C3增加45.2%,C4-C5置换导致C2-C3增加38.7%。(2)C4-C6 Hybrid手术:在屈伸、左轴转、右侧弯时置换节段的ROM增加,C4-C5置换分别增加146.4%、237.6%、145.0%。;C5-C6置换分别增加93.6%、146.9%、110.8%。C4-C5置换小关节Von Mises应力在后伸、左轴转、右侧弯时分别增加20%、53%、111%;C5-C6置换小关节Von Mises应力在后伸时降低8%,轴转、侧弯时分别增加297%、60%。前屈时邻近节段IDP增加,C4-C5置换导致C3-C4增加2.7%,C5-C6置换导致C3-C4增加2.1%。(3)C5-C7Hybrid手术:在前屈、后伸、左轴转、右侧弯时置换节段的ROM增加,C5-C6置换分别增加116.7%、179.2%、122.3%;C6-C7置换分别增加154.7%、323.6%、229.8%。C5-C6置换节段小关节Von Mises应力在左轴转、右侧弯时分别增加267%、63%;C6-C7置换节段小关节Mises应力在前屈、后伸、左轴转、右侧弯时分别增加202%、155%、204%、145%。前屈时邻近节段IDP增加,C5-C6置换导致C4-C5增加13.9%,C6-C7置换导致C4-C5增加20.1%。结论:1.C2-T1有限元模型成功建立,包含了比较精细的椎体、椎间盘、韧带和小关节等结构。模型经验证有效。2.与正常对照组相比,双节段融合导致整体刚度增加,邻近节段ROM、IDP、小关节Von Mises应力均增加。从生物力学角度看可能导致邻椎病的发生。3.双节段置换组的置换节段ROM、小关节Von Mises应力高于正常对照组,对邻近节段ROM、IDP和小关节Von Mises应力无明显不利影响。从生物力学角度看可以保护邻近节段。4.Hybrid手术组的置换节段ROM、小关节Von Mises应力高于正常对照组,对邻近节段的ROM、小关节Von Mises应力影响小,对邻近节段IDP有一定影响。从生物力学角度看可一定程度保护邻近节段。5.选择生理动度较大的节段予以置换,而相对较小的节段予以融合,这种Hybrid组合形式对颈椎生物力学的影响相对较小。
[Abstract]:BACKGROUND: The choice of surgical procedures for multilevel cervical spondylosis has been controversial. The choice of multilevel fusion inevitably results in loss of fusion motion. Biomechanics has shown that it has a greater impact on adjacent segments than single-level fusion. The choice of multilevel artificial cervical disc replacement is theoretically a better choice. The surgical guidelines for disc replacement are very strict, and one segment of the multilevel cervical spondylosis may not be suitable for replacement. In addition, the complications of multilevel replacement are unknown because of the increased difficulty and prolonged time. Given this trade-off, the combination of disc replacement and segmental fusion (Hybrid) for multilevel cervical spondylosis is is a compromise. A few clinical studies have reported that the short-term effect of Hybrid surgery is at least as good as that of conventional multilevel fusion. In view of this, we have designed this project. Objective: First, to analyze the biomechanical characteristics of two-segment replacement, two-segment fusion and Hybrid operation by finite element method, and to compare the biomechanical differences of the adjacent segments of the three methods. Two consecutive cervical hybrids were constructed by fusion and replacement in two consecutive segments of the cervical spine. The biomechanical differences between the two hybrids were compared, and the causes of the biomechanical differences were discussed. Methods: 1. The finite element model of C2-T1 cervical spine was established and validated by using thin-slice CT scans of healthy volunteers as data source. The C2-T1 finite element model was constructed by using Mimics 10.1 software, Rapidform 2006 software and Abaqus 6.11 software, and then loaded. Two-segment replacement, two-segment fusion, finite element biomechanical comparative analysis of Hybrid surgery with Prestige-LP prosthesis, anterior cervical plate system plus cancellous bone graft to simulate segmental fusion. According to the experimental design, a C4-C6 double-segment fusion group was constructed, C4-C6 double-segment fusion. Segmental replacement group, C4-C6 Hybrid operation group (C4-C5 replacement combined with C5-C6 fusion, Hybrid-M1 group), with displacement control as loading conditions, calculated the overall stiffness, segmental mobility, intervertebral disc pressure, Von Mises stress of facet joints. Contrast analysis of mechanical parameters between the normal control group and the two consecutive segments of the cervical spine. Finite element biomechanical comparative analysis of hybridization with the above method to construct hybrid-s1 group of c_3-c_4 replacement combined with c_4-c_5 fusion, hybrid-s2 group of c_3-c_4 fusion combined with c_4-c_5 replacement, hybrid-u1 group of c_5-c_6 replacement combined with c_6-c_7 fusion, hybrid-u2 group of c_5-c_6 fusion combined with c_6-c_7 replacement, hybrid-c_4-c_5 fusion combined with c_5-c_6 replacement D-m2 group. The stiffness, segmental mobility, intervertebral disc pressure and von Mises stress of facet joints were calculated with displacement control as loading conditions. The mechanical parameters of hybrid-s1 and hybrid-s2 were compared with those of normal control group. The mechanical parameters of hybrid-u1 and hybrid-u2 were compared. The mechanical parameters of hybrid-m1 and hybrid-m2 were compared. C2-t1 cervical finite element model was established and validated the successful construction of c2-t1 geometric model, including vertebral osseous structure, facet process overlying cartilage, intervertebral disc including nucleus pulposus and annulus fibrosus, annulus fibrosus into annulus matrix and annulus fibrous fiber, ligaments including anterior longitudinal ligament, posterior longitudinal ligament, ligamentum flavum, interspinous ligament, facet process joint. C2-t1 finite element model node 78631, the number of elements 190608.c2-t1 three-dimensional finite element model applied preload 75n, and then applied 1.0n*m driving torque, obtained flexion, extension, left axis turn, right bending four working conditions of the activity of the model as a whole is 35.24 degrees, 17.22 degrees, 17.14 degrees, 14.29 degrees. The two-segment replacement, two-segment fusion, hybridization biomechanical comparative analysis of finite element method, hybridization of the two-segment replacement group stiffness were lower than the normal control group. Hybrid surgery group, except for flexion, the overall stiffness was lower than the normal control group. The overall stiffness of the two-segment fusion group was higher than the normal control group. Compared with the normal control group, the ROM of the two-segment replacement group increased in the replacement segment, but decreased in the adjacent segment. The ROM of the two-segment fusion group decreased extremely in the fusion segment, but increased in the adjacent segment. The ROM of hybrid-m1 increased in the replacement segment, decreased in the fusion segment, and decreased in the adjacent segment except flexion in the normal control group. For comparison, the adjacent segment IDP decreased in the two-segment replacement group. The adjacent segment IDP increased in the two-segment fusion group. The adjacent segment IDP decreased in the hybrid-m1 group except for flexion. Vonmises stress in the facet joints of the hybrid-m1 group was increased in the replacement segment, but decreased in the adjacent segment except for flexion. 3. finite element biomechanical analysis of hybridization in the two consecutive cervical vertebrae in the alternating position The overall stiffness of c2-t1 was greater in the forward flexion than in the normal control group, but lower in the backward extension, left-axis rotation and right-lateral bending. (1) C3-C5 hybridbridization: flexion and extension, left-axis rotation, right-lateral bending, replacement segment ROM increased, C3-C4 replacement increased 146.5%, 207.9%, 172.7%, C4-C5 replacement increased 193.0%, 251.4%, 163.6% respectively. Von Mises stress in facet joints was increased by 256.5%, 186.9% and 185.1% for C3-C4 replacement, 50.1%, 54.1% and 124.4% for C4-C5 replacement, respectively. IDP in adjacent segments was increased during flexion, C3-C4 replacement increased by 45.2% for C2-C3, and C4-C5 replacement increased by 38.7% for C2-C3 during flexion-extension, left-axis rotation and right-axis rotation. The ROM of the replacement segment increased by 146.4%, 237.6% and 145.0% respectively, while that of the replacement segment increased by 93.6%, 146.9% and 110.8% respectively. C3-C4 increased by 2.7% after C4-C5 replacement, and C3-C4 increased by 2.1% after C5-C6 replacement. (3) C5-C7 Hybrid surgery: ROM increased during flexion, extension, left-axis rotation, and right-lateral bending, and C5-C6 replacement increased by 116.7%, 179.2%, 122.3% respectively; C6-C6 replacement increased by 154.7%, 323.6%, 229.8% respectively. The von Mises stress increased by 267% and 63% respectively in the left and right bends, while the Mises stress increased by 202%, 155%, 204% and 145% in the flexion, extension, left and right bends, respectively. The IDP of adjacent segments increased by 13.9% and C4-C5 increased by 20.1% in the C6-C7 displacement and C4-C5 increased by 20.1% in the C6-C7 displacement. The model proved to be effective. 2. Compared with the normal control group, bi-segmental fusion resulted in increased global stiffness, increased adjacent ROM, IDP, and Von Mises stresses in facet joints. Biomechanically, it may lead to the occurrence of adjacent vertebral diseases. 3. Bi-segmental placement. The von Mises stress of replacement segment and facet joint in the replacement group was higher than that in the normal control group, but there was no significant adverse effect on adjacent segment ROM, IDP and Von Mises stress of facet joint. From the biomechanical point of view, the adjacent segment can be protected to a certain extent. 5. Choose the segment with greater physiological mobility to be replaced, and the segment with smaller fusion. This Hybrid combination has a relatively small impact on cervical biomechanics.
【学位授予单位】：第三军医大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：R687.3

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