一体化C1椎板钩在寰枢椎融合术中应用的生物力学研究

发布时间：2018-07-06 13:41

本文选题：寰枢椎 + 一体化C1椎板钩　；参考：《第二军医大学》2015年博士论文

【摘要】：背景位于枕颈移行部的寰枢椎,解剖结构特殊,毗邻颈脊髓、椎动脉等重要结构,且承担了头颈部主要的旋转功能。肿瘤、畸形、炎症、退变疾病侵犯此区域可能导致寰枢椎不稳,寰枢椎不稳的处理是临床上比较棘手的问题之一,严重的寰枢椎不稳可以导致颈脊髓、神经根、血管等重要结构受压,引起一系列症状,甚至导致瘫痪或生命危险,需要手术干预。寰枢椎后路固定融合是解决寰枢椎不稳的主要手术方式。寰枢椎后路固定融合经历了钢丝固定(Gallie法、Brooks法等)、后路椎板钩(夹)固定(Halifax、Apofix)、C1-2经关节螺钉固定(Transarticular screw,TA)、后路C1-C2短节段钉棒系统固定等,目前主要采用C1-2经关节螺钉或C1-C2短节段钉棒系统固定,既往生物力学及临床研究证实此类固定技术能显著增强寰枢椎稳定性,提高植骨融合率。双侧C1-2经关节螺钉固定为二点固定,在控制屈伸方面仍有缺陷,联合后路钢丝固定植骨融合则达到三点固定,在控制寰枢椎所有方向运动方面均有很好的效果,被公认为目前寰枢椎固定的金标准,但C1椎板下穿钢丝有损伤脊髓的风险。我的导师倪斌教授在研究寰枢椎解剖基础上设计了C1椎板钩(专利号:200720075767.6),并联合C1-2经关节螺钉固定卡压植骨,该术式避免了C1椎板下穿钢丝带来的脊髓损伤的风险,操作简单,且双侧椎板钩有稳固植骨块的作用,生物力学研究证实其生物力学稳定性与双侧C1-2经关节螺钉联合后路钢丝固定植骨融合相当,临床应用证实可以很好地促进寰枢椎植骨融合,取得了满意的结果。然而,此C1椎板钩仍然存在安装过程中与C1-2经关节螺钉或C2椎弓根螺钉连接困难,装配繁琐等问题,我们依据寰枢椎解剖特点再次进行改良,设计了一体化C1椎板钩,将C1椎板钩与棒采用一体化设计,减少了手术中装配环节,也避免了钩与棒连接处松动、脱出的风险;钩与C1后弓接触处设计了突出的脊,减少了钩在C1后弓上滑动,并且根据寰枢椎解剖学特点在C1椎板钩与棒连接处采用向外侧倾斜15度设计以及棒的可折弯性能使得一体化C1椎板钩与C1-2经关节螺钉或C2椎弓根螺钉可以很好地匹配连接,使得手术更方便,更简单,更可靠,更安全。本课题选择尸体上颈椎标本,利用离体生物力学方法,研究一体化C1椎板钩联合C1-2经关节螺钉或C2椎弓根螺钉内固定卡压植骨的生物力学稳定性,为一体化C1椎板钩的临床应用提供理论指导。脊柱有着复杂的结构,离体生物力学研究在脊柱生物力学研究中起到重要作用,但尸体标本不好保存,获得比较困难,而且由于每个个体的差异导致不同的标本由于自身生物力学差异而对实验结果的准确性有很大影响。随着计算机技术的发展及有限元研究方法的进步,目前三维有限元不但可以模拟脊柱骨性结构,而且可以很好地模拟脊柱周围韧带等结构,不但可以模拟完整的脊柱模型,还可以模拟退变、创伤等脊柱模型进行生物力学研究,并可在脊柱模型上加载各种内固定,对内固定生物力学特点进行评估,为内固定的设计提供帮助。三维有限元方法对于脊柱结构、载荷条件等都可以进行数学形式模拟,通过任意变化参数从而了解对整个脊柱结构的影响。目前可以模拟接近人体正常的条件下脊柱的活动、应力等,结果更加可信,已成为研究脊柱生物力学的重要工具。本课题在离体生物力学研究基础上建立正常人上颈椎的三维有限元模型,并验证其有效性。通过三维有限元的方法研究一体化C1椎板钩联合C1-2经关节螺钉或C2椎弓根螺钉内固定卡压植骨的生物力学稳定性以及内固定、植骨块的应力分布,阐明生物力学机制,为内固定器械的设计、改进提供思路,为临床治疗提供理论指导。目的1、取尸体上颈椎标本,利用离体生物力学方法,研究一体化C1椎板钩联合C1-2经关节螺钉或C2椎弓根螺钉内固定卡压植骨的生物力学稳定性;2、建立正常人上颈椎的三维有限元模型,并验证其有效性。通过三维有限元的方法研究一体化C1椎板钩联合C1-2经关节螺钉或C2椎弓根螺钉内固定卡压植骨的生物力学稳定性以及内固定、植骨块的应力分布,阐明生物力学机制,为内固定器械的设计、改进提供思路,为临床治疗提供理论指导。方法1、离体生物力学研究:选择7具颈椎尸体标本(C0-C3),进行纯力矩加载,行屈伸、左右侧曲、左右旋转生物力学研究,测量C1-C2的运动范围(ROM)。生物力学研究的模型分别为:1)完整标本模型(Intact);2)Ⅱ型齿状突骨折失稳标本模型(Destabilized);3)C1侧块螺钉联合C2椎弓根螺钉固定植骨模型(C1+C2);4)C1-2经关节螺钉联合Gallie固定植骨模型(TA+G);5)一体化C1椎板钩联合C2椎弓根螺钉固定植骨模型(P+H);6)一体化C1椎板钩联合C1-2经关节螺钉固定植骨模型(TA+H)。对生物力学测量所得的屈伸、左右侧曲、左右旋转的运动范围(ROM)进行统计学分析。2、三维有限元研究:采用螺旋ct对健康青年男性志愿者进行颈椎薄层扫描,提取CT扫描数据进行建模,得到上颈椎(C0-C3)三维有限元模型。参照离体生物力学研究方式,制作失稳模型及加载不同内固定,加载1.5n.m的纯力矩,测量6种模型屈伸、左右侧曲、左右旋转的运动范围(ROM)及内固定、植骨块的应力值并分析应力分布情况,研究一体化C1椎板钩的生物力学特点。结果1、相对于Intact、Destabilized模型,四种固定方式能显著改善寰枢椎稳定性,C1+C2、TA+G、P+H、TA+H模型在屈伸、左右侧屈、左右旋转时ROM值明显小于Intact、Destabilized模型,差异有统计学意义(p0.05)。在屈伸、左右侧屈、左右旋转,P+H的ROM值均为最大,在屈伸、左右侧屈时,C1+C2、TA+G、P+H、TA+H模型ROM值差异无明显统计学意义(p0.05)。旋转时,C1+C2、TA+G、TA+H模型ROM值差异无统计学意义(p0.05),C1+C2、TA+G、TA+H模型与P+H模型ROM值差异有统计学意义(p0.05)。2、根据志愿者ct成功建立了完整上颈椎C0-C3的三维有限元模型,并验证证实其有效性。根据实际使用内固定相关参数建立了各种内固定三维有限元模型。在完整的上颈椎C0-C3三维有限元模型基础上建立ii型齿状突骨折的失稳模型,将内植入物和失稳模型进行组合,建立以下四种内固定模型:1)C1侧块螺钉联合C2椎弓根螺钉固定植骨模型(C1+C2);2)C1-2经关节螺钉联合Gallie固定植骨模型(TA+G);3)一体化C1椎板钩联合C2椎弓根螺钉固定植骨模型(P+H);4)一体化C1椎板钩联合C1-2经关节螺钉固定植骨模型(TA+H)。3、对1)完整标本模型(Intact);2)Ⅱ型齿状突骨折失稳标本模型(destabilized);3)C1侧块螺钉联合C2椎弓根螺钉固定植骨模型(C1+C2);4)C1-2经关节螺钉联合gallie固定植骨模型(TA+G);5)一体化C1椎板钩联合C2椎弓根螺钉固定植骨模型(P+H);6)一体化C1椎板钩联合C1-2经关节螺钉固定植骨模型(TA+H)六种不同三维有限元模型在屈伸、左右侧曲、左右旋转的六个方向上加载1.5nm的纯力矩,通过位移云图的方法计算寰枢椎运动范围(ROM),结果显示在屈伸、左右侧屈、左右旋转时ROM值均为TA+GTA+HC1+C2P+HIntactDestabilized,这与生物力学结果大致相符。4、通过应力云图研究内固定器械及植骨块应力情况,在TA+G、TA+H固定时应力云图显示在TA螺钉应力主要集中于螺钉穿过C1-2关节处,且一般是后伸时应力增大,侧屈、旋转时较小。椎弓根螺钉固定应力集中位于螺钉与骨的界面处,且在左右侧弯、左右旋转时应力较大,屈伸时应力较小。一体化C1椎板钩应力集中于一体化C1椎板钩与C1-2经关节螺钉或C2椎弓根螺钉连接处,C1椎板钩与棒一体化集成处无应力集中。在屈伸、左右侧屈、左右旋转时TA+G、C1+C2固定器械上应力较小,TA+H、P+H应力较大,其中TA+G中ta承受的应力最小,而Gallie承受应力在屈伸、侧屈、旋转时与其他内固定承受应力比较都为最大。植骨块承受应力主要为植骨块与寰枢椎接触处,P+H固定时植骨块在屈伸、左右侧屈、左右旋转时承受应力都为最大。不同的内固定模型在后伸时植骨块应力较前屈时增大,这与实际相符。结论1、一体化C1椎板钩与寰枢椎解剖结构贴合,与C1-2经关节螺钉或C2椎弓根螺钉连接时更简单,且安装方便快捷,手术更安全。与C1-2经关节螺钉联合行寰枢椎固定植骨提供与C1-2经关节螺钉联合Gallie固定植骨相似的生物力学稳定性。一体化C1椎板钩联合C2椎弓根螺钉固定植骨对旋转活动控制较差,可作为不满足C1-2经关节螺钉固定条件的患者的备选手术方案之一。2、一体化C1椎板钩无明显应力集中,可有效避免内固定断裂情况,但一体化C1椎板钩固定模型中TA螺钉应力较大,需要注意TA螺钉断钉可能。一体化C1椎板钩能限制卡压的植骨块活动,有效避免植骨块移位、脱落,植骨块在P+H模型时所承受应力最大,在所有固定模型中后伸较前屈时植骨块应力有增大,能很好促进了植骨融合。
[Abstract]:The background is located in the atlantoaxial vertebra of the occipital neck, with special anatomical structure adjacent to the neck and spinal cord, the vertebral artery and other important structures and the main rotation function of the head and neck. Tumor, malformation, inflammation, and degeneration may cause atlantoaxial instability in this area, and the treatment of atlantoaxial instability is one of the most difficult problems in clinical and serious atlantoaxial. Vertebral instability can lead to the compression of important structures, such as cervical spinal cord, nerve root, and blood vessel, causing a series of symptoms, even paralysis or life risk, requiring surgical intervention. Atlas and axis posterior fixation is the main operation to solve the atlantoaxial instability. The atlantoaxial posterior fixation has undergone steel wire fixation (Gallie, Brooks, etc.), posterior vertebra. The plate hook (Halifax, Apofix), C1-2 through the joint screw fixation (Transarticular screw, TA), and the posterior C1-C2 short segment screw rod system are fixed by the C1-2 through the joint screw or the C1-C2 short segment screw rod system. The previous biomechanical and clinical studies confirm that this kind of fixation technique can significantly enhance the stability of the atlantoaxial and improve the stability of the axis. The fusion rate of bone graft. Bilateral C1-2 is fixed at two points with joint screw fixation. It still has defects in the control of flexion and extension. The combined posterior wire fixation and bone graft fusion can reach three points. It has good effect in controlling all directions of atlantoaxial movement. It is recognized as the gold standard of atlantoaxial fixation, but the C1 underlaminar wear wire is damaged. The risk of the spinal cord. My tutor, Professor Ni Bin, designed the C1 vertebral plate hook (patent number: 200720075767.6) on the basis of the atlantoaxial anatomy, and combined the C1-2 transarticular screw fixation with the bone graft, which avoids the risk of spinal cord injury caused by the C1 interlaminar steel wire. The operation is simple, and the bilateral laminar hook has a solid bone graft. The biomechanical study confirmed that the biomechanical stability was equivalent to the bilateral C1-2 joint screw combined with the posterior wire fixation. The clinical application proved that the fusion of the atlantoaxial bone graft could be promoted well. However, the C1 laminar hook still existed with the C1-2 transarticular screw or the C2 pedicle screw during the installation process. Problems such as difficult and cumbersome, we modified the atlantoaxial anatomy again, designed the integrated C1 laminar hook, integrated the C1 laminar hook and rod design, reduced the assembly link in the operation, and avoided the risk of loosening and removal of the hook and rod connection. The hook designed a prominent ridge with the contact of the rear arch of the C1 and reduced the hook in C1 In the posterior arch, and according to the anatomical characteristics of the atlantoaxial anatomy, the 15 degree design of the lateral inclination of the C1 vertebral plate hook and the rod connection and the bending performance of the rod make the integrated C1 laminar hook fit well with the C1-2 screw or the C2 pedicle screw, making the operation more convenient, simpler, more reliable and safer. To study the biomechanical stability of the integrated C1 laminectomy hook combined with C1-2 transarticular screw or C2 pedicle screw fixation, the biomechanical stability of the integrated C1-2 laminectomy hook combined with the internal fixation of the pedicle screw of the pedicle screw was studied by using the biomechanical method in vitro. The spinal column has a complex structure, and the biomechanical study of the spinal column is in the spine. The study of physical mechanics plays an important role, but the specimen is not well preserved, and it is difficult to obtain. And the difference of each individual causes the different specimens to have a great influence on the accuracy of the experimental results because of their own biomechanical differences. With the development of computer technology and the progress of the finite element method, the present three-dimensional finite element method is used. It can not only simulate the bone structure of the spinal column, but also simulate the structure of the ligaments around the spinal column. It can not only simulate the complete spinal model, but also simulate the biomechanical study of the spinal model, such as degeneration and trauma, and can load various internal fixates on the spinal model and evaluate the internal fixation biomechanics. The three-dimensional finite element method can be used to simulate the structure of the spine, load conditions and so on. The effect of the spinal structure on the normal condition of the human body can be simulated, and the results are more credible. A three-dimensional finite element model of the normal human upper cervical spine was established on the basis of the study of the biomechanics in vitro, and its effectiveness was verified. The biomechanical stability and internal fixation of the integrated C1 laminectomy hook combined with C1-2 transarticular screw or C2 pedicle screw internal fixation was studied by the three-dimensional finite element method. To determine the stress distribution of bone graft, clarify the mechanism of biomechanics, design for internal fixation instruments, provide ideas for improvement and provide theoretical guidance for clinical treatment. Objective 1 to take the specimens of the cervical vertebrae on the cadavers and to study the birth of the integrated C1 laminectomy hook combined with C1-2 transarticular screw or C2 pedicle screw fixation. 2, a three-dimensional finite element model of the normal human upper cervical spine was established and its validity was verified. The biomechanical stability and internal fixation, the stress distribution of the bone graft, and the biomechanics of the integrated C1 laminectomy hook combined with C1-2 transarticular screw or C2 pedicle screw fixation were studied by the three-dimensional finite element method. Mechanism, for the design of internal fixation instruments, to provide ideas for improvement and to provide theoretical guidance for clinical treatment. Method 1, in vitro biomechanical study: select 7 cervical cadaver specimens (C0-C3), carry out pure torque loading, flexion and extension, left and right side curvature, left and right rotation biomechanics research, and measure the range of motion of C1-C2 (ROM). Biomechanical research model respectively 1) complete specimen model (Intact); 2) type II odontoid fracture instability specimen model (Destabilized); 3) C1 side block screw combined with C2 pedicle screw fixation bone graft model (C1+C2); 4) C1-2 via joint screw combined with Gallie fixed bone graft model (TA+G); 5) one bulk C1 laminectomy hook combined C2 pedicle screw fixation bone graft model (P+H); 6) integrated C1 vertebra Plate hook combined with C1-2 transarticular screw fixation model (TA+H). A statistical analysis of flexion and extension, left and right side curvature, and rotational motion range (ROM) obtained by biomechanical measurements,.2, three-dimensional finite element study: Spiral CT was used to scan the cervical vertebrae of healthy young male volunteers, and the CT scan data were extracted and the upper neck was obtained. The three-dimensional finite element model of vertebra (C0-C3) was used to make the instability model and load the different internal fixation and load the pure torque of 1.5n.m, to measure the flexion and extension of the 6 models, the left and right side curvature, the left and right motion range (ROM) and the internal fixation, the stress value of the bone graft and the distribution of the stress, and to study the birth of the integrated C1 vertebral lamina hook. Results 1, compared with Intact, Destabilized model, four fixed ways can significantly improve the stability of atlantoaxial, C1+C2, TA+G, P+H, TA+H model in flexion and extension, left and right lateral flexion, ROM value is obviously less than Intact, Destabilized model, the difference has statistical significance (P0.05). In flexion, left and right lateral flexion, P+H ROM values. There was no significant difference in ROM value between C1+C2, TA+G, P+H, TA+H model in flexion and extension and left and right side flexion (P0.05). The difference of ROM values of C1+C2, TA+G and TA+H model was not statistically significant (P0.05) when rotating, and there was a significant difference between the ROM values of C1+C2, TA+G and TA+H model. The three-dimensional finite element model of -C3 was verified and proved to be effective. Based on the actual internal fixation parameters, various internal fixed three-dimensional finite element models were established. On the basis of the complete C0-C3 three-dimensional finite element model of the upper cervical spine, the instability model of II odontoid fracture was established, and the internal implants and instability models were combined to establish the following four Internal fixation model: 1) C1 side block screw combined with C2 pedicle screw fixation bone graft model (C1+C2); 2) C1-2 through joint screw combined with Gallie fixed bone graft model (TA+G); 3) integrated C1 laminectomy hook combined with C2 pedicle screw fixation model (P+H); 4) integrated C1 vertebra hook combined with C1-2 transarticular screw fixation model (TA+H), to 1) complete standard The model (Intact); 2) type II odontoid fracture instability specimen model (destabilized); 3) C1 side block screw combined with C2 pedicle screw fixation bone graft model (C1+C2); 4) C1-2 via joint screw combined with Gallie fixed bone graft model (TA+G); 5) integrated C1 vertebral plate hook combined C2 vertebral pedicle screw fixation model (P+H); 6) integrated C1 laminectomy hook combined hook Six different three-dimensional finite element models of the joint screw fixation (TA+H) were used to load the pure torque of 1.5nm in the flexion and extension, the left and right sides and the left and right rotation. The movement range of the atlantoaxial (ROM) was calculated by the method of displacement cloud. The results showed that the ROM value was TA+GTA+HC1+C2P+HIntactDestab at the flexion and extension, the left and right side flexion and the left and right rotation. Ilized, which is roughly consistent with the biomechanical results,.4. The stress cloud map is used to study the stress situation of internal fixation instruments and bone graft. At TA+G, the stress cloud chart at the time of TA+G and TA+H shows that the stress in the TA screw mainly concentrates on the screw through the C1-2 joint, and generally the stress increases, the lateral flexion, and the rotation is smaller. The stress concentration of the pedicle screw is fixed. At the interface of screw and bone, and bending on the left and right side, the stress is larger in the left and right rotation, and the stress is small when flexion and extension. The integrated C1 laminar hook stress is concentrated on the integrated C1 laminar hook and C1-2 through the joint screw or the C2 pedicle screw, and the C1 laminar hook and the rod integration place has no stress concentration. At the flexion and extension, the left and right side flexion, and the right and left rotation TA+ G, C1+C2 fixed apparatus stress is small, TA+H, P+H stress is larger, of which TA+G TA bear the minimum stress, while Gallie bear stress in flexion and extension, lateral flexion, rotation and other internal fixation stress is the largest. The stress of the bone graft is mainly the bone graft and the atlantoaxial contact, P+H fixed bone graft in flexion and extension, left and right flexion, left, left, left, and left The stress at the right rotation is the largest. The stress of the different internal fixation models increases when the extension is more than the forward flexion. Conclusion 1, the integration of the integrated C1 lamina hook and the atlantoaxial anatomical structure is more simple with C1-2 through the joint screw or the C2 pedicle screw, and the installation is convenient and fast, and the operation is safer. The operation is more safe with C1-2. Joint screw fixation with atlantoaxial fixation provides similar biomechanical stability to C1-2 transarticular screws combined with Gallie fixation. The integrated C1 laminectomy hook combined with C2 pedicle screw fixation has a poor control of rotation activity, which can be used as one of the alternative surgical procedures for patients with unsatisfied C1-2 transarticular screws. There is no obvious stress concentration in the C1 vertebral lamina hook, which can effectively avoid internal fixation fracture. However, in the integrated C1 laminar hook fixation model, the stress of TA screws is larger. It is necessary to pay attention to the possibility of breaking the nail by the TA screw. The integrated C1 lamina hook can restrict the bone graft of the compression plate, effectively avoid the displacement of the bone graft and the maximum stress of the bone graft in the P+H model. In all the fixed models, the stress of the bone graft increased when compared with the anterior flexion, which promoted bone graft fusion.
【学位授予单位】：第二军医大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：R687.3

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