【作者】 韩宝君；

【导师】 雷伟； 吴子祥；

【作者基本信息】 第四军医大学 ， 外科学， 2009， 硕士

【摘要】 颈椎前路手术是治疗颈椎病、颈椎骨折、肿瘤、结核的主要手段,其中一些病例大多需要行椎体次全切术治疗,之后需要对颈椎进行稳定性重建。目前主要存在两种手术方式:一是植骨融合内固定术,一是人工椎体植入术,但这类手术都存在两个共同的问题:一是重建节段活动度完全丧失,患者颈椎正常活动受限;二是由于重建节段活动度完全丧失,造成应力集中以及颈椎活动度重新分配,最终导致远期邻近节段椎间盘退变加速的问题,而一旦发生这类问题,处理起来相当困难,效果更是不能令人满意。因此,在重建颈椎椎体次全切除术后颈椎稳定性的同时,保留节段的正常活动度,避免相邻节段加速退变,具有重要意义。如何解决这个问题,是颈椎外科的一个重要课题,课题组在前期工作中研制开发了“人工颈椎复合关节系统”,并对其进行了初步生物力学评价,结果表明这一假体所具有的球窝关节等独特设计在一定程度上可以实现颈椎稳定性与三维活动度的共存,避免邻近节段的活动度变化。研究目的:正常颈椎的运动模式是在运动过程中具有可变的运动中心,并且相邻椎体间存在相对位移,但该假体的球窝关节设计只是中心固定的旋转运动,尚不能实现该模式的重建,另外在假体与相邻椎体间的连接,以及与残余椎体间的固定与融合等方面需要进一步的改进,使其能够实现完全生理性的重建。本研究在前期设计的基础上,利用对国人颈椎进行精确测量获得的科学数据,并且从固定强度及仿生学方面对“人工颈椎复合关节系统”进行优化设计,并对假体植入后的人颈椎标本进行相关生物力学测试,评价其应用于颈椎稳定性重建及保留节段动度的价值,以期更好解决上述问题。研究方法:1)利用本课题组对国人颈椎的解剖学参数及生理活动度测量获得的数据,结合查阅参考国内外相关文献,获得椎体、椎间盘的相应几何参数,使用Solid Works及Auto CAD制图软件对假体进行设计。采用医用钛合金作原料,分别通过模具铸造及数控机床进行加工成型,装配整合成假体,并在假体相应表面均匀喷涂钛多孔涂层。2)将冷冻保存的14具新鲜成人下颈椎标本,进行实验前处理,随机抽取7具进行稳定性实验,之后将14具标本随机分为钉板固定组和假体植入组2组,每组7例,对每组标本分别进行实验前处理:钉板固定组依次行前路C5椎体次全切、植骨融合内固定术;假体植入组依次行C5椎体次全切、假体植入术。采用MTS858 Mini Bionix II生物材料实验系统对处理后各组标本进行稳定性实验。3)将冷冻保存的14具新鲜成人下颈椎标本,进行实验前处理,随机抽取7具进行正常颈椎各节段活动度测定,之后将全部标本随机分为钉板固定组和假体植入组2组,每组7例,同2)进行实验前处理。采用MTS 858 Mini Bionix II生物材料实验系统及立体摄像系统测定各组标本手术邻近节段椎间活动度。研究结果: 1)优化设计并制造出“人工颈椎复合关节系统”,改进后的“人工颈椎复合关节系统”由两端的关节头部件和中间的椎体部件构成,关节头的球窝结构与椎体部件的球面相关节,并以固定环固定,定位销锁定固定环,形成难以脱位的万向球窝滑槽关节,在各方向上允许0～14度的活动度,以及前屈、后伸允许0～2㎜的位移,左右侧屈中允许0～1㎜。该关节的特有球窝滑槽设计模拟了颈椎的正常运动模式,实现了椎体间的相对位移变化,在保证颈椎正常活动度的条件下,通过固定环的设计限制其位移的大小,防止颈椎失稳的发生。关节头上表面及椎体部件侧面的防退槽增加了假体固定的稳定性,结构简便,机械稳定性好。2)应用“人工颈椎复合关节系统”进行颈椎重建(假体植入组),与正常颈椎组相比,下颈椎的在三维六自由度的活动中ROM均无显著差异。而钉板固定组在前屈、后伸、左右扭转中的ROM均小于显著正常颈椎和假体植入组,左右侧弯活动中无显著差异。对于手术节段而言,钉板固定组在6个自由度上的ROM均显著小于正常颈椎组和假体植入组,而假体植入组仅在后伸运动中ROM显著大于正常颈椎组,其余活动中均与正常颈椎组无显著差异。3)对于C3/4椎间活动度,假体植入组与正常颈椎组无显著差异。钢板螺钉组前屈、后伸活动度均较其余两组显著增大,左右侧弯与其余两组均无显著差异。三组间C6/7椎间活动度无显著差异。结论:应用“人工颈椎复合关节系统”行颈椎重建后,颈椎的活动度获得了一定的保留,同时稳定性也与正常状态相接近。与标准的融合器植骨钢板螺钉内固定相比,更符合生理性重建的要求,在技术上向颈椎生理性重建迈出了一大步,为将来临床行颈椎前柱重建提供了一种全新的选择。同时未引起邻近节段椎间隙活动度异常增大,这对避免远期邻近节段退变的发生和加剧可能具有重要意义。更多还原

【Abstract】 Cervical spine syndrome is one of common and multiple diseases. Subtotal corpectomy is used for the treatment of many kinds of cervical spine syndrome clinically, and after that, cervical spine reconstruction of stability is need. Nowadays bone graft with internal fixation and artificial vertebral replacement are the most common methods used for reconstruction, but all of the two have two deficits as following: one is the loss of the motion of surgical region which leads to decrease of the motion of cervical spine. The other is long-term acceleration of adjacent segment degeneration caused by stress concentration and motion redistribution of cervical spine. In case it occurs, it’s very difficult to deal with it, and its clinical prognosis cannot give satisfaction to us. So, when do cervical spine reconstruction after subtotal corpectomy, it’s very important to restore segmental motion of surgical region in order to avoid long-term acceleration of adjacent segment degeneration. Now there is no technique which can either reconstruct the stability or restore segment motion used for reconstruction following cervical subtotal corpectomy. Our group designed and manufactured ACJC and did relative biomechanical tests on cervical spines into which ACJC were implanted earlier. Results showed that ACJC can restore segmental motion of surgical region fairly, in order to avoid long-term acceleration of adjacent segment degeneration.Objective: The movement of normal cervical spine has a variable center of motion, with the shift of adjacent segment. The structure of“artificial cervical joint complex”(ACJC) can not realize the movement as normal cervical spine. To realize physiological reconstruction totally, we should improve the fixation between prosthesis and adjacent segment, the fusion between prosthesis and remnant of Centrum. Based on the geometric and movement parameters o f human’cervical spine, we optimized and manufactured“ACJC”with titanium alloy.Methods: 1) Based on the geometric and movement parameters o f human’cervical spine, we optimized“artificial cervical joint complex”(ACJC) with Solid Works and Auto CAD software. Then manufactured the prosthesis with titanium alloy by numerical controlled machine tool, assembled them to the whole one and brushed it with Ti-porosity smear layer evenly. 2)Drawing out 7 samples of 14 fresh cervical spines as intact group randomly, carried on the experiments on stability under the biomaterial experimental system of MTS 858 Mini Bionix II. Divided 14 cervical spines into two groups including plate-screw fixation group and prosthesis-implanted group averagely and randomly, then tackled them before experiment respectively: conduct anterior C5 subtotal corpectomy, bone graft fusion and internal fixation by turns for the plate-screw fixation group; conduct C5 subtotal corpectomy and prosthesis implantation by turns for the prosthesis-implanted group, carried on the same experiments as the intact group. 3)Divided 14 cervical spines into two groups including plate-screw fixation group and prosthesis-implanted group averagely and randomly, Then tackled them with the same ways mentioned above in method Measured the motion of surgical adjacent segment with the biomaterial experimental system of MTS 858 Mini Bionix II and three-dimensional shot system.Results: 1) Optimized and manufactured“ACJC”, which was made up by articular head part on both sides and vertebrae part in the middle. The spherical surfaces of articular head part and vertebrae part structure the firm sphere-chute joint,with the fixation of fixed collar and locating pin. The activity of prosthesis changes from 0 to 14 degree in all directions. The shift in anteflexion and extension changes from 0 to 2㎜,and 0 to 1㎜ in Left and right axial rotation. The special structure of prosthesis not only imitates the movement of normal cervical spine, but also realize the shift of interbody. Devices on the articular head part and vertebrae part can avoid disarticulation. The prosthesis has simple structure and high mechanical stability.2) As for the lower cervical spine, there was no apparent difference between prosthesis-implanted group and intact group in the three-dimensions ROM. While in the plate-screw fixation group, ROM is smaller in the flexion, extension and tortion compared with the prosthesis implanted group and the intact group, with no difference in lateral bending. As for the surgical segment, ROM of the plate-screw fixation group is smaller in the three-dimensions ROM obviously compared with the prosthesis-implanted group and the intact group. ROM of the prosthesis-implanted group is the same in most of the activities as of the intact group while larger in the extension.3) As for the C3/4 intervertebral ROM, there is no obvious difference between the prosthesis-implanted group and the intact group. ROM of the plate-screw fixation group in flexion and extension is larger than the rest two groups without difference in lateral bending. They are the same in the C6/7 vertebra ROM.Conclusion: Using ACJC to reconstructing cervical spine following subtotal corpectomy, can either restore segmental motion or regain almost the same stability as in intact condition. Compared with the standard bone graft and palte-screw internal fixation, it fits the requirements of physiological reconstruction more and steps towards physiological reconstruction of the cervical spine technically, which offers a new option for the reconstruction of cervical spine in the future. Meanwhile, it avoids abnormal increase of intervertebral ROM in the adjacent segment, which may make sense of prevention of long-term occurences and acceleration of degeneration of adjacent segments.更多还原