骨干假体与辅助钛板联合重建肱骨干缺损的生物力学研究

发布时间：2018-03-10 13:30

本文选题：生物力学　切入点：组配式假体　出处：《天津理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：肱骨为原发恶性骨肿瘤及转移性骨肿瘤的好发部位之一,常以瘤段切除作为治疗方法。对于瘤段切除后的保肢重建目前有同种异体骨移植、自体瘤段骨灭活回植、人工假体重建等方法。随着影像学技术、假体制造技术以及外科手术技术的提高,人工假体重建术已广泛用于骨干肿瘤广泛切除后的保肢重建。骨干组配式假体作为近几年新兴人工假体因其有着手术操作相对简单、患者住院时间较短、可即刻负重、并发症低、生物力学性能好等诸多优势而备受关注。目前,骨干组配式假体应用于肱骨骨干的临床报道较少,对于假体置换后肱骨以及假体的生物力学性能尚不清楚,制约了其临床应用和进一步的优化设计。针对肱骨骨干髓腔直径较小,瘤段切除后残余骨干较短以及上肢生物力学环境复杂等特点,提出了肱骨骨干组配式假体外加辅助钛板固定联合重建肱骨干节段性缺损的思路,并通过体外尸体骨电测法实验和三维有限元分析的方法对该假体重建肱骨骨干的生物力学特性进行了研究。以期为假体的临床使用和优化设计提供科学的理论依据。本课题首先采用尸体骨电测实验进行研究,实验进行前使用3-D打印模型骨进行初步的预实验以熟悉实验操作流程和总结实验所遇问题及提出解决方案,然后取成人右侧新鲜尸体肱骨进行包埋、贴片和加载测试。为模拟肱骨在体力学环境,此次实验分别进行肱骨机械轴向的拉伸加载和绕轴的扭转加载,并得出位移及应变数据。实验分为三个步骤逐一进行:首先,对完整肱骨进行加载;其次,人为建立肱骨骨干中段5cm长度缺损并以无钛板辅助固定假体重建骨缺损后再次行相同方式加载;最后,外加辅助钢板后再次进行加载。每组实验分别进行五次拉伸和扭转力的循环加载后求拉伸位移、扭转角度以及贴片处应变平均值。尸体骨电测法实验虽能切实的反应所测位置的应变变化情况,但由于实验环境及一些不可预知因素会对实验结果造成一定的影响,并且该方法只能得到贴片位置的应变变化而不能得到整体的应力分布以及诸如假体置入后假体柄表面、紧固螺钉等关键部件的数据。因此,我们在尸体骨电测法实验的基础上进一步进行了三维有限元分析,建立了基于CT扫描的肱骨有限元模型和基于三维软件的假体模型,按照尸体骨电测法实验进行组装和加载,设置了与尸体骨实验相同的边界条件。实验结果表明,肱骨骨干组配式假体联合钛板辅助固定重建瘤段缺损可作为有效的保肢治疗方法。该固定方式使得假体有着更好的初始稳定性,可应对上肢复杂生物力学环境,外加辅助钛板的设计降低了假体松动和脱位的风险。同时,此次研究验证了所建肱骨三维有限元模型的有效性和准确性,得到了肱骨以及假体在拉伸和扭转载荷下的应力分布,为该假体的临床使用和进一步的优化设计提供了理论依据。
[Abstract]:Humerus is one of the most common sites of primary malignant bone tumor and metastatic bone tumor. Methods such as artificial prosthesis reconstruction. With the improvement of imaging technology, prosthesis manufacturing technology and surgical technique, Artificial prosthesis reconstruction has been widely used in limb salvage reconstruction after extensive resection of bone tumors. As a new artificial prosthesis in recent years, because of its relatively simple operation and short hospital stay, the patient can bear weight immediately. Low complications, good biomechanical properties and many other advantages have attracted much attention. At present, there are few clinical reports on the application of diaphyseal prosthesis in the humeral shaft, but the biomechanical properties of the humerus and prosthesis after prosthesis replacement are not clear. It restricts its clinical application and further optimization design. It aims at the smaller diameter of the medullary cavity of the humeral shaft, the shorter residual shaft after resection of the tumor, and the complex biomechanical environment of the upper limb. The idea of reconstruction of segmental defect of humerus shaft with combined prosthesis and titanium plate fixation was put forward. The biomechanical properties of the prosthesis for humeral shaft reconstruction were studied by means of in vitro cadaveric bone electrical test and three-dimensional finite element analysis, in order to provide a scientific theoretical basis for the clinical use and optimal design of the prosthesis. First of all, the experiment of cadaveric bone test was carried out. Before the experiment, 3-D printed model bone was used for preliminary pre-experiment to familiarize the experimental procedure, summarize the problems encountered in the experiment and propose solutions. Then, the humerus of the right side of the adult body was taken for embedding, and the humerus of the right side of the adult was taken for embedding. In order to simulate the humerus in the mechanical environment, the experiment was carried out by axial tensile loading and torsional loading of the humeral shaft respectively, and the displacement and strain data were obtained. The experiment was divided into three steps: first, The complete humerus was loaded. Secondly, the humeral bone defect was reconstructed by artificial 5cm length defect in the middle of the humeral shaft and then was reloaded in the same way after the reconstruction of the bone defect with the prosthesis without titanium plate. After adding the auxiliary steel plate, the tensile displacement was calculated after the cyclic loading of five tensile and torsional forces in each group of experiments. Although the electric measurement of cadaveric bone can effectively respond to the strain change of the measured position, the experimental environment and some unpredictable factors will have a certain effect on the experimental results. Moreover, the method can only obtain the strain change of the patch position, but not the overall stress distribution and the data of the key components such as the surface of the prosthesis handle and the fastening screw after the prosthesis is placed. On the basis of the experiment of cadaveric bone electrical measurement, we further carried out three-dimensional finite element analysis, established the finite element model of humerus based on CT scan and the model of prosthesis based on three-dimensional software, and assembled and loaded the model according to the experiment of cadaveric bone electrometric method. The same boundary conditions as the cadaveric bone experiment are set. The experimental results show that, The prosthesis of humeral diaphysis combined with titanium plate can be used as an effective method for limb salvage, which can provide better initial stability and can deal with the complex biomechanical environment of upper limb. The design of additional titanium plate reduces the risk of prosthesis loosening and dislocation. At the same time, the validity and accuracy of the 3D finite element model of humerus are verified, and the stress distribution of humerus and prosthesis under tensile and torsional loads is obtained. It provides a theoretical basis for clinical use and further optimization design of the prosthesis.
【学位授予单位】：天津理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R687;R318.01

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