组织工程用犬桡骨大段缺损模型的生物力学及有限元评价

Biomechanical and finite element evaluation of model of canine radius segmental defect used in tissue engineering

目的:发展一种新型骨组织工程用大动物大段骨缺损模型,为组织工程研究选用提供依据。方法:①选择成年家犬湿尺、桡骨标本1根行CT断层扫描后经软件处理进行有限元建模及约束处理,施加边界条件计算应力-应变和扭矩-扭角关系。②采用24根成年雄性家犬尺桡骨标本制成桡骨中段大段骨缺损模型,随机分别采用3种固定方式及对照组进行抗轴向压缩、抗拉伸、抗扭转的强度比较。结果:①有限元分析表明本研究设计的四孔半笼式半管型钢板与单边外固定架相比,钢板固定的骨应力分布较接近正常状态而其应力集中程度较小。②力学实验表明,各组应变值与载荷的大小呈正线性相关,在满足轴向压缩、拉伸及扭转方面,四孔半笼式半管型钢板比单边外固定架和国产AO四孔直钢板优越。结论:此种组织工程动物模型具有抗扭转,抗压缩及抗拉伸的独特优势,力学结构合理。

AIM: To develop a new type of big animal model of big segmental defect of bone used in tissue engineering to provide a basis for tissue engineering research. METHODS: ①One wet ulnar and radius specimen in adult dogs was scanned by CT, and then processed by software to build and restrain the finite element model, and the relationship between stress strain and torque twisting angle was computed with boundary condition pressed. ②The defect models of middle segmental and big segmental bone of radius were prepared from 24 ulnar radius specimens of adult male dogs, and were fixated respectively and randomly with three methods and control group, the anti axial compression, anti tension and anti torsion intensity were compared. RESULTS: ①The finite element analysis(FEA) indicated that comparing the four holes designed panel(PA) with the bracket, the panel provided a more similar stress distribution as the normal and produced lower stress concentration compared with the bracket. ②The mechanical experiment indicated that the strain value of each group was positively correlated with loads, and the newly designed internal fixation panel was better than that of AO four holes panel and one side external fixation bracket of bracket in all of axial compression, tension and torsion abilities. CONCLUSION: The animal model of tissue engineering has superiority in anti axial compression, anti tension and anti torsionwith a reasonable mechanical structure.