Comparison of methods for assigning the material properties of the distraction callus in computational models
Comparison of methods for assigning the material properties of the distraction callus in computational models
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DOI：
10.1002/cnm.3227
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发表时间：
2019-07-11
影响因子：
2.1
通讯作者：
Esther Reina-Romo, Maria
中科院分区：
文献类型：
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作者：
Mora-Macias, Juan;Angel Giraldez-Sanchez, Miguel;Esther Reina-Romo, Maria
在牵张、成骨和骨折愈合的硅胶模型中，新生骨组织通常具有恒定的力学性能。此外，这些模型并不总是能解释编织骨的孔隙度及其演化。在这项研究中，基于计算机断层扫描(CT)的有限元分析被用来预测骨痂僵硬到术后69周，使用在骨运输实验的不同阶段获得的15张CT图像，在该技术中，牵张成骨被用来矫正骨缺损。三种不同的方法被用来指定新生骨组织的力学性能。首先，假设硬骨痂组织具有恒定的机械性能，并且没有孔洞。然而，这种方法并没有显示出良好的相关性。其次，编织骨的弹性模数和孔隙率的随机变化来自于先前的实验研究。最后，根据CT图像中的灰度级对每个单元的弹性性质进行赋值。将数值预测的骨痂硬度与之前的活体测量结果进行了比较。结果表明，基于灰度的分配方法是预测骨痂硬度的最佳方法，考虑骨痂孔隙率和弹性模数随机分布的方法也适用于预测术后15周开始的骨痂硬度。这一发现为分配牵张骨痂的材料特性提供了一种方法，该方法不需要CT图像，并可能有助于改善硅胶模型中的电流。
In silico models of distraction osteogenesis and fracture healing usually assume constant mechanical properties for the new bone tissue generated. In addition, these models do not always account for the porosity of the woven bone and its evolution. In this study, finite element analyses based on computed tomography (CT) are used to predict the stiffness of the callus until 69 weeks after surgery using 15 CT images obtained at different stages of an experiment on bone transport, technique in which distraction osteogenesis is used to correct bone defects. Three different approaches were used to assign the mechanical properties to the new bone tissue. First, constant mechanical properties of the hard callus tissue and no porosity were assumed. Nevertheless, this approach did not show good correlations. Second, random variations in the elastic modulus and porosity of the woven bone were taken from previous experimental studies. Finally, the elastic properties of each element were assigned depending on gray scale in CT images. The numerically predicted callus stiffness was compared with previous in vivo measurements. It was concluded firstly that assignment depending on gray scale is the method that provides the best results and secondly that the method that considers a random distribution of porosity and elastic modulus of the callus is also suitable to predict the callus stiffness from 15 weeks after surgery. This finding provides a method for assigning the material properties of the distraction callus, which does not require CT images and may contribute to improve current in silico models.