Dipartimento di Ingegneria Meccanica e Gestionale, Politecnico di Bari, Bari, Italy.
Med Biol Eng Comput. 2012 Sep;50(9):947-59. doi: 10.1007/s11517-012-0937-1. Epub 2012 Jun 30.
In spite of the consolidated clinical use of minimally invasive percutaneous fixation techniques, little is reported in the literature providing a mechanobiological explanation for how the design of fixation devices can affect the healing process within fractured vertebrae. The aim of this study was to develop a multi-scale mechano-regulation model capable of predicting how the patterns of tissue differentiation within a vertebral fracture change in the presence or in the absence of fixation devices and how the dimensions of the device, and the materials it is made from (Ti-6Al-4V alloy and cobalt chrome alloy) can affect the outcome of the healing process. The macro-scale model simulates the spinal segment L3-L4-L5, including the fractured body of the L4 vertebra, while the micro-scale model represents a fractured portion of cancellous bone. The macro-scale model also includes a minimally invasive percutaneous fixation device. The model predicts that fixation devices significantly shorten healing times. Increasing values of the rod diameter D and decreasing values of its radius of curvature R lead to shorter durations of the healing period. Manufacturing the rods in cobalt chrome alloy is also predicted to reduce slightly the healing period by providing greater mechanical stability within the fracture callus.
尽管微创经皮固定技术在临床上得到了广泛应用，但文献中很少有报道从生物力学角度解释固定装置的设计如何影响骨折椎体内的愈合过程。本研究旨在开发一种多尺度力学调节模型，能够预测在存在或不存在固定装置的情况下，骨折椎体内组织分化模式如何变化，以及装置的尺寸和所用材料（Ti-6Al-4V 合金和钴铬合金）如何影响愈合过程的结果。宏观模型模拟了 L3-L4-L5 脊柱节段，包括 L4 椎骨的骨折体，而微观模型则代表了松质骨的骨折部分。宏观模型还包括微创经皮固定装置。模型预测固定装置可显著缩短愈合时间。增加杆直径 D 值和减小曲率半径 R 值都会导致愈合期持续时间缩短。用钴铬合金制造杆也被预测会略微缩短愈合期，因为它在骨折痂内提供了更高的机械稳定性。
