Casaroli Gloria, Villa Tomaso, Bassani Tito, Berger-Roscher Nikolaus, Wilke Hans-Joachim, Galbusera Fabio
Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, 20133 Milan, Italy.
IRCCS Istituto Ortopedico Galeazzi, 20161 Milan, Italy.
Materials (Basel). 2017 Jan 3;10(1):31. doi: 10.3390/ma10010031.
Finite element modeling has been widely used to simulate the mechanical behavior of the intervertebral disc. Previous models have been generally limited to the prediction of the disc behavior under simple loading conditions, thus neglecting its response to complex loads, which may induce its failure. The aim of this study was to generate a finite element model of the ovine lumbar intervertebral disc, in which the annulus was characterized by an anisotropic hyperelastic formulation, and to use it to define which mechanical condition was unsafe for the disc. Based on published in vitro results, numerical analyses under combined flexion, lateral bending, and axial rotation with a magnitude double that of the physiological ones were performed. The simulations showed that flexion was the most unsafe load and an axial tensile stress greater than 10 MPa can cause disc failure. The numerical model here presented can be used to predict the failure of the disc under all loading conditions, which may support indications about the degree of safety of specific motions and daily activities, such as weight lifting.
有限元建模已被广泛用于模拟椎间盘的力学行为。以往的模型通常局限于预测椎间盘在简单加载条件下的行为，从而忽略了其对复杂载荷的响应，而复杂载荷可能导致椎间盘失效。本研究的目的是建立一个绵羊腰椎间盘的有限元模型，其中纤维环采用各向异性超弹性公式进行表征，并利用该模型确定对椎间盘不安全的力学条件。基于已发表的体外实验结果，对屈曲、侧弯和轴向旋转幅度为生理值两倍的联合载荷进行了数值分析。模拟结果表明，屈曲是最不安全的载荷，轴向拉应力大于10MPa会导致椎间盘失效。本文提出的数值模型可用于预测椎间盘在所有加载条件下的失效情况，这可能有助于为特定运动和日常活动（如举重）的安全程度提供参考。
