The effect of vertebral material description during vertebroplasty

Vertebroplasty has attracted much attention as a medical treatment for the collapse of the spine by strengthening the vertebral body, correcting deformities, and relieving pain in patients through the injection of bone cement. The finite element method has become popular for analysing vertebroplasty. The numerical modelling of vertebrae under loading, as in many other cases of representing a composite bone with anatomically scattered properties through a simplified material model, entails difficulties in material assignment for analysis. The aim of this study is to compare and contrast material-assignment methods in the course of modelling through a tetrahedral meshing algorithm. In particular, the study seeks to contrast the element-wise material model with a uniform material assignment for trabecular bone and the bone-poly(methyl methacrylate) (PMMA) composite. The geometries of the vertebral body are constructed from computed tomography image data, which are obtained through scanning at intervals of 1 mm. The finite element models are constructed through a tetrahedral meshing algorithm. Various types of material assignment, which encompass the case of normal persons as well as the case of patients following vertebroplastic surgery, are analysed. The results clearly show that the oversimplification of the trabecular bone and the bone-PMMA composite body may lead to significant deviations in the assessment of the effectiveness of vertebroplastic surgery.