ABSTRACT
BACKGROUND: The fracture of adjacent vertebrae after vertebroplasty has been widely concerned. The finite element study of the influence of three cement diffusion types on the stress change of adjacent vertebrae after vertebroplasty has not been reported at home and abroad. OBJECTIVE: To analyze the stress changes of the adjacent vertebrae of the affected vertebrae under different loads using the finite element method. METHODS: Based on the original CT data of one L, vertebral compression fracture patient and three L, vertebral consolidation patients with bone cement distributed in the form of dispersion, mixture and agglomeration, the finite elements of T11-L2 vertebral functional unit compression fracture and three types of bone cement dispersion were established by dividing grids, defining material attributes and assembling models, using software such as Mimics 19.0, Geomagic Studio 2013 and SolidWorks 2017. The models underwent three levels of pressure 0.3 MPa (low pressure), 1.0 MPa (medium pressure) and 4.0 MPa (high pressure) and four load directions of forward bending, backward extension, lateral bending and rotation, respectively. The stress distribution of T12 and L2 vertebrae under different pressures and loads was observed. RESULTS AND CONCLUSION: (1) The increase of the stress of the adjacent vertebrae was positively correlated with the increase of the axial stress after the injection of bone cement. (2) The maximum stress of the adjacent vertebrae was significantly higher than that of the diffusion type and the mixed type under the four loading directions of the agglomerate type of bone cement, and the stress of the mixed type of the adjacent vertebrae was lower than that of the agglomerate type and the diffusion type under the forward bending and lateral bending loads (3) The results showed that the agglomerate type of bone cement is an important factor leading to the increase of the stress of the adjacent vertebrae. The mixed cement distribution may reduce the risk of adjacent vertebral fractures.