构建3D椎体模型比较经皮椎体后凸成形与经皮椎体成形治疗胸腰椎压缩性骨折的力学变化

BACKGROUND: Compared with general fractures, thoracolumbar fractures in the elderly have different pathological changes and are often accompanied by other systemic diseases. Percutaneous vertebroplasty and percutaneous kyphoplasty are the most commonly used surgical methods. The choice of different surgical methods is related to the incidence of re-fracture after operation. How to choose an effective internal fixation system and surgical methods is very important to reduce the failure of surgical treatment of thoracolumbar fractures in the elderly. OBJECTIVE: To study and compare the finite element mechanics of lumbar vertebral compression fracture by establishing 3D vertebral digital model and thoracolumbar compression fracture model. METHODS: A 56-year-old male patient with low back pain（later diagnosed as lumbar muscle strain） had no abnormal vertebral shape and a 54-year-old male patient with thoracolumbar vertebral compression fracture induced by osteoporosis were selected in this study. The two patients signed informed consent. This study was approved by the Hospital Ethics Committee. CT data of T12-L1 segments were obtained. Based on CT data of volunteers with low back pain, a three-dimensional digital model of vertebral body was established by using Mimics 10.0 software. Three-dimensional finite element analysis software Ansys 12.0 was used to establish the three-dimensional solid model of the vertebral body. L1 of vertebral compression fracture in finite element model of normal vertebral body was simulated with reference to fracture patient data. On this basis, the procedures of percutaneous vertebroplasty and percutaneous kyphoplasty were simulated to record Von Mises stresses and the deformation of different parts of the model under different loads. RESULTS AND CONCLUSION:（1） Compared with the results of in vitro biomechanical test, the experimental results of this model were basically consistent with those of in vitro（P > 0.05）.（2） Under vertical and forward bending, backward extension, lateral bending and right-handed loads, the deformations of T12 and L1 were significantly smaller in percutaneous kyphoplasty models than those of preoperative compressive fracture models and percutaneous vertebroplasty treatment models（P < 0.05）. There was no significant difference in the spinal deformations of T12-L1 under various loads between percutaneous vertebroplasty models and preoperative models（P > 0.05）.（3） The maximum stress of T12 and L1 was significantly lower in percutaneous kyphoplasty models than in preoperative models and percutaneous vertebroplasty models under vertical and forward bending, backward extension, lateral bending and right-handed loads（P < 0.05）. There was no significant difference in the maximum stress of T12 and L1 between percutaneous vertebroplasty models and preoperative models under various loads（P > 0.05）.（4） The deformation and stress of T12 and L1 segments of percutaneous kyphoplasty models were significantly less than those of preoperative compressive fracture models and percutaneous vertebroplasty models under vertical and forward bending, backward extension, lateral bending and right-handed loads. These suggest that percutaneous kyphoplasty can significantly increase the thoracolumbar stiffness of the spine, while percutaneous vertebroplasty has no significant effect on the thoracolumbar stiffness. [ABSTRACT FROM AUTHOR]