Abstract: BACKGROUND: The cortical bone reinforcement area of bone cement in the vertebral body during percutaneous vertebroplasty for osteoporotic vertebral compression fractures has an important influence on spinal biomechanics and clinical efficacy, but previous studies were mostly limited to the two-dimensional level. 
OBJECTIVE: To investigate the effect of the difference in cortical bone reinforcement of bone cement in the three-dimensional plane of the vertebral body on the biomechanical distribution of the vertebral body, adjacent intervertebral disc and endplate in osteoporotic vertebral compression fractures by finite element analysis during percutaneous vertebroplasty, so as to evaluate its effect.
METHODS: The finite element model of percutaneous vertebroplasty for osteoporotic vertebral compression fractures of T12 vertebrae was established. The presence or absence of cortical reinforcement of bone cement was analyzed in groups from the transverse, sagittal and coronal planes. The effects of cortical reinforcement on the biomechanics of T12 vertebral cancellous bone, cortical bone, T11/T12 intervertebral disc, T12/L1 intervertebral disc, T11 lower endplate, and L1 upper endplate under different body position changes were studied. 
RESULTS AND CONCLUSION: (1) Under the effect of vertical compression force, percutaneous vertebroplasty cortical reinforcement with or without bone cement had no significant changes in structural stress except for the injured vertebral cortical bone. (2) The Von Mises stress value of the injured cortical bone was significantly different in human forward flexion, left/right bend, and left/right axial rotation. The maximum Von Mises stress value in the best group of cortical reinforcement was significantly smaller than that in the non-cortical reinforcement group. The Von Mises stress value showed a downward trend with extensive cortical reinforcement in the same plane. (3) It is indicated that when percutaneous vertebroplasty is performed, bone cement should be distributed as broadly and symmetrically horizontally along the cortical edge of the vertebral body as far as possible in cross section. Bone cement in sagittal plane should be widely distributed longitudinally near the upper and lower endplates and the anterior and posterior walls. Bone cement in coronal plane should be widely distributed on both sides of the midline while symmetrically touching the upper and lower endplates and lateral walls. It can effectively avoid the risk of refracture of the injured vertebra and does not increase the risk of adjacent vertebral fracture and residual discogenic pain.

中国组织工程研究杂志出版内容重点：人工关节；骨植入物；脊柱；骨折；内固定；数字化骨科；组织工程

Key words: percutaneous vertebroplasty, cortical bone reinforcement, osteoporotic vertebral compression fracture, adjacent intervertebral disc, endplate, three-dimensional finite element analysis, biomechanics