Biomechanical Comparison of Vertbroplasty, Kyphoplasty, Vertebrae Stent for Osteoporotic Vertebral Compression Fractures -A Finite Element Analysis

Abstract

Vertebroplasty (VP), balloon kyphoplasty (BKP), and vertebral stent (VS) are usually used for osteoporotic compression fracture. However, these procedures may pose risks of secondary adjacent level fractures. This study simulates finite element models of osteoporotic compression fractures treated with VP, BKP, and VS. Vertebral resection method was used to simulate vertebra fracture with Young’s modulus set at 70 MPa to replicate osteoporosis. A compressive force of 1000N was applied on the T11 vertebra while the L1 vertebra were fully constrained as boundary condition. Moment loadings of 4.2 N-m in flexion, 1.0 N-m in extension, 2.6 N-m in lateral bending, and 3.4 N-m in axial rotation were applied. The VS model had the highest von Mises stresses on the bone cement under all different loading conditions (flexion/5.91 Mpa; extension/3.74 Mpa; lateral bending/3.12 Mpa; axial rotation/3.54 Mpa). The stress distribution and maximum von Mises stresses of the adjacent segments, T11 inferior endplate and L1 superior endplate, showed no significant difference among three surgical models. The postoperative T12 stiffness for VP, BKP, and VS are 2898.48 N/mm, 4123.18 N/mm, and 4690.34 N/mm, respectively. VS is the most effective surgical method to maintain vertebral body height without significantly increasing the risks of adjacent fracture.