Optimizing bone cement stiffness for vertebroplasty through biomechanical effects analysis based on patient-specific three-dimensional finite element modeling

Abstract

Vertebroplasty is a common and effective treatment for symptomatic osteoporotic vertebral compression fractures. However, the cemented and adjacent vertebras have a risk of recollapse due to largely unassured mechanisms, among which excessive stiffness of bone cement may be an important risk factor. This study aimed to find the most appropriate range of bone cement stiffness by analyzing its biomechanical effects on the augmented and adjacent vertebras of individual patient after vertebroplasty. A three-dimensional finite element model of T11-L1 osteoligamentous vertebras was reconstructed according to individual computed tomography data and validated by post mortem human subject experiment in literatures. Bone cement of varying stiffness was injected into the trabecular core of the T12 vertebra simulatively. The maximum von Mises stresses on cancellous and cortical bones of T11-L1 vertebras were analyzed under the loading conditions of flexion, extension, bending, and torsion. For the adjacent T11 and L1 vertebras, the stepwise elevation of the bone cement elastic modulus increased the maximum von Mises stress on the cancellous bone, but its effect on cortical bone was negligible. For the augmented T12 vertebra, the stresses on cancellous bone increased slightly under the loading condition of lateral bending and remained no impact on cortical bone. The linear interpolation revealed that the most suitable range of cement elastic modulus is 833.1 and 1408.1 Mpa for this patient. Increased elastic modulus of bone cement may lead to a growing risk of recollapse for the cemented vertebra as well as the adjacent vertebras. Our study provides a fresh perspective in clinical optimization of individual therapy in vertebroplasty. Graphical abstract ᅟ.

A Three-Dimensional Cement Quantification Method for Decision Prediction of Vertebral Recompression after Vertebroplasty

“…Patient-specific multidetector computational tomography- (MDCT-) based finite element analysis (FEA) is a promising tool for assessing clinically relevant parameters. For vertebroplasty, some homogeneous FEA research has studied different injection volumes, cement modulus, cement-endplate contacts, and so on [ 15 , 16 ]. For kyphoplasty, a study of the placement and symmetry of cement clouds [ 11 ], the author stated that the symmetric distribution of cement clouds is favorable.…”

A finite element analysis on different bone cement forms and injection volumes injected into lumbar vertebral body in percutaneous kyphoplasty

“…The element types of anterior longitudinal ligament, posterior longitudinal ligament, interspinous ligament, supraspinous ligament, ligament flava, and intertransverse process ligaments allow for tensile deformation without compressive behavior. The endplates, cortical bone, cancellous, cement, and intervertebral discs (nucleus pulposus and annulus fibrosus) were divided into 2 mm meshes, while the articular cartilage was split into 0.5 mm meshes [ 19 ]. The software itself generated the meshes and nodes.…”

Influence of cement-augmented pedicle screw instrumentation in an osteoporotic lumbosacral spine over the adjacent segments: a 3D finite element study

“…The mesh model generated in SolidWorks 2017CAD was imported into ANSYS Workbench 17.0 (ANSYS, Ltd., Canonsburg, PA, USA), and previous literature was referenced to set the cortical bone (osteoporosis), cancellous bone (osteoporosis), articular cartilage, endplates, annulus fibrosus, nucleus pulposus, bone cement, cages, and internal fixation ( Table 1). The ligaments were simulated using spring elements that were only stressed by pulling force (one ligament stimulated by one spring) [17][18][19][20]. The contact type between the models was defined in the connection, where in the facet joint contact type was frictional and the frictional coefficient was 0.2 [21]; the remaining contact types were set to be the bonded mode [20,22].…”