Bone Abstracts

Introduction: Vertebroplasty (VP) and ballon kyphoplasty (BKP) are used in the treatment of the vertebral compression fractures (VCF), that usually result in a typical wedged deformation. It is still under debate which technique is the best, in terms of efficacy, costs, and safety, mainly about the risk of a adjacent new fractures. The aim of this study is to evaluate the biomechanical outcome of vertebroplasty and kyphoplasty by a computational comparative analysis with finite element models.

Material and methods: A finite element model of intact T9–T11 spinal segment has been realized and then modified in order to simulate a wedge shaped VCF with a reduction of 25% (angle 13°) and 50% (angle 26°) of the original anterior height of T10 vertebral body. The following conditions have been considered for each model: osteoporotic bone (OP), vertebroplasty on T10 (VP), and kyphoplasty on T10 (KP).

Results: Vertebroplasty causes only a negligible variations in the intradiscal pressure (IDP) and on the stress values on the end-plates (EPs). Kyphoplasty with a total restoration produces a reduction of 5% in the IDP below the fracture, while in the EPs a significant reduction of the stress is noticed (20–50%). The presence of the cement core (effect of material) has a negligible, while the wedged shape of the fractured vertebra (effect of geometry has a significant effect.

Conclusions: In conclusion it can be stated that the effect of cement injection in the fractured vertebra causes slight variations in stress distribution, as already found in previous studies, that the effect of the geometry of the fractured vertebral body on stress distribution on the EPs is significant, and, consequently, that kyphoplasty offers some advantages respect to vertebroplasty in reducing the stress distribution, in particular on the EPs, if the height of the vertebral body is restored.