Finite element analysis of vertebroplasty in the osteoporotic T11-L1 vertebral body: Effects of bone cement formulation

Abstract

Vertebral compression fractures are one of the most severe clinical consequences ofosteoporosis and the most common fragility fracture afflicting 570 and 1070 out of100,000 men and women worldwide, respectively. Vertebroplasty (VP), a minimally inva-sive surgical procedure that involves the percutaneous injection of bone cement, is oneof the most efficacious methods to stabilise osteoporotic vertebral compression frac-tures. However, postoperative fracture has been observed in up to 30% of patients fol-lowing VP. Therefore, this study aims to investigate the effect of different injectablebone cement formulations on the stress distribution within the vertebrae and interver-tebral discs due to VP and consequently recommend the optimal cement formulation.To achieve this, a 3D finite element (FE) model of the T11-L1 vertebral body was devel-oped from computed tomography scan data of the spine. Osteoporotic bone was mod-eled by reducing the Young's modulus by 20% in the cortical bone and 74% incancellous bone. The FE model was subjected to different physiological movements,such as extension, flexion, bending, and compression. The osteoporotic model caused areduction in the average von Mises stress compared with the normal model in the T12cancellous bone and an increment in the average von Mises stress value at the T12 cor-tical bone. The effects of VP using different formulations of a novel injectable bonecement were modeled by replacing a region of T12 cancellous bone with the materials.Due to the injection of the bone cement at the T12 vertebra, the average von Misesstresses on cancellous bone increased and slightly decreased on the cortical bone underall loading conditions. The novel class of bone cements investigated herein demon-strated an effective restoration of stress distribution to physiological levels within trea-ted vertebrae, which could offer a potential superior alternative for VP surgery as theiranti-osteoclastogenic properties could further enhance the appeal of their fracture treat-ment and may contribute to improved patient recovery and long-term well-being.