In vivo assessment of lumbar vertebral strength in elderly women using computed tomography-based nonlinear finite element model

Study Design. In vivo study of a computed tomography (CT)-based nonlinear finite element model (FEM). Objective. To establish an FEM with the optimum element size to assess the vertebral strength by comparing analyzed data with those obtained from mechanical testing in vitro, and then to assess the second lumbar (L2) vertebral strength in vivo. Summary of Background Data. FEM has been reported to predict vertebral strength in vitro, but has not been used clinically. Methods. Comparison among the 3 models with a different element size of 1 mm, 2 mm, and 3 mm was performed to determine which model achieved the most accurate prediction. Vertebral strength was assessed in 78 elderly Japanese women using an FEM with the optimum element size. Results. The optimum element size was 2 mm. The L2 vertebral strength obtained with the FEM was 2154 +/- 685 N, and the model could detect preexisting vertebral fracture better than measurement of bone mineral density. Conclusion. The FEM could assess vertebral strength in vivo.