Virtual modelling of the impact of torsional loading on osteoporotic vertebrae buckling.

Purpose: This study aimed to evaluate the biomechanical response or load transfer on the osteoporotic L1 vertebra under torsional loading. Methods: To achieve this goal, a numerical model of osteoporotic vertebra in various trabecular bone degenerations was developed and tested. The mechanical behavior of the model was represented taking into account the anisotropic properties of the cancellous bone, which provided a more realistic mechanical picture of the biological subsystem. To ensure the reliability of osteoporotic degradation, the thinning of cortical bone and the appearance of gaps between trabecular bone and cortical bone were also taken into account when creating the models. Results: Finite element (FE) analysis showed that the deformations of cortical bone thinning and detachment of the cortical bone from the trabecular tissue lead to local instability of the vertebra. As a result, the cortical bone of a vertebra loses its load-bearing capacity, even if the strength limit is not reached. Conclusions: The results obtained allow us to state that taking into account the thinning of the trabeculae, which creates voids, is extremely important for load-bearing capacity of osteoporotic vertebrae. However, a limitation of this study is the lack of experimental data to ensure consistency with the computer simulation results.

Investigation of the Role of Osteoporotic Vertebra Degeneration on the Stability of the Lumbar Spine: In Silico Modelling under Compressive Loading.

An evaluation of the impact of osteoporosis on loss of spinal stability, with or without intervertebral disc degeneration, using computational analysis is presented. The research also investigates the correlation between osteoporosis and intervertebral disc degeneration. Three-dimensional finite element models of human lumbar spine segments were used to assess the influence of osteoporosis on spinal stability. Five different models of age-related degeneration were created using various material properties for trabecular bone and intervertebral discs. Calculation results indicate that in a spine with osteoporosis, the deformation of the intervertebral discs can increase by more than 30% when compared to a healthy spine. Thus, intervertebral disc deformation depends not only on the degree of degeneration of the discs themselves, but their deformation is also influenced by the degree of osteoporosis of the vertebrae. Additionally, the load-bearing capacity of the spine can decrease by up to 30% with osteoporosis, regardless of the degree of intervertebral disc deformation. In conclusion, osteoporosis can contribute to intervertebral disc degeneration.