CESAR AUGUSTO MARTINS PEREIRA
Projetos de Pesquisa
Unidades Organizacionais
Departamento de Ortopediae Traumatologia, Faculdade de Medicina
LIM/41 - Laboratório de Investigação Médica do Sistema Músculoesquelético, Hospital das Clínicas, Faculdade de Medicina
LIM/41 - Laboratório de Investigação Médica do Sistema Músculoesquelético, Hospital das Clínicas, Faculdade de Medicina
3 resultados
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- Biomechanical Trabecular Bone Behavior of Calcaneus Samples Using Finite Element Analysis and Experimental Tests(2014) CESAR, R.; BLANCO, J. O.; CASTILLERO, J. B.; RODRIGUEZ-RAMOS, R.; KUNKEL, M. E.; PEREIRA, C. A. M.; NETTO, A. M.; ROLLO, J. M. D. A.A finite element model was built as a first approximation to the experimental compression tests of trabecular bone samples extracted from the calcaneus of human cadavers. The goal was to simulate and study trabecular bone behavior under load action and to propose a scaffold finite element model, which could represent the trabecular architecture with different porosity values.
- Axial compressive strength of human vertebrae trabecular bones classified as normal, osteopenic and osteoporotic by quantitative ultrasonometry of calcaneus(2017) CESAR, R.; LEIVAS, T. P.; PEREIRA, C. A. M.; BOFFA, R. S.; GUARNIERO, R.; REIFF, R. B. D. M.; NETTO, A. M.; FORTULAN, C. A.; ROLLO, J. M. D. A.Introduction: Biomechanical assessment of trabecular bone microarchitecture contributes to the evaluation of fractures risk associated with osteoporosis and plays a crucial role in planning preventive strategies. One of the most widely clinical technics used for osteoporosis diagnosis by health professionals is bone dual-energy X-ray absorptiometry (DEXA). However, doubts about its accuracy motivate the introduction of congruent technical analysis such as calcaneal ultrasonometry (Quantitative Ultrasonometry - QUS). Methods: Correlations between Bone Quality Index (BQI), determined by calcaneal ultrasonometry of thirty (30) individuals classified as normal, osteopenic and osteoporotic, and elastic modulus (E) and ultimate compressive strength (UCS) from axial compression tests of ninety (90) proof bodies from human vertebrae trabecular bone, which were extracted from cadavers in the twelfth thoracic region (T12), first and fourth lumbar (L1 and L4). Results: Analysis of variance (ANOVA) showed significant differences for E (p = 0.001), for UCS (p = 0.0001) and BQI. Spearman’s rank correlation coefficient (rho) between BQI and E (r = 0.499) and BQI and UCS (r = 0.508) were moderate. Discussion: Calcaneal ultrasonometry technique allowed a moderate estimate of bone mechanical strength and fracture risk associated with osteoporosis in human vertebrae. © 2017, Brazilian Society of Biomedical Engineering. All rights reserved.
- Relating mechanical properties of vertebral trabecular bones to osteoporosis(2020) CESAR, R.; BRAVO-CASTILLERO, J.; RAMOS, R. R.; PEREIRA, C. A. M.; ZANIN, H.; ROLLO, J. M. D. A.Osteoporosis is an osteometabolic disease, which promotes structural degradation of bone tissue and reduction of mineral density. We reported here a mechanical resistance assay from normal, osteopenic and osteoporotic trabecular vertebral bones of human cadavers. We performed a compressed test on ninety samples, evaluating Young's modulus and X-ray microtomography to measure bone volume fraction and trabecular thickness. This experimental data are employed for computing the orthotropic macroscopic behavior of vertebral trabecular bones using known analytical formulae that were obtained by Galka et al. (Arch Mech 51: 335-355, 1999) via an asymptotic homogenization model. A geometrical model with a periodic orthogonal plate-like structure is applied. The properties of the bone-trabecular mass are considered linear, homogeneous and orthotropic. Average values for all technical or engineering elastic properties are computed for three important regions of the trabecular bones corresponding to thirty individuals classified as normal, osteopenic or osteoporotic by calcaneus ultrassometry. This study could be useful for a better understanding of the elastic behavior of trabecular bones in human vertebral bodies, allowing an estimation of bone answer under stress in different directions and the risk of fracture associated with osteoporosis.