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Effects of Whole Body Vibration on the Elderly
Published in Redha Taiar, Christiano Bittencourt Machado, Xavier Chiementin, Mario Bernardo-Filho, Whole Body Vibrations, 2019
Maíra Florentino Pessoa, Helga C. Muniz de Souza, Helen K. Bastos Fuzari, Patrícia E. M. Marinho, Armèle Dornelas de Andrade
Another aspect to be considered is the presence of osteoporosis or even osteopenia, associated with the risk of fractures. Osteoporosis is a metabolic condition identified by progressive decrease in bone density. Therefore, bones become more porous and lose resistance over time; in this context, the use of WBV has also been valuable, acting directly on improving bone density (Slatkovska et al., 2010; Segal et al., 2012).
X-ray computed tomography
Published in Elaine DiMasi, Laurie B. Gower, Biomineralization Sourcebook, 2014
Xianghui Xiao, Stuart R. Stock
Osteoporosis is a skeletal disease characterized by low bone mass, microarchitectural deterioration, and altered nanoscopic properties of bone (i.e., lowered material quality). The result is bone fragility and increased susceptibility to fracture. In 2004, an estimated 10 million Americans older than 50 years had osteoporosis, with 1.5 million fragility fractures occurring in these patients each year, and an additional 34 million Americans were at risk (US Surgeon General 2004). Osteoporosis is a significant biomineralization problem in that it may relate to an imbalanced bone removal versus bone addition during remodeling (Raisz 2008) or to changes in the mineralized tissue material properties (Ritchie et al. 2006). Dual-energy x-ray absorptometry (DXA) is a radiographybased approach for diagnosing osteopenia (lower than normal bone mineral density) and osteoporosis (Chun 2011). DXA measures the transmission of x-rays (at two tube potentials) through selected bone sites. Clinical CT is problematic for in vivo osteoporosis studies, because sites of greatest concern, the femoral neck and vertebrae (Harvey et al. 2010), are dominated by trabecular bone with relatively thin cortices and large amounts of bone partial volumes, making it di cult to quantify architectural parameters (volume fraction of mineralized tissue BV/TV, mean trabecular thickness <Tb. .>, connectivity, structure model index SMI (parameter quantifying how rod- or plate-like the structure is on average), etc. (Hildebrand and Rüegsegger 1997b; Odgaard 2001; see following section) or cortical thicknesses. Some progress is being made through advanced image analysis (Treece et al. 2012). Femoral head failure during sideways falls is reasonably well predicted by CT-based FEM, which also correlates with DXA-based measures of bone mineralization (Koivumaki et al. 2012). Quality of implant xation in the hip has also been studied with CT-based FEM (Shim et al. 2012). An ex vivo scan of a human femoral head is shown in Figure 15.3. Here, the trabeculae and thin cortex are clearly visible, and quanti cation of microarchitectural parameters would be straightforward. This particular specimen exhibits fracture, with the neck of the femur being partially pushed into the head and locally crushing the preexisting trabeculae. Formation of a fracture callus shows where healing is progressing. With voxel size of 26 m, the data in Figure 15.3 falls into the realm of microCT. The entire skeleton of small animals can be imaged and used to establish the phenotype of different knockout models. Examples
The Influence of Ageing on Mechanical Behaviour of Intervertebral Segment
Published in J. Middleton, M. L. Jones, G. N. Pande, Computer Methods in Biomechanics & Biomedical Engineering – 2, 2020
E.A. Meroi, A.N. Natali, H. Trebacz
The analysis pertains to normal and aged intervertebral segment. Osteopenia is physiological result of ageing and pathologically increased osteopenia can result in osteoporosis. Some general indications can be given as result of the analysis. The average value of load supported by cortical ring is approximately 60% and a slight increase of load transmitted by cortical shell is observed, about 10% more in thinner shell for old person. This is in agreement with experimental testing: cortical thickness has a primary role for the in vitro compressive strength of the whole vertebral body [3]. Even if shell thickness decreases slightly with age, considerable evidence indicates that decrease in trabecular bone mass and strength are the primary causes of age-related reductions in vertebral strength, and that the relative contribution of the shell to vertebral strength actually increases with age [2]. Mosekilde also observed that the relative load bearing effect of the cortical ring increases with age as the trabecular bone strength decreases [8]. Compact bone fails in compression with strains in the range 1.4% to 2.1%, but begins to yield at strains between 0.6% and 0.8%. Given that yielding involves rapid accumulation of microdamage within the bone, it seems adequate to base skeletal safety factors on the yield strain, rather than the ultimate failure strain of bone tissue [8] and 0.006 could be assumed as a limit value for strain in old bone. The maximum value for ultimate strain in vertebral core is about 2% [13]. In our model, at the same equivalent vertical load level, correspondent to different vertical imposed displacement, maximum compressive strain varies from 0.26% in young to 0.5% in old cortical bone and from 0.93% in young to 2% in old trabecular bone. It seems that the critic values are reached almost at the same time for cortical and trabecular bone, but when trabecular bone reaches the limit value, the cortical part is still under its limit strain. This is in agreement with the fact that in symptomatic osteoporosis the fractures often occur in the central trabecular bone without affecting the surrounding cortical ring. Different conditions of disc degeneration are considered, in terms of compressibility and hyperelastic coefficients for disc ground material. The importance of a proper description of disc behaviour is evidenced by its influence on stress distribution patterns and on deformed configuration, and this is in accordance with the observed relation between the degree of disk degeneration and fracture type [9]. If the disc response in time is under investigation, a poroelastic model can be adopted [26, 27].
Analysis of stress and stabilization in adolescent with osteoporotic idiopathic scoliosis: finite element method
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Qiaolin Zhang, Yan Zhang, Teo. Ee Chon, Julien S. Baker, Yaodong Gu
Osteoporosis (OP) is one of the most common metabolic bone disorders, and its increasing prevalence in the elderly population has become a major health problem. OP rarely affects adolescents (Saggese et al. 2001), but its prevalence is significantly higher in patients with adolescent idiopathic scoliosis (AIS) than in the general pediatric and adolescent populations (Cheng et al. 2000). There is a strong correlation between osteopenia and AIS. In 1982, Burner et al. (1982) reported for the first time that children with idiopathic scoliosis have osteopenia and are more prone to OP, several other investigators have confirmed low bone mineral status and other characteristics of OP in 27% to 38% of patients with AIS (Burner et al. 1982; Thomas et al. 1992; Cheng and Guo 1997; Cheng et al. 1999). Furthermore, osteopenia or OP had been reported to be one of the causes of scoliosis curvature aggravation (Hung et al. 2005). OP AIS osteopenia is systemic, including the spine, ilium, distal tibia, and calcaneus. If this systemic osteopenia causes a decrease in bone strength and bone mass, it can further lead to OP, osteoporotic fracture, aggravation of scoliosis, and other related complications in later adulthood.
Relating mechanical properties of vertebral trabecular bones to osteoporosis
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
R. Cesar, J. Bravo-Castillero, R. R. Ramos, C. A. M. Pereira, H. Zanin, J. M. D. A. Rollo
Osteoporosis is the most common osteometabolic disease in old age, especially in women, resulting in higher morbidity and mortality rates (Schweser and Crist 2017; Sozen et al. 2017; Kanis et al. 2018). This disease occurs when there is an imbalance between bone formation and reabsorption (turnover). This process causes a progressive reduction in mineral density (BMD) and mechanical resistance, increased fragility and risk of bone fracture ( (Fonseca et al. 2014; Chandran 2017; Sandino et al. 2017 ). Usually, fractures associated with this disorder have a higher occurrence in regions of the trabecular bone as the neck of the femur and vertebrae (Ballane et al. 2017; Borges et al. 2017; Loures et al. 2017). DXA is considered the gold standard for estimating the BMD, mechanical resistance and risk of bone fracture (Hans and Baim 2017; Michael Lewiecki and Binkley 2017; Subramaniam et al. 2018). However, BMD by itself does not fully explain the variation in bone strength and fracture risk in the clinical treatments (Griffith and Genant 2008; Tawara et al. 2010; Perilli et al. 2012). Therefore, complementary evaluation is fundamental to the success in determining fracture risk associated with osteoporosis (Curtis et al. 2017; Sandino et al. 2017; Ripamonti et al. 2018; Tomasevic-Todorovic et al. 2018). Osteopenia is a condition in which bone density levels are lower than normal but not as low as in osteoporosis. The World Health Organization (WHO) used the BMD as a T-score to classify individuals young normal (> -1,0), osteopenic (between -1.0 and -2.5), and osteoporotic (≤ -2.5) (Karaguzel and Holick 2010; Dimai 2017).
Surveillance results and bone effects in the Gulf War depleted uranium-exposed cohort
Published in Journal of Toxicology and Environmental Health, Part A, 2018
Melissa A McDiarmid, Marianne Cloeren, Joanna M Gaitens, Stella Hines, Elizabeth Streeten, Richard J. Breyer, Clayton H. Brown, Marian Condon, Tracy Roth, Marc Oliver, Lawrence Brown, Moira Dux, Michael R. Lewin-Smith, Frederick Strathmann, Maria A. Velez-Quinones, Patricia Gucer
Dual-energy x-ray absorptiometry (DXA) which measures bone mineral density, and enables the diagnosis of low bone mass (osteopenia) and osteoporosis has been performed on cohort members as these subjects reached the age of 50 years. A GE Lunar iDXA densitometer (analysis version 13.40) was used to measure bone mineral density at 5 sites (left and right total hip, left and right femoral neck and lumbar spine L1-4). A team of clinicians including a board-certified radiologist and endocrinologist then reviewed all the DXA scan images, blinded to the DU exposure group status of the subject, to identify any sites that needed to be excluded based on artifact, based upon guidelines from International Society for Clinical Densitometry (ISCD) (Schousboe et al. 2013). Several specific lumbar levels were identified that met criteria for exclusion based upon pathologically high bone density due to sclerosis. In these cases, the mean lumbar spine bone mineral density (BMD) was calculated using the remaining lumbar levels.