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Biomechanical Factors (biomechanical + factor)
Selected AbstractsSpinal degenerative disk disease (DDD) in female macaque monkeys: epidemiology and comparison with womenJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 3 2002Patricia Ann Kramer Spinal degenerative disk disease (DDD) in a radiographic, cross-sectional sample of 192 female macaque monkeys, approximately 5,30 years old, is described. The presence and extent of disk space narrowing (DSN) and anterior osteophytosis were assessed with reference to age, average lifetime body mass, and distribution within the thoracolumbar spine. Age was a strong correlate of disk narrowing and osteophytosis, with early signs appearing at equivalent ages in both species and increasing in prevalence thereafter. Macaques showed a far greater prevalence of DDD, especially in the oldest age group, than has been reported in the human data. Body mass was associated with disk narrowing in the macaque, but not with osteophytosis. The two species differed little in the pattern of distribution of DDD along the spine. Our results suggest that bipedality is not the singular, or even the most important, biomechanical factor in the development of human DDD. Rather, others shared postural regimes, e.g., sitting, may be responsible for the onset and progression of DDD in both species. The macaque model could substantially add to the under-standing and, potentially, treatment of this oftentimes debilitating condition. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] Individual and combined impacts of biomechanical and work organization factors in work-related musculoskeletal symptoms,,AMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 5 2003Grant D. Huang MPH Abstract Background Investigations of work-related low back (LB) and upper extremity (UE) disorders have increasingly utilized multivariable models that include biomechanical/physical and work organization factors. However, the nature of any interactive effects is not well understood. Methods Using questionnaires, high and low exposure groups for biomechanical/physical factors, cognitive demands, cognitive processing, interpersonal demands, participatory management, skill discretion, and time pressure for 289 individuals (U.S. Marines) were identified. Musculoskeletal symptom status was also determined by questionnaire. Individual and biomechanical,psychosocial combinations were examined in adjusted multivariable logistic regression analyses. Results Time pressure was associated with both LB and UE symptoms (odds ratio(s) (OR) range,=,2.13,3.09), while higher biomechanical exposures were risk factors for LB symptoms (OR,=,2.07; 95% confidence intervals (CI): 1.00,4.35) and concurrent LB and UE symptoms (OR,=,2.80; CI: 1.35,5.83). Greater risks for concurrent LB and UE symptoms were indicated for combinations involving higher biomechanical exposure and: time pressure (OR,=,2.21; CI: 1.19,4.10); cognitive demands (OR,=,2.25; CI: 1.23,4.09); cognitive processing (OR,=,2.08; CI: 1.16,3.75); interpersonal demands (OR,=,2.44; CI: 1.35,4.41); participatory management (OR,=,2.50; CI: 1.30,4.81). Results did not suggest any interaction between biomechanical and work organization factors. Conclusions While no synergism was indicated, the present findings emphasize the need to consider both biomechanical factors and specific work organization factors, particularly time pressure, in reducing musculoskeletal-related morbidity. Am. J. Ind. Med. 43:495,506, 2003. Published 2003 Wiley-Liss, Inc. [source] Asymmetry of the os pubis: Implications for the Suchey-Brooks methodAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2009Rebecca S. Overbury Abstract Studies of skeletal development frequently document populational incidences of bilateral asymmetry. Degenerative morphological skeletal changes, attributed to age related and irregular ossification, may also progress asymmetrically, either as the result of asymmetric biomechanical factors expressed over the lifespan, asymmetric expression of physiological processes, or progressive magnification of asymmetry acquired previously during development. This study illustrates the effects of bilateral asymmetry on age at death estimates obtained from human skeletal remains. The Suchey-Brooks method, which uses the pubic symphyseal face for age estimation (Katz and Suchey, Am J Phys Anthropol 69 1986 427,435), was selected for the study based on its widespread use. Asymmetry in the Suchey-Brooks symphyseal age phases was found in over 60% of a sample composed of 20th century White male individuals from 18 to 86 years of age (N = 130). However, results suggest that the presence of asymmetry does not compromise the accuracy of the Suchey-Brooks method if the morphologically older symphyseal face of an asymmetric individual is used to estimate age at death. In addition, weak directional asymmetry and a correlation between age and asymmetry were found. This suggests that a comparison of asymmetry in this area with that in other skeletal areas, where the factors originating and influencing asymmetry are better understood, may be useful in better understanding the biological processes which underlie the age markers used in the Suchey-Brooks method. Am J Phys Anthropol 2009. © 2009 Wiley-Liss, Inc. [source] Intervertebral disc degeneration: New insights based on "skipped" level disc pathologyARTHRITIS & RHEUMATISM, Issue 8 2010Kenneth M. C. Cheung Objective Typically, age and abnormal physical loading ("wear and tear") have been associated with the development of intervertebral disc degeneration. In the past decade, various additional etiologic factors for disc degeneration have been sporadically reported in the literature; however, many investigators continue to place tremendous emphasis on the effects of age and biomechanics associated with disc degeneration. The aim of this study was to provide additional insight into the notion that age and biomechanics are key factors in the development of disc degeneration. To this end, we addressed the prevalence of and risk factors associated with a unique pattern of disc degeneration of the lumbar spine, "skipped" level (nonconsecutive) disc degeneration (SLDD). Methods As part of a large genetics-based study in southern Chinese individuals (n = 1,989), a cross-sectional analysis was performed in subjects exhibiting disc degeneration in ,2 levels (n = 838) who were then categorized as having SLDD (n = 174) or non-SLDD (contiguous, multilevel; n = 664). Various radiographic parameters were assessed based on T2-weighted magnetic resonance imaging (MRI). Subject demographics were assessed, and univariate and multivariate logistic regression analyses were performed. Results Overall, 8.7% of the whole population (n = 1,989) had SLDD, while it was present in 20.8% of subjects with multilevel disc degeneration (n = 838). SLDD was more prevalent in male subjects (adjusted odds ratio [OR] 1.48, 95% confidence interval [95% CI] 1.04,2.10, P = 0.028). SLDD was significantly associated with the presence of Schmorl's nodes (adjusted OR 2.72, 95% CI 1.78,4.15, P < 0.001), which also presented in levels with no disc degeneration. A history of disc bulge/extrusion (P = 0.004) and/or a history of back injury (P = 0.010) was significantly associated with non-SLDD, and a greater degree of overall severity of disc degeneration was also associated with non-SLDD. Other demographic and MRI findings did not significantly differ between groups. Conclusion To our knowledge, this report is the first to describe the prevalence and risk factors associated with SLDD. Our study challenges the paradigm that age and biomechanics are the key factors associated with the development of disc degeneration. Although age and biomechanical factors may play a role in the manifestation of disc degeneration, our novel findings of SLDD patterns provide further awareness of and support for the notion that additional etiologic factors may play a role in the development of disc degeneration. Such factors warrant further investigation to shed light on the cause of disc degeneration. [source] 2151: Interaction of vascular and biomechanical aspects of glaucomaACTA OPHTHALMOLOGICA, Issue 2010M LESK Purpose In an attempt to understand some of the reasons why some optic nerves appear to be sensitive to IOP and others not, I will review studies describing the interaction between vascular and biomechanical factors in open angle glaucoma. Methods Studies using biomechanical modelling, epidemiologic data, measurements of ocular or systemic blood flow, measurment of peripheral vasospasticity, and measurement of ocular biomechanical parameters will be reviewed. Hypotheses will be presented regarding the interpretation of these data. Results Studies suggest that the optic nerves of vasospasctic patients may be more IOP-sensitive than those of non-vasospastic patients. Non-invasive measurements of ocular blood flow suggest that this pressure-sensitivity may be related to IOP-sensitive optic nerve blood flow. Biomechanical modelling suggests that scleral and lamina cribrosa elasticity, axial length, and eye wall thickness contribute to optic nerve head stress and strain. Cross-sectional clinical data supports the role of increased ocular elasticity in the susceptibilty of the optic nerve to glaucoma damage, especially in vasospastic patients. Some promising new avenues for research in this area will be presented. Conclusion There is increasing evidence that biomechanical and vascular ocular factors interact leading to an elevated susceptibilty of the optic nerve to glaucomatous optic nerve damage. Commercial interest [source] Biomechanics/risk management (Working Group 2)CLINICAL ORAL IMPLANTS RESEARCH, Issue 2009Mariano Sanz Abstract Introduction: The remit of this workgroup was to update the existing knowledge base in biomechanical factors, navigation systems and medications that may affect the outcome of implant therapy. Material and methods: The literature was systematically searched and critically reviewed. Five manuscripts were produced in five specific topics identified as areas where innovative approaches have been developed in biomechanical factors, navigation systems and medications that may affect the outcome of implant therapy. Results: The results and conclusions of the review process are presented in the following papers, together with the group consensus statements, clinical implications and directions for future research: , To what extent do cantilevers affect survival and complications of implant supported restorations in partially dentate patients? , To what extent does the crown,implant ratio affect survival and complications of implant supported restorations? , A systematic review on the accuracy and the clinical outcome of computer-guided template based implant dentistry. , What is the impact of systemic bisphosphonates on patients undergoing oral implant therapy? , What is the impact of anticoagulants on patients undergoing oral implant therapy? [source] | |||||||||||||