Spine
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Lower lumbar vertebral endplates from young and old sand rats were assessed in an Institutional Animal Care and Use Committee approved study for architectural endplate features using micro-computerized tomography (CT) 3-dimensional (3D) models and vascularization studies by an in vivo vascular tracer or immunocytochemical identification of blood vessels. ⋯ Findings show that disc degeneration in the sand rat occurs concomitantly with marked architectural bony changes on the endplate face, including loss of smoothness and development of irregular bony margins. Vascular connections were not present between the endplate and disc; this was verified with microCT studies, in vivo vascular tracers, and traditional immunocytochemistry. The canal system within the imaged endplate was revealed to consist of a complex 3D interconnected network.
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Comparative Study
Symptomatic and asymptomatic movement coordination of the lumbar spine and hip during an everyday activity.
This experimental study analyzed the movements of the lumbar spine and hip while putting on a sock. ⋯ Changes in the lumbar and hip kinematics when putting on a sock were related to back pain and limitation in SLR. Low back pain will affect lumbar-hip coordination.
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In vivo measurements and model studies are combined to investigate the role of lumbar posture in static lifting tasks. ⋯ Alterations in the lumbar lordosis in lifting resulted in significant changes in the muscle forces and internal spinal loads. Spinal shear forces at different segmental levels were influenced by changes in both the disc inclinations and extensor muscle lines of action as the posture altered. Considering internal spinal loads and active-passive muscle forces, the current study supports the freestyle posture or a posture with moderate flexion as the posture of choice in static lifting tasks.
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Comparative Study
Multilevel spinal growth modulation with an anterolateral flexible tether in an immature bovine model.
A bovine model was used to evaluate the effects of a multilevel anterolateral flexible tether in a growing spine. ⋯ Given adequate bony fixation, a flexible lateral spinal tether can affect growth modulation. This technique of growth modulation may serve as a future fusionless method of correction in a growing patient with scoliosis.
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Comparative Study
Effect of recombinant human bone morphogenetic protein-2 in an experimental model of spinal fusion in a radiated area.
An animal model of posterolateral intertransverse process spine fusion was used. ⋯ Use of rhBMP-2 produced a significantly greater rate of fusion compared with ICBG in a previously radiated area in an animal model, without the morbidity of ICBG harvesting and without the risk of inadvertently using autograft contaminated by micrometastases.