European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society
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The aim of this study was to determine the impact of free hydration on the mechanical parameters of the annulus fibrosus (AF) of the intervertebral disc (IVD), determined in a standard manner. Attention was also given to the hydration occurring in real time and geometric changes resulting from swelling of the AF. ⋯ The tests showed a significant dependence of the determined mechanical parameters on the cross-sectional area. The larger the cross-sectional area, the lower the obtained value of stress. By contrast, the value of the stiffness coefficient is independent of the cross-sectional area. The differences in mechanical parameters are related mainly to water absorption into structures of the AF during hydration. This is confirmed by microscopic analysis of geometric dimensions of the AF during hydration conducted in real time. The greatest changes occurred in the radial direction, where the thickness increased by 2.05 mm, while in the axial direction the main change concerned an increase in height by 0.69 mm. There were negligible changes in the circumferential direction.
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To examine the influence of volitional preemptive abdominal contraction (VPAC) and recurrent low back pain (rLBP) on trunk mechanics and neuromuscular control during a symmetric lifting task. ⋯ Our results provide evidence that a VPAC strategy performed during symmetric lifting may potentially reduce exposure to biomechanical factors that can contribute to lumbar spine injury. The hamstring muscles may play an important role in achieving pelvic balance during the lifting maneuver. Incorporating the VPAC during dynamic stressful activities appears to help improve sensorimotor control and facilitate positioning of the lower extremities and the pelvis, while protecting the lumbar spine.
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The aim of this study was to evaluate the lumbar trunk parameters by MRI and investigate their association with chronic low backache. ⋯ Tendency of smaller trunk musculature CSA may be a cause or a result of chronic LBP. A unique pattern of larger CSA at L3-L4 and L4-L5 disc levels and smaller CSA at L5-S1 of Rectus abdominis muscles is observed in LBP patients compared to healthy persons. Differences in disc angles and CSA of disc at L3-L4 and L4-L5 levels between the two groups signify that these may be the predisposing factors leading to LBP due to abnormal load/stress transmission and precipitating early degenerative changes in the disc.
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To evaluate the influence of osteoporosis on the microarchitecture and vascularization of the endplate in rhesus monkeys with or without intervertebral disc (IVD) degeneration using micro-computerized tomography (micro-CT), and to further analyze the correlation between osteoporosis and IVD degeneration. ⋯ In conclusion the osteoporosis could accumulate the calcification and decrease the vascularization in the endplates adjacent to the degenerated IVDs, which subsequently exacerbated degeneration of the degenerated IVDs.