Spine
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Intervertebral disc degeneration was evaluated by morphologic appearance, magnetic resonance imaging, and by biochemical matrix composition. Caliber and distribution of openings of the adjacent vertebral osseous endplates were measured. ⋯ A high indirect correlation between the density of openings in the osseous endplate (particularly of the size of the capillary buds) and the morphologic degeneration grade of the disc support the hypothesis that occlusion of these openings may deprive the cells of nutrients, leading to insufficient maintenance of the extracellular matrix and disc degeneration.
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Case Reports
Lumbar chance fracture in an adult snowboarder: unusual mechanism of a chance fracture.
A case of a Chance fracture in an adult snowboarder following a fall is presented. The mechanism of this fracture is reported. ⋯ Chance fractures are horizontal splitting fractures of the posterior elements of the vertebrae, and the mechanism of the injury is that of a hyperflexion of the spine over a fulcrum. A Chance-type fracture can be seen in an adult snowboarder, when acute hyperflexion of the spine occurs following a fall backward.
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Retrospective study of large-magnitude thoracic curves (> or =90 degrees ) treated with pedicle screw constructs. ⋯ Thoracic pedicle screw constructs can be safely used for large-magnitude curves. Curve correction (68%) is powerful for these curves, which are stiff and difficult to manage. Correction should be performed carefully with consideration given to convex compression for cases with concomitant hyperkyphosis for these "at risk" spinal cords. Screw accuracy (96.3%) was excellent in this review. The authors found that screws can consistently be placed according to the preoperative plan even in these large-magnitude curves.
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Graded endplate injuries were performed in porcine lumbar discs. The effects of such injuries were compared to control animals in which a sham operation was performed. ⋯ Injuries of vertebral endplates in porcine discs were found to cause degenerative changes in the disc tissue on MRI, histologic, and biochemical investigations. The severity of such degenerative changes was related to the severity of endplate injuries. Injuries of vertebral endplate may be one of the pathomechanisms leading to early changes in the disc matrix and eventually to abnormal biomechanical behavior of the whole disc. The present animal model seems to be a suitable experimental model for disc degeneration.
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The time courses of nerve growth factor content and pain-related behavior were examined using experimental disc herniation models. ⋯ These data suggest the possibilities that elevated nerve growth factor level is partly involved in pain behavior and further the combined model mimicking the clinical situation, which causes the marked neuronal responses, is helpful to advance the understanding of the mechanisms underlying sciatica due to lumbar disc herniation.