Spine
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Comparative Study
Biomechanical comparison of unipedicular versus bipedicular kyphoplasty.
A cadaveric study comparing the biomechanics of unipedicular versus bipedicular kyphoplasty in the treatment of osteoporotic vertebral compression fractures. ⋯ Unipedicular kyphoplasty is comparable to bipedicular kyphoplasty in the restoration of vertebral body strength, stiffness, and height in experimentally induced vertebral compression fractures. There was no greater risk for lateral wedging in the unipedicular group compared to the bipedicular group. Given the advantages of a unipedicular approach with respect to vertebral pedicle cannulation risk, operative time, radiation exposure, and cost, this study would support the use of a unipedicular approach to kyphoplasty in the treatment of vertebral compression fractures.
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An in vitro study was conducted to determine the biomechanical properties of a new simple, percutaneous, posterior fixation technique for the lumbar spine involving a new implant, the so-called Lumbar Facet Interference Screw. ⋯ Results of this study indicate that the new Lumbar Facet Interference Screw fixation yields initial biomechanical stability similar to translaminar screw fixation, yet inferior biomechanical stability compared to pedicle screw fixation. Although these results are encouraging, additional biomechanical studies including cyclic loading tests have to evaluate the mid- and long-term stabilization capacity of this new minimally invasive fixation technique before human application.
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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.