Spine
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A technique for posterior cervical hemilaminectomy reconstruction is described. ⋯ The advantages of this technique are restoration of normal anatomy, technical ease, and simplicity. A modification of this technique in children by using absorbable rather than metal plates should allow for normal spine growth.
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Comparative ex vivobiomechanical study. ⋯ Augmentation with Orthocomp results in similar or greater mechanical properties compared with Simplex P, but these biomechanical results have yet to be substantiated in clinical studies.
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A retrospective review of all the surgically managed spinal fractures at the University of Missouri Medical Center during the 41/2-year period from January 1989 to July 1993 was performed. Of the 51 surgically managed patients, 46 were instrumented by short-segment technique (attachment of one level above the fracture to one level below the fracture). The other 5 patients in this consecutive series had multiple trauma. These patients were included in the review because this was a consecutive series. However, they were grouped separately because they were instrumented by long-segment technique because of their multiple organ system injuries. ⋯ The Load-Sharing Classification is a straightforward way to describe the amount of bony comminution in a spinal fracture. When applied to patients with isolated spine fractures who are cooperative with 3 to 4 months of spinal bracing, it can help the surgeon select short-segment pedicle-screw-based fixation using the posterior approach for less comminuted injuries and the anterior approach for those more comminuted. The choice of which fracture-dislocations should be strut grafted anteriorly and which need only posterior short-segment pedicle-screw-based instrumentation also can be made using the Load-Sharing Classification.
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An animal study was performed to evaluate lumbar spinal fusion radiologically and mechanically. ⋯ Spinal arthrodesis using interconnected porous hydroxyapatite alone or mixed with bone as graft material reduced segmental motion. It was not, however, as effective as autologous bone graft material in achieving spinal arthrodesis. The sheep model using autologous bone achieved a 100% fusion rate. Because the nonunion rate for a single level in humans may be as high as 40%, the fusion rate with bone/interconnected porous hydroxyapatite in humans may be lower than the 72% found in the sheep model. The little resorption of the radiodense interconnected porous hydroxyapatite granules made the radiologic evaluation of the fusion masses difficult.