Spine
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To evaluate the effect of change in screw dimensions and hole augmentation in pedicle screw revisions, the insertional torque was determined, and results were compared with those in control specimens in an in vitro study using cadaveric thoracolumbar spines. ⋯ Removing and replacing a pedicle screw in its original hole substantially decreases its mechanical fixation. For pedicle salvage, increasing the diameter causes the greatest restoration of strength. Shims had no effect in pedicle salvage in osteoporotic specimens.
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A retrospective study was carried out using Shen instrumentation, which is a modified pedicle rod sleeve spinal system, to perform reduction and fusion in patients with unstable thoracolumbar fracture. ⋯ Based on the understanding of biomechanics and the present clinical results, Shen instrumentation is as efficacious as conventional devices available today and may serve as a cost-effective option for thoracolumbar injuries, especially in a developing country.
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Comparative Study
Biomechanical evaluation of translaminar facet joint fixation. A comparative study of poly-L-lactide pins, screws, and pedicle fixation.
Nine sheep cadaveric spines were used in this acute postoperative model. ⋯ The facet joint is the only true articulation in the lumbosacral spine. It is logical to fix this part directly to achieve spine fixation. Translaminar facet joint fixation with screws show similar biomechanical performance to pedicle screw fixation. Translaminar facet joint fixation with poly-L-lactide pins is significantly less stiff than either type of screw fixation, but it also restricts the facet joint and intervertebral motions significantly when compared with the intact spine.
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A 3-week tour of the Far East was coordinated by Dr. Ronald DeWald, senior travelling fellow appointed by the Scoliosis Research Society. Three junior fellows appointed by the Education Committee of the Scoliosis Research Society accompanied him. The purpose of this fellowship was to develop a comaraderie and exchange ideas, thoughts, and experiences in the field of spinal deformity.
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A prospective evaluation of adolescent idiopathic scoliosis patients undergoing operative treatment on the Orthopedic Systems Incorporated (OSI; Jackson) frame. ⋯ Performing adolescent idiopathic scoliosis correction on the OSI frame tends to decrease thoracic kyphosis, increase thoracolumbar lordosis, and increase segmental instrumented lumbar lordosis, while it maintains total lumbar lordosis.