Spine
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An anatomic study of the peripheral nerves innervating the occipital region. ⋯ The results of this study suggest that optimal locations for blockade techniques should be reconsidered. The acquired knowledge concerning greater auricular and minor occipital nerves behind the sternocleidomastoid muscle may aid in preventing intraoperative injuries.
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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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This was a retrospective study of 500 patients undergoing corrective surgery between 1987 and 1997 for spinal deformity caused by idiopathic scoliosis. ⋯ Combined somatosensory-evoked and neurogenic motor-evoked potentials monitoring during idiopathic scoliosis surgery represents a standard of care that obviates the need for an intraoperative wake-up test when reliable data are obtained and maintained.
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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.