Journal of neurosurgery
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Journal of neurosurgery · Jul 2003
Immunohistochemical analysis of the extracellular matrix in the posterior capsule of the zygapophysial joints in patients with degenerative L4-5 motion segment instability.
Although the hypertrophied shape of the zygapophysial joints in degenerative instability of the lumbar spine is well known, its underlying pathophysiological mechanism is unclear. The authors sought to provide evidence that there is increased fibrocartilaginous metaplasia in the posterior joint capsule resulting from greater mechanical loading; the authors suggest that these capsular changes are central to understanding the altered joint shape. ⋯ The results of this study provide molecular evidence for an altered loading history on the joint capsule. The pronounced loss of intervertebral disc height that occurred in all patients with severe degeneration of the lumbar motion segment promotes an increased range of axial rotation that places the posterior capsule under greater mechanical load. Compared with normal joints studied previously, the posterior capsules involved in these degenerative joint complexes were hypertrophied and fibrocartilaginous throughout. Cartilaginous metaplasia was especially pronounced at the attachment sites (entheses) where the fibrocartilage now extended beyond the original level of the joint space, and capped the osseous spurs arising from these attachment sites.
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Journal of neurosurgery · Jul 2003
Comparative StudyIn vitro biomechanical comparison of pedicle screws, sublaminar hooks, and sublaminar cables.
Three types of posterior thoracolumbar implants are in use today: pedicle screws, sublaminar titaniumcables, and sublaminar hooks. The authors conducted a biomechanical comparison of these three implants in human cadaveric spines. ⋯ These findings suggest that screws possess the greatest pullout strength of the three fixation systems. Sublaminar cables are the least rigid of the three. When screw failure occurred, the mechanism was generally screw back-out, without vertebral fractures.
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Journal of neurosurgery · Jul 2003
Kyphoplasty for vertebral compression fractures: 1-year clinical outcomes from a prospective study.
Over the past 15 years, vertebroplasty has emerged as a treatment for vertebral compression fractures. This technique, however, does not restore vertebral height and is associated with a high rate of cement leakage. Recently, kyphoplasty was developed in an effort to circumvent this problem. Although its immediate results have been reported, it is unclear whether the benefits endure. ⋯ Kyphoplasty is an effective treatment for vertebral compression fractures. The benefits presented in the early postoperative period and persisted at 1 year posttreatment.
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Journal of neurosurgery · Jul 2003
Case ReportsCategory-specific naming deficit identified by intraoperative stimulation mapping and postoperative neuropsychological testing. Case report.
Category-specific naming deficits and differential brain activation patterns have been reported in patients naming living as opposed to nonliving objects. The authors report on a case in which they used preoperative functional magnetic resonance (fMR) imaging, intraoperative electrocortical stimulation mapping (ESM), and postoperative neuropsychological testing to map language function. ⋯ These authors are the first to identify a specific and well-localized area of category-specific naming in the inferior temporal lobe and to demonstrate congruence of intraoperative and postoperative category-specific naming deficits. They also emphasize the roles of preoperative and intraoperative testing in predicting clinical outcomes.
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Journal of neurosurgery · Jul 2003
Case ReportsSpinal cord edema: unusual magnetic resonance imaging findings in cervical spondylosis.
Spinal cord edema is a rare radiological finding in chronic degenerative disorders of the spine. Between 1997 and 2001, the authors treated six patients with cervical spondylotic myelopathy in whom postoperative spinal cord edema was demonstrated. The authors describe the radiological and clinical features of this unusual condition. ⋯ The radiological characterization of spinal cord edema was based on the reversible white matter lesion most likely caused by disturbed local venous circulation induced by chronic spinal cord compression. Such unusual MR findings in cervical spondylotic myelopathy should be differentiated from intramedullary spinal cord tumors, demyelinating disorders, or inflammatory processes.