Journal of spinal disorders
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Axial computed tomography scans were performed on 14 cadaveric cervical spines to determine the location of the vertebral artery foramen on the anterior aspect of the lower cervical spine. The best scan through the vertebral artery foramen from each level at C3-C6 was selected. Measurements of the vertebral artery foramen included the foramen depth, foramen width, interforaminal distance, the distance from the anterior border of the transverse foramen to the anterior border of the transverse process, the distance from the posterior border of the transverse foramen to the posterior border of the lateral mass, and the distance from the medial border of the vertebral artery foramen to the lateral border of the vertebral body. ⋯ The average distance between the anterior borders of the vertebral artery foramina and the anterior border of the vertebral body gradually decreased from C3 (8.4 +/- 1.4 mm) to C6 (7.0 +/- 1.6 mm). This study suggested that the lateral border of the vertebral body may be a reliable landmark during anterior cervical decompression. The vertebral artery foramen should be free of violation if vertebrectomy or subtotal vertebrectomy is performed medial to the lateral border of the vertebral body.
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Because false-positive results are not infrequent when monitoring somatosensory evoked potentials during surgery, monitoring of motor evoked potentials (MEPs) has been proposed and successfully used during the removal of spinal cord tumors. However, this often requires direct visual placement of an epidural electrode after a laminectomy. We evaluated the use of MEPs, recorded via a transcutaneously placed epidural electrode, to monitor motor pathway functional integrity during surgery on the anterior cervical spine. ⋯ Patients showed no significant changes in spinal MEPs during surgery, and all had baseline or better motor function postoperatively. None had complications from epidural electrode placement or electrical stimulation. We conclude that motor pathways can be monitored safely during anterior cervical spinal surgery using spinal MEPs recorded via a transcutaneously placed epidural electrode, that MEP preservation during surgery correlates with good postoperative motor function, and that cerebral palsy patients may possess too few functional motor fibers to allow MEP recording.
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Only a few plate systems are available for anterior fixation of thoracolumbar vertebrae because of the difficulty in fastening a screw and a plate together. If the fixation is inadequate, the screws will become loose. The Rigix plate system consists of screws made of titanium alloy and a plate made of pure titanium. ⋯ In patients treated for bone metastases, the reconstructed spinal structure was able to be maintained for a long period. Of the screws used, five (5%) were not able to remain fixed as intended because they were inserted at inappropriate angles into the plate, but the fixation itself was excellent. Because of the low profile, ease of manipulation (mean instrumentation time was 25 min), and compatibility with magnetic resonance imaging, the Rigix plate is useful for anterior fixation of thoracolumbar vertebrae.
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Biography Historical Article
The lumbar spine--small is beautiful: the Third Annual Ian Macnab Memorial Lecture.
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Thirty-four patients with adolescent idiopathic thoracolumbar, lumbar, or lumbar components of double major curves between 20 and 55 degrees were identified. This study group was compared with an age- and sex-matched control group with regard to back pain, radicular symptoms, and perception of handicap. The objectives of this study were to define the natural history of moderate-range adolescent idiopathic thoracolumbar, lumbar, and double major curves with a lumbar component in this range. ⋯ None of the 34 study patients and 1 control patient underwent surgery for back pain. With an average follow-up of 22 years, the study group reported handicap scores comparable to those of the control group. The average age of the study patients was only 36 years, but it is encouraging that these individuals have continued to do well for at least 20 years past skeletal maturity.