Spine
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A study of 136 patients with lumbar intervertebral disc herniation was undertaken to test the hypothesis that asymmetry of the facet joints is associated with the level, type, and side of herniation. Fifty cases of central herniation and 86 cases of lateral herniation, all at the L4-5 or L5-S1 levels, were studied by computed tomographic scans. Adjacent (nonherniated) levels were used as controls. ⋯ The mean difference, however, was less than 3 degrees and not considered to be clinically relevant. There was no difference in the distribution of the more coronally or sagittally facing facet joints with respect to the side of lateral herniation. These results do not support the hypothesis that facet asymmetry is associated with lumbar intervertebral disc herniation.
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The effects of core temperature on three potentials--somatosensory spinal evoked potential, somatosensory cortical evoked potential, and spinal motor evoked potential--were studied in rats. Hyperthermia reduced the latency and increased the conduction velocity of all three potentials. Somatosensory spinal evoked potential amplitude was unchanged, whereas somatosensory cortical and spinal motor evoked potentials deteriorated above 42 C. ⋯ The amplitude of the spinal motor evoked potential decreased, and the somatosensory cortical and spinal motor evoked potentials disappeared below 28 C. Hyperthermia and hypothermia caused significant changes in the latency of all three potentials. The latency change of all three potentials became significant at 2-2.5 C above or below baseline, suggesting a range within which evoked potential studies should be performed.
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The interexaminer reliability of an inclinometer procedure to measure lumbar rotation was evaluated by two chiropractic clinicians who examined 25 chronic (greater than 6 months) low-back pain patients and 25 subjects without low-back pain. These groups were compared for differences in mean left, right, and total rotation. Patients who had lumbar spinal surgery were excluded. ⋯ Also, there was significantly more total rotation in the asymptomatic subjects (F = 4.143; df = 1; P less than 0.048). However, because of the large error attributed to this procedure, it is not possible to say whether the difference between the two groups is a result of the large error or some "real" difference. Therefore, the procedure described in this study should not be used as a clinical outcome measure.
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Comparative Study
An analysis of errors in kinematic parameters associated with in vivo functional radiographs.
A pair of functional radiographs, taken at each end of the range of motion, are used to determine spinal motions. Graphic construction and computer-assisted methods are available for the radiographic analysis. The later provides many more motion parameters. ⋯ There were only minimal differences, however, between the digitizers when the radiographic films were remarked and redigitized. The error ranges (2 x SD) for the motion parameters were 1) rotation = +/- 1.25 degrees; 2) translation of the inferior posterior vertebral body corner = +/- 0.86 degrees; and 3) coordinates for the center of rotation = +/- 4.3 mm. Both the spinal level and radiographic quality affected the magnitude of errors in all motion parameters.