Spine
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Computed tomography/discography was performed in 378 patients (403 discs) with lumbar disc herniation receiving intradiscal therapy. The grade of disc degeneration defined by the Dallas discogram description correlated closely with age. ⋯ The development of these herniation routes has been well explained by the findings of earlier histopathologic and biomechanical studies. Computed tomography/discography was very useful in observing the detailed features of HNP such as the range, site of maximum protrusion and protrusion size.
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Pain provocation was analyzed in 1477 intervertebral discs in 523 patients subjected to lumbar computed tomography/discography. The relation between pain provocation and the degree of general degeneration and anular disruption assessed according to the Dallas Discogram Description as indices of intradiscal deterioration was investigated. ⋯ Pain provocation showed little relation to intradiscal deterioration, whereas a strong relation was found between it and herniated nucleus pulposus. in herniated nucleus pulposus, discs with extraligamentous extrusion or sequestration, large protrusions, maximum protrusion site at the nerve root portion, and herniation routes passing through the central portion of the disc showed a high pain provocation ratio. Pain provocation ratios of discs associated with spinal canal stenosis were extremely low.
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The morphologic changes in denervation atrophy of paravertebral muscles after severance of the posterior rami in cats were investigated, using histochemical methods and electromyography. Using a paraspinal approach, three branches of the posterior rami on the left side were cut under microscopy at one, two, or three levels (L2 approximately L4). Muscle atrophy was evaluated, using the percent wet weight and the percent diameter of muscle fibers as parameters. ⋯ Muscle atrophy was revealed at one or two levels caudal to the injured nerve level. At 12 and 24 weeks, muscle atrophy recovered gradually. In more than two-level injury groups, however, recovery of percent wet weight reached up to 80% even after 24 weeks, despite the fact of reinnervation demonstrated in some parts of the denervated muscles.