Spine
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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.
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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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Comparative Study
A clinical study of degenerative spondylolisthesis. Radiographic analysis and choice of treatment.
Surgical treatment of degenerative spondylolisthesis in 27 patients by means of anterior lumbar interbody fusion and in 14 patients by means of posterior decompression yielded average degrees of recovery of 77% and 56%, respectively. Preoperative analysis of myelograms, and computed tomographies after myelography indicated that anterior shifting of the inferior articular process of the slipping vertebra was the main factor responsible for compression of the nervous tissue in the early stages of degenerative spondylolisthesis. ⋯ In the later stages of degenerative spondylolisthesis, osteophytes on the superior articular processes of the lower vertebra were an additional factor in compression, and patients should be treated by posterior decompression. Computed tomographies after myelography provided the key images for identifying pathologic processes in degenerative spondylolisthesis and selecting appropriate surgical procedures.
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This article has had as its purpose the delineation of the complexity of the production of pain on an organic basis as opposed to any psychological amplification. The issues addressed apply directly to the problem of spinal pain. Classical nociception arising in the structures of the spine thus would include the application of mechanical and chemical stimuli to muscles, ligaments, apophyseal joint capsules, bone, and other structures with adequate innervation, particularly the anterior dura and its extensions. ⋯ Further, the fact that the nervous system changes its activities in response to chronic pain, particularly that arising from damaged neural elements, is of paramount importance in understanding how chronic pain syndromes differ so greatly from simple nociceptive events. Insidious deafferentation ongoing in spinal nerve roots subject to chronic compression and fibrosis offers a fertile field for research into the origin of permanent pain in patients in whom application of accepted therapies does not result in relief. All of this material must be considered by the clinician who is challenged with analyzing spinal pain problems in patients.