Spine
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Comparative Study
Sagittal alignment of the spine and pelvis in the presence of L5-s1 isthmic lysis and low-grade spondylolisthesis.
A radiographic study of 82 patients with L5-S1 spondylolysis or spondylolisthesis of less than 50% displacement of L5 on S1. ⋯ These data suggest that differences in the sagittal alignment of the spine and pelvis may influence the biomechanical environment that results in the development of spondylolysis and progressive spondylolisthesis.
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Prospective observational study. ⋯ These results show that patients with chronic low back pain should be encouraged to continue working up until surgery.
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In vivo histologic study of nerve ingrowth in the rabbit anular-puncture disc degeneration model. ⋯ This study indicates that in the rabbit anular-puncture disc degeneration model, disc degeneration associated with a higher nerve growth into the scar tissue was more evident when induced by a 5 mm than a 1 mm puncture. Although nerve ingrowth was observed in the extruded disc tissue, nerve ingrowth into the outer anulus, which has been reported in patients with discogenic pain, was not observed during the short observation period in this disc degeneration model. The limitation in assessing pain by behavior analysis or histologic evaluation of nerve ingrowth should be considered. Further studies to identify a surrogate marker of pain should be encouraged.
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Immunohistochemical study of the sensory innervation of the human lumbar intervertebral disc. ⋯ Almost all of the nociceptive nerve fibers in the human intervertebral disc are peptide-containing nerve fibers, similar to the rat disc, suggesting that nerve fibers related to inflammation may transmit pain originating from human degenerated intervertebral discs.
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Seven adult human cadaveric cervical spines (C2-T1) were biomechanically tested in a programmable testing device. ⋯ Increase motion compensation occurred at segments immediately adjacent to a single-level fusion. Significant differences occurred at the level above the fusion site for the C3-C4 and C4-C5 fusion in both flexion and extension. When the lower levels (C5-C6, C6-C7) were fused, a significant amount of increased motion was observed at the levels immediately above and below the fusion. However, greater compensation occurred at the inferior segments than the superior segments for the lower level fusions (C5-C6, C6-C7).