Spine
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Sequential study of magnetic resonance imaging (MRI) of the spine for assessing the level of termination of the conus medullaris (CMT) and thecal sac (TST). ⋯ The CMT and TST displayed a wide range of values in our study. We detected small but systematic influences of gender and age on CMT and of age on TST, as well as a positive correlation between CMT and TST. These effects are small in amplitude, but they met all the criteria for statistical significance and have practical value for clinicians, as well as theoretical value for the medical and biologic community.
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We propose that chronic spondylolytic defects at L5 are influenced by insufficient differential mediolateral distances between inferior articular facets of L4 and the superior facets of S1, which results in these structures impinging on adjacent sides of the par interarticularis during hyperlordosis. Individuals with adequate increase in interfacet distances from L4 through S1 are less likely to develop or maintain defects. ⋯ Spondylolysis is the direct result of contact pressures on both sides of the pars interarticularis resulting from inadequate separation between the inferior articular processes of L4 and the superior articular facets of S1. Individuals lacking sufficient increase in transverse interfacet dimensions in their lumbar columns are at greater risk of developing and maintaining spondylolytic defects.
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The study used a small animal laminectomy model with kaolin to investigate the relationship of cauda equina pathology to pain, and the effects of systemic and intrathecal drugs to reduce pain. ⋯ An animal model of adhesive lumbar arachnoiditis yields a quantifiable pain-related response that can be used to evaluate the effects of various analgesic interventions.
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This study examined the differences in tactile hypersensitivity across 6 different strains of male mice, and between male and female rats of 3 different strains in a rodent model of low back pain associated with lumbar radiculopathy. ⋯ Different mouse strains, and male and female rats that are exposed to identical nerve root injuries have diverse levels of tactile hypersensitivity, supporting the hypothesis that genetic factors and sex play a key role in radicular pain. Our results correlate with data compiled in identical mouse and rat strains after L5-L6 nerve ligation, suggesting that the precise nature of the injury is not relevant to the inheritance of neuropathic symptom sensitivity.
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Randomized Controlled Trial Multicenter Study Comparative Study
Initial fusion rates with recombinant human bone morphogenetic protein-2/compression resistant matrix and a hydroxyapatite and tricalcium phosphate/collagen carrier in posterolateral spinal fusion.
Prospective, randomized, unblinded study of iliac crest bone graft (ICBG) versus recombinant human bone morphogenetic protein-2/compression resistant matrix (rhBMP-2/CRM)in a posterolateral instrumented fusion procedure. ⋯ These early results are encouraging and suggest a more rapid incorporation and development of the fusion mass with rhBMP-2/CRM than iliac crest autograft in a single level posterior instrumented fusion.