The spine journal : official journal of the North American Spine Society
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Brain-derived neurotrophic factor (BDNF) and its cognate receptor, the tyrosine kinase B (TrkB), are normally expressed in neurons and implicated in multiple pathological conditions. Brain-derived neurotrophic factor is produced in the central nervous system microglia in response to noxious stimuli and appear to potentiate central sensitization. Resiniferatoxin (RTX) is an excitotoxic agonist of the vanilloid receptor 1 (VR1), a cation channel protein considered an integrator for nociception. Resiniferatoxin, administered into the dorsal root ganglia (DRG), selectively eliminates the VR1-positive neurons and improves tactile allodynia in a neuropathic pain rat model. ⋯ Resiniferatoxin injection in the DRG of neuropathic rats upregulates BDNF expression in the same pattern as in the large-size neurons of non-neuropathic rats. Therefore, BDNF upregulation may have pain suppressive effects. These effects are likely mediated by TrkB.
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Understanding gene expression patterns of disc cells in culture is important as we develop biologic therapies for disc degeneration. The objective of the present study was to determine if cells from more degenerated discs expressed different genes, or differed in their expression patterns, compared with patterns of cells from healthier discs. ⋯ Data presented here show that annulus cells from more degenerated discs show modified gene expression in 3D culture. Important gene variations involved expression of interleukins, cytokines, ECM components, and apoptosis regulators. Results presented here have potential application in future cell-based biologic therapies for disc degeneration.
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Low back pain (LBP) is a common musculoskeletal disorder associated with a considerable social and economic burden within the working-age population. Despite an unclear etiology, numerous physical activities are suspected of leading to LBP. Declaring a causal relationship between occupational activities and LBP remains challenging and requires a methodologically rigorous approach. ⋯ The studies reviewed did not support a causal association between workplace manual handling or assisting patients and LBP in a Bradford-Hill framework. Conflicting evidence in specific subcategories of assisting patients was identified, suggesting that tasks such as assisting patients with ambulation may possibly contribute to LBP. It appears unlikely that workplace manual handling or assisting patients is independently causative of LBP in the populations of workers studied.
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Review
Causal assessment of occupational carrying and low back pain: results of a systematic review.
Occupational low back pain (LBP) is a common musculoskeletal disorder that results in high healthcare use and a heavy societal burden from morbidity and medical costs. The etiology of LBP is unclear, although numerous physical activities in the workplace have been implicated in its development. Determining the causal relationship between LBP and specific occupational activities requires a rigorous methodological approach. ⋯ This review failed to identify high-quality studies that supported any of the Bradford-Hill criteria to establish causality between occupational carrying and LBP. Based on these results, it is unlikely that occupational carrying is independently causative of LBP in the populations of workers studied.
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Achieving fusion across the lumbosacral junction is challenging because of the unfavorable biomechanics associated with ending a fusion at this level. Bicortical placement of S1 pedicle screws can increase the construct stability at the lumbosacral junction; however, construct failure and pseudoarthrosis can still result. Iliac screws have been shown to increase the stiffness of lumbosacral constructs, but disadvantages include difficulty in connecting the iliac screw to adjacent sacral screws, painful screw loosening or prominence requiring removal, and the inability to place the screws in some patients with previous iliac crest autograft harvest. ⋯ Three-dimensional image guidance allows for safe placement of large S2 sacral alar screws that can provide additional biomechanical stability to lumbosacral constructs or serve as an alternate point of sacral fixation when S1 pedicle screws cannot be salvaged or placed in a medial trajectory.