The spine journal : official journal of the North American Spine Society
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Insertion of intervertebral fusion devices between consecutive Smith-Peterson osteotomies (SPOs) provides an anterior fulcrum during compression, which has been documented to improve achievable Cobb angle correction. Extension of these principles to an expandable device would theoretically provide greater surgical adjustment for flatback and scoliotic cases than a static cage. ⋯ The expandable interbody did have a slight effect on lordotic correction; each additional millimeter in height expansion yielded approximately 1° in correction across the three SPO levels. Even without significant differences between the states, an expandable device may allow the surgeon more control of lordotic correction within the operating room than a static spacer alone.
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The presence or absence of marrow edema is used in the assessment of fracture acuity in magnetic resonance imaging (MRI). We have observed variability in the degree of marrow edema in acute trauma. Our aim was to characterize the utility of marrow edema in fracture detection and fracture acuity on MRI. We hypothesized that only vertebral body compression injuries reliably generate marrow edema and that distraction injuries or fractures without compression do not reliably generate marrow edema and may give a false negative MRI examination. ⋯ There is variability in the presence or degree of marrow edema on MRI evaluation after traumatic injury. Only fractures derived from vertebral body compression reliably generate marrow edema. Fractures without compression and/or fractures with distraction do not reliably generate marrow edema and can lead to a false negative MRI. An awareness of fracture types that produce more or less marrow edema can be beneficial when evaluating fractures by MRI.
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Comment
Anterior cervical discectomy and fusion surgery for cervical radiculopathy: is time of essence?
Burneikiene S, Nelson EL, Mason A, Rajpal S, Villavicencio AT. The duration of symptoms and clinical outcomes in patients undergoing anterior cervical discectomy and fusion for degenerative disc disease and radiculopathy. Spine J 2015;15:427-32 (in this issue).
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Intervertebral disc (IVD) degeneration, a major cause of low back pain, is considered to be induced by daily mechanical loading. Mechanical stress is widely known to affect cell survival and extracellular matrix metabolism in many cell types. Although the involvement of integrin α5β1 transmembrane mechanoreceptor in IVD degeneration has been reported, the precise function of integrin α5β1 remains obscure. ⋯ The dynamic loading organ culture system simulated cellular responses to mechanical loading of the IVD. Our results suggest that IVD cells recognize the mechanical stress through RGD integrins, particularly the α5β1 subtype that is highly expressed in NP and AF cells. Further experiments using this system will provide information about pathomechanisms of IVD degeneration through the mechanotransduction pathways.
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Previous studies have demonstrated the use of bone marrow mesenchymal stem cells (BMSCs) in tissue-engineering treatments to slow or reverse diseased intervertebral discs. Several approaches have successfully used the coculturing of stem cells with disc-native nucleus pulposus cells (NPCs) with the evidence of transformed BMSCs into NP-like cells, increased activity and matrix production by NPCs, or elements of both. The influence of the cytokine transforming growth factor-beta (TGF-β) in the differentiation of BMSCs into NP-like cells and its upregulation in coculture to increase matrix production are well established. However, the role of the inflammatory signaling molecule nuclear factor kappa B (NF-κB) in intervertebral disc degeneration is far less clear, although there is some existing evidence suggesting its role in the pathogenesis and progression of disc disease. A limited number of studies in other pathologies have alluded to the antagonistic relationship between both proteins. To date, there is no such investigation of their dynamic role in coculture of BMSCs and NPCs. ⋯ Coculture of BMSCs may be able to delay NPC matrix degeneration potentially through the concomitant upregulation of TGF-β and the downregulation of NF-κB pathway.