European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society
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While much evidence suggests that adjacent segment degeneration is merely a manifestation of the natural degenerative process unrelated to any spine fusion, a significant body of literature supports the notion that it is a process due in part to the altered biomechanics adjacent to fused spine segments. The purpose of this study was to review and critically analyze the published literature that investigated the in vivo kinematics of the adjacent segments and entire lumbar spine in patients receiving spinal fusion or motion-preserving devices. ⋯ There appears to be no overall kinematic changes at the rostral or caudal levels adjacent to a fusion, but some patients (~20-30%) develop excessive kinematic changes (i.e., instability) at the rostral adjacent level. The overall lumbar ROM after fusion appears to decrease after a spinal fusion.
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In the literature, inter-vertebral MRI signal intensity changes (Modic changes) were associated with corresponding histological observations on endplate biopsies. However, tissue-level studies were limited. No quantitative histomorphometric study on bone biopsies has yet been conducted for Modic changes. The aim of this study was to characterise the bone micro-architectural parameters and bone remodelling indices associated with Modic changes. ⋯ Significant differences were found in bone micro-architectural parameters and remodelling indices among Modic types. Modic 1 biopsies had evidence of highest bone turnover, possibly due to an inflammatory process; Modic 2 biopsies were consistent with a reduced bone formation/remodelling stage; Modic 3 biopsies suggested a more stable sclerotic phase, with significantly increased BV/TV and Tb.Th compared to Modic 1 and 2, linked to increased bone formation and reduced resorption.
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The anterior and lateral cervical muscles (ALCM) are generally considered to be postural, yet few studies have investigated ALCM fiber types to help clarify the function of these muscles. This study aimed to systematically investigate ALCM fiber types in cadavers. ⋯ The ALCM do not share a common functional fiber type distribution, although similar fiber type distributions are shared by longus colli and longus capitis, and by the scalene muscles. Contrary to conventional descriptions, longus colli and longus capitis have type I fiber proportions indicative of postural as well as phasic muscle function.
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To explain the intra-operative transcranial motor evoked potential (MEP) monitoring can work well in patients with neural axis abnormality (NAA). ⋯ Intraoperative MEP monitoring can be used accurately and satisfactorily in NAA patients and show no difference compared with AIS.
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Fresh-frozen intervertebral disc transplantation was determined to be an effective treatment for degenerative disc diseases in rhesus monkeys and in humans. Further research in improving different aspects of disc allografts transplantation is needed and will be investigated in large animal models. This study reports the detailed surgical technique of intervertebral disc transplantation without internal fixation and the important notes to ensure success in goats. ⋯ Lumbar intervertebral disc transplantation without internal fixation can be successfully performed in goats.