Spine
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A biomechanical study of lumbar threaded interbody cage construct under varying compressive preloads of similar magnitudes to those experienced in vivo during daily activities. ⋯ In vivo during activities of daily living, interbody cage constructs are subject to varying compressive preloads due to external loads generated by paraspinal musculature, and our results suggest that the stability created by the cage (reduction in segmental angular motion) is not constant. The cage construct is likely to be least stable in extension during activities that impart low compressive preloads to the lumbar spine. Supplemental translaminar facet screw fixation will enhance stability of the motion segment treated with threaded cages, particularly during conditions of low compressive preloads, the very condition in which the cage alone is least effective in providing stability.
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A retrospective study of 43 consecutive patients who underwent percutaneous endoscopic lumbar discectomy for recurrent disc herniation. ⋯ Percutaneous endoscopic lumbar discectomy is effective for recurrent disc herniation in selected cases. The posterolateral approach through unscarred virgin tissue can prevent nerve injury and could preserve the spinal stability. Both foraminal and intracanalicular portions can be decompressed simultaneously.
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Comparison of occlusion of lumbar arteries in magnetic resonance angiography (MRA) with patient-reported sciatica symptoms during a 3-year follow-up. ⋯ Arterial stenosis is associated strongly and consistently with patient-estimated physical ability,but only slightly with subjective pain symptoms. Interestingly, new stenosis is preceded by pain symptoms. The evaluation of lumbar blood flow may thus be useful in clinical practice.
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The authors reviewed a series of nontraumatic spinal cord injuries associated with surfing lessons. ⋯ Surfer's myelopathy is a nontraumatic paraparesis/paraplegia that affects first-time surfers. Although most patients have a complete or near-complete recovery, complete paraplegia has occurred.
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Prospective study of the sagittal plane alignment of the spine and pelvis in the normal pediatric population. ⋯ Pelvic morphology, as measured by the pelvic incidence angle, tends to increase during childhood and adolescence before stabilizing into adulthood, most likely to maintain an adequate sagittal balance in view of the physiologic and morphologic changes occurring during growth. Pelvic tilt and lumbar lordosis, two position-dependent parameters, also react by increasing with age, most likely to avoid inadequate anterior displacement of the body center of gravity. Sacral slope is achieved with the standing posture and is not further significantly influenced by age. These results are important to establish baseline values for these measurements in the pediatric population, in view of the reported association between pelvic morphology and the development of various spinal disorders such as spondylolisthesis and scoliosis.