Spine
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Comparative Study
Effects of charité artificial disc on the implanted and adjacent spinal segments mechanics using a hybrid testing protocol.
Finite element model of L3-S1 segment and confirmatory cadaveric testing were used to investigate the biomechanical effects of a mobile core type artificial disc (Charité artificial disc; DePuy Spine, Raynham, MA) on the lumbar spine. ⋯ The hybrid testing protocol is advocated because it better reproduces clinical observations in terms of motion following surgery, using pure moments. Using this approach, we found that the Charité artificial disc placement slightly increases motion at the implanted level, with a resultant increase in facet loading when compared to the adjacent segments, while the motions and loads decrease at the adjacent levels. However, in the load control mode that we believe is not that clinically relevant, there was a large increase in motion and a corresponding increase in facet loads, as compared to the intact.
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A retrospective review of spine, chest, and pelvic dimensions of normal CT scans from 1999 to 2004 was performed. ⋯ Pelvic inlet width is an age-independent predictor of pediatric chest width and thoracic dimensions that may be used to assess thoracic and spine growth in early onset spine deformity patients.
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Comparative Study
Biomechanical assessment of the pediatric cervical spine under bending and tensile loading.
Cadaveric head-neck complexes from pediatric donors aged 2-12 years were subjected to a test battery consisting of nondestructive flexion-extension bending, nondestructive tensile step-and-hold tests, and tensile distraction loading to failure. ⋯ The current study provides valuable new information on the response and tolerance of the pediatric cervical spine to quasi-static flexion-extension and tensile distraction loading.
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Comparative Study
Balloon kyphoplasty is effective in deformity correction of osteoporotic vertebral compression fractures.
A prospective radiographic analysis of deformity correction during the balloon kyphoplasty procedure. ⋯ The restoration of height in kyphoplasty is attributed to dynamic fracture mobility as well as to the expansion of the inserted balloon tamp.
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Computer modeling and parametric analysis were used to determine the effect of reflex contraction of the neck muscles in the unaware occupant in whiplash. ⋯ Because reflex contraction did not substantially alter spinal kinematics, muscle contraction likely does not initiate in sufficient time to mitigate whiplash injuries that may occur during the retraction phase.