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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To date, the mechanisms of disc failure have been explored at a microstructural level in relatively simple postures. However, in vivo the disc is known to be subjected to complex loading in compression, bending and shear, and the influence of these factors on the mechanisms of disc failure is yet to be described at a microstructural level. The purpose of this study was to provide a microstructural analysis of the mechanisms of failure in healthy discs subjected to compression while held in a complex posture incorporating physiological amounts of flexion and facet-constrained shear. ⋯ The complex posture as used in this study significantly reduced the load required to cause disc failure, providing further evidence that asymmetric postures while lifting should be avoided if possible.
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To examine the radiological and clinical outcomes of a single-center case series of selective thoracic fusions (STF) in adolescent idiopathic scoliosis with Lenke C modifier curves, with a long-term follow-up. ⋯ STF is an effective treatment option both in clinical and radiographical terms. The results at 10-year follow-up confirm both the stability of the correction and the improvement of the clinical outcome scores. Risser and Lenke grading systems are not relevant variables predictive of clinical efficacy.
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Aim of the study was to evaluate the role of the mechanical properties of the rod and of the characteristics of the patients (age, skeletal maturity, BMI, and Lenke type) in determining the deformity correction, its maintenance over time and the risk of mechanical failure of the instrumentation. ⋯ Rod diameter and material as well as patient characteristics such as BMI, age, and Risser grade play an important role in deformity correction and its maintenance over time.
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The aim of this study is to understand how many anchor sites are necessary to obtain maximum posterior correction of idiopathic scoliotic curve and if the alloy of instrumentation, stainless steel or titanium, may have a role in the percent of scoliosis correction. ⋯ When stainless steel instrumentation is used non-segmental pedicle screw constructs seem to be equally effective as segmental instrumentations in obtaining satisfactory results in patients with main thoracic AIS. When the implant alloy used is titanium one, an implant density of ≥60% should be guaranteed to achieve similar results.
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The investigation was based on finite-element simulations. ⋯ The use of cages is crucial to ensure anterior support and decrease loads and stresses on the posterior instrumentation.