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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Little is known about the coupled motions of the spine during functional dynamic motion of the body. This study investigated the in vivo characteristic motion patterns of the human lumbar spine during a dynamic axial rotation of the body. Specifically, the contribution of each motion segment to the lumbar axial rotation and the coupled bending of the vertebrae during the dynamic axial rotation of the body were analyzed. ⋯ This study demonstrated that a dynamic lumbar axial rotation coupling with lateral bendings is segment-dependent and can create a coordinated dynamic coupling to maintain the global dynamic balance of the body. The results could improve our understanding of the normal physiologic lumbar axial rotation and to establish guidelines for diagnosing pathological lumbar motion.
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Clinical Trial
Negative beliefs and psychological disturbance in spine surgery patients: a cause or consequence of a poor treatment outcome?
Chronic musculoskeletal pain is often associated with psychological distress and maladaptive beliefs and these are sometimes reported to have a negative impact on surgical outcome. The influence of a surgical intervention, and in particular its outcome, on the course of change in psychological status is poorly documented. In this prospective study, we sought to examine the dynamic interplay between psychological factors and outcome in patients undergoing decompression surgery for spinal stenosis/herniated disc. ⋯ In a multivariable prospective (predictive) model, FABQ-PA was the only baseline psychological factor that significantly predicted outcome. Future studies should assess whether pre-operative cognitive-behavioural therapy in patients with maladaptive beliefs improves treatment outcome. Psychological disturbance did not significantly predict outcome, but it improved post-operatively in patients with a good outcome and worsened in those with a poor outcome. Rather than being a risk factor for poor outcome, in this group it appeared to be more a consequence of long-standing, unremitting pain that improved when symptoms resolved after successful surgery.
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The objective of this study was to investigate the impact of the less invasive procedures of hemilaminectomy and unilateral multilevel interlaminar fenestration (UMIF) on the cervical spinal biomechanics. ⋯ The less invasive approaches of UMIF and MHL greatly preserved the flexion motion (more than 48 %) of the cervical spine compared with laminectomy, and the preserved motion mean the low-risk of postoperative spinal instability. UMIF and MHL also reduced the increased stress of annulus caused by ML, and the lesser stress will lower the risk of postoperative disc degeneration. The posterior bone elements play a slight role in spinal stability after removal of the attached ligaments.
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The purpose of this study was to analyze explanted PEEK rod spinal systems in the context of their clinical indications. We evaluated damage to the implant and histological changes in explanted periprosthetic tissues. ⋯ This study documents the surface changes and tissue reactions for retrieved PEEK rod stabilization systems. Permanent indentations by the set screws and pedicle screws were the most prevalent observations on the surface of explanted PEEK rods.
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Development of a dynamic stabilization system often involves costly and time-consuming design iterations, testing and computational modeling. The aims of this study were (1) develop a simple parametric model of lumbar flexion instability and use this model to identify the appropriate stiffness of a flexion restricting stabilization system (FRSS), and (2) in a cadaveric experiment, validate the predictive value of the parametric model. ⋯ Testing demonstrated excellent predictive value of the parametric model, and that the FRSS attained the desired biomechanical performance developed with the model. A simple parametric model may allow efficient optimization of kinematic design parameters.