Clinical orthopaedics and related research
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Clin. Orthop. Relat. Res. · Mar 2010
Vertebral column resection for the treatment of severe spinal deformity.
The ability to treat severe pediatric and adult spinal deformities through an all-posterior vertebral column resection (VCR) has obviated the need for a circumferential approach in primary and revision surgery, but there is limited literature evaluating this new approach. Our purpose was therefore to provide further support of this technique. We reviewed 43 patients who underwent a posterior-only VCR using pedicle screws, anteriorly positioned cages, and intraoperative spinal cord monitoring between 2002 and 2006. Diagnoses included severe scoliosis, global kyphosis, angular kyphosis, or kyphoscoliosis. Forty (93%) procedures were performed at L1 or cephalad in the spinal cord (SC) territory. Seven patients (18%) lost intraoperative neurogenic monitoring evoked potentials (NMEPs) data during correction with data returning to baseline after prompt surgical intervention. All patients after surgery were at their baseline or showed improved SC function, whereas no one worsened. Two patients had nerve root palsies postoperatively, which resolved spontaneously at 6 months and 2 weeks. Spinal cord monitoring (specifically NMEP) is mandatory to prevent neurologic complications. Although technically challenging, a single-stage approach offers dramatic correction in both primary and revision surgery of severe spinal deformities. ⋯ Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
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Clin. Orthop. Relat. Res. · Mar 2010
P value and the theory of hypothesis testing: an explanation for new researchers.
In the 1920s, Ronald Fisher developed the theory behind the p value and Jerzy Neyman and Egon Pearson developed the theory of hypothesis testing. These distinct theories have provided researchers important quantitative tools to confirm or refute their hypotheses. The p value is the probability to obtain an effect equal to or more extreme than the one observed presuming the null hypothesis of no effect is true; it gives researchers a measure of the strength of evidence against the null hypothesis. ⋯ Perhaps the most common misconception is to consider the p value as the probability that the null hypothesis is true rather than the probability of obtaining the difference observed, or one that is more extreme, considering the null is true. Another concern is the risk that an important proportion of statistically significant results are falsely significant. Researchers should have a minimum understanding of these two theories so that they are better able to plan, conduct, interpret, and report scientific experiments.
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There are few good surgical options that allow for continued spinal growth in patients with early-onset scoliosis. The "Shilla" is a growth guidance system that does not require repeated surgical lengthenings. The Shilla system guides growth at the ends of dual rods with the apex of the curve corrected, fused, and fixed to the rods. ⋯ All of the goat spines grew with the implants in place; growth occurred in both the thoracic and lumbar ends of the rods for a total average of 48 mm. None of the implants failed, although we observed minor wear at the rod/screw interface. Growth guidance with the Shilla rod system allowed for continued growth in this goat model.
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Clin. Orthop. Relat. Res. · Mar 2010
Preoperative pain catastrophizing predicts pain outcome after knee arthroplasty.
Psychologic status is associated with poor outcome after knee arthroplasty yet little is known about which specific psychologic disorders or pain-related beliefs contribute to poor outcome. To enhance the therapeutic effect of a psychologic intervention, the specific disorders or pain-related beliefs that contributed to poor outcome should be identified. We therefore determined whether specific psychologic disorders (ie, depression, generalized anxiety disorder, panic disorder) or health-related beliefs (ie, self-efficacy, pain catastrophizing, fear of movement) are associated with poor outcome after knee arthroplasty. We conducted a cohort study of 140 patients undergoing knee arthroplasty at two hospitals. Patients completed a series of psychologic measures, provided various sociodemographic data, and were followed for 6 months. Patients were dichotomized to groups with either a favorable or a poor outcome using WOMAC pain and function scores and evidence-based approaches. After adjusting for confounding variables, we found pain catastrophizing was the only consistent psychologic predictor of poor WOMAC pain outcome. No psychologic predictors were associated consistently with poor WOMAC function outcome. An intervention focusing on pain catastrophizing seems to have potential for improving pain outcome in patients prone to catastrophizing pain. ⋯ Level I, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.