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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Scoliosis is a complex three-dimensional deformity of the spine and rib cage frequently treated by brace. Although bracing produces significant correction in the frontal plane, it generally reduces the normal sagittal plane curvatures and has limited effect in the transverse plane. The goal of this study is to develop a new optimization approach using a finite element model of the spine and rib cage in order to find optimal correction patterns. ⋯ The optimization produced an average of 56% and 51% reduction of the objective function respectively in the two studies. Optimal forces were mostly located on the convex side of the curve. This study demonstrates the feasibility of using an optimization approach with a finite element model of the trunk to analyze the biomechanics of bracing, and may be useful in the design of new and more effective braces.
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Case Reports
Pain pattern in multiple vertebral hemangiomas involving non-adjacent levels: report of two cases.
Hemangioma of the bone is a benign tumor usually involving the spine and the bones of the skull and pelvis. It may be either a single lesion or part of a generalized multifocal disease. Multiple lesions involving non-adjacent vertebrae are rare. ⋯ Investigation revealed multiple hemangiomas involving three non-adjacent vertebrae in the first patient and four in the second. We stress the fact that the existence of multiple non-adjacent lesions may remain undiagnosed for a considerable period of time and may be responsible for even longer-term recurrent episodes of pain. Multifocal location of back pain in patients with a known vertebral hemangioma may be considered a relative indication for the presence of multiple non-adjacent level lesions.
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Comparative Study
A method to evaluate the in vivo behaviour of lumbar spine implants.
The aim of the study was to design a method for evaluating the stabilizing effect of different lumbar spine implants in vivo, and to apply this method to a comparison of plates versus rods in lumbar spine posterolateral fusion using transpedicular screw fixation. Fourteen patients, seven operated on with transpedicular plates and screws (VSP), and seven operated on with rods and screws (Diapason), matched according to number of levels fused, had tantalum markers inserted in the vertebrae at surgery, enabling roentgen stereophotogrammetric analysis (RSA). Mean patient age was 45 (range 33-56) years. ⋯ One patient stabilized with rods and screws between L5 and S1 displayed a sagittal translation of 1.01 mm but no mobility along the transverse or vertical axes. In the remaining 13 patients, positional change from supine to standing did not provoke any intervertebral mobility above the RSA accuracy along any of the axes. With the limited provocation described, in line with the postoperative regimen for lumbar fusion patients, plates with transpedicular screws and rods with transpedicular screws both seem to give adequate intervertebral stability in posterolateral lumbar fusions.
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Randomized Controlled Trial Comparative Study Clinical Trial
Accuracy of pedicle screw insertion with and without computer assistance: a randomised controlled clinical study in 100 consecutive patients.
We performed a randomised controlled study to assess the accuracy of computer-assisted pedicle screw insertion versus conventional screw placement under clinical conditions. One hundred patients scheduled for posterior thoracolumbar or lumbosacral pedicle screw instrumentation were randomised into two groups, either for conventional pedicle screw placement or computer-assisted screw application using an optoelectronic navigation system. From the computer-assisted group, nine patients were excluded: one because of an inadequate preoperative computed tomography study, seven because of problems with the specific instruments or the computer system, and one because of an intraoperative anesthesiological complication. ⋯ Pedicle perforations of more than 4 mm were found in 1.4% (4/277) of the screw insertions in the conventional group, and none in the computer-assisted group. Complications not related to pedicle screws were two L5 nerve root lesions, one end plate fracture, one major intraoperative bleeding and one postoperative death in the conventional group, and one deep infection in the computer-assisted group. In conclusion, pedicular screws were inserted more accurately with image-guided computer navigation than with conventional methods.