Spine
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Bilateral facet dislocation represents approximately 11% of all thoracolumbar spine injuries requiring surgical stabilization. The injury can be caused by either flexion distraction (29/30 cases) or by pure distraction (1/30). Recognition of the injury is possible on plain radiographs, and confirmed by the empty facet sign on the computed tomography (CT) scan. ⋯ Distraction instrumentation that imparts significant extension is advised for patients with incomplete lesions. It is safe and reliable, and eliminates the posterior bulging of the injured disc that can occur with compression. For low lumbar injuries where compression is desirable in order to achieve the shortest possible instrumentation, a discectomy is recommended.
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Pain drawings were obtained from two groups of patients and one of nonpatients, in a total of 264 subjects, all suffering from back pain. The pain drawings were rated in four grades according to the degree of nonorganic and extended pain. ⋯ A correlation was also found to ethnic background and social situation but not to alcohol abuse or psychiatric illness. Pain drawings afford an important clue to nonorganic factors in the assessment of back pain.
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Case Reports
Combined single stage anterior and posterior osteotomy for correction of iatrogenic lumbar kyphosis.
Fifty-four patients were treated by a standardized single stage anterior opening wedge and a posterior closing extension wedge osteotomy for back pain associated with postoperative loss of lumbar lordosis (iatrogenic flat back syndrome). Presenting complaints were fatigue, pain and a stooped posture. Etiological factors were, in descending order of frequency, distraction instrumentation with the lower end at the L5 or S1 vertebra, thoracolumbar junction kyphosis greater than 15 degrees, especially if associated with a hypokyphotic thoracic spine, and degenerative changes above and below a previous fusion. ⋯ Follow-up averaged 4 years. Average preosteotomy lordosis L1-S1 was 21.5 degrees and was restored to 49 degrees (equal to the lordosis before the initial surgery) for an average correction of 29 degrees, (range 24 degrees to 63 degrees). Prevention of this complication can be accomplished by maintaining normal lordosis at the time of initial surgery.
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Twenty-one bipedal rats were prepared by forelimb amputation and reared with 19 control rats. All of the bipedal rats became proficient upright walkers. There was significant anterior wedging of the lower lumbar vertebral bodies in all of the bipedal rats and four had radiographic evidence of degenerative disc disease. ⋯ There was no difference in radionuclide uptake between the two groups. Histochemical analysis of the psoas and multifidus muscles showed a significant shift from type I to type II fibers in the psoas and from type II to type I fibers in the multifidus in the bipedal population. These results indicate that upright posture places considerable stress on the lumbosacral spine and paravertebral muscles of the rat.
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Thirty patients who had posterior vertebral fusion for scoliosis, performed without metallic implants, were examined using computer-assisted tomography to study the configuration of the evolving fusion mass. It was observed that the deposition of bone followed lines of force, according to Wolff's Law. ⋯ Further, it was observed that usually the fusion mass, seen in section, has a hollow "box-section" shape, which means that a resorption of unstressed central bone occurs. The hypothesis that the torsional forces are the predominant forces acting on the scoliotic spine can explain the characteristic "box-section" of the CT scans obtained.