Journal of spinal disorders
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Provocative discography is a controversial diagnostic tool for pathologic discs. Modic has identified vertebral endplate signal changes on magnetic resonance imaging (MRI) that are thought to signify advanced discogenic degeneration. These two distinct diagnostic tools are examined to determine if there is association between them. ⋯ In discs with positive T1 MRI findings, 34.8% of patients had concordant pain and 17.4% had discordant pain. 79.5% and 74.4% of levels with patient concordant pain on discography had no endplate changes on T1- and T2 weighted MR images, respectively (compared with 84.5% and 81.7%, respectively, for levels with no patient pain on discography). Our data showed no significant relationship between these distinct diagnostic tools. Further investigation of their relative roles in this application is recommended.
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A simple and inexpensive method was developed to obtain a coaxial view of the pedicles to assist with screw insertion. The authors evaluated the accuracy of this device to place transpedicular vertebral screws in a human adult cadaver model. A dual radiation targeting system, a laser targeting system for fluoroscopically guided procedures, was developed to provide an accurate surface entry point and angle of approach to radiographic landmarks. ⋯ Five other screws, four in the thoracic spine and one in the lumbar spine (error rate of 2.7%) were directed too far laterally and perforated the lateral vertebral body. This low rate of pedicle wall cortical perforation by inexperienced surgeons compares favorably with much higher pedicle perforation rates by experienced surgeons when no imaging was used. In conclusion, this in vitro model using a dual radiation targeting system assisted with the accurate placement of transpedicular vertebral screws with minimal radiation exposure.
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A severe isolated thoracolumbar and lumbar hyperlordosis spinal deformity occurring in a patient with cerebral palsy is rare and has not been reported before. The authors describe the presentation, operative considerations, and treatment of patients with this unusual hyperlordotic spinal deformity, particularly those with cerebral palsy. A multiple-stage surgical reconstruction was required to correct this complex spinal deformity. ⋯ Finally, a posterior spinal fusion with instrumentation from T2 to the pelvis definitively corrected his deformity. The patient responded well to surgical intervention without complications and continues to have stable correction of his hyperlordosis deformity 2 years after surgery. Severe lordotic sagittal plane spinal deformities can be treated with anterior and posterior spinal fusion and instrumentation with intervening traction in the properly selected and prepared patient who has cerebral palsy.
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The current experiment reexamines this laboratory's frequently cited previous experimental conclusion that a mechanism underlying the beneficial effects of glucocorticoids in the treatment of spinal cord injury may be the enhanced preservation of spinal cord tissue potassium. For the first time, similar methodology also has been applied to study the effects of hypothermia. Canine spinal cords were injured at T13 by use of an epidural balloon and then were treated with local hypothermia or intramuscular dexamethasone or both. ⋯ At either 6 days or 7 weeks, spinal cords T8 through L4 were removed and divided into 10 ordered blocks, which were analyzed for wet and dry weight, potassium concentration, and sodium concentration. Correlations between clinical motor and chemical results were evaluated. The conclusions drawn are as follows: 1) The canine severe rapid compressive injury model, unlike the previously published less severe feline impact injury model, is not associated with widespread early loss of spinal cord tissue potassium content (dry weight). 2) The dog compressive model, unlike the cat impact model, does not provide evidence that one fundamental mechanism of the confirmed beneficial action of steroids entails enhanced early preservation of tissue potassium content. 3) At 6 days, decrease in the percentage of dry weight and increase in sodium concentration, representing edema, occurred at and adjacent to the direct compression site in all lesioned dog groups except those treated with dexamethasone, demonstrating an antiedema effect of dexamethasone that was nullified by concurrent local hypothermia. 4) This antiedema effect of dexamethasone was associated with superior early motor improvement but did not lead to superior long-term function, in comparison with hypothermia. 5) At 7 weeks, decrease in the percentage of dry weight and potassium concentration, and increase in sodium concentration, all restricted to the directly compressed segment, signify necrosis. 6) This new chemical index of necrosis was highly correlated with clinical motor performance.