Myeloggraphy During Operation On Lumbar Bursting Fracture

Objective: spine fracture takes 5%-6% of the fractures over the whole body, but fractures with spinal injury are mostly seen in patients with thoracolumbar fractures. In recent years, with the rapid development of transportation and architecture industries, high-energy injuries are more and more common, and the incidence of lumbar facture is continuously increasing. Because of the importance of the anatomy and function of lumbar vertebrae, it is always the emphasis of clinical study. For a long period, clinical doctors have been studying the diagnosis, classification, operational indications, operative approaches, reduction technique, internal fixation method, internal fixation devices and rehabilitation training post operations, etc. of the bursting fractures of lumbar vertebrae with the purpose that good prognosis should be obtained. The bursting fracture of lumbar vertebrae is a common lumbar fracture, and there is still a controversy on its therapeutic method, especially for the patients with spinal injury. The major controversial focus is that whether the treatment method should adopt operation or expectant treatment, and if operation is chosen, should it be early operation or late operation?The study of Petitjean, et al demonstrated that complete paralysis had no decompression indication in early stage, while the early decompression for incomplete paralysis could promote the recovery of nervous functions. Waters et al indicated in a study that, there was no marked difference between operational and conservative treatment. Prasad et al demonstrated in their study that it was better to promote to recover the spinal function within two weeks post operations. Through the study on 64 cases of thoracolumbar bursting fractures treated during 1978-1995 and 54 cases of past thoracolumbar fracture or dislocation, Xu Shaoting, Liu Shuqing demonstrated that: 1. For the incomplete paralysis caused by oppression on spine by spinal stenosis, the effect of decompression was obvious; 2. for incomplete paralysis patients, the effect obtained from early decompression or late decompression was the same, while for the patients with complete paralysis, if the recovery of spinal function was wanted, early decompression within 24 hours should be adopted. But for the current operational indications, it is generally believed that, when area of spinal stenosis is more than 50%, sagittal diameter is less than 1/2 for patients without nervous symptoms or patients with nervous symptoms, operation should be adopted. Denis divided bursting factures into five groups: A. severe vertical stress induces the fracture of upper and lower endplates of vertebrae, backward angulation can not be produced and the fracture is commonly seen on lumbar vertebrae. B. axial stress and anteflexion stress induce the fracture of upper endplate, the vertebra has a wedge shape and angles could be produced backwardly, the fracture is mostly seen on thoracolumbar vertebrae. C. Injury of lower endplate is not commonly seen. D. injury caused by axial stress and shearing stress, on the basis of bursting fracture, dislocation can not happen, and the injury is mostly seen on lumbar vertebrae. E. injury of great axial stress and lateroflexion stress, i.e. bursting fracture, and lateral compression change is produced. According to the three column concept of spine proposed by Denis, anterior, medium column and even posterior columns are injured in lumbar bursting fracture, the spine is unstable, and there is a tendency of further injury. Therefore, the range of operational indications of lumbar bursting fracture tends to be broadened.With the continuous development of imaging, the diagnosis of lumbar bursting fracture is more accurate and complete. At present, routine X-ray examination is commonly carried out for the first before the operation of thoracolumbar fracture, it can display the vertebrae facture and facture-dislocation very well, but the display of accessory fracture is relatively poor, which brings out difficulties in the judgment of operational indications and approaches. Therefore, CT, MRI or even visualization should be carried out before operation to define the diagnosis. CT can display the detailed condition of fracture and changes of spinal canal, but the degree of ligament injuries can not be displayed. MRI has the advantages of X-ray and CT, it can also display the injury of ligament and spine as well as the degree of injury, but the display of fracture is not good, the price is expensive, and the detailed conditions of the changes of spinal canal are not clear than that of CT. Because of the existence of ligament taxis, the bone blocks in the vertebral canal can recover partially on their own after the lumbar bursting facture is internal fixed with vertebral arch nail. Because CT can not be applied in the operation at present, whether the decompression can be realized or not is depending on the CT before operation, and the unnecessary damage on anterior or posterior column will aggravate the unstable condition of the spine. So in this study plan, X-ray fluoroscopy after visualization in vertebral canal and CT post operation are applied, compare the consistency of smoothness of vertebral canal in the X-ray fluoroscopy after visualization in vertebral canal with that in CT scan post operation, analyze their advantages and disadvantages, and provide reference to clinical doctors for correct judge on whether decompression should be carried out or not.Method: summarize the reduction and internal fixation on injured vertebrae with vertebral arch nail, combining with whether the vertebral canal is smooth or not, to determine whether to directly open the vertebrae to decompress. In the 18 cases, 12 cases of E grade of Frankel grading system , 4 cases of D grade of Frankel grading system , 2 cases of C grade of Frankel grading system. 12 cases of E grade of Frankel grading system did not apply direct decompression. Fixation and distraction reduction with vertebral arch nail system were operated, canal visualization was applied before and after the operation, C-arm fluoroscopy was combined to dynamically observe the smoothness of vertebral canal, the most narrow diameter of the canal was determined, at the same time, vertebral angle, Bobb angle and anterior height of vertebral body were determined before and after fixation and distraction reduction with vertebral arch nail system. CT scan was applied after operation to determine the posterior sagittal diameter of the biggest deck of canal erosion surface. SAS statistical software was used to carried out t test, and the correlation analysis between the changes of vertebral angle, Cobb angle, anterior height of vertebral body and the recovery of the sagittal diameter of the biggest deck of canal erosion surface was carried out, to confirm the consistency between canal visualization and CT scan after operation on the smoothness of vertebral canal, and the correlation between the recovery of the sagittal diameter of the biggest deck of canal erosion surface and the changes of vertebral angle, Cobb angle, vertebral height.Results: 1 On the consistency of canal smoothness between vertebral canal visualization and CT scan, it was found in statistical analysis that, there was no obvious difference between the diameter of most narrow vertebral canal in visualization after reduction and the sagittal diameter of the biggest deck of canal erosion surface in CT scan (P>0.05). It was demonstrated that, the judge on vertebral canal smoothness in canal visualization during operation was consistent with that of the CT scan after operation. 2 In the correlation analysis between the changes of vertebral angle, Cobb angle, anterior height of vertebral body and the recovery of the sagittal diameter of the biggest deck of canal erosion surface, it was found that there was a positive correlation between the recovery of sagittal diameter and the recovery of anterior height of vertebral body (r=0.96, P=0.001), but it was negatively correlated with the increases of vertebral angle (r=0.75, P=0.0048),but not correlated with Cobb angle. It was demonstrated that, in order to obviously change the recovery of posterior sagittal diameter, the anterior height of vertebral body must be completely recovered and the vertebral angle and Cobb angle should be reduced, and it was further demonstrated that, in order to increase the smoothness degree of vertebral canal in canal visualization, the anterior height of vertebral body must be completely recovered and the vertebral angle and Cobb angle should be reduced. 3 Through 3 cases with over E grade of Frankel grading system, it was shown that the vertebral canal was not smooth and direct decompression was applied, in the analysis, it was found that visualization could direct whether it should decompress or not, and the second visualization after decompression could confirm whether the vertebral canal was smooth, or the decompression was complete.Conclusion: the judge on the smoothness of vertebral canal in canal visualization during operation was consistent with that in the CT scan after operation. Canal visualization during operation had the advantage of diagnosis during operation, by applying canal visualization during operation, and the unnecessary damage on spinal stability could be avoided. Through factor analysis on the factors affecting smoothness in canal visualization during operation, bases could be provided to the clinical doctors for judging whether the vertebral canal was smooth in visualization. Visualization during operation could instruct whether to decompress or not, and visualization after operation could confirm whether the vertebral canal was smooth, or the decompression was complete, thus to provide bases for clinical doctors to judge the decompression conditions.