| Thoracolumbar junction is also a transitional zone of spinal cord and cauda equina.When damage happens, spinal cord or cauda equina may be injuried. the strategy choice of the surgical treatment of thoracolumbar fractures has a wide range of disputes. Anterior surgery can achieve good anterior support, long-term follow-up could be good, but due to the complexity of operations, and risk surgery this kind of surgery has been limited. Posterior surgical treatment of thoracolumbar fractures is an alternative. Now the operation strategy of stable thoracolumbar fractures has been gradually shifting from the long-segment fixation to the short-segment posterior pedicle screw fixation. Some scholars try to solve the question: How to get a choice from the anterior and posterior surgery.Now many them begin to use load sharing classification of the fracture reported by McCormack.The load sharing classification gives scores from the sagittal CT scan of the degree of vertebral body crush, Axial CT scan of the degree of fracture displacement,the degree of kyphosis in the lateral X-ray plain film.The Evaluation of the fracture will add up the three sets of scores. When the Score is more than 7 ,we should be choos the anterior fracture surgery, and when the total score is less than 6 points,the posterior thoracolumbar fracture surgery is feasible. However, a simple short-segment fixation with a high failure rate, the loss of the correction in long-term follow-up is not unsatisfactory.Although the reasons of the loss and the failure is Diverse.The following three is considered to be the most important ones:the decline of anterior vertebral height,the defects of the injured fracture vertebral, the degeneration of the adjacent segments. In order to reduce the correction of loss of the posterior pedicle screw fixation,some scholars began to use short-segment pedicle screw at the level of the injured vertebral and they achieved a certain degree of clinical effect.The 12 patients of who were all injured in thoracolumbar junction had a classification of Magerl A ,including 10 cases of fracture of A1-type, 2 cases of A2 type. After being anesthetized,the patients were given a position reset under the surveillance of C-arm X-ray machinet. After reset, the restoration of the injured vertebral height(AVH)is satisfactied.Take the injured vertebral as the center of incision. The segment on and below the injured vertebral were all inserted pedicle screws in both pedicles.Both sides of the of the injured vertebral had a pedicle screw .The internal fixation devices made by Beijing Fuller Company SCOFIX system.All 12 cases had a direct spinal canal decompression. Once again use the C-arm X-ray machine to make sure the height of the injured vertebral had a full restoration. Then gave a segmental fusion.When we get the X-ray and the CT film of preoperation , postoperation and follow-up , we give a compare of the following indicators:⑴Percentage of Anterior Vertebral Height (AVH%).⑵Percentage of Posterior Vertebral Height (PVH%).⑶The angle of the injured vertebral.⑷Kyphosis angles.⑸Sagittal Index (SI).⑹Observation of the location of the pedicle screw holes.⑺the hollow rate of injured vertebral. Due to disruption of trabecular bone, disorders, bone and intervertebral disc embedded of vertebral fracture,the varying degrees on the vertebral bone defects was called "shell-like" (eggshell) changes. In CT scans show vertebral empty state of the body. We introduce the concept of the " hollow rate of injured vertebral," to measure the extent of bone defect. Application of image processing methods, the edge of bone defect area is divided.And then use "the limits of law" to seek to change the size of shell-like volume with the vertebral body. Hollow rate of injured vertebral = V (shell) / V (vertebral body)×100%. Further analysis of the rate of vertebral hollow after injury and loss of vertebral height and vertebral injury perspective the existence of the relationship between changes. Comparison of preoperative and postoperative follow-up data in the AVH%, PVH%, lumbar vertebral injury angle, kyphosis angle, sagittal index (SI) . Anterior Vertebral Height was found immediately resumed after the surgery with an average correction rate of 81%, and the postoperative follow-up shows no statistical significance (P> 0.05), which indicates no significant loss of Anterior Vertebral Height.The Posterior Vertebral Height shows no significant change after the injury.And in the postoperative or follow-up there is no significant change too (P> 0.05). Vertebral body for vertebral injury angle, kyphosis angle, sagittal index (SI) of the three indicators of the degree of postoperative correction (rates) were: 16.0°±4.3°, 20.5°±5.90°, 119 %, while the three indicators are in the follow-up, there is a clear loss: 2.75°±2.63°(P <0.05), 3.17°±2.54°(P <0.01), 2.50°±2.30°(P < 0.01). As the Literature review, compared with the simple short segment fixation for the treatment of thoracolumbar fracture patients,patients in this group have a more effective follow-up. Compared to the cases reported with the same kind of fixtion as the in this article, the two all have made a better follow-up results. However, the loss of the correction still existed. According to the Follow-up CT,the location of implantation of all the pedicle screws are perfect.There is no loose or broken nails.Calculate the rate of Hollow of injured vertebral according to the formula:Rate= V(shell) / V (vertebral body) X100%.And then give a further analysis of relationship between the the rate and the loss of AVH ,PVH and the other indicators.However,through the correlation analysis there is no significant correlation.After the above analysis we have the following conclusions:⑴Short-segment fixation of thoracolumbar fractures using pedicle fixation at the level of the fracture is an effective way compared with the traditional simple short-segment fixation alone.However, the loss of correction angle still exists.⑵Although the shell-like changes in vertebral body is considered as an important reason for the loss in SSPF, but the data we got shows there is no relationship between the rate and the loss of the indicators. |
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