MRI在胸腰段损伤AO分类评估中的价值

The influence and effect of MRI on the AO classification for thoracolumbar spine injury

目的 ：评估MRI在胸腰段损伤AO分类评估中的价值。方法：回顾分析2010年1月～2013年12月收治的80例胸腰段损伤患者,所有患者均有X线片、CT和MRI检查资料。分析患者骨折数目及骨折节段;根据AO系统评定患者分类为A型压缩损伤、B型牵张损伤、C型旋转损伤,后方韧带复合体（PLC）的状态为无损伤、不确定损伤、完全损伤。第一次评估使用X线片和CT数据（CT组）;6周后重复评定,同时加入MRI数据（CT＋MRI组）。使用Wilson的置信区间方法分析比较联合MRI后AO分类改变的比例。结果 ：CT组检查发现128处胸腰段骨折,其中A型损伤98处,B型损伤24处,C型损伤6处;CT＋MRI组发现23处新骨折,共151处骨折,其中A型损伤91处,B型损伤54处,C型损伤6处。与CT组比较,CT＋MRI组AO分类出现改变的患者共17例（21.3%）,95%的置信区间为（0.14,0.31）;无改变63例（78.7%）,95%的置信区间为（0.68,0.86）。在AO分类出现改变的患者中,15例（18.75%）由A型改变为B型,95%的置信区间为（0.11,0.27）;2例（2.5%）由B型改变为A型,95%的置信区间为（0.01,0.08）。CT评估PLC状态,无损伤58例,不确定损伤1例,完全损伤21例;CT联合MRI评估PLC状态,无损伤45例,不确定损伤2例,完全损伤33例。CT和MRI联用,PLC损伤分级无改变63例（78.7%）,95%的置信区间为（0.67,0.88）;PLC损伤分级发生改变17例（21.3%）,95%的置信区间为（0.13,0.33）。结论：联合MRI比仅用CT能够检出更多的骨与韧带损伤,MRI检查可能改变胸腰段损伤患者的AO分类,检出的PLC是分类发生改变的重要原因。

Objectives： To evaluate the influence and effect of MRI on the AO classification for thoracolubar spine injury. Methods： A retrospective analysis of 80 patients suffering from thoracolumbar injury from Jan-uary 2010 to December 2013 was performed. All patients in this study accepted X-ray, CT and MRI scans.The number and level of fractures in patients were analyzed. According to AO classification, the injury mor-phology was classified into type A compression injury, type B distraction injury, and type C rotation injury.The status of posterior ligamentous complex（PLC） were ranked with intact, indeterminate and injured. The first evaluation was done by X-ray and CT data（CT group）. Six weeks later, the second evaluation was performed by adding MRI data（CT＋MRI group）. The ratios of rank changes of injury in AO classificatoin were evaluated with Wilson CIs. Results： CT alone revealed 128 thoracolumbar fractures in which 98 fractures were classified as AO type A, 24 as type B, 6 as type C. CT and MRI together revealed 23 new fractures with a total of 151 fractures in which 91 fractures were classified as AO type A, 54 as type B, 6 as type C. Compared with CT group, the AO types changed in 17 patients（21.3%） in group of CT＋MRI, 95% Wilson CI（0.14,0.31）; unchanged 63 patients（78.7%）, and 95% Wilson CI（0.68, 0.86）. Among those that changed, 15（18.75%）patients changed from AO type A to B, 95% Wilson CI（0.11, 0.27）; 2（2.5%） patients changed from AO type B to A, 95% Wilson CI（0.01, 0.08）. With CT alone, the status of PLC was defined as intact in 58 cases,suspect injury in 1 case, and disrupted in 21 cases. With CT and MRI, the PLC was assessed as intact in45 cases, suspect in 2 cases, disrupted in 33 cases. Using CT and MRI data together, 63 patients（78.7%）whose PLC assessment did not change, with 95% Wilson CI（0.67, 0.88）. The number of patients whose PLC assessment changed reached 17（21.3%） with 95% Wilson CI（0.13, 0.33）. Conclusions： The combination of MRI can detect bone and ligament injury more clearly than CT alone, which probably leads to the change of AO classification. Ligamentous injuries revealed by MRI are mainly responsible for these changes.