基于连续骨盆轴向CT扫描的上骶段分型

Classification of upper sacral segment based on continuous axial pelvic computed tomography scan

目的:介绍基于连续骨盆轴向CT扫描的上骶段的分型及其意义。方法:对127例全骨盆2.0 mm层厚轴向扫描图像进行观察,测量S1的平向骶髂螺钉通道,根据平向通道的大小对上骶段进行分型。如平向通道存在且在至少4层扫描图像上其宽度均>7.3mm,则将其定义为正常型上骶段;如平向通道存在且在扫描层面上其最大宽度≤7.3mm,则将其定义为过渡型;如平向通道不存在,即在所有扫描层面上其宽度均≤0 mm,则将其定义为变异型。计算各型的例数、百分比及平向螺钉通道的平均值。结果:正常型58例(45.7%),其平向螺钉通道平均宽度13.9 mm;过渡型42例(33.1%),其平向螺钉通道的平均宽度5.2 mm;变异型27例(21.2%),其平向螺钉通道的平均宽度为0.9 mm。所有病例的上骶段可归属于3型中的1型。结论:正常型上骶段因存在平向安全通道而可置入平向骶髂螺钉,过渡型及变异型上骶段因无平向通道而无法置入平向骶髂螺钉。过渡型较变异型的优势表现在其标准骶骨侧位像上的有限平向通道可以作为进钉点的选择区域。

Objectives：To introduce a classification system of upper sacral segment and its significance based on the continuous pelvic axial computed tomography scan.Methods：The whole pelvis 2.0 mm thick axial scan images of 127 cases were observed,the sacroiliac screw channel of S1 were measured,according to the size of the transverse screw channel the upper sacral segment were classified.Such as transverse screw channel existed and in at least 4 layer scan images its width was ＞ 7.3 mm,it was defined as sacral segment of the normal type.Such as transverse screw channel existed and its maximum width was 7.3 mm or less on scanning level,it was defined as a transitional.Such as transverse channel did not exist,or its width on all scanning level was 0 mm or less,it was defined as dysplastic.Various cases,percentage,and the average of the transverse screw channel were calculated.Results：There were 58 normal （45.7％）,42 transitional （33.1％）,and 27 dysplastic （21.2％） upper sacral segments with an averaged width of the tansverse screw channel of 13.9 mm,5.2 mm,and 0.9 mm,respectively.Each specimen could be defined as one of the three types of upper sacral segment without exceptions.Conclusion：It is possible to insert a transverse iliosacral screw into a normal upper sacral segment when indicated because of the capacious transverse screw channel.The transverse iliosacral screw placement into the transitional and dysplastic upper sacral segments was contraindicated because of the limited or none transverse screw channel.The transitional upper sacral segment was superior to the dysplastic segment due to its starting point location restriction on the true lateral sacral view.