经坐骨结节至髋臼后柱置钉安全区域的CT测量研究

CT measurement for the safety range of screws from ischial tuberosity to acetabular posterior column

目的探讨利用CT测量经坐骨结节至髋臼后柱置钉的安全范围。方法收集60例正常成人骨盆的螺旋CT扫描数据,在扫描结果中包含股骨头最大界面的扫描平面,进行二维及三维重建,然后进行有效切割,获得内平面、外平面及后平面,分别测量经坐骨结节至三个平面的最大角度(α、β、γ),测量获得髋臼后柱三角形内切圆面积及直径。结果坐骨结节至内平面的最大角度α约8.1°,坐骨结节至外平面的最大角度β约23.5°,坐骨结节至后平面的最大角度γ约32.2°,髋臼1/2高度处后柱骨质最狭小(内切圆直径最小),是判断置钉安全性的关键位置。结论经坐骨结节至髋臼后柱置钉的安全范围较小,有必要在置钉时精确量化与精确操作,严格按照个体化进行置钉。

Objective To explore the use of CT measurement for the safety range of screws from ischial tuberosity to acetabular posterior column. Methods The pelvic spiral CT scan data of 60 healthy adults were collected, containing the largest part of the femoral head, 2D and 3D reconstruction. And then the inner plane, outer plane and posterior plane were get after effectively cut. The three maximal angles （ct, 13, 3＇） between the ischial tuberosity with the 3 planes, the area and diameter of the inscribed circle of the acetabular posterior column triangle were measured. Re- suits The mamximal angle of ischial tuberosity to the inner plane （angle c~） was about 8.1~. The mamximal angle of ischial tuberosily to the outer plane （angle 13） was about 23.5~. The mamximal angle of ischial tuberosity to the posterior plane （angle 3＇） was about 32.2~. The 1/2 height of acetabu- lar has narrowest posterior column （with smallest diameter of inscribed circle）. It is key position to judge the safety of screws. Conclusion The safety range is small for screws from ischial tuberosity to the acetabular posterior column. It is necessary to accurately and precisely quantify the safety range for the screws in operation.