髋臼后柱的CT测量及其X线投照角度的探讨

Projection angle for C-arm-assisted insertion of posterior acetabular column screws

目的 探讨C型臂X线机透视下经皮置入髋臼后柱螺钉的最佳透视角度. 方法 对10具尸体标本的20侧髋臼进行CT扫描,在扫描结果中包含股骨头最大界面的扫描平面内,测量后柱后表面与冠状面的交角（α角）及后柱后表面与髋臼口所在平面的交角（β角）. 结果 髋臼后柱后表面与冠状面的交角（α角）为28.2°±2.3°,髋臼后柱后表面与髋臼口所在平面交角（β角）为95.4°±5.3°.结论 当C型臂X线机以平行于后柱后表面的方向进行投照时,球管与冠状面成约30°角,即在闭孔斜位的基础上增加15°,与闭孔斜位投照相比,能更准确地了解螺钉与后柱后表面之间的关系.

Objective To explore the optimal projection angle when cannulated screws are placed into the posterior acetabular column under the help of a C-arm fluoroscopic unit. Methods Twenty acetabular sides in 10 corpses were scanned with CT to find the scan plane which contained the maximum cross section of the femoral head. On this scan plane, we measured angle α which was between the posterior surface of the posterior column and the coronal plane, and angle β which was between the posterior surface of the posterior column and the acetabular fringe plane. Results Angle α was 28. 2°± 2. 3° and angle β was 95.4°± 5.3°. Conclusions When the projection direction is paralleled with the posterior surface of the posterior column, the angle between the bulb and the coronal plane is about 30°, 15° more than the obturator oblique view. Compared with the obturator oblique view, 30° can show more exactly the spatial relation between the screw and the posterior surface of the posterior column. The direction perpendicular to the acetabulum fringe plane can also be considered for projection.