三维重建模型模拟拉力螺钉固定髋臼后柱骨折的研究

目的　为经坐骨小切迹置入拉力螺钉内固定髋臼后柱骨折提供应用解剖学基础。 方法　用60例正常成人骨盆CT数据（男30例，女30例），导入Mimics14.1行三维重建，观测骨盆三维模型髋臼后柱的纵轴走向，模拟置钉并确立螺钉穿出点。测量髋臼后柱纵轴的长度、后柱纵轴与冠状面夹角α和矢状面的夹角β，测量进针点及后柱盆腔侧、髋臼侧骨皮质厚度。 结果　髋臼后柱轴线向下穿出点位于坐骨小切迹中点，向上穿出点位于弓状线后端与髂前上棘连线中点。髋臼后柱纵轴的长度男性（105.04±　4.29）mm、女性（101.80±3.20）mm，α角男(33.41±2.18)°、女(31.56±2.71)°，β角男(21.74±1.19)°、女(19.15±　1.24)°。进钉点骨皮质厚度为(5.54±0.46)mm，盆腔侧和髋臼侧分别为(1.45±0.13)mm、(1.04±0.10)mm。 结论　三维重建模拟经坐骨小切迹中点行后柱拉力螺钉内固定，可快捷、准确测量钉道参数并进行术前评估，用该方法置入拉力螺钉固定后柱安全简便。

Three-dimensional reconstruction model for simulation of percutaneous lag screw internal fixation for acetabular posterior column fracture

Objective　To provide anatomical basis for lag screw internal fixation for acetabular posterior column fracture via the lesser sciatic notch.　Methods　Pelvic CT scanning data from 60 adults（30 males and 30 females）were imported into Mimics14.1 for 3D image reconstruction. The direction of longitudinal axis of the acetabular posterior column was observed in the three-dimensional pelvic model, screw placement was simulated, and the point where the screw pieced out was determined. Measurements were made about the length of the longitudinal axis, α angle between the longitudinal axis and the frontal plane, and β angle between the long axis and the sagittal plane.　Results　The point where the longitudinal axis of the acetabular posterior column terminated inferiorly was located at the midpoint of the sciatic notch, and the point where it terminates superiorlyat the midpoint between the rear end of arcuate line and anterior superior spine. The length of the longitudinal axis was (105.04±4.29) mm (male) and(101.80±3.20)mm (female), α angle 33.41°±2.18° (male) and 31.56°±2.71°(female), β angle 21.74°±1.19°(male) and 19.15°±1.24°(female). The bone cortex thickness at the screw entrance point was(5.54±0.46)mm, and that of lateral pelvic and of acetabular side was (1.45±0.13)mm and(1.04±0.10)mm, respectively.　Conclusions　The three-dimensional reconstruction model for simulation of lag screw internal fixation via the lesser sciatic notch is a speedy and accurate way for measurement of the screw path parameters as well as for preoperative evaluation. Using the model to place screws for fixation of posterior column fracture proves easy and safe.