髋臼后柱顺行螺钉置入的3D影像测量研究

3D imaging measurement of anterograde screw placement in the posterior column of the acetabulum

摘要:

［目的］提出一种髋臼后柱顺行螺钉置入新的参考方法和相关解剖学参数，为后期导板设计提供基础。［方法］收集 40 例成人骨盆 CT 数据，通过 Mimics 软件重建三维模型。从髂翼内侧顺行置入一圆柱体通过后柱，调整到理想位置，该圆柱体从髂翼内侧的穿入点 （A） 作为拉力螺钉的入钉点，从坐骨结节下方的穿出点 （B） 作为拉力螺钉的出钉点。在弓状缘上取点 C，使 AC 为入钉点到弓状缘的最短距离，D 点为骶髂关节最前缘，连接 AC 和 CD。在 Mimics 上找到方形区靠近坐骨大切迹后缘的一块较平整的区域，做一平面 β 平行于此区域，再做一平面 γ 垂直于平面 β 并与坐骨大切迹后缘相切。测量 AC，CD 的距离、拉力螺钉的最大半径和长度、拉力螺钉与平面 β 的夹角（a）及与平面 γ 的夹角（b）。［结果］在同一侧别男性与女性比较中，男性的螺钉最大半径和最大长度大于女性，线段 CD 小于女性，差异均有统计学意义（P<0.05）；线段 AC、夹角 a 和夹角 b 差异无统计学意义（P>0.05）。在同一性别左侧和右侧比较中，螺钉的最大半径、最大长度、线段 AC 、CD、夹角 a 和 b 差异均无统计学意义（P>0.05）。［结论］根据相关解剖学数据，使置钉过程更加精准安全，并为后期导板设计提供基础。

Abstract:

[Objective] To propose a new reference method and related anatomical parameters for anterograde screw placement in the posterior column of the acetabulum, and to provide a basis for the design of the 3D printed guider. [Methods] The CT data of 40 adult pel- vis were collected and three-dimensional (3D) models were reconstructed by Mimics software. A cylinder was placed from the inner side of the iliac wing reaching to the posterior column and adjusted to the ideal position. The insertion point of the cylinder of the inner side of the iliac wing (A point) was set as the insertion point of the lag screw, whereas ischial tuberosity (B point) represented exiting point of lag screw. The C point was marked on the arcuate edge, which was the shortest distance to the arcuate edge from A point. In addition, the D point was marked on the most front of sacroiliac, and then the A point and C point, as well as the C point and the D point were connected. A flat square region near the posterior edge of the greater sciatic notch was found on mimics, a plane β was made parallel to this region, and a plane γ was made perpendicular to and tangent to the posterior edge of the greater sciatic notch. The distance between AC and CD, which represented the maximum radius and length of lag screw, as well as the angle between lag screw and plane β (a) and the angle between lag screw and plane γ (b) were measured. [Results] In term of gender, the males had the maximum radius and length of the screw significantly greater than the females (P＜0.05) , whereas the males had significantly shorter CD segment than females (P＜0.05) . However, there were no significant differences in terms of AC segment and angle a and angle b between the two genders (P＞0.05) . In term of bilateral sides, there were no statistically significant differences in the maximum radius, maximum length, AC segment, CD segment, and angle a and angle b be- tween the left and right sides (P＞0.05) . [Conclusion] According to the relevant anatomical data, the screw placement process will be more accurate and safe, which provides a basis for the design of 3D printed guider later.