同侧双枚第2骶椎骶髂螺钉固定钉道的影像学研究

Imaging study of unilateral/bilateral dual second sacral alar-iliac screws placement in adults

中文关键词:  骶髂螺钉  内固定  骨盆  CT测量

英文关键词:Sacral alar-iliac screw  Internal fixation  Pelvis  CT measurement

中文摘要:

  【摘要】 目的：模拟正常成人骨盆置入同侧双枚第2骶椎骶髂（second sacral alar-iliac，S2AI）螺钉，测量钉道的影像学参数，评估同侧双枚S2AI螺钉置钉的安全性与可行性。方法：回顾性分析2019年1月~2020年7月于我院行骨盆CT平扫及三维重建的患者影像学资料，选取骨盆无解剖学异常者50例，其中男性25例，女性25例，年龄25~75岁，平均55.7±12.3岁。在Light Speed影像学工作站上模拟同侧两枚S2AI螺钉的固定钉道：选取第1骶孔外缘1mm的垂线和上缘1mm的水平线的交点为近端S2AI螺钉的进钉点，选取第1骶孔与第2骶孔外缘1mm处连线的中点为远端S2AI螺钉的进钉点，分别以两个进钉点为中心，对其三维骨盆图像进行旋转、切割，以得到髂骨髓腔最长与最宽的理想钉道。测量钉道的尾倾偏角（sagittal angle，SA）、外向偏角（transverse angle，TA）、钉道最大长度（maximal length，ML）、钉道在骶骨内的长度（sacral length，SL）、进钉点与皮肤的垂直距离（skin distance，SD）。同性别S2AI螺钉钉道参数之间比较采用配对设计t检验，不同性别参数之间比较采用完全随机设计t检验。结果：所有研究对象双侧均能建立出理想的S2AI螺钉钉道，男性近端的S2AI螺钉钉道SA为42.31°±3.71°，TA为37.31°±2.39°，ML为105.51±5.92mm，SL为29.32±3.87mm，SD为26.52±3.31mm；远端S2AI螺钉钉道的SA为24.57°±2.17°，TA为41.65°±2.39°，ML为125.89±6.01mm，SL为48.57±11.34mm，SD为43.53±8.01mm；男性的两枚螺钉钉道的SA、TA、ML、SL组间比较存在统计学差异（P<0.05），SD组间比较无统计学差异（P=0.078）。女性近端的S2AI螺钉钉道的SA为43.05°±3.05°，TA为36.53°±1.98°，ML为102.38±7.44mm，SL为31.31±4.11mm，SD为28.01±2.91mm；远端的S2AI螺钉钉道的SA为29.38°±2.67°，TA为40.96°±2.58°，ML为118.74±6.68mm，SL为51.87±10.52mm，SD为47.72±12.63mm；女性的两枚螺钉钉道的SA、TA、ML、SL组间比较存在统计学差异（P<0.05），而SD的组间比较无统计学差异（P=0.223）。将不同性别患者两枚S2AI螺钉的钉道参数进行比较分析，无论对于近端还是远端的螺钉，男性均具有更大的ML（P＜0.05）。远端的S2AI螺钉，男性与女性SA的差异有统计学意义（P＜0.001）。结论：国人正常成人骨盆中可以构建出双枚S2AI螺钉钉道，近端的S2AI螺钉比远端的螺钉更为尾倾及内收；与男性相比，女性的钉道更为尾倾且更短。

英文摘要:

  【Abstract】 Objectives: To simulate placing two ipsilateral S2AI screws in the pelvis of normal adults and measure the imaging parameters of the screw trajectories, and to investigate the feasibility and safety of such technique. Methods: The imaging data of patients who received plain CT scan and three-dimensional reconstruction of the pelvis in our hospital from January 2019 to July 2020 were selected, and 50 patients with no anatomical abnormalities in the pelvis were also selected. There were 25 males and 25 females, aged from 25 to 75 years old, with an average of 55.7±12.3 years old. The fixation trajectories of two S2AI screws on the same side was simulated on the Light Speed system: the intersection point of the vertical line 1mm at the outer edge of the 1st dorsal foramen and the horizontal line 1mm at the upper edge was selected as the anchoring point of the proximal S2AI screw, and the midpoint of the connection between the 1st dorsal foramen and the outer edge of the 2nd dorsal foramen 1mm was selected as the anchoring point of the distal S2AI screw. Then the three-dimensional pelvis images were rotated and cut with the two anchoring points as the center, so as to obtain the ideal trajectories. After the construction of the trajectories, the imaging parameters were measured, including sagittal angle(SA), transverse angle(TA), maximal length(ML), sacral length(SL), and skin distance(SD). Paired-samples′ t test was used to compare the parameters of S2AI screws in the same gender, and independent-samples′ t test was used to compare the parameters between different genders. Results: The trajectories of virtual bilateral dual S2AI screws could be constructed on every patients′ pelvic CT scan images. The imaging parameters of male′s proximal S2AI screw were SA: 42.31°±3.71°, TA: 37.31°±2.39°, ML: 105.51±5.92mm, SL: 29.32±3.87mm, SD: 26.52±3.31mm, and of the distal S2AI screw were: SA: 24.57°±2.17°, TA: 41.65°±2.39°, ML: 125.89±6.01mm, SL: 48.57±11.34mm, SD: 43.53±8.01mm. There were statistically significant differences between the SA, TA, ML, SL(P<0.05), but there was no statistical difference between the values of SD(P=0.078). For female, the imaging parameters of proximal S2AI screw were: SA: 43.05°±3.05°, TA: 36.53°±1.98°, ML: 102.38±7.44mm, SL: 31.31±4.11mm, SD: 28.01±2.91mm, and the imaging parameters of distal S2AI screw were: SA: 29.38°±2.67°, TA: 40.96°±2.58°, ML: 118.74±6.68mm, SL: 51.87±10.52mm, SD: 47.72±12.63mm. There were statistically significant differences between the SA, TA, ML, SL(P<0.05), but there was no statistical difference between the values of SD(P=0.223). The screw trajectories parameters of two S2AI screws from patients of different genders were compared and analyzed. Both proximal and distal screws showed that males had larger ML(P<0.05). At the same time, for distal S2AI screws, the difference in SA between men and women was statistically significant(P<0.001). Conclusions: Generally, the proximal S2AI screw is more tailward and adducted than the distal S2AI screw. And the females′ screw trajectories are more tailward and shorter than males′.