个体化导航模板辅助第2骶椎髂骨螺钉置钉的临床应用

S2 alar-iliac screwing assisted by an individualized navigation template

目的探讨3D打印导航模板辅助经后路第2骶椎髂骨（S2AI）螺钉置入的可行性及准确性。方法回顾性分析2015年3月至2017年7月收治的5例采用S2AI置钉治疗的患者资料，男2例，女3例；年龄41～61岁，平均54．8岁；将患者术前骨盆CT数据进行三维重建，设计导航模板并用3D打印技术制作成实物，并在术中使用导航模板辅助S2AI螺钉置人；术后复查患者骨盆CT、Mim．ics重建后观察图像中螺钉与骶骨及髂骨骨皮质的位置关系，测量并比较术前模拟及术后的钉道在矢状面上尾向偏角（SA）、在横断面上与正中线的夹角（TA），进钉点与骶正中棘的水平距离（HD）与第1骶后孔下缘的垂直距离（VD）。结果5例患者共置入S2AI螺钉10枚，所有螺钉穿透骶髂关节，无侵犯及穿出髂骨骨皮质。术前模拟置钉设定进钉角度SA（32．22°±5．57°）、TA（42．59°±4．55°）、HD[（5．04±0．40）mm]、VD[（19．58±1．49）mm]，与术后复查CT后三维重建术测量的SA（31．95°±5．78°）、TA（42．21°±5．29°）、HD[（5．00±0．41）mm]、VD[（19．54±1．12）mm]比较，差异均无统计学意义（P〉0．05）。结论在成人骨盆固定术中，个体化导航模板辅助经后路S2AI螺钉置钉技术为一种可行的置钉技术，准确性较高。

Objective To evaluate the accuracy and feasibility of S2 alar-iliac screwing assisted by an individualized navigation template in clinic. Methods Five patients underwent S2 alar-iliac screwing from March 2015 to July 2017. They were 2 men and 3 women, aged from 41 to 61 years （average, 54. 8 years）. After their preoperative CT scan data of the pelvis were used for 3D reconstruction, their individualized navigation templates were designed, 3D printed and used to assist the implantation of S2 alar-iliac screws. After operation, their postoperative CT data were reviewed and reconstructed using software Mimics. The caudal angulation on the sagittal plane （sagittal angle, SA）, lateral angulation on the transverse plane （transverse angle, TA）, horizontal distance to the median sacral crest （horizontal distance, HD）, and vertical distance to the first posterior sacral foramen＇s inferior margin （vertical distance, VD） of the screws were measured and compared with the corresponding values in the preoperative design. Results In the 5 patients, altogether 10 S2 alar-iliac screws were implanted through the sacroiliac joint without piercing the iliac bone cortex. There were no significant differences between the preoperative design and postoperative measurements in terms of SA （32. 22° ± 5.57°versus 31.95°± 5.78°）, TA （42. 59° ± 4.55° versus 42. 21 ° ± 5.29°）, HD （5. 04 ± 0. 40 mm versus 5. 00 ± 0. 41mm） orVD （19. 58° ±1. 49 mm versus19. 54 ± 1. 12 mm） （ P 〉 0.05）. Conclusion In the adult pelvic fixation, the S2 alar-iliac screwing can be assisted by an individualized navigation template to achieve high accuracy in implantation.