成人后路经第2骶椎骶髂螺钉固定钉道的CT测量

Computed tomography study of posterior S2 alar-iliac screw placement in adults

中文关键词:  第2骶椎  内固定  骶髂螺钉  CT三维重建  CT测量

英文关键词:The second sacrum  Fixation  Sacral alar-iliac screw  Three-dimensional CT reconstruction  CT measurement

中文摘要:

  【摘要】 目的：对成人后路经第2骶椎骶髂（S2 alar-iliac，S2AI）螺钉固定钉道各参数进行CT测量，探讨S2AI螺钉固定的可行性与安全性。方法：选取骨盆正常的50例腰椎病变患者，年龄20～60岁，平均46.1岁，其中男25例，女25例。对其骨盆行螺旋CT薄层扫描和三维重建，采用Light Speed工作站模拟理想的S2AI螺钉固定钉道。选择S1骶孔外缘1mm的垂线和下缘1mm的水平线的交点为进钉点，前后旋转三维骨盆图像，得到骨髓腔最长与最宽的骨盆横断面，在此横断面穿过髂骨中央部位的直线即为理想的S2AI螺钉固定钉道，测量此钉道在矢状面上尾向偏角（sagittal angle，SA）、在横断面上与正中线的夹角（transverse angle，TA）、钉道最大长度（maximal length，ML）、钉道在骶骨内的长度（sacral length，SL）、横断面上髂骨髓腔的最窄宽度（iliac width，IW）及进钉点与皮肤的垂直距离（skin distance，SD）。结果：所有患者均存在理想的S2AI螺钉固定钉道，该钉道穿过骶骨侧块和骶髂关节，穿行于髂骨内。SA、TA、ML、SL、IW及SD在男性分别为29.56°±8.38°、36.11°±3.38°、120.94±7.89mm、26.56±4.08mm、17.00±3.16mm和44.01±12.10mm，在女性分别为35.11°±7.03°、36.69°±3.21°、115.21±8.80mm、27.85±5.56mm、14.85±2.51mm和47.97±13.39mm，女性钉道SA、ML和IW与男性比较有统计学差异（P＜0.001），但女性TA、SL和SD与男性比较无统计学差异（P＞0.05）。结论：临床应用S2AI螺钉固定具有可行性，但要注意置钉方向、长度以及性别间的差异等；术前骨盆CT三维重建及钉道模拟有助于术中S2AI 螺钉的准确置入。

英文摘要:

  【Abstract】 Objective：To investigate the feasibility and safety of the posterior S2 alar-iliac（S2AI） screw placement in adult pelvises by computed tomography（CT）. Method：50 adults with normal pelvises，including 25 males and 25 females，with the age ranging from 20 to 60 were chosen.Based on three-dimensional（3D） CT reconstructions of these specimens，virtual S2AI screw channels were identified and measured.The anchoring point was defined as 1mm inferior and 1mm lateral to the S1 dorsal foramen.Then virtual S2AI screw channel holding the greatest length and width of osseous channel was meassured by rotating the 3D pelvis.The parameters of the determined channels including caudal angulation on the sagittal plane（sagittal angle，SA），lateral angulation on the transverse plane（transverse angle，TA），the maximal length of the channel（maximal length，ML），the intrasacral length of the channel（sacral length，SL），the narrowest width of iliac medullar cavity（iliac width，IW） and the vertical distance from the insertion point to skin（skin distance，SD） were measured respectively.Result：There existed virtual S2AI screw channels going through the sacral ala as well as sacroiliac joint and into the ilium in each specimen.The SA，TA，ML，SL，IW and SD was 29.56°±8.38°，36.11°±3.38°，120.94±7.89mm，26.56±4.08mm，17.00±3.16mm and 44.01±12.10mm respectively in males，and 35.11°±7.03°，36.69°±3.21°，115.21±8.80mm，27.85±5.56mm，14.85±2.51mm and 47.97±13.39mm respectively in females，which showed significant sex-related difference with respect to these indexes of SA，ML and IW（P＜0.001）.However，no significant sex-related difference was found with respect to TA，SL and SD（P＞0.05）.Conclusion：It is feasible and reliable to insert the S2AI screw when performing sacropelvic fixation.Preoperative CT imaging and 3D reconstruction may help to choose correct anchoring point and screw channel individually.