标准骶骨侧位像上骶神经根管前缘线对置入骶髂螺钉的作用

目的：了解骶神经根管于S1、S2骶段内的方位、走行,探讨标准骶骨侧位像上骶神经根管前缘线对置入骶髂螺钉的作用.方法：将全骨盆2.0 mm层厚轴向平扫数据导入到Mimics 10.0,并应用其分别将骶骨、双侧无名骨、骶管及骶神经根管制作成3D图像并旋转至标准骶骨侧位及骨盆出入口位后观察骶神经根管的方位、走行.辨识标准骶骨侧位及骨盆出入口位X线片上骶神经根管并观察其特点.结果：在S1、S2骶段内骶神经根管始于同节段椎管的头端前缘的两侧,止于同节段骶前孔,其走行由头端、后方、内侧至尾端、前方、外侧;在X线片上其密度低,尤其在标准骶骨侧位像上常仅其前缘线显像且多有中断现象而需要仔细辨识.结论：在标准骶骨侧位像上辨识骶神经根管前缘线并以之作为骶髂螺钉安全通道的尾后界,则可以避免内置物进入神经根管及骶管,从而提高置钉的安全性.

Effect of the anterior aspect of sacral nerve root tunnel on iliosacral screw placement on the standard lateral image of sacrum

Objective: To introduce the location and course of S1,S2 sacral nerve root tunnel and to clarify the significance of the anterior aspect of sacral nerve root tunnel on placement of iliosacral screw on the standard lateral sacral view.Methods: Firstly the data of 2.0 mm slice pelvic axial CT images were imported into Mimics 10.0,and the sacrum,innominate bones,and sacral nerve root tunnels were reconstructed into 3D views respectively,which were rotated to the standard lateral sacral views,pelvic outlet and inlet views. Then the location and course of the S1,S2 sacral nerve root tunnel on each view were observed.Results: The sacral nerve root tunnel started from the cranial end and anterior aspect of the vertebral canal of the same segment and ended up to the anterior sacral foramen with a direction from cranial-posterior-medial to caudal-anterior-lateral. The tunnel had a lower density than the iliac cortex and greater sciatic notch on the pelvic X-rays,especially on the standard sacral lateral view,on which it showed up as a disrupted arc line and required more careful recognition.Conclusion: It can prevent the iliosacral screw from penetrating the sacral nerve root tunnel and vertebral canal when recognizing the anterior aspect of sacral nerve root tunnel and choosing it as the caudal-posterior boundary of the "safe zone" on the standard lateral sacral view.