Hilgert R E, Finn J, Egbers H-J
Klinik für Unfallchirurgie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Kiel.
Unfallchirurg. 2005 Nov;108(11):954, 956-60. doi: 10.1007/s00113-005-0967-3.
During percutaneous iliosacral screw fixation, fluoroscopy with a conventional C-arm X-ray unit is still the standard procedure for intraoperative orientation. Lateral sacral images in combination with the inlet and outlet view are always necessary. Nevertheless, the complex pelvic anatomy makes it difficult to prevent malpositioning of screws.
Defining the correct entry into the bone is the decisive step for ideal screw placement. The better this is defined, the larger safety margins will be concerning cortical perforation by the screws. In the lateral view, an entry ventral to the sacral canal has to be avoided as well as an entry into the cranial half of the first sacral vertebra. To improve the surgeon's three-dimensional orientation with the help of his personal experience and two-dimensional images, it is recommended to place the tip of the screws in the center of the sacrum (in AP view) whenever possible. Routinely performed postoperative CT imaging of 24 screws, consecutively implanted according to the standards described, revealed no case of malpositioning.
Standard X-ray views in combination with standardized aiming of screw entry position and final screw thread position enable the surgeon to find the "safe zone" for iliosacral screw insertion and to prevent iliosacral screw malpositioning with high accuracy.
在经皮髂骶螺钉固定术中，使用传统C形臂X线设备进行透视仍是术中定位的标准方法。骶骨侧位影像结合入口位和出口位影像始终是必要的。然而，复杂的骨盆解剖结构使得防止螺钉位置不当变得困难。
确定正确的进针点是理想螺钉置入的决定性步骤。进针点确定得越好，螺钉穿透皮质的安全 margins 就越大。在侧位片上，必须避免在骶管前方进针以及进入第一骶椎的上半部分。为了借助外科医生的个人经验和二维影像改善其三维定位，建议尽可能将螺钉尖端置于骶骨中心（前后位片）。按照所述标准连续植入24枚螺钉后常规进行的术后CT成像显示，无一例位置不当情况。
标准X线影像与螺钉进针位置及最终螺纹位置的标准化瞄准相结合，使外科医生能够找到髂骶螺钉置入的“安全区”，并高精度地防止髂骶螺钉位置不当。
