S_2骶髂螺钉的置入技术

S_2 iliosacral screw insertion technique

目的 ：介绍S2骶髂螺钉的置入技术。方法：通过术前骨盆CT或标准骶骨侧位X线片测量确定S2节段有足够的置钉空间。全麻后患者仰卧或俯卧,常规消毒铺巾。首先在标准骶骨侧位透视像监视下将导针尖确定在S2神经根管前缘线、椎体前缘线及S1骶前孔下缘三者所围成的区域内并打入髂骨外板1~2 mm,然后在骨盆出口位透视像监视下引导导针沿S1骶前孔下缘及S2骶前孔上缘之间的区域行进,在骨盆入口位透视像监视下确认导针位于S2椎体及侧块前缘的后方,将导针打至合适长度,再次透视标准骶骨侧位像确认导针尖位于椎体前缘线后方及S2骶神经根管前缘线的前方。之后沿导针测量长度,钻孔、攻丝后拧入骶髂螺钉。结果：应用此技术于不稳定型骨盆后环损伤患者27例,置入30枚S2骶髂螺钉。经术后骨盆出入口位X线及CT检查确认所有螺钉均位于S2椎体及侧块骨质内,置钉均准确。结论：S2骶髂螺钉置入技术安全且可复制,可用于指导S2骶髂螺钉的置入以增加不稳定型骨盆骨折后环固定的稳定性。

Objective：To introduce a technique pertaining to S2 iliosacral screw insertion. Methods：The screw pathway was first measured on the preoperative pelvic CT scan or the standard sacral lateral radiograph to make sure the existence of the＂safe zone＂ in the S2 segment for screw insertion. Under general anesthesia,patients were positioned supine or prone,depending on the injury pattern of pelvic ring or associated injuries requiring concomitant operation. The operation field was routinely sterilized using iodine and subsequent alcohol solution and draped. The tip of a guide wire was inserted through a stab wound to the posterior outer iliac table,manipulated in the ＂safe zone＂ being enclosed by the anterior aspect of the S2 nerve root tunnel,the anterior aspect of the sacral vertebrae,and the inferior aspect of the S1 foramen under the guidance of the standard sacral lateral fluoroscopy,and then the tip was hammered one to two millimeters into the iliac cortex. The guide wire progressed along the trajectory between the inferior aspect of the S1 foramen and the superior aspect of the S2 foramen on the pelvic outlet fluoroscopic view,and then along the posterior to the anterior aspect of the S2 sacral vertebrae and alae on the pelvic inlet fluoroscopic view with a predetermined length. At that moment,in order to ensure the safety,another standard sacral lateral view was imaged to detect the guide wire’s tip which should locate posterior to the anterior aspect of the sacral vertebrae and anterior to the anterior aspect of the S2 nerve root tunnel. Subsequently,the depth was measured,the trajectory was drilled and tapped,and the screw was inserted. Following the removal of the guide wire,the wound was irrigated and sutured. Results：Utilizing this insertion technique,there were 30 S2 iliosacral screws in total being placed to stabilize the injured and unstable posterior pelvic ring in 27 patients. Each S2 screw was accompanied by an ipsilateral S1 screw. The S2 screw location was completely intraosseous in all patients,which was verified by postoperative pelvic outlet and inlet radiographs and CT scans. The insertion accuracy was100 percent in the present series. Conclusion：The S2 iliosacral screw insertion technique is safe and reproducible to guide the placement of the S2 screw,enhancing the stability for the compromised posterior pelvic ring.