The surgical technique utilized in this study was previously described in the initial report by Rappoport et al. (9). Fluoroscopically guided intra-articular injections were used to diagnose the patients. The SIJ fusion implant utilized in this study (SI-LOK, Globus Medical, Inc., Audubon, Pennsylvania, USA) was a novel HA-coated slotted screw designed specifically for a lateral approach MIS fusion of the SIJ. The slot allows for bone through-growth resulting in biological fixation of the screw. The HA coating of the screw is designed to promote osseous apposition to the implant. The washer design of the screw assists the surgeon in optimizing proper screw insertion depth.

Following prone positioning on a Jackson table, scout inlet, outlet and lateral C-arm images are obtained. The skin is marked (Figure 1) at the confluence (A) of the alar lines (B) and the posterior cortex of the sacrum (C) on the lateral image. An approximate 2–3 cm incision (D) is made 1 cm distal (E) to the intersection of these 2 lines. Blunt finger dissection is performed down to the fascia. The first guide pin is initially inserted using the lateral projection, beginning in the region of the posterior sacrum, staying caudal to the alar line and angled approximately 10–15 degrees downward. Pin projection is checked in the inlet and outlet views as well, with the outlet view used to determine screw length. Drilling is performed across the joint over the guide pin and the screw slot is filled with bone from the drill reaming.

The skin is marked at the confluence (A) of the alar lines (B) and the posterior cortex of the sacrum (C) on the lateral image. An approximate 2–3 cm incision (D) is made 1 cm distal (E) to the intersection of these 2 lines.

The screw is then inserted across the joint into proper position on the outlet view. The washer can be seen to tilt when the lateral cortex is engaged. The inlet view is then used to check the screw position, and the second pin is placed using the dual parallel pin guide. Switching to the lateral view, the first screw position is confirmed, as well as the position of the second pin. On the working outlet view, the guide pin is advanced staying lateral to the S1 foramen. Screw length is determined, and the screw is packed and inserted in the same fashion. The third screw is placed using the same technique. Once all 3 screws have been placed, final position is determined with outlet (Figure 2A), inlet (Figure 2B) and lateral views. If intra-operative CT scan is available, further precise confirmation of screw position can be determined (Figure 3). All patients had 3 screws placed in this study.

Images taken of a single patient instrumented with sacroiliac screws. (A) Outlet view; (B) inlet view.

CT images of the first (A), second (B) and third (C) screw placed in the same patient as Figure 2.

注意:以上内容是从某篇研究文章中自动提取的,可能无法正确显示。



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