Superior gluteal artery injury risk from third sacral segment transsacral screw insertion

Area of Science:

• Orthopedic surgery
• Anatomy
• Radiology

Background:

• Pelvic ring injuries often require stabilization with iliosacral (IS) or transsacral (TS) screws.
• The superior gluteal artery (SGA) runs near common screw insertion paths.
• The S3 segment offers a potential osseous fixation pathway (OFP), but its proximity to the SGA is uncharacterized.

Purpose of the Study:

• To evaluate the anatomical relationship between the superior gluteal artery (SGA) and potential screw insertion paths in the sacrum.
• To determine the safety of using the third sacral segment (S3) as an osseous fixation pathway (OFP) for transsacral (TS) screws.

Main Methods:

• Fifty pelvic CT angiograms (CTA) from uninjured patients were analyzed.
• Screw starting points for S1 IS/TS, S2 TS, and S3 TS screws were identified.
• Distances from screw paths to the SGA were measured on 3D CTA reconstructions.

Main Results:

• The average distance from S1 IS screws to the SGA was 23.0 ± 7.9 mm.
• The average distance from S2 TS screws to the SGA was 14.3 ± 6.4 mm.
• The average distance from S3 TS screws to the SGA was 25.9 ± 6.5 mm.
• No S1 or S3 TS screw paths, but 10% of S2 TS paths, were projected to be within 3.5 mm of the SGA, indicating potential injury risk.

Conclusions:

• The S3 TS screw pathway is anatomically remote from the SGA, suggesting a safe option for pelvic stabilization.
• The S1 IS and S3 TS pathways offer greater distance from the SGA compared to the S2 TS pathway.
• The S2 TS pathway presents a theoretically higher risk of SGA injury in patients with an available S3 OFP.