Neurovascular relations in modified iliac screws and the traditional iliac screw: An anatomical study

Abstract Introduction This study describes a modified iliac screw technique and compares it to the traditional iliac screw with regards to neurovascular structures at risk. Few studies have detailed the insertion point’s surrounding anatomy and its relationship to vulnerable neurovascular structures when this modified technique is used. Therefore, we describe our modified iliac screw entry and trajectory and detail the surrounding anatomy and neurovascular structures at risk with this technique in comparison to the "gold standard" trajectory. Methods The traditional iliac screw (TS) and the modified iliac screw (MS) were placed into 12 fresh-frozen adult cadavers (3 female, 9 male). We measured the screw to SGANV bundle and screw to sciatic notch distances. Further, we dissected the medial cortical border of the iliac screw to identify its final position with respect to the surrounding anatomy. Results No medial or lateral cortical breaches were visualized after screw placement. The MS was 18.31 mm from the greater sciatic foramen compared to 18.65 mm with the TS. The smallest distance from the MS to the greater sciatic foramen was 13.9 mm compared to 14.8 mm with the TS, a nonsignificant difference. The SGANV bundle to MS distance was 20.6 mm, and SGANV bundle to TS distance was 20.77 mm, again, a nonsignificant difference Conclusion Using the modified Iliac screw technique does not change the intraosseous pathway (and thus, bone purchase) with respect to the distance between the screw and neurovascular structures at risk.