Computational simulation of sacral-alar-iliac (S2AI) screw fixation of pelvis and implications for fluoroscopic procedure: A cadaver study.

The ideal entry point of S2AI screw showed a wide range of tolerance between the first and second dorsal sacral foramen; and thus, there was no need for deep dissection to identify the first dorsal sacral foramen. Considering the tendency to shift the pilot hole laterally and the ideal screw trajectory was consistently directed toward AIIS, the entry point is better to be located with a medial shift.