Fig. 2

 A: C-arm fluoroscope unit laser localisation identified the body entry point of the iliosacral screw guide needle at the intersection of the line connecting the anterior superior iliac spine with the posterior inferior iliac spine and the upward extension of the femoral stem; B: marking of the body entry point; C: the entry point of the guide needle was located at the intersection of the S1/2 endplate extension with the posterior wall of the sacral canal (+); D: pelvic outlet position indicated by the guide pin between the S1 superior endplate and the S1 sacral foramen; E: pelvic entry position indicated by the guide pin within 0.5 cm of the anterior edge of S1 before the midpoint of the section; F: lateral view of the sacrum showing the iliosacral screw entry point at the posterior edge of the spinal canal