Anatomical Location of the Common Iliac Veins at the Level of the Sacrum: Relationship between Perforation Risk and the Trajectory Angle of the Screw

Table 5

Length of transarticular surface screw, toward promontorium and parallel to S1 endplate at three different angles.

	Toward tip of S1 endplate (mm)		Parallel to S1 endplate (mm)
	Mean ± SD	ICC (95% CL)	Mean ± SD	ICC (95% CL)	value
RL10°		0.79–0.87		0.79–0.87	>0.05
RL0°		0.76–0.86		0.76–0.86	>0.05
RL-10°		0.71–0.83		0.71–0.83	>0.05
LL10°		0.88–0.93		0.88–0.93	>0.05
LL0°		0.72–0.83		0.72–0.83	>0.05
LL-10°		0.84–0.91		0.84–0.91	>0.05

RL0: screw length from insertion point of transarticular surface screw toward anterior wall of S1 at an angle perpendicular to horizontal line passing through the facet joint on an axial computed tomography image; RL10: length of screw at 10° lateral trajectory toward anterior wall of S1 from insertion point on the right side; RL-10: length of screw at 10° medial trajectory toward anterior wall of S1 from insertion point on the right side; LL0, LL10, and LL-10 indicate the same information on the left side.