Figure 7.

Pelvis and left sacral-alar-iliac drill axis (red). The anterior pelvic plane, defined by the anterior superior iliac spines and the pubic tubercles (all in green circles), was defined as the frontal plane (green). The axial plane (blue) was defined as perpendicular to both frontal and anatomical sagittal (reddish) planes. The cranio-caudal inclination angle was measured between the drill axis and the axial plane. The medio-lateral convergence angle was measured between the drill axis and the sagittal plane. The angles were measured between the axis and their orthogonal projection onto the respective plane using multiplanar reconstruction of the computed tomography data.