Quantification of the upper and second sacral segment safe zones in normal and dysmorphic sacra

Area of Science:

• Orthopedic surgery
• Anatomy
• Radiology

Background:

• Sacral dysmorphism presents unique challenges for surgical fixation.
• Understanding the safe zones for iliosacral screw placement is critical in pelvic trauma.

Purpose of the Study:

• To quantify the safe zones for iliosacral screw placement in the upper and second sacral segments.
• To compare these safe zones between normal and dysmorphic sacral morphologies.

Main Methods:

• Retrospective analysis of 50 pelvic CT scans.
• Characterization of sacra as normal or dysmorphic.
• 3D reconstruction to measure safe zone dimensions and obliquity.

Main Results:

• Sacral dysmorphism identified in 44% of patients.
• Dysmorphic upper sacral segment safe zones were smaller (36%) and more oblique but accommodated screws in 91% of cases.
• Dysmorphic second sacral segment safe zones were larger (2x) and suitable for transverse screw placement in 95% of cases.

Conclusions:

• Sacral morphology significantly impacts iliosacral screw safe zones.
• The dysmorphic upper sacral segment, despite challenges, remains amenable to screw fixation.
• The second sacral segment offers a valuable fixation option in dysmorphic sacra.