Radiographic parameters and feasibility analysis of dual sacral-2 alar-iliac screw fixation using three-dimensional...

Area of Science:

• Spinal surgery
• Orthopedics
• Medical imaging

Background:

• Sacral-2 alar-iliac (S2AI) screw fixation is a critical technique in spinal fusion.
• Accurate trajectory planning is essential for successful S2AI screw placement.
• 3D digital technology offers advanced simulation capabilities for surgical planning.

Purpose of the Study:

• To evaluate the feasibility of dual S2AI screw fixation using 3D digital technology simulation.
• To analyze the trajectories and parameters of dual S2AI screw placement.
• To provide data for optimizing S2AI screw fixation in clinical practice.

Main Methods:

• Pelvic CT scans from 60 Chinese adults (30 male, 30 female) were used for 3D reconstruction.
• Dual S2AI screw trajectories were simulated using 3D software with varying cylinder radii (5mm, 4.5mm, 4mm).
• Key parameters including screw trajectory length, width, angles, and distances to anatomical landmarks were measured.

Main Results:

• Dual S2AI screw placement was feasible in all simulated cases.
• No significant sex-based differences were observed in screw head inclination, abduction angles, or screw dimensions.
• Significant differences in the shortest distance from the greater sciatic notch to the screw trajectory were noted between sexes.

Conclusions:

• Dual S2AI screw fixation is feasible in the Chinese adult population, with a 4mm screw diameter as a standard.
• Optimal placement involves trisecting the S1-S2 lateral process, with screws in the upper and lower thirds.
• Preoperative 3D simulation analysis provides accurate trajectory data for clinical S2AI screw placement.