Does the Iliac Wing Influence L5 Pedicle Screw Fixation?

Area of Science:

• Spinal Surgery
• Anatomy
• Biomechanics

Background:

• Pedicle screw (PS) fixation is a cornerstone of lumbar spine stabilization.
• Anatomical variations, such as the iliac wing, can influence screw trajectory and fixation.
• Understanding these influences is crucial for optimizing surgical outcomes.

Purpose of the Study:

• To investigate the impact of the iliac wing on L5 pedicle screw (PS) fixation.
• To identify methods for mitigating the iliac wing's influence on L5 PS placement.

Main Methods:

• Analysis of 100 lower lumbar and pelvic CT scans (50 male, 50 female).
• 3D reconstruction and simulation of 6.5-mm diameter L5 PS trajectories.
• Measurement of trajectory lengths, lateral angles, and distances from the iliac wing.

Main Results:

• Significant differences in trajectory lengths and lateral angles were observed.
• Iliac wing influence on L5 PS fixation was more pronounced in male subjects.
• Trajectories starting at Du's entry point showed less iliac wing interference compared to pedicle axis trajectories.

Conclusions:

• The iliac wing significantly influences L5 pedicle screw fixation, especially in male patients.
• Combining Du's technique with percutaneous methods can reduce iliac wing interference.
• Preoperative simulation is vital for minimizing L5 PS fixation complications.