Anatomical considerations of safe drilling corridor upper sacral segment screw insertion

Area of Science:

• Orthopedics
• Spine Surgery
• Anatomy

Background:

• The upper sacrum is critical for stabilizing the lumbosacral spine with pedicular screw fixation.
• Accurate anatomical knowledge is essential to prevent complications during S1 screw insertion.

Purpose of the Study:

• To provide precise morphometric data of the upper sacrum (S1-S2) for optimizing pedicular screw placement.
• To guide surgical technique for S1 pedicular screw insertion, minimizing risks.

Main Methods:

• Measurements of sacral wings, pedicles, foramina, and the sacral canal were performed on 87 human sacrums.
• Key parameters including screw trajectory depth and angles were quantified.

Main Results:

• Mean S1 pedicle depth was 25.8 ± 2.3 mm; mean sacral wing depth was 50.1 ± 1.7 mm.
• Mean anteromedial sacral pedicle angle was 29.6 ± 0.9°; mean sacral wing angle was 29.7 ± 2.1°.

Conclusions:

• Understanding these specific anatomical measurements is vital for safe and effective S1 pedicular screw placement.
• Precise screw trajectory depth and angle are critical to avoid anterior vascular and medial nerve root injuries.