Neurovascular Relations in Modified Iliac Screws and Traditional Iliac Screw: Anatomic Study

Area of Science:

• Spinal surgery
• Orthopedic biomechanics
• Anatomical studies

Background:

• The traditional iliac screw technique is a common spinal fusion method.
• Limited data exists on the safety profile of modified iliac screw techniques regarding nearby neurovascular structures.
• Understanding the anatomical relationship of modified iliac screw placement is crucial for surgical safety.

Purpose of the Study:

• To describe a modified iliac screw technique.
• To compare the modified technique with the traditional iliac screw regarding risks to neurovascular structures.
• To detail the surrounding anatomy and vulnerable structures associated with the modified technique.

Main Methods:

• Twelve fresh-frozen adult cadavers were used for the study.
• Traditional iliac screws (TS) and modified iliac screws (MS) were placed.
• Measurements of distances from screws to the supragluteal artery, vein, and nerve (SGANV) bundle and sciatic notch were taken. Medial cortical border dissection identified final screw position.

Main Results:

• No medial or lateral cortical breaches occurred with either technique.
• The modified iliac screw (MS) showed distances of 18.31 mm to the sciatic foramen (TS: 18.65 mm), and 13.9 mm minimum distance (TS: 14.8 mm).
• Distances to the SGANV bundle were 20.6 mm for MS and 20.77 mm for TS, with no significant differences observed.

Conclusions:

• The modified iliac screw technique does not alter the intraosseous pathway.
• Bone purchase is maintained with the modified technique.
• The distance between the modified screw and at-risk neurovascular structures is comparable to the traditional technique.