Risk of Axillary Nerve Injury With Medial Support Screws in Intramedullary Nails: An Anatomical Study.

Area of Science:

• Orthopedic surgery
• Anatomy
• Surgical complications

Background:

• Modern intramedullary nails for proximal humeral fractures utilize medial support screws.
• Potential iatrogenic axillary nerve injury is a concern with these devices.
• Previous studies have not detailed the anatomical relationship between these screws and the axillary nerve.

Purpose of the Study:

• To investigate the anatomical relationship between medial support screws of proximal humeral nails and the axillary nerve.
• To assess the risk of axillary nerve injury from these screws.

Main Methods:

• Dissection of 29 cadaveric shoulders (mean age 82.6 years).
• A specific proximal humeral nail with medial support screws was used.
• Measurements of the distance between medial support screws and the axillary nerve and its branches were taken.

Main Results:

• Direct contact between medial support screws and the axillary nerve occurred in 6.90% of specimens.
• In 93.10% of shoulders, the axillary nerve was positioned proximal to the medial support screws.

Conclusions:

• Medial support screws in proximal humeral nails pose a potential risk of injury to the axillary nerve and its branches.
• Awareness of this anatomical relationship is important for surgical safety.