Relationship of the axillary nerve to the proximal screws of a flexible humeral nail system: an anatomic study.
OBJECTIVE
To investigate the risk of axillary nerve injury during placement of the proximal interlock and tension screws of the Synthes Titanium Flexible Humeral Nail System (Synthes, Paoli, PA).


METHODS
Cadaver study.


METHODS
Anatomic relationships.


METHODS
A titanium flexible humeral nail was inserted in an antegrade manner in 10 fresh-frozen cadaver shoulders. Proximal interlock and tension screws were inserted. The axillary nerve was carefully exposed, and the distance from the center of the nerve to each screw was measured.


RESULTS
In 8 of 10 specimens, the nerve traversed the interval between the proximal interlock screw and the tension screw. The average distance from the axillary nerve to the closer of the two proximal screws was 2.6 mm. The proximal interlock screw transected the axillary nerve in one specimen.


CONCLUSIONS
There is significant risk to the axillary nerve when inserting the proximal interlock screw and the tension screw of this flexible humeral nail system. We recommend blunt dissection through the deltoid, direct visualization of the lateral humeral cortex, and use of a soft tissue protection sleeve when predrilling and placing these screws.
Albritton
Mark J
MJ
Division of Orthopaedics, Department of Surgery, Duke University Medical Center, Durham, North Carolina, USA.
Barnes
Christopher J
CJ
Basamania
Carl J
CJ
Karas
Spero G
SG
D001365:Axilla / Q000033:anatomy & histology*; D001863:Bone Screws; D005594:Fracture Fixation, Intramedullary; D006801:Humans; D006811:Humerus / Q000033:anatomy & histology*; D013127:Spinal Nerves / Q000033:anatomy & histology*