Preoperative Determination of the Position of the Radial Nerve in the Posterior Approach to the Humerus using the Transepicondylar Width: A Cadaveric Study
Anupong Laohapoonrungsee MD1, Phornphong Isariyaphruet MD1
Affiliation : 1 Department of Orthopaedics, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
Background : Iatrogenic radial nerve injury following posterior approach of the humerus has been reported from 3 to 11%.
The surgeon’s awareness of nerve location may lower this complication.
Objective : The objective of this study was to evaluate a system to preoperatively determine the location of the radial nerve
using superficial osseous landmarks to help avoid radial nerve injury, a potential complication in fixation of a fracture of the
humerus.
Materials and Methods : Twenty-six fresh frozen upper extremities from adult cadavers were dissected and the distances
from the radial nerve at the midhumeral axis to the medial epicondyle, to the lateral epicondyle and to the ulnar border of the
olecranon were measured and the correlation with the transepicondylar width [TW] was calculated.
Results : The radial nerve was located an average of 2.33 times the TW from the medial epicondyle, 2.27 times the TW from
the lateral epicondyle and 2.74 times the TW from ulnar border of olecranon. The correlation between those distances and the
radial nerve was found to be statistically significant.
Conclusion : The transepicondylar width is an easily accessed bony reference which can be used to calculate the location of
the radial nerve in the posterior MIPO approach, allowing the surgeon to protect the nerve by limiting exposure at the point
predicted by the transepicondylar width.
Keywords : Radial nerve, Posterior approach to humerus, Distal humeral shaft fracture
