Advanced Imaging of Pediatric Radial and Axillary Nerve Anatomy for Intraoperative Use

Koshinski Jessica,Cornell Max,Seeley Mark,Mandel Mark

doi:10.36959/765/400

Abstract

Abstract Introduction: Lateral percutaneous pin placement, intramedullary screw placement, and plate placement during surgical fixation of distal humeral fractures all risk iatrogenic injury to the radial nerve as it crosses from the posterior to anterior compartment at the level of the mid-humeral shaft. Current literature describing the "safe zone" to avoid damaging the radial nerve at this location focuses on adult vascular anatomy. Radial nerve anatomy changes throughout childhood, and determination of age specific safe zones will help minimize iatrogenic nerve palsy in the pediatric population. Axillary nerve anatomy was also assessed. Methods: Electronic medical records were queried for humeral and shoulder MRIs that included the proximal humeral physis and the lateral epicondyle to assess the radial nerve or the lateral edge of the acromion and the upper 1/3 of the humeral diaphysis to assess the axillary nerve. Results/Discussion: Our study suggests the axillary nerve reaches its adult location around 14 years of age while the radial nerve does not reach its approximate adult location until 16 years of age. Before these ages extra precaution should be taken during surgical dissection and fracture fixation.

Highlights

Lateral percutaneous pin placement, intramedullary screw placement, and plate placement during surgical fixation of distal humeral fractures all risk iatrogenic injury to the radial nerve as it crosses from the posterior to anterior compartment at the level of the mid-humeral shaft
There is a lack of research identifying surgical “safe zones” to avoid iatrogenic injury to important neurovascular structures traversing over the proximal and mid shaft of the humerus in the pediatric population
The evolving anatomical location of the axillary and radial nerves over the proximal and mid humeral shaft of the aging child are of particular concern as lateral approaches to the proximal humerus and shoulder put terminal branches of the axillary nerve at risk [1]

Summary

Introduction

Intramedullary screw placement, and plate placement during surgical fixation of distal humeral fractures all risk iatrogenic injury to the radial nerve as it crosses from the posterior to anterior compartment at the level of the mid-humeral shaft. Lateral percutaneous pin placement, intramedullary screw placement, and proximal extension of lateral plate placement during surgical fixation of supracondylar humerus fractures all risk iatrogenic injury to the radial nerve as it exits the spiral groove and crosses from the posterior to anterior muscular compartment [2]. We have chosen to examine the radial nerve at the vulnerable point as it exits the spiral groove and transitions from the posterior to anterior muscular compartment, and we have decided to examine the axillary nerve as it hugs the lateral aspect of the proximal humeral shaft just after it traverses from medial to lateral along the posterior aspect of the surgical neck. The purpose of this study is to use magnetic resonance imaging (MRI) in order to gain a more thorough understanding of the maturing locations of the axillary and radial nerves in growing children

Objectives

Methods

Results

Conclusion