Anatomical relationship of the posterior minimally invasive surgical approach of the humerus with the radial nerve. A cadaveric model study

Abstract

Background: It is well known that the various minimally invasive approaches described improve outcomes for the surgical fixation of diaphyseal humerus fractures. However, there is a lack of information between the anatomical relationship of the radial nerve for the required incisions or for the position of the plate when a posterior approach is used. The objective of the study is to describe the anatomical relationship of the radial nerve with both incisions of the posterior minimally invasive approach, and with the distal tip of the osteosynthesis plate.
Materials and methods: A descriptive study was performed on cadavers without trauma of upper limbs, in prone with 45º of abduction of shoulder and 90º of elbow flexion. After sliding a plate of 2.7 mm, the distances of the radial nerve with respect to the reference points of the approach and distal tip of the plate were recorded in millimetres.
Results: A mean humeral length of 286.6 mm was found. The mean distance from the lateral epicondyle to the radial nerve was 155.1 mm. The mean distance from the tricipital aponeurosis to the radial nerve was 138.9 mm, and from the distal tip of the plate to the radial nerve was 155.6 mm.
Discussion: Plate fixation using minimal invasive technique using a posterior surgical approach may be safe for diaphyseal fractures of the humerus with respect to radial nerve injuries, as long as the plate screws are located outside the range of 128.5 mm to 169.5 mm measured from the tip of the plate. Clinical studies are required to demonstrate the safety of this approach.
Evidence level: IV.