Posterior Interosseous Nerve Syndrome from Thermal Injury

Background. Due to anatomical proximity to bone, the radial nerve is the most frequently injured major nerve of the upper extremity, frequently secondary to fractures (Li et al. (2013)). We describe an incidence when a branch of the radial nerve is injured as a result of a thermal injury. Observation. Radial nerve injury can occur anywhere along the anatomical course with varied etiologies, but commonly related to trauma. The most frequent site is in the proximal forearm involving the posterior interosseous branch. However, problems can occur at the junction of the middle and proximal thirds of the humerus and wrist radially. When the radial nerve is injured by a burn, a new rehabilitation dynamic arises. Not only does one agonize about the return of nerve function but also fret about the skin grafts that replaced the devitalized tissue housing that compartment. Discussion. Although posterior interosseous nerve syndrome has been described in the context of many different etiologies, it has not previously been discussed in relation to burn injuries. In this case, not only did the patient’s rehabilitation involve aggressive therapy for return of sensation and function of the arm, but also prevention of contracture normally seen in replacement of full thickness burns. 1. Introduction Due to its anatomy, the radial nerve is the most frequently injured major nerve of the upper extremity [1]. Proximally, the nerve is closely related to the shaft of the humerus, while at the elbow, it divides into superficial and posterior interosseous branches, the latter of which is closely related to the neck of the radius [1, 2]. Given the close proximity of the nerve to the bone along its course, it is frequently damaged in the context of closed fractures to the upper extremity [1, 2]. It is estimated that as many as 12% of humeral shaft fractures are associated with radial nerve paralysis [3]. The posterior interosseous nerve is the deep motor branch of the radial nerve supplying the majority of the forearm and hand extensors (including the extensor carpi radialis brevis, supinator, extensor digitorum communis, extensor digiti quinti, extensor carpi ulnaris, abductor pollicis longus and brevis, and extensor indicis proprius) [1]. Damage to this branch of the radial nerve results in the posterior interosseous nerve syndrome, a pattern seen when the muscles supplied by this nerve do not function [4]. Classically, the patient is unable to extend the thumb and fingers of the involved extremity at their metacarpophalangeal joints [5]. These patients may be able to dorsiflex