Primary exploration for radial nerve palsy associated with unstable closed humeral shaft fracture

BACKGROUND: The treatment of radial nerve palsy caused by closed humeral shaft fracture is a matter of debate. The purpose of this study is to evaluate the outcome of early surgical management of radial nerve palsy in patients with unstable closed humeral shaft fractures and to determine whether patients with this injury should be surgically explored. METHODS: Medical records of 15 consecutive patients who had undergone open reduction and internal fixation for unstable closed humeral shaft fractures were reviewed. Injury mechanisms, radiographs, intraoperative findings of the injured nerve, and clinical improvement were analyzed. Of the 15 patients, two were injured during simple falls, two during baseball pitching, one by a fall from a height, one during skiing, and one by direct machine impaction during work. Fracture locations were middle humerus in six patients, middle-distal in eight patients, and middle-proximal in one patient. Fracture patterns were transverse fracture in six patients, butterfly segment fracture in four patients, oblique segment fracture in three patients, and spiral fracture in two patients. RESULTS: Eleven patients showed macroscopically intact nerves, and four had total nerve transection. All four patients with total nerve transection were injured in traffic accident. Of these four patients, one showed comminuted fracture with butterfly fragment on the middle-distal shaft and the other three showed displaced transverse fracture on the middle to middle-distal shaft area. Transected nerves were directly repaired in two patients. In the other two patients, humerus shortening and nerve grafting were performed because of mangled nerve endings. All patients who had intact nerves showed fully recovered function at the last follow-up. CONCLUSION: For radial nerve palsy accompanied by unstable humeral shaft fracture, primary exploration of the radial nerve and open reduction and plate fixation of the fracture should be considered as a treatment of choice. High-energy trauma, fracture location at the middle-distal humerus, and simple transverse fracture or comminuted fracture with butterfly fragment seems to be risk factors for radial nerve transection.