The majority of authors preferred a lateral approach of the humerus in semi-sitting position. This is also our standard approach. A lateral skin incision is made from the tip of the deltoid V to the lateral epicondyle; it can be extended proximally as for a deltopectoral approach if needed. The radial nerve is first identified at its emergence from the lateral intermuscular septum and dissected anteriorly and distally between brachialis and brachioradialis muscles. At this point, the nerve is isolated, and reduction and fixation of the fracture with plate and screws is finally achieved [6] (Fig. 19.2).

Many authors preferred the posterior approach [6–30, 40, 59–62], in lateral position to explore the radial nerve. A longitudinal incision is made in the midline of the posterior aspect of the arm, from 8 cm below the acromion to the olecranon fossa. The deep fascia of the arm is incised in line with skin incision. The gap is indentified between the lateral and long heads of the triceps muscle. The interval between the two heads is proximally developed by blunt dissection, retracting the lateral head laterally and the long head medially. Their common tendon is distally split along the line of the skin incision by sharp dissection. The radial nerve and the accompanying profunda brachii vessels are identified. The fracture is exposed and fixed with a plate that is put on the posterior surface of the humerus anterior to the radial nerve.

If the nerve is severed, there are no doubts on its reconstruction by means of suture or grafts. If the nerve is in continuity, its function of the nerve is tested by intraoperative electric nerve stimulation and also by detecting the nerve integrity by its normal glistening whitish color, soft in consistency with normal nerve sheath containing longitudinal blood vessels. The use of magnification facilitates the identification of healthy nerve tissue from the injured and edematous nerve tissues. Resection of the damaged portion of the nerve is followed by cable graft reconstruction using sural nerve. If nerve reconstruction is unsuccessful or not indicated, tendon transfers are an ideal procedure to restore function, since the major contribution of the radial nerve to the hand is the motor function.

Some authors reported trans-fracture transposition of the radial nerve through lateral approach [6, 7, 63, 64]. The authors believe that this procedure allows a better exposure of the fracture site, protects the radial nerve during manipulations and reduction, and facilitates the application of longer plates.

Humeral shaft fractures with radial nerve palsy has been the debate since this entity was originally described and continues to be a controversial subject among upper extremity surgery.

Generalized guidelines based on the literature can be stipulated as follows. Open fractures or any fracture with concomitant radial nerve palsy that warrants operative fixation should undergo exploration of the nerve at the time of fixation. Some types of injuries, i.e., high-energy trauma and/or oblique fractures of the lower third of the humerus, are highly suspicious for an important radial nerve lesion. In such cases, an open reduction and fixation of the fracture with early nerve exploration is more suggested than other fracture treatments. Then, the indication for early exploration of the radial nerve appears to be based best on the type of trauma and type of fracture and on the decision of how to treat the fracture than on the clinical suspect of severe nerve lesion.

Radial nerve status can be kept under clinical control in fractures that would otherwise be treated nonoperatively. Ultrasound shows promise as a useful adjunct for visualizing the radial nerve. If the nerve is intact, observation can be continued. If the nerve is clearly severed, exploration is warranted. Repairable nerves should be microsurgically reconstructed by means of suture or graft. When ultrasounds or MRI suggests the possibility of an entrapped nerve, it should be explored.

We agree with many authors that there is no need to be too aggressive and that, except the clear indications for an early exploration, we may wait for a spontaneous nerve recovery. In studies drawn from major trauma centers where consecutive series of patients with humeral shaft fractures complicated by radial nerve palsy were evaluated, virtually all the authors [12, 13, 37, 65, 66] agree that nonoperative management of the radial nerve palsy is the treatment of choice. However, the waiting time should not be too long: if no sign of recovery appears by 3–4 months from the injury, a radial nerve exploration is suggested. In fact, we think that an excessive delay would lessen the chances for good functional recovery (need of longer grafts, long denervation time of the muscles, etc.).

Tendon transfers are indicated for irreparable nerves or for patients with long persistent nerve palsy.

Finally, a different approach should be used for secondary nerve palsies: especially in cases where open procedures (plates) in which the nerve was not well visualized or even in closed reduction fixed by external devices with “dangerous positioned screws,” we think that early nerve exploration could avoid to underestimate a severe nerve lesion, reducing the medicolegal sequelae.