J Shoulder Elbow Surg (2015) 24, e96-e100
Radial nerve transection associated with closed humeral shaft fractures: a report of two cases and review of the literature Philipp Leucht, MDa,*, Jessica H.J. Ryu, MDb, Michael J. Bellino, MDb a
Department of Orthopaedic Surgery, New York University Langone Medical Center, Hospital for Joint Diseases, New York, NY, USA b Department of Orthopaedic Surgery, Stanford University School of Medicine, Stanford, CA, USA Humeral shaft fractures make up approximately 3% of all long bone fractures,3 and about 10% of all humerus fractures are associated with injuries to the radial nerve.7 Fractures of the middle third of the humerus present with the highest incidence of nerve injury because the nerve lies immediately adjacent to the periosteum in this region.1 Farther distally, the nerve pierces the lateral intermuscular septum, representing another frequent location of nerve damage. Recent studies have provided evidence that closed fractures are most commonly associated with radial nerve neurapraxia, whereas neurotmesis is more common in open fractures.4 From these studies, new guidelines have evolved that recommend conservative treatment for most closed humeral shaft fractures with radial nerve palsy. This recommendation also applies to patients with initially intact findings on neurologic examination who then experience a radial nerve deficit after manipulation of the fracture.11 Here we present 2 cases in which patients sustained a closed, middle-third humeral shaft fracture with immediate radial nerve palsy. Both patients underwent operative fixation of the humerus fracture, one due to an ipsilateral forearm fracture and brachial plexus injury and the other due to a lower extremity fracture. Exploration of the nerve in these 2 patients revealed a complete transection of the nerve at the level of the fracture. Without the
*Reprint requests: Philipp Leucht, MD, Hospital for Joint Diseases, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA. E-mail address: [email protected]
accompanying injury, these 2 patients would have been prime candidates for nonoperative treatment in a functional brace, which might have resulted in bone union without radial nerve recovery.
Case report Case 1 A 36-year-old man without significant past medical history was admitted to the orthopedic service after sustaining a left humeral shaft fracture (Fig. 1), a left both-bone forearm fracture, a left closed distal tibia fracture, and an anteriorposterior compression type 2 pelvic ring injury. Further injuries included a left brachial plexus injury with predominance of the inferior trunk. After initial stabilization, the patient was taken to the operating room for reduction and application of an external fixator for the distal tibia fracture and closed reduction and percutaneous sacroiliac screw placement for the anteriorposterior compression pelvic ring injury. The left upper extremity injury was stabilized in a splint until the next day, when the patient was taken to the operating room again for an open reduction and internal fixation of the humeral shaft fracture and the both-bone forearm fracture. During the anterolateral approach to the humerus, the distal radial nerve was identified, and after provisional length and alignment of the humerus were achieved, the nerve appeared to lack the usual physiologic tension; therefore,
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Radial nerve palsy in humerus fractures
Figure 1 (A) Preoperative anterior-posterior radiograph showing a transverse humeral shaft fracture with moderate comminution. (B, C) Portable anterior-posterior and lateral radiographs taken in the operating room demonstrate anatomic alignment and fixation. (D) Intraoperative photograph demonstrating the radial nerve transection at the level of the fracture. (E, F) Radiographs at 3-month follow-up reveal a partially healed fracture with intact implants.
the decision was made to dissect farther proximally. During this dissection, the transection of the radial nerve was noted. At this point, the plastic surgery team was consulted, and because of the significant bruising and the inability to define the zone of injury, the decision was made to tag the nerve with a 5-0 Prolene suture (Ethicon, Bridgewater, NJ, USA) and to return at a later point for resection of the zone of injury and nerve grafting of the gap. Three months later, the patient was taken to the operating room for a radial nerve exploration and grafting procedure with a sural nerve graft. Another 2 months later, he underwent a nerve transfer of the brachialis motor branch to the median nerve and a capsulodesis of the second through fifth metacarpophalangeal joints. At the 1-year follow-up, the patient exhibited some recovery of the radial nerve with a twitch of the brachioradialis and some wrist extension with gravity eliminated.
Case 2 A 65-year-old woman without significant past medical history presented to the emergency department after a car ran onto the sidewalk and hit a metal pole, which then struck the patient on the right arm. She complained of pain and deformity of her right upper extremity and pain in her right hip joint with inability to bear weight. Physical examination of her right upper extremity revealed a complete motor and sensory radial nerve palsy. Radiographs in the emergency department demonstrated a right, middle-third, transverse humeral shaft fracture (Fig. 2) and a right Garden I femoral neck fracture. Before this injury, the patient had no pain in her hip and was walking without assistive devices. She is right hand dominant and was not complaining of any neurologic issues before the accident.
P. Leucht et al.
Figure 2 (A) Initial radiograph showing a transverse humeral shaft fracture with minimal comminution. (B) The radial nerve transection is visible at the level of the fracture. (C-F) Intraoperative fluoroscopy views and postoperative radiographs reveal anatomic reduction of the humeral shaft fracture.
Because of the femoral neck fracture, the patient was anticipated to require some sort of assistive device after the surgical fixation of her hip fracture. Therefore, the decision was made to perform an open reduction and internal fixation of the humeral shaft fracture to allow early weight bearing of the right upper extremity. The patient was subsequently cleared for surgical treatment of both fractures. One day after her accident, the patient underwent an uncomplicated percutaneous screw fixation of the right femoral neck fracture, followed by surgical fixation of the humerus fracture. The humeral shaft fracture was located in the proximal aspect of the middle third of the humerus, and therefore a decision was made to approach the humerus through an anterolateral approach. During this approach, the radial nerve was identified in the interval between the brachialis and brachioradialis muscle. Posterior dissection for visualization
of the fracture fragments was not needed as both the proximal and distal fragments were stripped of any muscle attachments at the time of the fracture event. After alignment of the fracture fragments, the nerve was again examined and was found to be tortuous. This resulted in further surgical dissection of the proximal nerve, which revealed a complete transection of the radial nerve at the level of the fracture. At this point, the plastic surgery service was consulted for evaluation and management of the radial nerve injury. The surgical team made the decision to perform an immediate repair as the current approach allowed sufficient exposure. For a tension-free repair to be obtained, a 3-cm allograft was interposed. The patient tolerated the procedure well and was discharged home on postoperative day 3. She returned to China, from where she was visiting, and thus we are unable to report any further long-term outcome.
Radial nerve palsy in humerus fractures
Discussion The majority of humeral shaft fractures can be managed nonoperatively, with union rates of up to 90%.12 Malunions of up to 20 of anterior angulation and up to 30 of varus angulation are usually well tolerated in the arm. Therefore, functional bracing is now well accepted as the mainstay of treatment for closed humeral shaft fractures.3,12 Radial nerve palsies after closed humeral shaft fractures occur in approximately 11% of patients.14 Recent systematic reviews have shown a spontaneous recovery of nerve function in about 70% of patients, and in these instances recovery was noted between 3 and 6 months after injury.5,13,14 Current practice guidelines based on these data suggest that presence of a radial nerve palsy at the time of fracture is not an indication for surgical exploration. In contrast, open humeral shaft fractures are associated with high-energy injuries and therefore present with a significantly higher incidence of radial nerve injuries. Recent analyses estimate that about 50% of open humeral shaft fractures are associated with a radial nerve injury.6,13 As current standards dictate operative fixation of open fractures or at least surgical debridement and irrigation, surgical exploration of the nerve can easily be performed in this patient population. The most difficult management issue presents, therefore, in the patient with an obvious radial nerve deficit but no absolute surgical indication. What should be done if the humerus fracture unites but the nerve does not recover after 3 or even 6 months? Studies have shown that even on electrophysiologic evaluation, the nerve and muscles exhibit the first signs of recovery only about 1 month before clinical recovery.10,13 Here lies the dilemma. In our 2 patients, associated injuries resulted in the decision to treat the humeral shaft fracture with open reduction and internal fixation. Without these other injuries, there would not have been an exploration and identification of the laceration and thus no recovery of the nerve at any future follow-up. Likely, we would have ordered nerve conduction studies to further assess continuity of the radial nerve, but as mentioned before, these studies usually cannot distinguish between a severed nerve and an injured nerve in continuity. In addition, recovery of the nerve conduction is usually not evident much earlier than clinical recovery. In these 2 cases, the humeral shaft fracture was exposed through an anterolateral approach. This approach is indicated for fractures of the middle third and more proximal extent of the humeral shaft as it allows implant placement without dissection and transection of muscle origins and insertions. During this approach, the radial nerve is identified between the brachialis and brachioradialis muscles. Once it is localized, the nerve can be traced farther proximally until it follows the spiral groove and disappears in the
e99 posterior soft tissues. Initial dissection of the nerve did not identify the transection. Only after reduction of the fracture and restoration of anatomic length did the surgical team notice the tortuous appearance of the distal extent of the radial nerve. This in turn led to further surgical dissection, which then revealed the complete transection of the nerve. After these 2 cases, the discussion arose whether to approach humeral shaft fractures with associated radial nerve palsy through a posterior approach. During this approach, the radial nerve is easily identified as it courses around the humeral shaft. In addition, the posterior exposure would also allow an easier surgical repair of the nerve by the microsurgical team. At this point, there is no formal consensus on the surgical approach in these challenging cases. As described before, electrophysiologic tests are not sensitive enough to distinguish a radial nerve transection from a neurapraxia; therefore, other modalities have to be investigated. One report suggested ultrasound evaluation as an imaging modality that might guide surgical decisionmaking. In experienced hands, ultrasonography can detect compression of the nerve within the fracture or from fracture fragments as well as discontinuity of the nerve. In this study, the ultrasound findings were confirmed during the surgical exploration in all 5 patients who were indicated for surgical treatment.2 The patient in case 1 underwent a 2-stage procedure. During the open reduction and internal fixation of the humerus fracture, the distal stump of the radial nerve was tagged with a nonresorbable suture, and the patient was then taken back to the operating room for repair of the radial nerve with a sural nerve graft. The second patient underwent immediate repair with an allograft interposition. Current data on immediate vs. delayed nerve repair after high-energy injuries are inconclusive and warrant further investigation. Proponents of the 2-stage approach argue that the extent of nerve damage and the resultant zone of injury cannot be declared at the initial stage.8,9 During the delayed reconstruction, injured nerve tissue can be precisely identified and resected, followed by graft interposition. In the acute setting, this distinction between healthy and injured nerve is not possible, and therefore damaged nerve may be left behind, which could consequently jeopardize a satisfactory outcome.
Conclusion Even though nonoperative treatment of closed humeral shaft fractures is highly successful and leads to radial nerve recovery in the majority of cases, there are still a few patients in whom a radial nerve transection will be missed if they are treated nonoperatively. Current diagnostic modalities are not able to detect these injuries yet, and thus orthopedic surgeons have to rely on experience
e100 and subtle clinical cues, such as injury mechanism, to detect these few outliers.
Disclaimer The authors, their immediate families, and any research foundation with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article.
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