Radial nerve transection after ballistic humeral shaft fractures: A retrospective cohort study.

Introduction: Radial nerve palsy following fracture of the humeral shaft is common. However, the incidence of nerve transection in the setting of ballistic trauma is unknown. The purpose of this study was to estimate the incidence of radial nerve transection after ballistic fracture of the humerus.

Methods: Patients presenting to an urban, level-1 trauma center with a ballistic fracture of the humeral shaft were retrospectively reviewed. Patient demographics, clinical exam on presentation, and operative data were reviewed to determine the incidence of radial nerve palsy on initial examination, the incidence of operative treatment, the incidence of how frequently the nerve was directly visualized, and the incidence of radial nerve transection.

Results: One-hundred and thirteen ballistic humeral shaft fractures were identified. Of these, 30 (26.5%) patients had a complete radial nerve palsy on exam. Of patients with a radial nerve palsy, on exam 20 were taken to the operating room and the nerve was visualized in 17 of those cases. There 2 were partially lacerated nerves and 12 nerves were completely transected. Thus, in patients with a complete nerve deficit on examination who underwent operative treatment with nerve exploration, the rate of nerve transection was 70.6%. The lower bound rate of nerve transection for all patients with radial nerve palsy (assuming all unexplored nerves were intact) was 40.0%.

Conclusion: The rate of nerve transection in patients with humerus shaft fractures with associated radial nerve palsies is likely higher than the rate of nerve transection in similar injuries caused by blunt mechanisms. The authors recommend early exploration and fixation of these injuries.