Strangulation of Radial Nerve Within Nondisplaced Fracture Component of Humeral Shaft Fracture
Rates of radial nerve injury, which is commonly associated with humeral shaft fractures, range from 8% to 12%. This neurapraxia typically recovers with nonoperative management. In some conservatively treated cases, the radial nerve is lacerated or entrapped. Patients with a lacerated or entrapped nerve may have better outcomes with early operative management.
We report on a rare case of the radial nerve entrapped within a nondisplaced segment of a closed humeral shaft fracture and describe the clinical outcome of early operative management.
In a standard history or physical examination, there are no particular features indicating nerve entrapment. Absolute indications for humeral shaft fractures with radial palsy are limited to open fractures, vascular injuries, and unacceptable fracture alignment. Relative indications are polytrauma and secondary palsy after attempted fracture reduction. For all other humeral shaft fractures with radial nerve palsy, observation is still the mainstay of treatment, with spontaneous recovery occurring in up to 90% of patients.2,8-12 Our patient did not have an absolute indication for operative treatment; surgery was nevertheless performed to address the polytrauma and to facilitate earlier mobilization.
Electromyelogram (EMG) studies typically are not useful after acute injury. EMG studies are better used serially to evaluate reinnervation after the acute phase. Bodner and colleagues13,14 used ultrasonography to identify the radial nerve in a patient with unimproved radial nerve palsy 6 weeks after humeral shaft fracture. They found the nerve within the fracture site, whereas magnetic resonance imaging (MRI) could not follow its course. Neither ultrasonography nor MRI would likely be used after acute injury. More research is needed to improve evaluation of patients with continued palsy after nonoperative treatment.
In the case of our patient’s humeral shaft fracture, surgery was performed early because of polytrauma and radial nerve entrapment. If left interposed between 2 fracture fragments, the nerve would have been subjected to continued ischemia and likely would not have recovered spontaneously. Ikeda and Osamura7 reported on a case of radial nerve palsy that occurred after humerus shaft fracture. The nerve, entrapped between fracture fragments, was explored later, after function failed to return. As it was found within callus, the nerve was cut and then repaired end-to-end. In our patient’s case, early exploration led to release of the radial nerve from the fracture site—preventing irreversible nerve damage and allowing for spontaneous recovery over subsequent months.
Surgery for polytrauma patients with a humeral shaft fracture and radial nerve palsy may also be beneficial with respect to early nerve exploration and early mobilization. Although our patient’s fracture was well aligned and as an isolated injury would not have required surgery, the polytrauma called for early surgical management, which revealed radial nerve entrapment and led to early recovery of nerve function.
