Sonographic evaluation of primary peripheral nerve repair

Objective. This feasibility study was undertaken to define the potential of sonography for the follow-up evaluation of patients with surgical repair after nerve transection and persistent impairment of nerve function. Methods. Nineteen patients with primary repair of a transected peripheral nerve because of direct trauma or complex fractures were evaluated with sonography. All patients had persistent clinical symptoms and neurologic signs of impaired nerve function. In 11 patients who underwent second operations, the intraoperative findings were correlated with those of sonography. Results. Reliable identification of repaired nerves with sonography was feasible in all patients. However, in some cases, sufficient visualization of the site of nerve coaptation was problematic because of extensive scarring. Sonographic findings included the appearance of partial discontinuity of nerve fascicles, detection of neuromas, and compression of nerves by overlying scars. Surgical correlation with sonographic findings was excellent for neuroma detection, however, definition of nerve continuity on sonography was sometimes impaired by scarring. Conclusions. Sonography has a high potential for follow-up examinations of peripheral nerves in relation to previous nerve repair in patients with persistent neurologic signs and symptoms of nerve impairment. Sonography may help in decisions for follow-up surgery by identifying lesions such as neuromas in continuity or discontinuous nerve elements-lesions that will possibly benefit from a second look.