Short-segment nerve conduction studies in ulnar neuropathy at the elbow.

The aim of the study was to assess the diagnostic value of short-segment nerve conduction studies (NCS) at 2-cm intervals from 4 cm above to 4 cm below the medial epicondyle in a large group of patients with ulnar neuropathy at the elbow (UNE). Furthermore, we wanted to compare electrodiagnostic and clinical findings. We evaluated 73 arms in 70 patients with UNE and observed the following abnormalities on short-segment NCS: focal conduction block (CB) in 1, focal CB with increased latency change in 34, and increased latency change alone in 25. Short-segment NCS had an additional localizing value in 28 arms of the 37 patients (76%) with motor conduction velocity (MCV) slowing across the elbow only or with nonlocalizing electrodiagnostic findings. The lesion was located above the elbow in 32 arms (53%), at the epicondyle in 16 arms (27%), and below the epicondyle in 12 (20%) of the 60 arms with focal CB or increased latency change on short-segment NCS. Patients with CB on routine and short-segment NCS had muscle weakness significantly more often than patients without CB. Thus, short-segment NCS are useful in localizing the lesion in patients with UNE and CB on routine NCS and have additional diagnostic value in patients with MCV slowing across the elbow or with nonlocalizing signs on routine nerve conduction studies. We recommend its use in all patients in whom UNE is suspected.