The Diagnostic Usability of Dorsal Ulnar Cutaneous Response in Ulnar Neuropathy at the Elbow

J Korean Assoc EMG Electrodiagn Med 2002;4(1):8-13.
Published online May 10, 2002.

Abstract

Objectives : To evaluate diagnostic usability of dorsal ulnar cutaneous sensory nerve (DUCSN) in ulnar neuropathy at the elbow. Methods : Twenty-five patients with ulnar neuropathy at the elbow were studied and twenty two arms of thirteen neurological intact adult were tested. Dorsal ulnar cutaneous nerve conduction studies were performed with surface electrodes on the 4th dorsal web space, stimulating 8 cm from active electrode. Results : Twenty males and five females were studied (age: range 17~69, average 53) in patients group. Seven males and six females were studied (age: range 19~51, average 30) in asymptomatic group. In patients group, ulnar nerve conduction studies showed focal conduction block across the elbow or axonal loss in all. The DUCSN response was abnormal in 19 of 25 (76%) patients. In asymptomatic group, average distal sensory latency at 8 cm was 1.47 0.13 with average amplitude of 26.4 . Conclusion : We conclude that dorsal ulnar cutaneous response is useful to help distinguish distal entrapment from compression at or near the elbow, especially in cases when segmental motor conductions or EMGs are equivocal. Therefore electrophysiologic measurement should be performed in the case of suspected ulnar neuropathy at the elbow.

Key Words: Dorsal ulnar cutaneous nerve, Ulnar neuropathy, Conduction block.