Electrophysiology and Magnetic Resonance Neurography Findings of Nontraumatic Ulnar Mononeuropathy From a Tertiary Care Center.

Background: Ulnar nerve is frequently involved in mononeuropathies of the upper limb. Ulnar neuropathies have been diagnosed conventionally using clinical and electrophysiological findings. Physicians opt for nerve imaging in patients with ambiguous electrophysiological tests to gain additional information, identify etiology and plan management.

Objectives: The aim of this study was to describe the electrophysiological and the magnetic resonance neurography (MRN) findings in patients with nontraumatic ulnar neuropathy.

Methods: All consecutive patients with suspected nontraumatic ulnar mononeuropathy were recruited; clinical assessment and electrophysiological studies (EPSs) were done in all. After EPS, patients with localization of lesion along the ulnar nerve underwent MRN.

Results: All 39 patients recruited had clinical findings suggestive of ulnar neuropathy; Electrophysiological confirmation was possible in 36/39 (92.30%) patients. Localization of ulnar nerve lesion to elbow and wrist was possible in 27 (75%) and 9 (25%) patients, respectively. MRN was done in 22 patients; a lesion was identified in 19 of 22 (86.36%) ulnar nerves studied. Thickening and hyperintensity in T2 W/short TI inversion recovery images of ulnar nerve at the level of olecranon, suggesting ulnar neuropathy at elbow, was the commonest (8/22) imaging finding.

Conclusions: MRN acts as a complimentary tool to EPS for evaluating nontraumatic ulnar neuropathy. By identifying the etiology, MRN is likely to modify the management decision.