Ulnar neuropathy at or distal to the wrist: traumatic versus cumulative stress cases.
OBJECTIVE
To identify clinical and electromyographic characteristics of ulnar neuropathy at or below the wrist, comparing those caused by unitary trauma with those caused by suspected cumulative stress.


METHODS
Retrospective case series.


METHODS
University hospital electromyography laboratory.


METHODS
Patients with electrodiagnostic evidence of an ulnar neuropathy at or distal to the wrist over a 3-year period. Forty-seven hands from 42 patients (age range, 20-80y; mean, 52y) were identified and evaluated in this study.


METHODS
Record review of clinical history, physical examination, electromyography, and treatment.


METHODS
Etiology of injury, physical signs and symptoms, and electromyographic testing results.


RESULTS
Ulnar neuropathy at or distal to the wrist is commonly mischaracterized because of other mononeuropathies in the upper extremity and because of peripheral polyneuropathy. Ulnar neuropathy because of cumulative stress presents typically with sensory symptoms (63%) and a normal examination (71%), whereas trauma cases present with motor with or without sensory symptoms (92%) with motor abnormalities (92%) confirmed on examination. Traumatic cases are characterized by electromyography by decreased sensory and motor-evoked amplitudes, prolonged motor distal latencies, and abnormal needle examination. The amplitude changes are noted comparing with laboratory norms and comparing side to side. No characteristic pattern of abnormalities on electromyography is noted in the cumulative stress cases. Patients with no motor symptoms, regardless of etiology, are more apt to have sensory distal latency prolongation, whereas those with motor symptoms have motor amplitude and needle examination abnormalities.


CONCLUSIONS
Traumatic ulnar neuropathy at or distal to the wrist is characterized by motor symptoms and sensory and motor axonal loss by electromyography, whereas cumulative stress cases have sensory symptoms and electromyographic findings that are highly variable and noncharacteristic. Patients with no motor symptoms are more apt to show sensory distal latency abnormalities on electromyography, whereas those with motor symptoms show motor-evoked amplitude and needle electromyography abnormalities.
Chiodo
Anthony
A
Department of Physical Medicine and Rehabilitation, University of Michigan Hospital, Ann Arbor, MI 48108, USA. tchiodo@umich.edu
Chadd
Edmund
E
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004568:Electrodiagnosis; D004576:Electromyography; D006801:Humans; D008875:Middle Aged; D012189:Retrospective Studies; D013312:Stress, Physiological; D020424:Ulnar Neuropathies / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D014947:Wounds and Injuries; D014953:Wrist