Neuromuscular ultrasound in ulnar neuropathy at the elbow : correlation with electrodiagnostic studies

Abstract EN

Ulnar nerve entrapment is the second most common entrapment neuropathy in the upper limb after carpal tunnel syndrome, and, if left untreated, it may lead to significant functional impairment and disability.

Objective The aim of this study was to perform clinical, electrodiagnostic (EDX), and neuromuscular ultrasound assessment for patients with ulnar neuropathy at the elbow, to determine the possible roles of neuromuscular ultrasound in the localization of the neuropathy, in the detection of its possible etiologies and in the determination of its severity.

Patients and methods A sample of 15 (22 elbows) patients was recruited and subjected to full medical history, neurological assessment, EDX studies, and neuromuscular ultrasound examination.

Ten (20 elbows) age-matched and sex-matched healthy volunteers were also recruited and served as a control group.

Results This study revealed significantly enlarged ulnar nerve cross-sectional area (CSA) at the ulnar groove and below the elbow and supracondylar sites in patients compared with the control group.

receiver-operating characteristic curve analysis revealed high diagnostic accuracy of the absolute CSA at the ulnar groove, and below the elbow and supracondylar sites, with an area under the curve of 0.8, 0.8, and 0.9, respectively, and the cutoff values were >9, >8, and >8, respectively.

The area under the curve for the ‘maximum CSA/midforearm CSA ratio’ was 0.9, with a cutoff value of more than 1.3.

Conclusion Our study data suggest that neuromuscular ultrasound (NMUS) examination may play a potentially important role in the assessment of ulnar neuropathy at the elbow.

It can localize the lesion and disease severity, and it can differentiate between patients and controls, given its high diagnostic ability.

Abnormalities in ultrasonographic features of ulnar nerve entrapment with regard to CSA and ratio between ‘maximum CSA and midforearm CSA’ at the elbow was correlated with EDX findings.