Submitted by: Elliot Bodofsky, MD
Utility of Nerve Conduction Studies and Ultrasonography in Ulnar Neuropathies at the Elbow of Different Severity
Clinical Neurophysiology 131(2020):1672-1677
This study compared ultrasound (US), short segment nerve conduction studies (SSNCS), and 10 cm NCS across the elbow, for detection and localization of ulnar nerve compression at the elbow (UNE). Patients that were included had either numbness or paresthesia in the 4th and 5th finger, weakness in ulnar innervated muscles, or reduced hand dexterity. Those with previous elbow trauma, cervical radiculopathy, polyneuropathy, or evidence of ulnar compression at the wrist were excluded. There were 202 arms from 197 patients. Clinical severity was assessed.
All three techniques had high sensitivity for clinically moderate and severe cases. All showed low sensitivity for clinically very mild cases (sensory symptoms only), and moderate sensitivity for mild cases. SSNCS had a significantly higher sensitivity for moderate and severe UNE than US. There were no significant differences between the techniques for accuracy of localizing UNE. US cross section area increased with more severe UNE, but was significantly larger only in severe cases. By contrast, SSNCS and 10 cm across elbow NCS velocity were both lower as clinical severity became more severe. Of note, the study design did not allow specificity to be calculated. Overall, NCS appears to be somewhat more sensitive than US in detecting UNE.
A very good study comparing US and NCS techniques for detection and localization of UNE, a very common problem in neurodiagnostic practice. Utilizes clinical presentation as the standard. Had very few clinically mild cases. Overall, neither NCS nor US were very sensitive for mild UNE.