Ultrasonography and electrodiagnostic studies in ulnar neuropathy: an examination of the sensitivity and specificity and the correlations between both diagnostic tools.

PURPOSE: This study determines the sensitivity and specificity of ultrasonography (US) and electrodiagnostic studies in ulnar neuropathy at the elbow (UNE) in clinical practice and explores the correlation between both diagnostic tools.
METHODS: Patients were classified on clinical grounds as UNE or patient controls. Electrodiagnostic studies were performed, and nerve cross-sectional area was measured by US.
RESULTS: Sensitivity and specificity were examined in 30 cases of UNE and 33 patient controls. Electrodiagnostic studies had a sensitivity for UNE of 63.3% and a specificity of 87.9%. Ultrasonography had a sensitivity of 76.7% and a specificity of 72.7%. Ultrasonography is more sensitive if complaints exist for 6 months or less. If complaints persisted for more than 6 months, sensitivity and specificity of the electrodiagnostic studies were superior. Correlation was examined in 30 cases of UNE. There was no significant correlation between cross-sectional area and absolute motor nerve conduction velocities across the elbow, motor nerve conduction velocities slowing across the elbow, and compound muscle action potentials amplitude reduction.
CONCLUSIONS: Ultrasonography is more sensitive if complaints exist for 6 months or less. Electrodiagnostic studies are more sensitive and specific compared with US for longer existing cases of UNE. No significant correlation could be demonstrated between both diagnostic tools.