Objective: To evaluate and compare the morphologic changes of the ulnar nerve at the elbow, using ultrasonography, between patients with cubital tunnel syndrome and retrocondylar compression syndrome determined with electrodiagnosis.
Design: Prospective study using electrodiagnosis and ultrasonography.
Setting: An outpatient rehabilitation clinic in a tertiary university hospital in South Korea.
Participants: Thirteen patients (8 men, 5 women; mean age, 48.2y).
Interventions: Not applicable.
Main outcome measures: In the electrodiagnostic study, we used the inching technique to localize the ulnar nerve lesion at the elbow. In the ultrasonography study, we measured the length of the swollen ulnar nerve and the ratio of the nerve diameter between the proximal end of the medial epicondyle to the elbow joint level and the tip of medial epicondyle to the elbow joint level.
Results: The mean length of the swollen ulnar nerve segment in retrocondylar compression syndrome (2.58+/-0.58cm) was significantly longer than that of cubital tunnel syndrome (1.64+/-0.31cm). The mean ratio of the nerve diameter between the proximal end of medial epicondyle and the elbow joint level was significantly larger in retrocondylar compression syndrome (1.52+/-0.25) than that of cubital tunnel syndrome (1.06+/-0.06).
Conclusions: Ultrasonography detected the morphologic changes and the extent of the ulnar nerve lesion at the elbow, and it can become a screening and follow-up imaging modality in patients with ulnar neuropathy at the elbow.