Ultrasound Assessment of the Ulnar Nerve Around the Elbow and Diagnosis of Cubital Tunnel Syndrome, Clinical Outcomes

Abstract

Background: There is increased interest in ultrasound (US) for the diagnosis of cubital tunnel syndrome (CuTS). We hypothesize that ulnar nerve cross-sectional area (CSA) correlates with disease severity and electrodiagnostic studies (EDX). Methods: ARetrospective review was performed at a tertiary medical center. One hundred seventeen patients (166 ulnar nerves) were evaluated. Maximum CSA at 3 points around the elbow (proximal, groove, and distal) and EDX results (American Board of Electrodiagnostic Medicine-certified physiatrist’s interpretations) were collected. Results: US was positive (CSA > 0.1 cm2) in 95/117 cases (81.20%) versus 84/117 (71.79%) positive for EDX. CuTS patients treated surgically had significantly greater (0.13 cm2, standard deviation [SD] 0.038) preoperative CSA than non-operative patients (0.10 cm2, SD 0.033) ( p = .003). CSA increased as EDX increased in severity; mild (0.116 cm2, SD 0.031), moderate (0.121 cm2, SD 0.035), and severe (0.163 cm2, SD 0.047) with a significant difference between the mild and severe groups ( P = .001) and between the moderate and severe groups ( p = .01). Significant differences were seen between patients with positive US and EDX studies compared to those with negative US and EDX in the average physical function scores (57.26, SD 8.57 versus 43.18, SD 7.70; p < .001); average sleep scores (50.14, SD 9.53 versus 56.62, SD 7.31; p = .02); average physical function scores (43.04, SD 8.68 versus 57.08, SD 6.34; p < .001) and average depression scores (49.10, SD 10.88 versus 45.043, SD 7.06; p = .02). Conclusions: US is a reliable tool for diagnosis and surgical decision-making for CuTS. Type of Study/Level of Evidence: Diagnostic/III.