Back to 2026 ePosters
Ulnar Nerve Cross-Sectional Area and Dynamic Instability on Ultrasound Are Independent Predictors of Surgery in Cubital Tunnel Syndrome
Terry L. Hayes, M.M.S.
1, Ignacio Garcia Fleury, MD
2; Joseph A Buckwalter V, MD, PhD
2(1)University of Iowa Hospitals & Clinics, Iowa City, IA, (2)University of Iowa, Iowa City, IA
Introduction: Ultrasonography (US) is increasingly utilized in the evaluation of cubital tunnel syndrome (CuTS). However, its role as a primary diagnostic modality and in guiding surgical decision-making lacks clear consensus. This study examines its potential as a standalone diagnostic tool. We aim to assess the association between ultrasound findings and surgical treatment in CuTS, evaluate the association between cross-sectional area (CSA) on ultrasound and progression to surgical treatment, and assess the prevalence and clinical significance of dynamic ulnar nerve instability and its predictive value in surgical intervention.
Methods: This was a retrospective analysis of data for adult patients who received diagnostic ultrasound at a single tertiary academic medical center between January 1, 2018, and August 1, 2023. History, physical examination, and ultrasound imaging data were obtained via chart review. Determination of abnormal CSA was based on established cutoffs for diagnosis of CuTS (<11mm
2). Instability was defined as "perching" or "complete subluxation." Patients under 18 years of age, incarcerated, and concomitant upper extremity trauma were excluded. Baseline sample characteristics were analyzed including age, race, BMI, and worker's compensation.
Results: A total of 673 scans from 570 patients (103 bilateral) met inclusion criteria (mean age 48.8 ± 15.0 years; 52.5% female). Ultrasound preceded any intervention. Surgery was performed in 383 patients (56.9%).
Surgical patients had significantly higher mean CSA at the medial epicondyle than nonoperative patients (13.0 ± 5.8 mm˛ vs 11.4 ± 4.8 mm˛;
p<0.0008).
Nerve instability was present in 34% of patients overall and more frequent in those undergoing surgery (54.7% vs 45.3%;
p<0.0001).
Conclusion: Both increased CSA and presence of ulnar nerve instability on dynamic ultrasonography are associated with progression to surgical treatment for CuTS. Other measured sites do not demonstrate strong predictive value. These findings support the integration of high-resolution ultrasonography into primary diagnostic and surgical triage workflows in the management of CuTS.
Back to 2026 ePosters
