Median nerve ultrasound in carpal tunnel syndrome with normal electrodiagnostic tests.

INTRODUCTION: To evaluate the ultrasound findings of the median nerve in patients with clinical assigned carpal tunnel syndrome but normal nerve conduction studies. METHODS: This prospective, cross-sectional study involved 41 patients (51 hands) with clinically assigned CTS and normal nerve conduction studies and 20 healthy controls (30 hands). Ultrasonography was performed in all participants, and cross-sectional area (CSA), hypoechogenicity, and mobility of the median nerve were evaluated. All patients were assessed with Boston Carpal Tunnel Questionnaire (BCTQ). RESULTS: CSA of the median nerve in the wrist was significantly higher in the patient group when compared to the control group. Echogenicity and mobility were significantly decreased in the patient group. Ultrasound abnormalities were positively correlated with clinical features. A significant correlation was observed among sensory loss, provocative tests, body mass index, BCTQ, and high CSA. CONCLUSION: US can help the clinicians with the diagnosis of carpal tunnel syndrome in patients with clinical symptoms but negative nerve conduction study results.