Complementary Role of Ultrasound and Clinical Features in Assessing Carpal Tunnel Syndrome Severity: A Cross-Sectional Study

<b>Background/Objectives</b>: The goal of this study was to assess the correlation between ultrasound measurements and nerve conduction study (NCS)-defined carpal tunnel syndrome (CTS) severity and to explore clinical and demographic factors associated with CTS severity in a sample of Romanian patients. <b>Methods</b>: We prospectively evaluated consecutive patients with clinically diagnosed CTS. All patients underwent standardized clinical assessment, ultrasonographic examination of the median nerve, and NCS. CTS severity was graded electrophysiologically (three-level scale), and associations with demographic, clinical, and ultrasound parameters were examined using univariate analyses and multivariable generalized estimating equation (GEE) models to account for within-patient clustering. <b>Results</b>: Among 193 CTS hands (100 patients, mean age 58 years, 93% female), electrophysiological severity correlated significantly with several ultrasound and clinical parameters. In multivariable GEE models, the presence of nocturnal symptoms, sensory loss, thenar weakness/atrophy, male sex, larger maximal median nerve cross-sectional area (mCSA), and impaired median nerve mobility were independent predictors of higher NCS-defined severity. Pseudo-R² increased from 0.04 in the core clinical model to 0.25 when ultrasound parameters were included, indicating improved model performance. <b>Conclusions</b>: Ultrasound parameters, particularly mCSA and median nerve mobility, together with clinical features, such as nocturnal symptoms, sensory loss, and thenar weakness, are independently associated with NCS-defined CTS severity. These findings support the complementary role of ultrasound alongside NCS in severity grading and highlight its potential to guide timely diagnosis and management.