Salem BRAHAM ^1,2 Amen Moussa ^2,3* Marwa BOUHOULA ^2,3 Nihel BEN MERIEM ^1,2 Ichraf ANNEN ^2,4 Ghazi SAKLY ^2,4 Asma CHOUCHANE ^2,3 Malek BEN ABDELKADER ^2,3 Asma ALOUI ^2,3 Imène KACEM ^2,3 Maher MAOUA ^2,3 Houda KALBOUSSI ^2,3 Olfa ELMAALEL ^2,3 Houda MHABRECH ^1,2 Souheil CHATTI ^2,3 Aicha BRAHEM ^2,3

• ¹ Department of Radiology, Farhat Hached University Hospital, Sousse, Tunisia
• ² Medical faculty Ibn Jazzar, University of Sousse, Sousse, Tunisia
• ³ Occupational Medicine Department, Farhat Hached University Hospital, Sousse, Tunisia
• ⁴ Department of Neurophysiology, Sahloul University Hospital, sousse, Tunisia

Background: To assess the contribution of ultrasound in diagnosing occupational carpal tunnel syndrome (CTS), compare it with electromyography (EMG) results, and evaluate the ultrasound characteristics of CTS patients. Methods: A nine-month cross-sectional study (January- September 2021) involved CTS patients and a control group, utilizing a structured form for data collection. EMG was performed on the patient group ('cases') and ultrasound examinations were conducted on both groups. Statistical analysis was performed using SPSS software. Results: Among 44 cases and 30 controls, CTS patients (mean age 44.9 years) exhibited predominantly bilateral symptoms (90.9%). The optimal cross-sectional area (CSA) threshold for diagnosis was 10.3 mm² (89% sensitivity, 84% specificity). Significant differences in ultrasound criteria were observed between patient and control groups, including the "notch sign" (p = 0.012), hypoechoic appearance (p = 0.016), and reduced median nerve mobility (p = 0.021). Quantitatively, CSA (13.7 mm² vs. 7.4 mm²), flattening ratio (3.3 vs. 2.1), and retinaculum bulging (3.2 mm vs. 1.9 mm) significantly differed between cases and controls (p = 0.0019, 0.025, and 0.01, respectively). Positive Phalen tests correlated with higher CSA (p = 0.005) and retinacular bulging (p = 0.02). CSA correlated with EMG parameters, indicating slower conduction velocities, lower amplitudes, and longer latencies (p < 10^(-3), r = -0.56, -0.62, -0.36, and -0.68, respectively). Conclusion: This study highlights ultrasound’s diagnostic potential for CTS, particularly in occupational settings. Its non-invasiveness and reliability advocate for its integration into routine diagnostic protocols, supporting evidence-based management strategies. Further research is needed to explore long-term efficacy and broader applicability.