Enhancing Carpal Tunnel Syndrome Diagnosis: The Combined Use of CTS-6 and Ultrasound Measured Median Nerve CSA.

Abstract

While clinical examination for carpal tunnel syndrome (CTS) is the first-line diagnostic method, its accuracy can vary, particularly among clinicians without specialized training. The CTS-6 questionnaire and ultrasound measurement of the median nerve's cross-sectional area (CSA) are two widely studied diagnostic methods. Combining these tools may provide a more reliable and standardized approach to CTS diagnosis. A review was conducted of patients aged 18 years or older screened for CTS from June 2023 to Sept 2023. We combined scores using the formula (CTS-6 score + 2 × CSA) based on a previous study by Kimura et al. We then used the Index of Union and positive likelihood ratio (PLR) to analyze the optimal cutoff values for the combined score. A total of 142 hands were analyzed. The combined score had the highest sensitivity, while the CTS-6 alone had the highest specificity. The accuracy of the combined score with a cutoff value of 31.25 was equal to that of the CTS-6 score alone. Per the Index of Union, the optimized cutoff for the combined score was 27.68. Maximizing the PLR, the combined score cutoff was found to be 34.08. Combining the CTS-6 and median nerve CSA offers the most accurate method for diagnosing CTS. A lower cutoff value (27.68 vs. 31.25) improved the sensitivity of the combined score, demonstrating a strong diagnostic performance for CTS as a screening tool. Alternatively, using the PLR-optimized cutoff (34.08), this becomes a highly specific confirmatory test.