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

Abstract

Background:

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.

Methods:

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.

Results:

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.

Conclusions:

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.