Analysis of the CTS-6 Questionnaire and Development of a Carpal Tunnel Syndrome Decision Tree

Purpose: Carpal tunnel syndrome (CTS) is a common compressive neuropathy with no gold standard for diagnosis. The CTS-6 questionnaire is a previously validated tool used to determine the likelihood that a patient has CTS; however, numbness and tingling in the median nerve distribution is not a required symptom for a positive test result. The purpose of this study was to re-evaluate the components of the CTS-6 questionnaire to determine if a more succinct carpal tunnel screening tool could be developed. Methods: A database of 295 upper extremities who had previously undergone CTS-6 testing were analyzed. All charts were reviewed to determine which patients were offered carpal tunnel release, used as the reference standard for a true positive diagnosis. We split the data into training (80%) and test (20%) sets that were used to develop and validate a decision tree for CTS, respectively. The performance metrics for this decision tree, the CTS-6 questionnaire, and variations of the questionnaire were calculated. Results: The CTS-6 had a sensitivity of 76%, specificity of 60%, and overall accuracy of 71%. Variations of the CTS-6 had sensitivity of 72% to 93% and specificity of 37% to 65%, where a higher sensitivity came at the cost of lower specificity. The CTS decision tree had the best performance metrics, with 100% sensitivity, 65% specificity, and 88% overall accuracy. Conclusions: A simple CTS decision tree has the potential to be an efficient screening tool to assist in determining which patients may be a good candidate for carpal tunnel release. Further investigation into this screening tool in a larger patient population should be performed to determine its usefulness in a clinical setting. Type of study/level of evidence: Diagnostic IV.