Combined Median Score Increasing Sensitivity of Carpal Tunnel Syndrome Diagnosis

Abstract

Carpal tunnel syndrome (CTS) is the most common of all focal neuropathies. Electrodiagnostic (EXD) of CTS has advanced to include Combined Sensory Indexes (CSI) improving the specificity and sensitivity of EXD by employing intra-hand comparative data. Ultrasound (US) is a popular tool for the assessment of CTS. Cross Sectional Area (CSA) is the most consistent US parameter, but as a single test, it has a similar false negative profile to EXD. This study describes a dual method of CTS interrogation by EXD and US with the results applied to a single numerical score; the Combined Median Score (CMS). This is the product of CSA of median nerve at Carpal Tunnel inlet and CSI. In a series of 100 suspected cases, standard EDX identified 89 positive cases, CSI identified 92 positives, CMS identified 95 positives. This new method further reduced the false negative rate in CTS.