Can we define severity of carpal tunnel syndrome by ultrasound?

Carpal tunnel syndrome (CTS) is a common entrapment neuropathy. Diagnosis of CTS is usually based on a combination of clinical symptoms and electrodiagnostic study (EDS). Ultrasonography (US) also has been shown to be a useful diagnostic tool in CTS and is based on an increase in the median nerve cross-sectional area (CSA) at the level of the pisiform bone. In this study we assessed findings in US in correlation with severity of CTS.

This was a cross-sectional case-control study, which was carried out on November 2012 to July 2013. Subjects were chosen from patients who referred to the Alzahra Hospital (Isfahan, Iran). Patients were classified as having mild, moderate, and severe CTS according to EDS and high-resolution US was performed for CSA measurement at the tunnel inlet.

A total of 87 individuals screened and 52 subjects (81 hands) met all inclusion and no exclusion criteria. The mean ± SD of the CSA was 0.12 ± 0.03 cm(2) (range, 0.08-0.18) in mild, 0.15 ± 0.03 cm(2) (range, 0.08-0.19) in moderate, and 0.19 ± 0.06 cm(2) (range, 0.11-0.32) in severe CTS. We detected a significant correlation between MN CSA and the severity of CTS (P < 0.001).

In conclusion it is expected that sonography may serve as an additional or complementary method which is useful and reliable in assessing the severity of CTS.