Carpal arch and median nerve changes during radioulnar wrist compression in carpal tunnel syndrome patients

The purpose of this study was to investigate the morphological changes of the carpal arch and median nerve during the application of radiounlarly directed compressive force across the wrist in patients with carpal tunnel syndrome. Radioulnar compressive forces of 10 N and 20 N were applied at the distal level of the carpal tunnel in 10 female patients diagnosed with carpal tunnel syndrome. Immediately prior to force application and after 3 min of application, ultrasound images of the distal carpal tunnel were obtained. It was found that applying force across the wrist decreased the carpal arch width (p < 0.001) and resulted in increased carpal arch height (p < 0.01), increased carpal arch curvature (p < 0.001), and increased radial distribution of the carpal arch area (p < 0.05). It was also shown that wrist compression reduced the flattening of the median nerve, as indicated by changes in the nerve's circularity and flattening ratio (p < 0.001). This study demonstrated that the carpal arch can be non-invasively augmented by applying compressive force across the wrist, and that this strategy may decompress the median nerve providing symptom relief to patients with carpal tunnel syndrome.