Change in Carpal Tunnel Pressure With Dynamic Wrist Flexion/Extension and Radioulnar Deviation: A Cadaveric Study

Carpal tunnel pressure (CTP) is affected by flexion/extension and radioulnar deviation of the wrist. The purpose of this study was to investigate the elevations in CTP as a function of dynamic wrist motion in cadaveric hands. A goniometer was attached on hand dorsal side of cadaveric hands (n = 5). A micro-tip catheter pressure transducer was placed inside the carpal tunnel. With a baseline pressure set around 30 mmHg, the wrist was dynamically and randomly moved in its flexion/extension and radioulnar workspace while position and CTP were simultaneously recorded. CTP as a function of flexion/extension and radioulnar wrist angle was fitted with a third-degree polynomial. A two-way repeated measures ANOVA was used to determine the effect of flexion/extension and radioulnar deviation on CTP (α = 0.05). Flexion-extension or radioulnar deviation significantly affected CTP (p < 0.05). CTP increased beyond 20° of flexion/extension or radioulnar deviation. The polynomial function captured the relationship of CTP with flexion/extension and radioulnar deviation with a coefficient of determination of R² = 0.90 ± 0.06. At 50° of flexion and 50° of extension, the CTP, on average, was 160.7 and 172.0 mmHg, respectively, more than 5 times greater than baseline CTP. CTP was dependent on the direction of the deviation. For the same ulnar deviation at 10°, the CTP at 50° of extension was 46% greater than that at 50° of flexion. CTP remains near baseline for small degrees of flexion/extension and radioulnar deviation and becomes increasingly elevated for greater deviations.