A non-invasive technique for estimating carpal tunnel pressure by measuring shear wave speed in tendon: a feasibility study.

Although a close relationship between carpal tunnel pressure and median nerve dysfunction has been found, the current methods for pressure measurements are invasive, using a catheter in the carpal canal to monitor the pressure. A noninvasive method for quantifying carpal tunnel pressure would be useful as an alternative to the catheter method. In this study, a simplified experimental model was developed to measure the shear wave speed in a canine Achilles tendon under different tunnel pressures. The results showed that the speed of waves through the inside-tunnel tendon had a linear relationship with the pressure in the tunnel (first measurement: r=0.966, P<0.001; second measurement: r=0.970, P<0.001). This indicates that the tendon could serve as a strain gauge to evaluate the tunnel pressure by detecting the changes of wave propagation speed. However, further validations in human cadavers and clinical subjects are necessary.