Evaluation of sympathetic vasomotor fibres in carpal tunnel syndrome using continuous wave Doppler ultrasonography.

Sympathetic vasomotor fibres carried by the median nerve and ulnar nerve innervate their respective sensory territories. The sympathetic vasomotor fibres of the median nerve were evaluated in patients with carpal tunnel syndrome and in healthy volunteers using continuous wave Doppler ultrasonography. The pulsatility index of the radialis indicis artery and the radial palmar digital artery of the little finger were measured at baseline and after stimulation. The maximal increase in the pulsatility index of each artery was measured. This was significantly lower for the radialis indicis artery in the CTS group than in the healthy controls. However, there was no significant difference in the maximal increase in pulsatility index of the radial palmar digital artery of the little finger between both groups. Sympathetic vasomotor fibres of the median nerve are affected in carpal tunnel syndrome. Continuous wave Doppler ultrasonography is easy to use and should be investigated further as a possible diagnostic tool for the confirmation of carpal tunnel syndrome.