In vivo measurement of carpal tunnel pressure in the functioning hand.

We recorded directly the pressure within the carpal tunnel during nine different functional positions of the hand and wrist in 102 hands of 92 subjects. Carpal tunnel syndrome was present in 81 hands, and 21 served as controls. A significant rise in pressure was recorded not only with wrist flexion but also with wrist extension, making a fist, holding objects, and isolated isometric flexion of a finger against resistance. Intratunnel pressure dropped after 1 minute of hand and wrist exercises and remained below the resting pressure for over 15 minutes of continuous measurement. We did not observe a rebound phenomenon. Clinical Application: Non-surgical treatment of carpal tunnel syndrome should also include a significant reduction in making a fist, holding objects, pushing, and isolated finger work such as key punching and typing. Activities that require sustained contracture of finger flexor muscles (eg, grasp and hold) also should be avoided. Brief intermittent wrist and hand exercise is recommended to reduce the intratunnel pressure.