Division of the transverse carpal ligament and flexor tendon excursion: open and endoscopic carpal tunnel release.

Ten fresh cadaver upper extremities from 10 different subjects were used in this study of the effect of both open and endoscopic carpal tunnel release on flexor tendon excursion. The amount of excursion necessary to bring each finger from the fully extended to the fully flexed position with the fingertip just touching the palm was measured with the extremity mounted in a device that moved the wrist from extension through flexion. Endoscopic carpal tunnel release, open release, and transverse carpal ligament reconstruction were performed with tendon excursion measurements made in each of four wrist positions after each procedure. Fingertip to palm distance was also measured. The measurements of flexor tendon excursion in neutral wrist position with intact transverse carpal ligament served as the norm for each finger and as the denominator in the ratio of postoperative to preoperative excursion distances. The study confirmed the importance of the transverse carpal ligament as a flexor pulley; transection of the ligament increased the amount of flexor tendon excursion necessary to achieve finger flexion and fingertip-to-palm contact. Tendon excursion/digital flexion improved after transposition flap repair. Neither open nor endoscopic carpal tunnel release conferred any particular benefit to flexor tendon excursion postoperatively. The proximal palmar aponeurosis does not seem to have the same pulley effect as the transverse fibers of the distal palm.