"Fat pad" and "little finger pulp" signs are good indicators of proper release of carpal tunnel.

OBJECTIVE: The release of the transverse carpal ligament (TCL) for relief of carpal tunnel syndrome has been a standard operative procedure since the early 1950s. Although complications are not common after the open surgical technique, a small but significant group of patients will have similar symptoms after surgery or will experience new symptoms in the postoperative period. Incomplete section of the TCL is the major cause of these complications. The authors have described two signs that confirm a complete release of the TCL, called the "fat pad" and "little finger pulp" signs.

METHODS: Between 2000 and 2003, we treated 643 hands in 611 patients (45 men and 566 women; age range, 32-76 yr; mean age, 58.2 yr). All patients were examined 6 months after the procedure, with special attention given to the persistence or recurrence of symptoms. The presence of palmar scar pain, residual numbness, patient satisfaction, and time to return to work were also evaluated. A longitudinal incision (2 cm) at the base of the palm was used to release the TCL. A good indicator that the distal TCL has been released is the visualization of a fatty tissue ("fat pad" sign). This fatty tissue is always present underneath the most distal fibers of the TCL, covering the sensory digital branches of the median nerve. To confirm the complete release of the proximal fibers of the TCL, we should be able to introduce the little finger pulp in a proximal direction underneath the distal flexion crease of the wrist ("little finger pulp" sign). When both signs are confirmed, we can be certain that the TCL is completely released.

RESULTS: Night pain disappeared immediately after surgery in all patients except three. There were seven complications (1%) not related to the palmar scar and 10 complications (1.5%) related to it. However, all of these complications disappeared an average of 3 months postoperatively. Patient satisfaction was 100%, and the mean time to return to work and full activity was 22 days (range, 14-36 d).

CONCLUSION: Two surgical observations that are reliable to confirm a complete release of the TCL were described. The first, called the "fat pad" sign, is useful to determine whether or not the distal end of the TCL has been adequately released, whereas the "little finger pulp" sign indicates whether or not the proximal end of the TCL has been fully divided.