Use of Distal Hypothenar Perforator Free Flaps for Pulp Defects

Background: A hypothenar perforator free flap, which is harvested from the palm, is suitable for reconstruction of a finger pulp skin defect, but this flap has rarely been reported, and most of these flaps in previous published reports were designed on the proximal zone of the hypothenar area. In the present report, hypothenar perforator free flaps on the distal zone, namely distal hypothenar perforator free flaps, including two sensate flaps, were used for four cases with pulp defects. Methods: Four distal hypothenar perforator free flaps were used for four patients with skin defects of the finger pulp, including one thumb, two index fingers, and one little finger. The average period from the injury to reconstruction was 30.3 days (range 21 to 47 days). The age of the patients ranged from 49 to 68 years, and the flap size ranged from 18 × 30 to 25 × 45 mm². Two cutaneous branches of the ulnar palmar digital nerve of the little finger were harvested for the sensate flaps. At final follow-up, sensory restoration of the flap was measured using the Semmes-Weinstein monofilament test and the static two-point discrimination test. Results: All donor sites were closed directly, and all flaps survived totally. The average postoperative period was 12 months (range 5 to 15 months). The Semmes-Weinstein monofilament test was all blue (3.61, 3.22, 3.61) for the three flaps followed-up for more than 12 months, including two sensate flaps and one insensate flap. The surgical scars were inconspicuous, and there were no donor site complications. Conclusions: We consider that a distal hypothenar perforator free flap has a high degree of usability for a medium-sized defect such as the whole finger pulp. In the future, whether sensory nerve branches of this flap should be sutured will need to be clarified.