The second dorsal metacarpal artery flap relaying the dorsal island flap of the index finger for the repair of soft tissue defect of thumb

Abstract

To investigate the effectiveness of the second dorsal metacarpal artery fascial vascular pedicle retrograde island flap relaying the dorsal island flap of the index finger in repairing skin and soft tissue defects of the thumb. The clinical data of 8 patients with skin and soft tissue defects of thumb between October 2019 and January 2021 were retrospectively analyzed. There were 3 males and 5 females with an average age of 35 years (range, 18-52 years). The causes of injury included machine injury in 2 cases, crush injury in 3 cases, and cutting injury in 3 cases. There were 2 cases of dorsal defect of the proximal part, 1 dorsal defect of the distal part, and 5 instances of the distal part defect. The skin and soft tissue defects ranged from 1.7 cm×1.4 cm to 3.0 cm×2.5 cm. The time from injury to flap repair was 7-21 days, with an average of 14 days. Firstly, the dorsal island flap of the index finger (dorsal side of the proximal part of the index finger) was used to repair the defect of the thumb. Then the second dorsal metacarpal artery fascia vascular pedicle retrograde island flap (near the radial side of the back of the hand) was used to repair the dorsal defect of the index finger; the donor site was sutured directly. Vascular crisis of the flap occurred in 1 case within 48 hours after operation, and the flap was bloated and bruised in 1 case due to excessive suture tension, and all the flaps survived after symptomatic treatment; partial skin margin of the flap was necrotic in 1 case after operation, and the incision healed after dressing change; the other 5 flaps survived, and all the wounds in the donor and recipient sites healed by first intention. All the 8 patients were followed up 3-10 months, with an average of 6 months. One patient had mild scar; the other patients had no significant difference in the color of the flap and the surrounding skin, no adhesion of tendons, and little interference of index finger function, and there was no obvious pain and dysfunction in the donor and recipient sites of the flap. At last follow-up, the extension-flexion range of motion of the metacarpophalangeal joint of the thumb was 0°-55°, and that of the interphalangeal joint was 0°-75°; the extension-flexion range of motion of the metacarpophalangeal joint of the index finger was 0°-82°, that of the proximal interphalangeal joints was 0°-90°, and that of the distal interphalangeral joints was 0°-65°. The application of the second dorsal metacarpal artery fascial vascular pedicle retrograde island flap relaying the dorsal island flap of the index finger to repair skin and soft tissue defect wounds of thumb is a feasible treatment with reliable blood supply, less postoperative complications, no need for skin grafting, less interference to the function of the index finger, and satisfactory wound repair effect.