Utility of First Dorsal Metacarpal Artery Flap for Thumb Defects

Background  Reconstruction of thumb tip, while providing a durable and sensate flap, is a challenging task. It is important as thumb accounts for 50% of hand functions. Options for coverage are: healing by secondary intention, local/regional flaps, microsurgical toe wraparound flap, etc. First dorsal metacarpal artery (FDMA) flap is one regional flap that has been used for thumb cover, usually for defects till interphalangeal joint or just distal to it. We present our case series for FDMA flap and its variations for thumb reconstruction. We also report reverse FDMA flap cover for reconstruction of defects over distal phalanx of thumb. Methods  The procedure was performed in patients with partial loss of thumb soft tissue in 16 patients presenting during 2017 to 2020. The FDMA flap was performed according to the standard technique. In case after "planning in reverse," it was seen that the reach of FDMA flap was insufficient, reverse FDMA flap was done. Physiotherapy for index finger and thumb was started on day 10. Patient satisfaction, in terms of cosmesis and function was recorded (graded as poor, good, and very good). Static two-point discrimination (2-PD) was assessed at 6 months' follow-up. Patients were followed up for 6 months. Results  The operative time was 1 to 2 hours. Out of total 16 cases, 8 patients underwent racquet-shaped (intact skin paddle) FDMA flap. Islanded flap was performed in five and reverse FDMA flap in three. Twelve patients had uneventful recovery and four patients (three islanded and one reverse FDMA) had partial skin loss. Static 2-PD was assessed at the 6 months postoperative period. Conclusion  FDMA flap is a useful regional flap for thumb reconstruction. It provides good supple, durable, and sensate cover. The reverse FDMA flap that increases the pedicle length can be used for more distal defects, where conventional FDMA flap is doubtful.