Clinical experiences and surgical techniques of the dorsal ulnar artery perforator free flap in reconstruction of medium-sized defects of the digits.

[INTRODUCTION] Our study aims to share our surgical experiences in utilising the dorsoulnar artery perforator-based (DUAP) free flap for reconstruction of medium-sized defects of the digits.

[METHODS] Five patients, from 2014 to 2022, all of whom sustained critical defects of the digit(s), either due to trauma or infection, underwent resurfacing with an ipsilateral DUAP free flap. The size of the defects ranged from 2.5 to 3.5 cm in width and 3.5 to 7 cm in length. The main outcomes included active range of movement, sensory recovery of the flap, and time to return to work.

[RESULTS AND TECHNIQUES] All five patients demonstrated favourable outcomes following reconstruction of medium-sized digital defects using the DUAP free flap. The patients were followed up for an average of 5 months postoperatively. There were no cases of partial or complete flap failure, and none of the cases required re-exploration of anastomoses. Flap neurotisation was performed in selected cases using either end-to-end or end-to-side neurorrhaphy, achieving a 2-point discrimination of up to 7 mm at 10 weeks postoperatively. All donor sites had healed well and demonstrated good final wrist range of movement, even when flaps extended into the ulnar wrist crease. Technicial refinements included adjusting the flap position to accommodate longer pedicle lengths for defects with short recipient vessels or a wider zone of injury, using a cuff of the main ulnar artery for anastomosis in cases of vessel size mismatch, and using either the dorsal digital vein or superficial dorsal hand vein to mitigate venous congestion.End-to-side (ETS) neurotization was performed in one of the cases, which allowed for preservation of thumb sensation.

[CONCLUSION] The DUAP free flap is reliable and consistently reproducible and serves as a good option for reconstruction of medium-sized defects of the digit. It provides satisfactory functional and aesthetic outcomes, minimal donor site morbidity and the potential for sensory restoration through end-to-end and end-to-side neurotisation. Our experience supports the application of this flap beyond pulp defects, especially when selected technical modifications are employed to address the individual anatomical challenges and optimze outcomes.

[LEVEL OF EVIDENCE] 4.