The free flap based on a single proximal perforator of the radial artery: ultrasonography study and clinical applications in reconstruction of soft tissue defects in finger.

[OBJECTIVES] To locate an anastomosable constant perforator of the radial artery on the proximal forearm using ultrasonography and describe the application of a free radial artery flap based on a single proximal perforator for the reconstruction of soft tissue defects in finger.

[METHODS] In 20 forearms (ten right and ten left) from ten volunteers, the perforators in the proximal half of the forearm from the radial artery were visualized using ultrasonography. The free radial artery perforator flaps based on the single perforator were used to reconstruct digital soft tissue defects in four cases between October 2017 and May 2018.

[RESULTS] Of the 20 forearms, an anastomosable perforator was consistently detected in the radial artery in the forearm's proximal half. The perforator diameter was 0.7 ± 0.1 mm, and the pedicle length was 12 ± 3 mm according to ultrasonography. The perforator's location was far from the elbow crease (8.8 ± 1.4 cm), and the relative distance of the perforator's location from the elbow crease to the wrist crease was 37.2% ± 4.8%. In clinical cases, all flaps survived. Flap size ranged from 3.5 to 6.5 cm in length and 2.3-3.0 cm in width. Donor sites of the forearm were closed primarily in all cases. During a mean period of 12 months (8-14 months) follow-up, the average static 2-PD was 13.8 mm (10-18 mm) in the flap area, and the ROM of DIP was 35° (30-40°), PIP was 82° (45-110°), and MP was 85° (70-90°) of the affected finger. The mean Brief Michigan Hand Questionnaire (BMHQ) score was 72.9 (60.4-85.4) in the affected hand.

[CONCLUSIONS] An anastomosable perforator is consistently located on the radial artery in the proximal half of the forearm. The free radial artery flap based on this single perforator provides acceptable functional and cosmetic outcomes for reconstructing digital soft tissue defects. With the preservation of the forearm's main vessel (radial artery), this flap provides another reliable option for hand surgeons to reconstruct small soft tissue defects in finger.