Purpose: To investigate the necessity and possibility of digit fusion with an advanced island flap in thumb dysplasia of radial polydactyly. Methods: We collected the patients with radial polydactyly, whose nail width or thumb girth was less than 80% of contralateral side, from February of 2007. Among them, some patients were also associated with radial deviation deformities in two thumbs or a shorter radial thumb compared with ulnar thumb. In these cases,the proper palmar digital artery island flap was harvested and advanced to eliminate the tension between the radial and ulnar duplicate. Besides the island compound flap containing a part of the distal phalanx and nail bed was harvested from the accessory radial duplicate to augment the retained ulnar duplicate. The patients only with a smaller thumb girth were treated by an island flap to augment the thumb size. There were 26 patients, including 29 sides. Preoperative Doppler ultrasonic examination was assigned to observe the amount and distribution of princepspollicisartery (PPA)and proper palmar digital artery (PPDA). Appearances were evaluated by Wang-Gao scoring system and functions were evaluated by Tada scoring system. Results: There were two basic artery forms through preoperative ultrasonography and surgical exploration in 29 hands: both thumbs only had one PPDA which was observed in 82.76% (24 hands); the main thumb had two while the extra thumb still had one which was observed in 17.24% (5 hands). All cases were operated according to preoperative design using an island compound flap. 26 hands in 23 patients were followed up more than 6 months. Flap results included survival in 22 patients, tension vesicle in 2 patients and tip necrosis in 2 patients. The incision was infected in one patient with the treatment of changing dressing regularly. The function results were excellent in 21 patients, good in 4, fair in 1. In terms of aesthetic, there were 13 excellent results, 4 good and 1 fair. Conclusion: There is one developed PDAA, which can be used to design a flap, in the accessory radial duplicate. The longitudinal advanced flap can also eliminate the tension caused by unequal length in two thumbs. Using an axial or island flap to reconstruct a new thumb can not only change the appearance, but also make the reconstructed thumb acquire two sets of blood supply and nerve system.
