[Reconstruction for dysplastic polydactyly of thumb with an island compound flap].

Objective: To investigate the necessity and feasibility of digit fusion with an advanced island flap in thumb dysplasia of radial polydactyly.

Methods: From February 2007 to January 2015,we collected the patients with radial polydactyly, whose nail width or thumb girth was less than 80％ of contralateral side. 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, an island compound flap, which was based on proper palmar digital artery (PPDA) in radial thumb and contained nail, part distal phalanx and skin, combining with ulnar side of ulnar thumb was used to reconstruct a new thumb. Only the patients 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 PPDA. Appearances were evaluated by Wang -Gao scoring system and functions were evaluated by Tata scoring system.

Results: There were two basic artery forms through preoperative ultrasonography and surgical exploration in 29 hands: both thumbs only had one PPDA; the main thumb had two while the extra thumb still had one. The former was responsible in 82.76％ (24 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.Aesthetic results were excellent in 13 patients, good in 4 and fair in 1.

Conclusions: There is always one developed PDAA in extra thumb, which can be used to design a flap. 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.