Title: A New Surgical Technique for Lateral Ray Polydactyly without Skin Graft: The Bell-Bottom Flap
Abstract: Sir: Lateral ray polydactyly is one of the most common congenital anomalies of the limbs. In this article, we present a favorable surgical outcome for lateral ray polydactyly using a bell-bottom flap developed by modifying the conventional dorsal rectangular flap.1 Skin incision lines were prepared as shown in Figure 1. The base of flap A was designed at the metatarsophalangeal joint to enable the reconstruction of a deep interdigital space. Compared with the conventional dorsal rectangular flap, flap A was designed in a different shape in which the distal end of the flap was made approximately 3 mm longer than its base (approximately 5 mm), and lines ce and ab were made as shallow-curved lines. We named flap A the bell-bottom flap based on its shape.Fig. 1.: Schema of the surgical procedure. The following four local flaps were designed using this technique: a modified dorsal rectangular flap designed on the dorsal side of the fourth web (flap A); a dorsal triangular flap based on the fourth toe (flap B); a trapezoidal flap designed on the volar side (flap C); and a volar triangular flap based on the fourth toe (flap D). Flap A was used for reconstruction of the interdigital space, flaps B and D were used for reconstruction of the sidewall of the fourth toe, and flap C was used for reconstruction of the sidewall of the sixth toe. The length between two points in each line was determined according to the following rules: (1) line bd was extended outward from line bc for it to be as long as line ab; (2) point l was placed at the same level as that of the web of the fourth interdigital space, and curved line lf was designed to be as long as line dc plus line ce; (3) line lk was designed to be 10 to 20 percent longer than the interdigital distance; (4) line jk was designed to be as long as the line on top of the bell-bottom flap (line bc); (5) line fg was designed to be as long as line gi; and (6) line dh was designed to be as long as line hi.After incisions around the nail, flap B was elevated over the periosteum of the fifth digit. The fifth toe was then removed as a mass of nail components and digital bony structures. Flap A was then elevated, with care taken to include as much subcutaneous tissue in the pedicle of the flap as possible. Flaps C and D on the volar side were then elevated, with sufficient care taken to not damage the neurovascular bundle. Wound closure was performed as follows. First, flap A was inserted into the fourth interdigital space to form a new web. Then, flaps B and D were rotated inward to construct the lateral side of the fourth toe, followed by rotation of flap C to construct the lateral side of the sixth toe. In this procedure, a back cut was made on the tip of the toe to ease movement of flap C downward. A triangular flap obtained from the area around the nail of the removed toe was then fitted into the open space, making efficient use of the excessive skin in the distal region. The present technique was performed in eight feet, with lateral ray polydactyly in eight patients (two boys and six girls). The ages of the patients ranged from 10 months to 3 years 2 months. The mean follow-up period was 1 year. Cosmetic outcome was highly satisfactory, with no web formation postoperatively. From our previous experience, we believe that the most common cause of web formation following surgery for lateral ray polydactyly is postoperative scar contracture on the volar and lateral sides of the toe. The bell-bottom flap was designed to make the distal end of the flap wider than its base by approximately 3 mm, with the lateral margins of the flap designed in curved lines to extend the length. The shape of the cross-section of a toe is naturally round, and the most physiologically distinct shape is the interdigital space being between two circles. The bell-bottom flap with extended incision lines on the volar and lateral sides enables the construction of a natural interdigital space and also prevents web formation and the elevation of the interdigital region caused by scar contracture after the construction of the interdigital space. Hajime Matsumine, M.D. Yuichiro Yoshinaga, M.D. Kousuke Morioka, M.D., Ph.D. Department of Plastic and Reconstructive Surgery Kagoshima City Hospital Kagoshima, Japan Kenji Sasaki, M.D., Ph.D. Department of Plastic and Reconstructive Surgery Nihon University School of Medicine Tokyo, Japan Motohiro Nozaki, M.D., Ph.D. Department of Plastic and Reconstructive Surgery Tokyo Women's Medical University Tokyo, Japan DISCLOSURE The authors have no financial interests in this article.