Pedicled Osteo-Onchyocutaneous Island Flap for Finger Macrodactyly: A Review of Literature

An 8-year-old right-handed boy presented with isolated macrodactyly of his right middle finger (Fig. 1). There was no evidence of any other congenital anomalies in the child or his parents. He underwent surgery under general anesthesia with tourniquet control. A segment of the grossly enlarged radial digital nerve (Fig. 2A) from the base of the finger to the distal interphalangeal joint was excised. The radial digital artery was traced to the anastomotic arch in the pulp (Fig. 2B). The artery was divided, and the nail complex, along with the radial lateral nail fold, hyponychium, proximal nail fold, and dorsal cortex of the distal phalanx, was elevated en bloc along with the radial digital artery (Fig. 2C). The dorsal cortex of the distal phalanx was elevated using a scalpel, leaving behind the epiphysis and terminal extensor insertion, which was amputated along with the remainder of the distal segment of the finger (Fig. 2D). The skin on the radial and dorsal aspects of the middle phalanx, the extensor tendon on the dorsum of the middle phalanx (except the central slip insertion), and a segment of the dorsal cortex of the middle phalanx were excised. The bone from both sides of the middle phalanx was also removed to narrow the width of the middle phalanx, preserving the insertion of the flexor digitorum superficialis (Fig. 3A). An epiphysiodesis of the middle phalanx was performed by passing a K-wire through the growth plate multiple times.

The island nail flap complex was anchored to the dorsum of the middle phalanx using a 3.0 monofilament nonabsorbable horizontal mattress pull-out suture (Fig. 3B). The redundant arterial pedicle was gently laid in a curved fashion to avoid kinking and prevent any circulatory disturbances. The skin was sutured using 5.0 absorbable sutures, and a small split-thickness skin graft harvested from the excised skin was placed on the radial lateral aspect of the finger to achieve tension-free closure (Fig. 3C). The pull-through suture was removed at 6 weeks. Follow-up at 12 months revealed a satisfactory outcome (Fig. 4). We offered additional soft-tissue debulking of the finger, but the patient’s parents refused.

Different methods of preserving the nail complex have been proposed for macrodactyly (Figure 5, Figure 6).^{,  ,  ,  ,}  Mouly and Debeyre suggested the use of a free nail-bed graft to improve the cosmesis of the finger (Fig. 5A). Sabapathy et al transferred the nail complex as a graft, combined with shortening, in 2 patients with toe macrosyndactyly. They reported nail deformity in one patient. They suggested harvesting the nail graft along with the lateral and proximal nail folds to improve cosmesis as well as de-epithelization and placement of the nail graft over the dermis rather than excision of the skin and placement of the nail graft over subcutaneous fat. They posited that a de-epithelized bed provides better vascularity and decreases the “wobble” of the graft. Overall, free nail-bed grafting results in a deformed and discolored nail, which is visually unappealing.

Barsky proposed the resection of the proximal portion of the distal phalanx and distal portion of the middle phalanx along with the dorsal skin (Fig. 5B). The nail complex, along with the fingertip and distal segment of the distal phalanx, was mobilized based on a palmar flap and approximated to the proximal segment of the middle phalanx, in effect, fusing the distal interphalangeal joint. This technique requires shortening of the flexor tendon and a secondary procedure to excise redundant palmar skin. Tsuge mobilized the nail complex along with the dorsal cortex of the distal phalanx as a dorsally based flap with the excision of the remnant distal phalanx and fingertip (Fig. 5C). A corresponding segment of the dorsal cortex from the middle phalanx was excised, and the dorsally based osteo-onychocutaneous flap was mobilized proximally in a worm-like fashion to inset on the dorsum of the middle phalanx. This method required a secondary operation to excise surplus skin from the dorsal aspect of the finger, although shortening of the flexor tendon was not required. The Barksy technique preserves the fingertip and the 3 phalanges with the fusion of the distal interphalangeal joint, whereas the Tsuge technique results in the loss of fingertip and preserves only 2 phalanges. The latter technique is simpler, although the vascularity of the nail complex is not as good as that provided by the palmar flap in the former technique. Both the techniques maintain a relationship between the nail bed and distal phalanx, avoiding the so-called “wobble.”

Rosenberg et al described a vascularized nail island flap based on 1 neurovascular bundle with the disarticulation of the distal phalanx (Fig. 6A), basing the flap on the ulnar aspect of the neurovascular bundle to keep the contact radial aspect of the middle finger unscarred. The flexor and extensor tendons were sutured to each other at the distal part of the middle phalanx after removing the cartilage. The dorsum of the eponychium was also de-epithelized and buried inside a subcutaneous pocket created on the dorsum of the middle phalanx using 2 pull-through sutures to improve the adherence and vascularity of the germinal matrix. Compared with the 2-stage Barsky and Tsuge techniques, this is a single-stage procedure. It includes the skin on the noncontact radial side of the digit but sacrifices the fingertip, preserving only the hyponychium. Another disadvantage is poor adherence between the nail bed and the dorsum of the middle phalanx. The authors mentioned the possibility of harvesting the nail bed with a portion of the distal phalanx, referring to the Foucher method of microsurgical partial toe transfer. Pho et al described a case report of the successful treatment of digital macrodactyly in an 11-month-old child using the Rosenberg technique. Dautel et al reported the use of the Rosenberg technique for a 9-year-old child with great-toe macrodactyly, with a good aesthetic outcome.

Uemura et al reported the first use of an osteo-onychocutaneous island flap for the reconstruction of the nail complex in a patient with toe macrodactyly. They used a nail island flap raised along with 2 mm of the dorsal cortex of the distal phalanx based on the tibial digital artery of the second toe. The osseous segment was fixed to the dorsum of the middle phalanx using a pull-out wire suture secured over a button over the nail. They reported good nail growth and bony union at 1 year. Downey-Carmona et al reported the use of a similar method in 2 children with isolated macrodactyly of the great toe. They used a nylon suture for bone fixation instead of the wire suture used by Uemura et al. In 1 patient in the study by Downey-Carmona et al, the nail was lost, and they attributed it to scarring due to a previous surgery, leading to compromised circulation.

We were unable to find any reports of digital macrodactyly that used an osteo-onychocutaneous island flap for nail-bed reconstruction (Fig. 6B). We used the patient’s father’s nail as a guide to determine the size of the child’s nail, as suggested by Gluck and Ezaki. The main difficulty with excising a portion of the nail is that it is difficult to reconstruct an aesthetic nail fold. We excised 1 of the digital nerves because the nerve was grossly enlarged. Although this is associated with sensory loss, nerve excision may decelerate the possible ongoing process of overgrowth as the disease might be driven by the nerve itself. Gluck and Ezaki also discovered that the remaining digital nerve from the other side can potentially reinnervate the remaining denervated skin because of neuroplasticity in the pediatric population. For subsequent cases, we will consider raising the nail complex flap on the ulnar side of the middle finger to maintain sensation and avoid scarring on the contact side of the finger, as suggested by Rosenberg et al. An ideal procedure for the treatment of macrodactyly reduces the size of the digit, corrects the deformity, and limits its growth. Procedures that retain the nail bed allow for a better cosmetic outcome compared with procedures that do not. Our technique fulfills these characteristics in a single-stage procedure.