A 29-year-old man sustained a dorsal hand injury while working on an assembly line. Following debridement and dressing changes, definitive coverage required a thin flap as bone and tendon were exposed. The extensor tendons to the index finger had a segmental defect that would need grafting to restore function (▶Fig. 33.1).
The patient has a dorsoradial full-thickness skin defect of the left hand. The wound extends from the wrist to the level of the proximal interphalangeal joint of the long finger, mid-proximal phalanx of the index, and to the first web space. Extensor tendon is exposed and there is a segmental defect of extensor tendons over the second metacarpal. The majority of the wound bed has healthy granulation tissue.
A pedicled fasciocutaneous radial forearm free flap with palmaris tendon was chosen for reconstruction. A template of the defect was created and used to design the skin paddle to be transferred (▶Fig. 33.2a,b). The flap fitted nicely into the defect (▶Fig. 33.2c) and excellent function was obtained postoperatively (▶Fig. 33.3).
Fig. 33.1 A full-thickness wound to the dorsum of the left hand. Tendons are exposed and there is a segmental defect in the extensor indicis proprius and the extensor digitorum communis to the index finger.
Fig. 33.2 (a) A reverse radial forearm flap is designed on the volar forearm. A template is used to harvest the exact skin paddle required for the dorsal defect. (b) The reverse radial forearm flap is harvested on the distal radial artery. The palmaris longus tendon is also harvested in continuity with the flap to provide a vascularized tendon graft for the extensor tendon reconstruction. (c) The flap is tunneled and inset providing stable coverage for form and function.
Fig. 33.3 (a–c) The recipient site on the dorsum of the hand has great long-term contour and excellent finger extension.
Although good function was obtained, the use of a fasciocutaneous radial forearm flap can leave the donor site with quite an unappealing defect. Due to the paucity of excess skin in this area, the donor site can rarely be closed primarily, necessitating a skin graft for closure (▶Fig. 33.4). The skin graft requires healthy muscle and paratenon to heal, often with a period of immobilization, and is prone to skin graft shearing from movement of these structures. Tethering of the scar to the underlying tendons and muscle bellies can lead to pain and limitations of tendon excursion, in addition to the poor aesthetic outcome.
Dorsal hand defects present a unique reconstructive dilemma. The ideal tissue for coverage requires several specialized properties. First, it should be thin, so it does not hinder placement of the hand into small places like pants pocket. Thin tissue should also maintain the aesthetic contours in this location. Second, it should be pliable to accommodate the large arch of motion at the wrists and fingers. Next, it should allow smooth gliding of the extensor tendons underneath it. And, finally, it should have an aesthetic donor site that limits morbidity.