Island Pedicle Flaps (V-to-Y Advancement)

Island pedicle flaps are fundamentally different from all other local flaps in their blood supply. Whereas advancement, rotation, and transposition flaps maintain a cutaneous base that provides blood flow through the subdermal plexus, island pedicle flaps are completely circumscribed at the skin level and depend entirely on deep subcutaneous perforating vessels for their perfusion. The skin island is connected to the body only through a deep stalk of subcutaneous fat, fascia, and/or muscle that contains the feeding vessels. This deep pedicle allows the flap to advance perpendicular to the skin surface rather than sliding along it, which is the mechanism of traditional advancement flaps. The V-to-Y nomenclature describes the closure pattern: the initial incision is V-shaped (converging lines), and after the island is advanced, the donor site is closed, converting the V into a Y-shaped scar.

The success of island pedicle flaps depends on the local tissue characteristics: the tissue must have sufficient elasticity, subcutaneous volume, and deep vascular supply to support the island on its deep stalk. The best locations include the nasal tip and supratip (rich blood supply from the lateral nasal branch of the angular artery), the melolabial fold and medial cheek (abundant subcutaneous fat and vascular supply from the facial artery branches), the lip (submucosal and muscular blood supply), and the periorbital region (in selected cases). Areas with thin or inelastic tissue such as the nasal dorsum, forehead, and extremities are generally less favorable for this technique.

The classic V-to-Y island pedicle technique proceeds as follows: (1) The defect is assessed and the island flap is designed immediately adjacent to the defect. The island shape is typically triangular (V-shaped) with the apex pointing away from the defect. The width of the island at its base should match or slightly exceed the defect width. (2) The skin of the island is incised through the dermis, but the underlying subcutaneous tissue is left intact as the pedicle. (3) The tissue surrounding the island (but not beneath it) is undermined to create space for the island to advance. (4) The island is gently advanced into the defect by pushing it forward on its deep stalk. Skin hooks or stay sutures on the dermis of the island can guide it without traumatizing the pedicle. (5) The island is sutured into the defect with interrupted deep and cutaneous sutures. (6) The donor site is closed in a V-to-Y fashion, converting the triangular donor defect into a Y-shaped closure. The tails of the Y are the original V incision lines, and the stem of the Y is the new closure line of the donor site.

The modified single-sling myocutaneous island pedicle flap, described by Willey et al. in a 61-patient series, represents an important refinement of the classic technique for nasal reconstruction. This flap is based on the lateral nasal branch of the angular facial artery and incorporates the nasalis muscle as part of the deep pedicle, providing a strong myocutaneous blood supply. The key innovation is bilevel undermining: the medial aspect of the flap is undermined in the subnasalis plane (beneath the nasalis muscle), while the lateral aspect is undermined in the supramuscular plane (above the muscle but beneath the skin). This bilevel dissection preserves the lateral nasal artery perforators that supply the flap while allowing adequate mobilization. The flap is then rotated and advanced into the defect. Trimming the flap into a fusiform shape improves scar camouflage by aligning the final scar with the alar crease or sidewall junction.

The classic V-to-Y and the Willey modified island pedicle differ in several important respects. Understanding these differences helps the surgeon select the optimal technique for each clinical scenario.

Island pedicle flaps offer several distinct advantages over other local flap designs. First, they are tissue-sparing: the island is harvested immediately adjacent to the defect, minimizing the total area of tissue disturbance. Second, the color and texture match is typically excellent because the donor tissue is harvested from the same cosmetic subunit or an immediately adjacent one. Third, island pedicle flaps are single-stage procedures, avoiding the need for a second pedicle division surgery as required by interpolation flaps. Fourth, the deep blood supply from the subcutaneous pedicle is often more strong than the random subdermal plexus that supplies conventional flaps, particularly in areas with rich deep vasculature (nasal tip, melolabial fold). Fifth, the V-to-Y closure pattern distributes tension evenly and avoids the standing cones (dog-ears) that complicate many other flap designs.

The primary complications of island pedicle flaps are pincushioning (trapdoor deformity), bridging of natural creases (particularly the alar crease), and partial flap necrosis from inadvertent damage to the deep pedicle. Pincushioning occurs because the circumferentially incised island contracts centripetally as it heals, causing the central portion of the flap to mound above the surrounding skin level. This is exacerbated by lymphatic disruption and excessive subcutaneous tissue beneath the island. Prevention includes thinning the peripheral edges of the island, wide undermining of the surrounding tissue, and tacking the flap periphery to the dermis of the surrounding skin. Treatment of established pincushioning includes intralesional triamcinolone acetonide (10-40 mg/mL), which can be highly effective, and secondary surgical revision with scar release and flap thinning if conservative measures fail. Bridging of the alar crease occurs when the flap is advanced across this natural concavity without recreating it; this is prevented by placing a deep tacking suture from the flap to the periosteum or perichondrium at the depth of the crease.

Island pedicle flaps are best considered for defects where the following criteria are met: (1) the defect is in an area with elastic, well-vascularized subcutaneous tissue; (2) the defect is small to moderate in size (0.5 to 2.5 cm); (3) adjacent tissue of similar color and texture is available immediately next to the defect; (4) a single-stage procedure is preferred; and (5) the resulting scar can be placed along a natural crease or cosmetic subunit boundary. The flap is less suitable for defects larger than 2.5 cm, defects in areas with thin or inelastic tissue, and defects where the deep vasculature has been compromised by prior surgery or radiation. For nasal defects larger than 2.5 cm, a paramedian forehead flap is generally preferred despite the two-stage requirement.