Advancement Flaps

Skin defects created by trauma or excision of benign or malignant lesions may be repaired by numerous methods. Techniques include healing by secondary intention, full or partial-thickness skin grafts, or local skin flaps (ie, rotation, advancement flaps).

More substantial defects, or those that also involve soft tissue, bone, and nerve, are usually repaired with axial pattern flaps, regional flaps, or revascularized free flaps.

Many variables determine the type of repair chosen. Variables include defect size, functional deficit, anatomic location, donor site morbidity, likelihood of infection (particularly in human and animal bites), need for tumor surveillance, overall patient health, and surgeon experience and preference.

Advancement flaps are used when the patient is in overall good health and the defect is free of tumor and obvious infection. Flaps should match thickness, color, and texture of excised skin. Resultant scars should fall in relaxed skin-tension lines.

An image depicting advancement flaps can be seen below.

Celsus, of ancient Rome, is the first person credited with using advancement flaps to close skin defects. In the early 1800s, French surgeons described and advocated advancement flaps under the term "lambeau par glissement" (sliding flaps).

Today, advancement flaps are widely used to close skin defects of the face, scalp, and neck.

Advancement flaps are indicated when the skin defect lies next to an area of skin laxity, and prospects for a favorable resultant scar appear strong.

Favorable scars respect anatomical subunits of the face and lie in relaxed skin-tension lines. Advancement flaps are typically used in forehead, scalp, eyelid, and upper lip areas.

Any viable flap must have an adequate blood supply. Blood flow of 1-2 mL/min/100 g of tissue is adequate. Circulation to the skin starts with large, named, segmental vessels branching from the aorta. Segmental vessels branch to give rise to perforating arteries that run through overlying muscles. Perforating arteries arrive at the skin either by direct cutaneous arteries (the basis for axial pattern flaps) or by anastomosis with the subdermal or dermal plexus.

Advancement flaps are based on a random pattern blood supply, which comes from the anastomoses within the subdermal or dermal plexus. The perfusion pressure of feeding vessels and intravascular resistance determines the viable length of an advancement flap. These flaps in the head and neck region may achieve a length-to-width ratio of 4:1. The sympathetic nervous system, with control over arteriovenous (A-V) shunts in the subdermal plexus, regulates arterial resistance. Local skin flap failure may be due to preferential blood flow through A-V shunts.

Advancement flaps are contraindicated by poor patient health (eg, uncontrolled diabetes, extensive smoking history, bleeding disorder), concurrent wound infection, or the need for postoperative tumor surveillance. Other forms of reconstruction may be more favorable because of better cosmesis.

Monopedicled, bipedicled, and V-Y flaps constitute the 3 types of advancement flaps. Undermine the donor site of an advancement flap at a level below the subdermal plexus. Preserve a minimal amount of adipose tissue on the flap undersurface to preserve the subdermal plexus. Advance the flap in a straight line to the defect.[1, 2, 3]

When creating monopedicled or bipedicled flaps, redundant tissue at the flap base usually remains, which may be excised using Burrow triangles. On the face and scalp, generally a length-to-width ratio as great as 3-4:1 may be achieved. The flap is typically advanced a distance equivalent to the width of the flap (see the images below), although the primary determinant of flap vascularity is perfusion pressure.[4]

Standing cone deformities may occur within the surrounding skin, particularly near the flap base, as there is a discrepancy between the length of the incision on the surrounding skin (which also includes the length of the defect) and side the length of the incision on the flap side. This excess skin often can be distributed acceptably along the length of the closure, so the wound should be "closed by halves", reapproximating the wound edges through sutures that progressively divide the remaining wound in half. When the skin excess cannot be distributed successfully through this method, Burrow triangles can be excised. These wedges of skin surrounding the incision are based on the wound edge and are shaped and placed so as to fall into relaxed skin tension lines or existing skin creases or folds.

Monopedicled and bipedicled flaps are useful whenever defects lie near an area of skin laxity and incisions resulting from flap creation appear favorable. Exercise caution when pulling tissue from the donor site so that tension does not create a cosmetic deformity (eg, ectropion, distortion of the vermilion border). These flaps are typically used around the upper lip or forehead.

A V-Y advancement flap is created by making a V-shaped incision and advancing the broad base of the V into the defect.[5] The resulting defect is closed primarily in a Y-shape (see the image below).

All advancement flaps should be under minimal tension. Further undermining may relieve excessive tension. Close incisions in multiple layers with interrupted stitches and absorbable sutures placed deep to the skin. Use nonabsorbable, nonreactive sutures for skin closure. Flaps may be revised later. If a long or tenuous flap is contemplated, surgeons may want to raise the flap in one procedure and wait 1-3 weeks before advancing the flap.

This action takes advantage of the delay phenomenon, which increases flap survival. The exact mechanism of the delay phenomenon is unknown, but it may work by opening choked vessels within the flap, thus increasing flap perfusion.

Sutures are removed 1 week after surgery. As with any near-circumferential scar, wound contract may cause flap pincushioning or a trapdoor deformity. Flaps that show signs of pincushioning may be treated with subdermal triamcinolone injection (Kenalog) in small amounts (10 mg/cc, 0.05-0.15 cc). Any scar widening can be treated with scar excision, additional undermining, and meticulous closure. Scar dermabrasion may be offered to patients generally no earlier than 6 weeks postoperatively. Persistent scar erythema or peri-cicatricial telangiectasias, if unresolved in 8-12 weeks, may be treated with an appropriate wavelength laser, such as a 1064 nm Nd-YAG.

In general, properly planned and executed advancement flaps are very reliable. Failure is generally unpredictable. Vascular insufficiency is the main cause of flap failure and may result from undermining in the wrong plane, excessive tension on the flap, hematoma, infection, or compression of the pedicle. Inadequate undermining or excessively larger defects may be associated with unacceptable wound tension and can lead to postoperative scar widening.

The advancement flap is a valuable tool for the surgeon repairing skin defects in the head and neck region. Proper patient selection and planning are essential. Advancement flaps are desirable because skin advanced from adjacent areas is usually a good match for color, thickness, and texture. Incisions can be hidden well in relaxed skin-tension lines or in borders of facial aesthetic units. Recent examples of advancement flap use in the literature include use of a crescentic flap to repair small defects of the perialar upper lip,[6] for repair of small central defects in bilateral cleft lips,[7] and in combination with other flaps for lip reconstruction.[8]

The advancement flap is one of many techniques available to close skin defects of the head and neck. Often, a given defect may be closed in more than one way, and talented surgeons may disagree. Current research topics include the role of vasodilating agents, antiplatelet drugs, and hyperbaric oxygen. These research areas will probably improve techniques or provide agents to increase flap survival.