Summary: Advancement Flaps

•A rotation flap is a random pattern flap. The primary movement of an advancement flap is the one-dimensional sliding of tissue directly into a defect, redistributing tissue redundancy. There are several variations, including single and bilateral advancement flaps and island pedicle flaps.

33.4Advancement Flaps

The primary movement of an advancement flap is the one-dimensional sliding of tissue directly into a defect. In essence, incisions are made tangentially to the defect to free up neighboring tissue. With the wound edge acting as the free margin of the flap, the tissue is advanced into place, displacing tissue cones. While some adjacent tissue laxity may be tapped into with an advancement flap, the tension vectors of the closure remain the same, and therefore the primary advantage

of an advancement flap is the displacement of closure lines into more cosmetically acceptable locations.

33.4.1 Single Advancement

The simplest example of a pure advancement flap is the U-plasty, whereby double, non-parallel incisions are made tangential to the Mohs defect. The flap is undermined, advanced into the defect, and secured with sutures, creating a U-shaped scar (Fig. 33.1). Redundant tissue cones may be sewn out using the rule of halves or removed as Burow’s triangles at the base of the flap. The U-plasty is often used in the repair of a forehead, placing scars horizontally and running with the natural skin tension lines. However, the tension vectors are unchanged, and therefore this flap does not significantly free up tissue, limiting its utility.

An L-plasty or O to L advancement is a single tangent flap where an incision is made at one end of a defect extending outward for some length, and the tissue mobilized is then advanced into the defect (Fig. 33.2). Tissue redundancy is created on the side

of the defect opposite the flap incision and must be removed or carefully sewn out. While this type of advancement flap may tap into some distant laxity, it is generally minimal. Advancement flaps spread the tension out over a longer distance and offer some of the closure line to be perpendicular to the vector of tension. O to L advancement flaps are particularly useful with defects where the limb of the flap may be incorporated into RSTLs or cosmetic unit junctions or where a linear closure may otherwise cross a free margin or cosmetic unit junction, as may be the case on the eyebrow, nose, or upper lip.

A larger single advancement flap is the cheek advancement flap, used to repair medium to large defects of the medial cheek and/or lateral nose (Fig. 33.3). The

incision may placed in the alar crease or nasolabial fold by removing tissue above and below the defect to allow the cheek to advance into the nasofacial sulcus. It is usually advantageous to tack the leading edge of a cheek advancement flap into periosteum at the nasal sidewall– cheek junction, even if the defect is on the nasal sidewall. Tacking the flap to periosteum at the nasal sidewall–cheek junction will take pressure off the leading edge and recreate the natural concave surface of the area, preventing unnatural webbing.

Helical rim advancement flaps may be used to repair defects of the helix, utilizing the tissue laxity of the lobule. Traditionally, this flap was created with a through-and-through incision inferior to the defect along the scaphoid fossa, terminating in the lobule and

creating a narrow pedicle to be advanced (conceptually similar to the U-plasty). The survivability of this flap is proportional to the length to width ratio and could only be performed on inferior helical defects where this ratio will not exceed 3–4:1. A more popular modification of this flap is to use a single tangent incision along the scaphoid fossa, leaving the posterior auricular skin intact [12] (conceptually analogous to the L-plasty) (Fig. 33.4). This allows for the maintenance of a more reliable blood supply via the tissue inferiorly and posteriorly and permits the repair of defects more distant from the lobule. It is important to

have good eversion when closing this flap at the helical rim as forces of contraction during healing will tend to invert the wound edge and create an aesthetically unpleasant notch.

33.4.2 Bilateral Advancement

If two sets of parallel incisions are made symmetrically on both edges of the defect, a bilateral advancement flap, termed an H-plasty, has been created. This flap is essentially a bilateral U-plasty and is occasionally used