Preoperative Preparation

The surgical site is cleansed with a preoperative cleansing solution of the surgeon's choice, and typically, a sterile field is created. For cutaneous surgery, there are multiple case series demonstrating that a "clean," as opposed to a truly "sterile" technique, results in similar rates of postoperative infection.

Patient Counseling

As with any closure, setting realistic expectations before surgery helps patients prepare for the normal healing process. Beyond typical counseling for infection, bruising, swelling, and scar formation, a few unique situations warrant extra counseling. Advancement flaps on the lower eyelid occasionally are complicated by prolonged postoperative swelling that may take months to completely resolve.  Also, incision lines that fall along natural grooves or creases camouflage well in the long run, but they may be noticeable in the early postoperative if the wound edges are everted. The "tincture of time" and occasional use of intralesional corticosteroids usually corrects the eversion.

Tension Vector

The direction in which the flap slides toward the defect is called the primary tissue motion, and the countermovement of the surrounding tissue to meet the flap is considered secondary tissue motion. As opposed to rotation and transposition flaps, advancement flaps do not significantly alter the direction or magnitude of the primary tension vector for wound closure. Both the site of maximal tension and the magnitude of the tension vector required to close an advancement flap is nearly identical to a linear closure in the same location for a given defect. Occasionally, tacking sutures that anchor the flap to immobile deeper structures, such as the orbital rim, or superficial musculoaponeurotic system plication sutures can be used to offset some of the wound closure tension away from the defect. 

Standing Cones

The standing cones created by an advancement flap may be handled with multiple strategies. Often the entire standing cone is moved laterally in one or two directions. Also, a small standing cone or a portion of a large standing cone can be "sewn out" using the rule of halves along the base of the flap. Alternately, the standing cone may be removed in a crescentic fashion, especially along the Vermillion cutaneous junction and the nasolabial fold or alar groove. 

Altering the Defect to Optimize Advancement Flaps

When closing defects arise after the removal of a tumor, especially after Mohs surgery, an initial consideration is whether the surgeon should deepen the defect to a uniform anatomic depth. Deepening the defect to a uniform depth that corresponds to the anatomic plane for undermining permits efficient surgery and ensures that the tissue that "slides" into the wound matches the thickness of the defect.  

While not always necessary or preferred, excising tissue between the surgical defect and a nearby cosmetic subunit junction may be helpful. Placing scar lines along cosmetic subunit junctions camouflage scars by hiding them in natural creases and shadows. To motivate this principle with an example, consider the upper cutaneous lip. In this location, relaxed skin tension lines emanate radially from the vermilion-cutaneous junction, and horizontal scars on the cutaneous lip may be very noticeable. Enlarging a wound from the middle of the upper cutaneous lip to the vermilion helps to hide the base of the advancement flap in the vermilion-cutaneous junction.

Infection is the most common complication after flap closure, but it appears to be relatively independent of surgical closure technique (sterile versus clean) according to the Mohs surgery literature. In many instances, infection ensues at the site of flap necrosis. The appropriate depth of flap undermining can minimize this risk. Bleeding with potential hematoma formation is the next most common complication. However, even in patients on multiple blood thinners, hematomas are rare with appropriate intraoperative hemostasis. Lastly, displacement of free margins, such as the eyelid, lip, or nasal alar margin, is a predictable result from flap designs that place tension on these freely mobile structures. To avoid "pulling" on a free margin, the primary tension vector for closure should be parallel to the free margin. [5][10][11]

Advancement flaps are a versatile reconstruction that permits scar camouflage along cosmetic subunit junctions. Advancement flap design and execution require mastery of a few key concepts: the direction of the primary tension vector, handling the displaced standing cone(s), balancing factors that impact flap vascularity, and deciding when to alter the defect.

Advancement flaps are usually performed by the plastic surgeon. These flaps play a vital role in wound coverage. the monitoring of patients with advancement flaps is usually done by nurses trained in surgery. The key is to inform the plastic surgeon ASAP when the flap has poor perfusion or is showing signs of flap necrosis. The advancement flaps have to be monitored until complete healing has occurred.[12][13]