BACKGROUND
The lower cutaneous lip represents an important aesthetic subunit of the face, and regional reconstruction aims to preserve the function and appearance of the adjacent oral aperture and chin. This anatomic area can be challenging to repair given the variability of skin tension lines and mobility of surrounding structures of the lower face. Optimal wound closure techniques depend on assessment of a number of factors including tension lines, skin laxity, natural folds, gravity, sun damage, and prior radiation and procedures, as well as the size, depth, and site of the defect within the lower cutaneous lip.1 For small defects, simple primary or side-to-side repairs often provide excellent results. When healing by second intention or primary closure are deemed sub-optimal, consideration of a skin graft or flap should be considered.2 We describe the use of random pattern transposition flaps for the repair of lower lateral cutaneous lip defects.
PATIENTS AND METHODS
Four patients, all treated at the Skin & Laser Surgery Center of Pennsylvania, each with a lower cutaneous lip defect following Mohs micrographic surgery were reconstructed with transposition flaps. Patient demographics are listed in Table 1. Patients were prepped and draped according to standard sterile protocol and anesthetized with lidocaine and epinephrine (1:200,000). In several instances, appropriate nerve blocks were utilized to minimize the discomfort of multiple local injections. The dilute epinephrine was very useful in minimizing intraoperative bleeding and facilitating surgery.Surgical Technique A transposition flap is by definition one in which donor tissue contiguous with the defect is carried or transposed over intervening “normal skin” and placed into the defect. Such a flap utilizes skin laxity distant to the surgical defect to redirect tension during the repair. Two transposition flaps useful for repair of lower cutaneous lip defects are the inferiorly-based melolabial fold flap and rhombic flap, both variants of the standard “rhomboid” flap.Inferiorly-Based Melolabial Fold Flap (Patient 1, 2, and 4)The inferiorly-based melolabial fold flap is indicated for reconstruction of large defects of the lower cutaneous lip, especially those along the lateral chin inferior to the nasolabial fold. This technique takes advantage of the redundant tissue of the medial cheek seen in some patients. The medial edge of the flap extends from the defect superiorly along the nasolabial fold; the other connects at a 30° angle as shown in 1. The flap is incised and mobilized at the level of the subcutaneous fat, with care being taken not to inadvertently transect underlying vessels or nerves. The wound as well as the flap is undermined, and the flap is transposed to cover the defect. It should be noted that trimming of some of the adipose tissue from the flap helps to make the flap less bulky. Care should be taken not to trim so aggressively as to compromise blood flow to the flap. Tailoring the thickness of the flap to the corresponding depth of the wound is advantageous.Benefits of this technique include hiding the secondary defect in the nasolabial fold, and providing significant long range mobility of the donor tissue. Additionally, placing adjacent similar type and texture of skin into the wound enhances cosmesis. The comparatively bulky nature of the flap helps buttress the lower lip against the downward pull of gravity and the surrounding musculature. Full thickness grafts while utilizable lack these advantages. Of additional interest is that the horizontal pull of the flap tends to blunt the marionette line that can be so prominent in some patients. The effect can be so appealing that
