Mucosal Advancement Flaps

The most favored method of restoration of the vermilion is anterior advancement of the mucosa that lines the inner surface of the lip (Fig. 19-4). A mucosal flap is created by undermining beneath the labial mucosa in a plane that is deep to the minor salivary glands and superficial to the posterior surface of the orbicularis oris. If necessary, dissection may extend the entire vertical height of the lip to the apex of the gingivolabial sulcus. The flap is advanced forward over the free margin of the lip to the desired point, which is usually the anterior vermilion line. Because the vermilion is actually a modified mucosal surface, reconstruction with labial mucosa offers a close substitute. In most cases, a slight prominence of the soft tissue at the mucocutaneous junction is considered to be a favorable feature of lip contour. However, it is difficult to restore this fullness in areas reconstructed by mucosal advancement flaps. This may be related to contraction of the mucosal flap as the wound heals. There is less flap retraction when dissection of the flap requires limited undermining of the mucosa of the lip.

Reconstruction of the vermilion with a mucosal advancement flap may produce a pleasing aesthetic restoration of either lip. However, several difficulties may be encountered with this technique. An early difficulty is restoration of accurate positioning of the anterior vermilion line when there is an adjacent skin defect at the lip margin. In such instances, wound contraction inherent to wound maturation may influence the position of the vermilion line. If distortion or displacement of the anterior vermilion line occurs, repositioning of the reconstructed line may be possible with revision surgery. Another difficulty encountered with mucosal advancement flaps is that the flaps tend to display a slightly deeper red color than that of the natural vermilion, especially in those with more “weathered” lips. In some cases, the darker red color can impart a slightly feminine appearance to the reconstructed vermilion, particularly when the flap covers a large surface area (Fig. 19-5).

Because greater scar contraction occurs when mucosal advancement flaps cover a large surface area, eventual wound contraction may cause the body of the lip to assume a more rounded appearance. As the vermilion line is pulled posteriorly by wound contraction, adjacent whisker hairs may begin to turn up slightly and become a source of irritation to the opposing lip when the mouth is closed. This may require repositioning of the anterior vermilion line of the reconstructed lip.

Whereas a majority of patients regain some degree of touch, pain, and temperature sensation to the reconstructed vermilion within a matter of several months after the employment of mucosal advancement flaps, there are individuals in whom sensory return is inadequate. Influenced by Karapandzic’s concept of lip flap design, this author performs dissections with a selective spreading technique in an attempt to preserve the small neural and vascular structures that are encountered as the mucosal advancement flap is dissected (see Fig. 19-4B).^1,5,6 These neurovascular structures are then gently stretched forward with advancement of the mucosal flap.

Mucosal V-Y Island Advancement Flaps

In some cases, small volume deficiencies of the vermilion may be restored with V-Y advancement flaps of labial or buccal mucosa (Fig. 19-6). The advancement flap is created by a V-shaped incision with the apex of the incision positioned toward the gingivolabial sulcus. Mucosal V-Y advancement flaps may also be created as island flaps to repair small adjacent vermilion defects. Incisions are made to the level of the orbicularis oris, creating an island flap that is pedicled on the underlying deep tissue. The triangle-shaped island is advanced into the adjacent recipient site, maintaining sufficient deep tissue attachments to ensure its viability. The donor site is closed primarily by direct approximation of the adjacent wound margins, resulting in a Y configuration to the wound closure. Closure of the donor site assists with securing the position of the advancement flap. Most V-Y island advancement flaps of the lip are designed to advance in a vertical or near-vertical orientation. There are some cases in which horizontal tissue movement is employed, with use of either a single island flap or bilateral opposing island flaps. Mucosal V-Y island advancement flaps are best suited for repair of small defects of the vermilion.

Mucosal Cross-Lip Flaps

A vermilion defect may in some cases be restored with an interpolated cross-lip transfer of labial mucosa or vermilion along with some underlying soft tissue (Fig. 19-7). Cross-lip transfer may be accomplished with a single-pedicle flap for small defects or a bipedicle flap (“bucket handle”) for wider defects that extend horizontally across the lip (Fig. 19-8). A cross-lip mucosal flap is typically designed as a linear band of mucosa, harvested from the region immediately posterior to the posterior vermilion line of the donor lip. The width of the band is determined by the width of the vermilion defect and by what will allow donor site wound closure. The mucosal flap is most often elevated in the plane immediately superficial to the orbicularis muscle, although some muscle may be included in the flap when it is necessary to fill a soft tissue defect of the recipient lip. The labial artery may be incorporated into larger flaps, providing an axial circulation and ensuring a greater likelihood of flap viability. Once it is dissected, the flap is transferred across the oral aperture to the vermilion defect and sutured in place (Fig. 19-9). The donor site is closed primarily. Division of the pedicle and flap inset are performed 3 weeks later as a second-stage procedure.

An alternative design of a cross-lip mucosal flap that does not require an axial pattern vascular supply is a broad flap pedicled on the free margin of the donor lip that can be separated after 16 days.⁷ Use of this flap causes greater restriction of mouth opening while the pedicle is in place.

Tongue Flaps

Portions of the mucosal surface of the anterior tongue may be transferred to the lip to repair a vermilion defect. A mucosal flap in the form of an interpolated tongue flap is constructed for this purpose (Fig. 19-10).^8,9 Mucosa transferred to the lip from the dorsal surface of the tongue will maintain the many fine filiform papillae that are characteristic of the glossal surface. Use of a tongue flap to restore the vermilion will likely create a red vermilion that can be surprisingly satisfactory. A glossal flap is usually harvested from the ventral surface of the tongue for lower lip repair and from the dorsal surface of the tongue for repair of the upper lip. It is also possible to design a flap from the lateral margin of the tongue. In nearly all cases, the pedicle is created at or near the free margin of the tongue. The leading edge of the flap is sutured to the anterior border of the vermilion defect in the best possible manner, anticipating that there will be considerable pulling with tongue movements. Attachment of the flap to the posterior border of the defect is accomplished at a second stage after division of the pedicle and flap inset. The second stage is usually performed 3 weeks after initial flap transfer. The tongue donor site wound may be closed partially or allowed to granulate while the pedicle of the flap remains attached to the recipient lip. Tongue flaps are awkward and difficult for the patient. For this reason, tongue flaps are not considered a first choice for vermilion reconstruction.

Vermilion Advancement Flaps

A full-thickness loss of vermilion and immediate underlying muscle may be a difficult defect to reconstruct. If the defect involves less than one-third of the width of the lip vermilion, it is possible to repair the defect by creating an advancement flap of the remaining vermilion (Fig. 19-11).^2,10 A full-thickness incision is made along the anterior vermilion line inferior to the labial artery. The flap includes the vermilion portion of the orbicularis muscle. Flap dissection may require a lengthy incision to allow adequate stretch. A meticulous wound closure is necessary to minimize visible scars in this aesthetically sensitive region.

Fusiform Repair

The preferred method for dealing with most cutaneous tumors of the lip remains fusiform excision and primary wound repair. When possible, the fusiform excision is oriented with its long axis parallel to relaxed skin tension lines of that region of the lip. From an aesthetic viewpoint, it is preferable that fusiform excisions be confined within the boundaries of the lip, avoiding extension beyond the melolabial or mental crease lines. An M-plasty at the end of the excision line may be useful in avoiding the need to extend an incision beyond the aesthetic borders of the lips or into the vermilion (Fig. 19-12). This will require closure of two small and slightly diverging incision lines near the involved end. M-plasty may also reduce tissue redundancies, particularly near the free margin of the lip.

Intralabial and Perilabial Flaps

Labial Rotation and Advancement Flaps

Labial cutaneous rotation and advancement flaps are used to repair skin defects of either lip. Flaps are designed to move skin medially from the area immediately lateral to the defect. Transfer of such flaps often involves moving skin around the oral commissure in a manner that employs variable degrees of rotation and advancement. The nature of the tissue movement is dependent on the exact location, size, and shape of the defect. Defects located laterally require flaps that are transferred to the recipient site with greater pivotal movement (Fig. 19-14). Defects located medially require flaps that are transferred primarily by advancement. For laterally located upper lip skin defects, rotation flaps are designed so that the lateral border of the flap is in or parallel to the melolabial crease. Flaps may extend inferiorly below the level of the oral commissure on the involved side (Fig. 19-15). Because the distance between the melolabial crease and vermilion diminishes near the oral commissure, the peripheral border of the flap is extended lateral to the crease into the cheek as necessary to achieve adequate flap width. Careful flap design is required to ensure that the width of the flap provides adequate vertical height to the reconstructed lip.

Dissection of labial rotation and advancement flaps is in the subcutaneous tissue plane superficial to the level of the orbicularis and facial muscles. For rotation flaps, a longer wound border is expected in the cheek lateral to the flap. This disparity in wound length can usually be accommodated by equally dividing the skin redundancy during wound closure. If necessary, a small equalizing Burow triangle of skin is excised from the cheek opposite the most inferior portion of the flap or in the alar-facial sulcus.¹¹

Cutaneous lip rotation flaps are most frequently employed to repair defects involving the more lateral portion of lip skin (see Fig. 19-14). In contrast, advancement flaps are most commonly used to repair centrally located cutaneous defects. As the flap is advanced medially, its base often overlaps the oral commissure. This redundancy of skin at the commissure may require excision. In more extreme cases, the oral commissure may be pulled superiorly or inferiorly with medial advancement of the flap. This may be self-correcting as the natural pulling of the lip musculature causes a corrective adjustment over time (see Figs. 19-14 and 19-15).

For unilateral cutaneous lip defects, the surface area requirements of a laterally based labial rotation or advancement flap designed for repair of the defect may be reduced by use of a concurrent opposing medially based flap constructed of skin from the opposite side of the defect. For upper lip defects, the opposing flap is designed with incisions extending from the defect beneath the base of the nose and along the anterior vermilion line to a desired point. For lower lip defects, incisions for the medial opposing flap are usually placed along the anterior vermilion line and in the mental crease. Movement of the opposing medially based flap is considerably less than that of the laterally based flap as there is less skin redundancy of the central lip. For upper lip defects, it is easy to distort the philtrum and nasal base when bilateral flaps are used. Extending the incision across the superior margin of the philtrum causes it to widen somewhat, whereas use of a shorter incision tends to cause the philtrum to be displaced laterally.

Melolabial Flaps

Transposition of skin from the medial cheek or melolabial fold may be used to restore a cutaneous defect of either lip. The typical melolabial flap has a linear and triangular design with an outline that tapers to a distal point. The medial border of the flap is designed in the melolabial crease. The lateral border is marked so that the flap is sufficiently wide to meet the requirements of the lip defect. The flap is designed slightly wider than the height of the lip defect in anticipation of wound contraction. This is particularly important when reconstruction involves a large defect or the defect encroaches on the free margin of the lip. Wound contraction may result in a deficient height of the reconstructed lip. For this reason, flaps used to repair defects near the lip margin must be of sufficient width to prevent the need for stretching of the flap in the vertical plane.

Melolabial cutaneous transposition flaps may be designed with a pedicle that is either superiorly or inferiorly based. A flap with a superiorly based pedicle is commonly used to reconstruct defects of the central upper lip. A flap with an inferiorly based pedicle is often used to reconstruct defects involving more lateral portions of the upper or lower lip. Use of melolabial flaps to repair the lips incurs some degree of flattening of the melolabial folds. Flaps with a superiorly based pedicle produce the greatest degree of distortion of the melolabial fold as they extend across the most defined and visible portion of the fold. A second surgical stage involving revision of the pedicle to align scars parallel to the melolabial crease is frequently indicated in cases in which a melolabial transposition flap is used to reconstruct the upper lip.

There is considerable tendency for linear transposition flaps to become slightly raised, causing a trap-door deformity as scar tissue matures beneath the flap and along its margins. Trap-door deformities may be minimized by wide undermining around the margins of the wound and by approximation of deep tissue layers, creating eversion of all skin edges. In some cases, it may be helpful to place one or more “tacking” sutures on the ventral surface of the flap before approximation of wound edges. This reduces the space available for collection of blood between the flap and recipient site. A collection of blood beneath a flap is a common cause of trap-door deformity.

Distortion of the melolabial fold and crease, alteration in the orientation of facial hair growth pattern, and tendency toward development of trap-door deformity are reasons that melolabial cutaneous transposition flaps are not frequently used to repair skin defects of the lips. Cutaneous defects in the central portion of the lip are often best reconstructed with bilateral advancement flaps. Larger (≥2 cm) central defects usually are converted to full-thickness defects and closed primarily (Fig. 19-16). Similar to centrally located defects, small laterally located cutaneous defects of the lip can be closed with bilateral advancement flaps, often in the form of an A-T plasty (Fig. 19-17). Larger (≥2 cm) laterally located cutaneous defects of the upper lip are effectively reconstructed with V-Y subcutaneous tissue pedicled melolabial advancement island flaps (see Chapter 12) (Fig. 19-18). The flap is freed from its orbicularis muscle attachments near the commissure and is based solely on the abundant subcutaneous fat located just lateral to the commissure. This is only when the flap is sufficiently large to necessitate the incorporation of skin of the melolabial fold into the flap.

For sizable (2-3 cm) lip skin defects adjacent to the inferior border of the ala, it may be beneficial to excise the small peninsula of skin between the ala and melolabial fold in the process of enlarging the defect so that the defect extends to an aesthetic boundary.⁸ The peninsula is then reconstructed by appropriately designing the island flap so that the superior portion of the flap replaces the peninsula (Figs. 19-18 and 19-19). This technique provides the best camouflage because the superior border of the flap is positioned within the aesthetic boundaries of the alar-facial sulcus and melolabial crease. When this peninsula is not replaced, the flap must cross the base of the peninsula and may mar an otherwise excellent result.

The major advantage of subcutaneous tissue pedicled melolabial advancement flaps used to repair sizable cutaneous defects of the upper lip is that there is no need to resect standing cutaneous deformities because these do not develop with this flap. For this reason, they are particularly advantageous compared with transposition and cutaneous pedicled advancement flaps, which often have sizable deformities that must be resected and discarded. There is no wasted skin with the island flap. Another important advantage of the island flap is that there is considerably less dead space beneath the flap as well as beneath skin surrounding the donor defect compared with use of cutaneous pedicled flaps. Less dead space means less space available for collection of blood and serum. Therefore, there is less risk for development of a hematoma compared with use of other types of flaps.

Primary Repair

Primary repair of either lip provides satisfactory results for full-thickness defects of as much as one-third the width of the lip. Wedge or V-shaped full-thickness lip excision and primary wound closure have long been the most common method of treatment of most malignant neoplasms of the lip (see Fig. 19-20). Closure of the V-shaped defect is oriented parallel to relaxed skin tension lines of the lip. In the central portion of the lip, the V-shaped excision is oriented vertically, with equal length given to the two borders of the V (Fig. 19-20). In more lateral regions of the lip, the V is skewed to produce a more angulated wound closure line matching the natural relaxed skin tension lines of the lateral lip (Fig. 19-21).

Optimal primary repair of full-thickness lip defects requires approximation of at least four tissue layers: mucosa, muscle, subcutaneous tissue including deep dermis, and epithelium of the skin. The tendency toward development of a retracted and depressed lip scar is appreciably reduced when the wound is repaired with accurate approximation of the lip muscle. Precise approximation of the subcutaneous tissue layer is accomplished with sutures that are adjacent to or include the deep portion of the reticular dermis. The epithelium of the skin is closed in a manner that ensures a slight eversion of the skin edges. Attention to detail throughout wound closure will achieve an optimal scar that is narrow and flush with adjacent lip tissue.

The anterior vermilion line is the principal landmark of the lip. To ensure symmetry, its precise location on opposing edges of the wound should be identified early in the course of lip repair. Once it is identified, the line is marked in some way as a reference to help guide the rest of the lip repair. To serve this purpose, a 6-0 silk suture may be inserted at the anterior vermilion line and initially left untied. Of equal aesthetic importance is satisfactory approximation of the posterior vermilion line, which for the purpose of repair is the visible posterior limit of the vermilion.

It is important to minimize irregularity or disparity in vertical height and contour of the vermilion between the two margins of a lip defect. The vermilion of the lateral portion of the lip is normally narrower than the central portion. As the two borders of the lip defect are approximated, accommodation for the disparity of the width of the vermilion is accomplished by forward advancement of vermilion of the lateral lip segment and simultaneous slight posterior advancement of vermilion of the medial border of the wound.

The portion of the orbicularis muscle that lies immediately beneath the vermilion and superior to the horizontal plane of the anterior vermilion line is known as the vermilion muscle and is the principal tissue that produces the fullness and rounded appearance of the free margin of the lip. Failure to achieve accurate muscle approximation of this region will significantly increase the likelihood of development of a notched or retracted vermilion with wound maturation. This portion of the orbicularis muscle is approximated with two or three sutures placed immediately beneath the vermilion, between the anterior and posterior vermilion lines.