The initial wound that is to be reconstructed is the primary defect, and here it refers to the result of the removal of a skin tumor (Figure 13-2). Once a flap has been advanced, transposed, or rotated into position to close the primary defect, the wound that remains behind at the donor site of the flap is the secondary defect. The primary motion of a flap is the movement that the flap makes when it advances, transposes, or rotates into and closes the primary defect (Figure 13-2). The secondary motion is the movement that the tissue adjacent to and surrounding the flap makes when the final defect is closed. Both the primary and secondary motion of a flap are important in proper flap design. The very end of the flap that fills the primary defect, furthest from the donor site is the flap tip. The flap pedicle is that portion of the flap that connects it to the surrounding skin, and is the conduit for the vascular supply of the flap. The key suture of a local flap is the location in which the first suture is typically placed to provide the initial correct alignment of a flap to fill the primary defect and to direct additional placement of sutures to close the secondary defect. Standing cutaneous cones (dog ears) are areas of local tissue redundancy that occur in wound closure, but that can be minimized, eliminated, or moved to more cosmetically advantageous locations by the correct choice of and meticulous planning for a flap.

FIGURE 13-2 The initial wound to be reconstructed is the primary defect and the wound that remains behind at the donor site of the flap is the secondary defect. The primary motion of a flap is the movement that the flap makes when it advances, transposes, or rotates into and closes the primary defect. The secondary motion is the movement that the tissue adjacent to and surrounding the flap makes when the final defect is closed.

Use of Flaps Following Treatment of Malignant Tumors

Although malignant tumor clearance is always very important, it is even more critical prior to employing flap reconstruction. If a flap is used, and later the surgical margins are determined to be positive histologically for persistence of tumor, the cure rate for a subsequent excision may be reduced due to the loss of the true surgical margins by the significant movement of tissue that occurs in flap mobilization. In addition, using a flap prematurely may “burn bridges” and prevent further reconstruction using adjacent tissue if a re-excision is necessary. A potentially worse scenario can arise if there is a persistence of tumor that is buried under a flap. Such tumors can grow to great size and depth before they become clinically obvious, and may lead to severe morbidity and need for extensive reconstruction at the time of re-excision. Mohs micrographic surgery can achieve cure rates of up to 99% in primary tumors and is the gold standard for margin clearance of cutaneous malignancy. Mohs surgery should be strongly considered for more aggressive tumors or those in critical anatomic areas. Margin control of skin tumors can be achieved using standard frozen section pathology, but if this is not available, wounds can be bandaged following tumor excision with a plan for delayed repair following clearance of the tumor with permanent section pathology.

Contraindications

Although there are no absolute contraindications, factors to consider when planning for the use of a flap include underlying disorders that may lead to increased rates of intraoperative or postoperative complications. These include patients who are highly anticoagulated or with bleeding diatheses who may experience troublesome intraoperative bleeding or postoperative hematoma formation. Patients who smoke excessively experience a much higher risk of flap tip necrosis and flap failure, and encouraging smoking cessation in the perioperative and postoperative course is helpful to achieve the best healing. The use of flaps must also be carefully weighed in those patients who may have underlying skin conditions that can lead to increased complications. Decreased flexibility and therefore impaired movement of skin can be seen in patients with extensive scarring from burns or other injuries, previous radiotherapy, or an underlying skin disease such as scleroderma. Decreased perfusion of skin leading to flap failure or infection can be seen in conditions such as diabetes mellitus, lung disease, or poor circulation secondary to atherosclerosis, especially in peripheral areas. Finally, the use of a flap may not be possible in patients with extremely thin skin that will not bear the stresses of flap movement. Examples includes elderly patients who have extreme photodamage or long-term users of corticosteroids.

Planning the Flap

Careful planning is essential for successful flap reconstruction. Following confirmed tumor clearance of the surgical margins, the primary defect is lightly infiltrated with local anesthetic so that it may be manipulated without patient discomfort. It is important for the surgeon not to proceed immediately with an anticipated flap procedure before carefully considering the ramifications of tissue movement for surrounding structures. At this point the defect should be evaluated for surrounding tissue laxity and any potential reservoirs of loose skin that may be recruited for repair. This may be done by pinching the skin with gloved fingers. If the fingers are inadequate in more inflexible areas, the skin hook is a very useful surgical instrument for gauging tissue movement without tissue damage even in large defects of inflexible skin. Careful flap planning will then include not only the evaluation of possible sources of skin for flap creation, but also the consideration of nearby anatomic structures that could be distorted by either the primary or secondary movement of the flap. Especially vulnerable areas are the free margins of the eyelids, lips, and the nasal tip. The vectors of flap movement should be placed perpendicular to such structures, lest tissue movement distort their anatomy.

Tissue texture, and color should be matched whenever possible; a flap from similar adjacent skin will lead to the best results. A defect on the nose should be filled with similar-appearing skin from the nose instead of skin from a flap on the cheek. Finally, anticipated tissue redundancies from wound closure should be considered, with thought to how these redundancies or dog ears may be best camouflaged along anatomic borders. The proposed flap should always be drawn out prior to incision, and this may be done with a surgical marker.

Advancement Flap

Conceptual

The primary motion of the advancement flap is the sliding of the flap, usually in a single linear vector as it advances into the primary defect. This sliding motion may be unidirectional (single advancement flap) or bidirectional (double advancement flap).³ Although there are several variations on this type of flap, the two main benefits of the advancement flap are as follows:

1. Redirection of tissue movement. It may be critical to keep the repair within a single cosmetic subunit or to selectively move certain skin into the primary defect. This can be helpful when a defect lies within an eyebrow or the mustache, and the advancing primary motion can restore uninterrupted hair growth (Figure 13-3).

2. Reorientation of tissue redundancy. When closing a skin defect, tissue redundancies (dog ears) are inevitable. A properly employed advancement flap can redistribute tissue redundancies to more acceptable locations that may be far from the primary defect. This is useful in moving the tissue redundancies away from a certain structure (lips or eyebrow), or aligning them along the boundary of an anatomic subunit (alar crease) to camouflage the scar (Figure 13-4).

FIGURE 13-3 Double advancement flap (bidirectional) within an eyebrow to restore uninterrupted hair growth after resecting a tumor within the eyebrow.

FIGURE 13-4 Reorientation of tissue redundancy to a more acceptable location away from the primary defect.

Note that the purpose of the advancement flap is not to increase laxity to close a wound under high tension. Although an advancement flap may appear to provide superior tissue movement over a primary linear closure, this is rarely the case. In preoperative planning, if a defect cannot be approximated primarily by pinching the skin or mobilizing the skin edges with hooks, an advancement flap will not be the best option because the amount of additional tissue movement that it provides over primary closure is often minimal.

Advancement flaps are also limited by their blood supply. The pedicle of skin and soft tissue must not be compromised. A length:width ratio should ideally not exceed 3 : 1. A long, thin advancement flap in violation of this ratio runs a high risk of distal flap tip necrosis (Figure 13-5).

FIGURE 13-5 Advancement flaps are also limited by their blood supply so the length:width ratio should not exceed 3 : 1. A long, thin advancement flap in violation of this ratio runs a high risk of distal flap tip necrosis.

Single-Pedicle Advancement Flap (U-Plasty)

The classic form of the advancement flap is the single-pedicle advancement flap, also known as the U-plasty (Figure 13-6). This is an older technique that has been advocated for repairs on the forehead, because it may fit in well with horizontal relaxed skin tension lines in this area. It may also be used on the sideburn or eyebrow to move hair-bearing skin together and hide the scars in the hair. A significant disadvantage to the flap is that it creates numerous surgical lines, and in an area such as the forehead, may provide an inferior surgical result compared to a primary linear closure. It has been advocated as well for use on the glabella and nasal bridge, but other flaps are nearly always preferable in these areas.

FIGURE 13-6 (A) Single-pedicle advancement flap (U-plasty) on the forehead may fit in well with horizontal relaxed skin tension lines in this area. (B) The flap is sutured in its place.

(Courtesy of Ryan O’Quinn, MD.)

Bilateral Advancement Flap (H-Plasty)

The bilateral advancement flap is similar to the classic single-pedicle advancement flap except that another pedicled advancement flap is created on the opposite side of the defect. The two flaps need not necessarily be symmetrical or parallel, but may be curved or slightly shortened on one side as anatomic structures allow. Unfortunately, this flap creates even more incisions than the single-pedicle advancement flap and therefore its clinical usefulness is limited. This flap could be useful for the closure of a defect in the eyebrow, because the lines could be camouflaged along the brow’s edges (Figure 13-7). It may also be reserved for situations in which a single pedicle is first employed and then judged inadequate to close a defect. At that point, a second pedicle is created to provide further tissue movement.

FIGURE 13-7 The bilateral advancement flap (H-plasty) could be useful for the closure of a defect in the eyebrow, because the lines could be camouflaged along the brows edges. (A) The “H” is cut. (B) The “H” is sutured in, preserving the eyebrow anatomy.

(Courtesy of Ryan O’Quinn, MD.)

T-Plasty (O-T Flap)

The T-plasty bilateral advancement flap has great utility in facial reconstruction. It is best suited for the repair of defects at the edge of a free margin such as the lip, or at the junction of two cosmetic subunits when it is preferable to keep the repair from crossing the junction such as when closing a chin defect and preventing the closure from crossing the mental crease. The final suture line in the T configuration is a result of a Burow’s triangle excision on one side of the defect that is approximately the length of the defect, and two incisions (each the width of the defect) on the other side to create the bilateral flaps. These incisions need not be completely straight and can be somewhat curved and tailored to the necessary skin tension lines (Figure 13-8). The resulting redundancies along the flap edges can be sewn out by the rule of halves, or resolved with small Burow’s triangle excisions.

FIGURE 13-8 The T-plasty (O-T flap) is best suited for the repair of defects at the edge of a free margin such as the nasal ala or lip, or at the junction of two cosmetic subunits. (A) The “O”-shaped defect. (B) The “T”-shaped repair.

(Courtesy of Ryan O’Quinn, MD.)

L-Plasty

The L-plasty is a single advancement flap that is employed to redirect tissue redundancy and maintain the repair in a single cosmetic subunit. The tissue redundancy has been distributed along the edge of the advancing flap and no Burow’s triangle has been excised (Figure 13-9).

FIGURE 13-9 The L-plasty is a single advancement flap that is employed to redirect tissue redundancy and maintain the repair in a single cosmetic subunit. (A) The defect on the lip margin. (B) The “L”-shaped repair. (C) Repair healing 1 week after surgery.

(Courtesy of Ryan O’Quinn, MD.)

Advancement Flap: Step-by-Step Instructions

1. A moderately large wound results from the removal of a BCC using the Mohs surgical technique (Figure 13-10A). The location immediately above the eyebrow presents a dilemma. Horizontal linear closure would result in unnatural elevation of the eyebrow margin. Vertical linear closure would extend the Burow’s triangle through the brow into the upper eyelid.

2. A laterally based advancement flap is planned. The Burow’s triangle is drawn superiorly, and the inferior edge of the flap is created running along the lateral margin of the brow (Figure 13-10B). A smaller Burow’s triangle is drawn to anticipate skin redundancy.

3. The flap is incised, and both Burow’s triangles removed (Figure 13-10C). The level of undermining in this area is fairly superficial with the flap containing epidermis, dermis, and several millimeters of subcutaneous fat. This is to avoid injury to the underlying superficial temporal branch of the facial nerve. All surrounding wound edges are undermined. Hemostasis was achieved with electrosurgery.

4. A skin hook illustrates the location of the buried key suture for this flap (Figure 13-10D). This initial suture advances the tissue into the defect and shows proper alignment of the final closure. At this point, the deep absorbable sutures are placed to secure the flap and hold tension. Once the flap is in place, a running polypropylene suture is placed to nicely approximate epidermal edges.

5. The final result achieves excellent closure of the primary defect without anatomic distortion (Figure 13-10E).

FIGURE 13-10 Advancement flap: step-by-step instructions. (A) Circular wound from the removal of a BCC using the Mohs surgical technique. (B) The Burow’s triangle is drawn superiorly, and the inferior edge of the flap is created running along the lateral margin of the brow. A smaller Burow’s triangle is drawn to anticipate skin redundancy. (C) The flap is incised, and both Burow’s triangles removed. (D) A skin hook is used here to illustrate the location of the buried key suture for this flap. (E) The final result achieves excellent closure of the primary defect without anatomic distortion.

(Courtesy of Ryan O’Quinn, MD.)

Island Pedicle Flap

Conceptual

Although the primary movement is advancement of tissue into the defect, the island pedicle flap is so fundamentally different from the previously described advancement flaps that it occupies a class of its own. Unlike the other advancement flaps, it does provide significantly increased tissue movement over primary closure. Uniquely, the epidermis and dermis of the island pedicle flap are completely severed from the surrounding skin, and instead the pedicle is an “island” of rich, vascular subcutaneous and muscle tissue underneath the flap. Because of this, it is very rare to experience ischemic necrosis of a properly designed and executed island pedicle flap. The flap is not subject to the 3 : 1 rule of advancement flaps and moves a thinner flap over a greater distance. It may be an ideal choice in patients with poorly perfused skin or smokers. Another advantage of the flap is that it may limit reconstruction of a large or complex defect to a single cosmetic subunit. This is the case in the area of the lateral upper cutaneous lip, where the flap is the most useful.

Island Pedicle Flap: Step-by-Step Instructions

1. Reconstruction of a large defect of the upper cutaneous lip presents a particular challenge (Figure 13-11A). Care must be taken to avoid anatomic distortion of the upper lip and nasal ala. An island pedicle flap is drawn inferiorly and lateral to the angle of the mouth. This will allow the lax skin of the area to be moved upward into the primary defect. The lines are drawn such that the flap fits nicely into the nasolabial fold laterally. The curvilinear shape of the flap ensures that the secondary defect will be closed horizontally to avoid raising the lip.

2. The flap is incised along planned lines (Figure 13-11B). The depth of incision is to the deep subcutaneous layer. The central deep portion of the flap is left undisturbed to avoid compromising vascular supply. The flap tip and primary defect edges are trimmed so that the advancing edge of the island flap fits nicely.

3. All surrounding wound edges are undermined. In Figure 13-11C the richly supplied pedicle is visible. It is not undermined to avoid vascular compromise. Hemostasis is achieved with electrosurgery.

4. The key suture is placed in the center of the advancing edge of the island pedicle flap (Figure 13-11D). As the flap is advanced, it fills the primary defect, and creates a smaller secondary defect lateral to the angle of the mouth.

5. The secondary defect is then closed with a buried suture at the inferior tip of the flap (Figure 13-11E). The vector of tension in this example is horizontal, avoiding pull on the upper lip.

6. After completion of the layered closure, the final result nicely reconstructs the upper cutaneous lip with no anatomic distortion (perioperative swelling will resolve) (Figure 13-11F).

FIGURE 13-11 Island pedicle flap: step-by-step instructions. (A) Large defect of the upper cutaneous lip. The lines are drawn such that the flap fits nicely into the nasolabial fold laterally. The curvilinear shape of the flap ensures that the secondary defect will be closed horizontally to avoid raising the lip. (B) The flap is incised along planned lines. (C) All surrounding wound edges are undermined. The pedicle is not undermined. (D) The key suture is placed in the center of the advancing edge of the island pedicle flap. (E) The secondary defect is then closed with a buried suture at the inferior tip of the flap. The vector of tension here is horizontal, avoiding pull on the upper lip. (F) The final result reconstructs the upper cutaneous lip with no anatomic distortion (perioperative swelling will resolve).

(Courtesy of Ryan O’Quinn, MD.)

Rotation Flap

Conceptual

The rotation flap consists of tissue rotating in an arc to fill the primary defect. The rotation flap differs from primary closure and the advancement flap in that the tension is directed not in a single, linear vector, but rather from several different directions. Once the flap is put into position with the first key suture, the primary defect is filled, leaving a much longer curvilinear secondary defect. Closing this secondary defect results in the redirection of wound tension, as well as the redirection of tissue redundancy. This redistribution of wound tension is the great advantage of a well-chosen rotation flap. It can recruit significant laxity from the surrounding tissue and greatly aid in closing defects under significant tension such as large, tight scalp defects, or it can result in moving the secondary motion of a flap away from a critical anatomic structure, such as when a rotation flap is used to close a wound in the infraorbital region.⁴

Single-Rotation Flap

The single-rotation flap is the rotation flap in its most basic form. A single flap is rotated into the defect. A single Burow’s triangle is excised to remove tissue redundancy created by primary flap movement (Figure 13-12).

FIGURE 13-12 (A) A single rotation flap is drawn to repair this scalp defect. A single Burow’s triangle is drawn to remove tissue redundancy created by primary flap movement. (B) The flap is rotated into the defect and sutured.

(Courtesy of Ryan O’Quinn, MD.)

Bilateral O-Z Rotation Flap

The bilateral rotation flap is helpful with wounds under high tension. Often, a wound can be approached with a single rotation flap, and if it is inadequate to close a very tight wound, another rotation flap can be incised and rotated in to provide more movement for final wound closure. Often, no Burow’s triangle need be excised (Figure 13-13).

FIGURE 13-13 (A) Bilateral O-Z rotation flap on the scalp is drawn. (B) The flap is sutured and resembles a “Z.”

(Courtesy of Ryan O’Quinn, MD.)

Rotation Flap: Step-by-Step Instructions

1. The rotation flap works very well in areas of inflexible skin or wounds under considerable tension where a primary closure may be impossible. In Figure 13-14A, a single rotation flap is planned, with a Burow’s triangle drawn inferiorly.

2. The rotation flap is incised and the Burow’s triangle removed (Figures 13-14B and C). All wound edges are widely undermined and hemostasis is achieved with electrosurgery (Figure 13-14D).

3. The flap is rotated in to fill the primary defect and the key suture is placed (Figure 13-14E). Note that a long, curved secondary defect is created.

4. The secondary defect is then closed with buried sutures by the “rule of halves” (Figure 13-14F). This effectively redistributes the tension from the initial primary defect over a much larger area.

5. Running sutures are placed to approximate the epidermis (Figure 13-14G).

FIGURE 13-14 Rotation flap: step-by-step instructions. (A) The rotation flap works very well in areas of inflexible skin or wounds under considerable tension where a primary closure may be impossible. Here, a single rotation flap is planned, with a Burow’s triangle drawn inferiorly. (B) The Burow’s triangle is incised and removed. (C) The rotation flap is incised. (D) The flap and all wound edges are widely undermined and hemostasis achieved with electrosurgery. (E) The flap is rotated in to fill the primary defect and the key suture is placed. Note that a long, curved secondary defect is created. (F) The secondary defect is then closed with buried sutures by the rule of halves. This effectively redistributes the tension from the initial primary defect over a much larger area. (G) The final result is achieved with running sutures to approximate the epidermis.

(Courtesy of Ryan O’Quinn, MD.)

Transposition Flap

Conceptual

Both the design and tissue movement of the transposition flap is more difficult than with the other random pattern flaps. Like the rotation flap, tissue is harvested from an area of laxity to be used to repair the primary defect, but instead of advancing or rotating into the defect, the flap is transposed over an area (Figure 13-1B) of normal skin. The great advantage of the transposition flap is its ability to redirect the wound closure tension. A wound inferior to the free margin of the lower eyelid is often at high risk for ectropion. A transposition flap can transpose skin into the defect to close the wound while reorienting the tension parallel to the eyelid margin. Similarly, a wound of the lower nose can often be difficult to close without pulling up on the nasal tip. A transposition flap can be employed to redirect the tension away from the tip, while moving more pliable skin from the upper nose to resurface the wound.

Rhombic Transposition Flap

The rhombic flap may be the most commonly used type of transposition flap. Although many variants exist, the classic rhombic flap is easily visualized as a parallelogram with the flap tip having a 60-degree angle. The primary defect may be cut to fit the flap, or the flap may be trimmed to fit the defect when it is placed. It is useful to redirect wound tension away from the primary defect. This type of flap is often deployed on the upper nose and periorbital areas (Figure 13-15).

FIGURE 13-15 Rhombic transposition flap is useful to redirect wound tension away from the primary defect, and is often used on the upper nose. (A) Flap drawn with 60-degree angle. (B) Repaired flap looks like a parallelogram.

(Courtesy of Ryan O’Quinn, MD.)

Zitelli Bilobed Transposition Flap

The Zitelli bilobed flap is a more specialized variant of the transposition flap. Although more complex, we include it here because of its great usefulness in reconstruction of wounds of the sebaceous and inflexible skin of the lower nose. The bilobed flap is excellent for closing small to intermediate-sized wounds less than 1.5 cm in diameter. The placement of the extra lobe allows greater movement of tissue from the upper nose ^5,⁶ (Figure 13-16).

FIGURE 13-16 The bilobed transposition flap is excellent for closing small to intermediate-sized wounds less than 1.5 cm in diameter on the lower nose. The placement of the extra lobe allows greater movement of tissue from the upper nose. (A) Small lower nose defect after excising a BCC. (B) Bilobed transposition flap completed.

(Courtesy of Ryan O’Quinn, MD.)

Transposition Flap: Step-by-Step Instructions

1. The primary defect is a small one of the inflexible sebaceous skin of the distal nose (Figure 13-17A). The rhombic flap taps into the more mobile skin of the proximal nose.

2. The flap is incised and the laterally placed Burow’s triangle is removed (Figure 13-17B). On the mid to distal nose, the flap will be incised slightly deeper to improve flap perfusion. A small amount of nasalis musculature is included at the bottom of the flap. All wound edges are undermined and hemostasis is obtained with electrodesiccation.

3. The key suture is placed initially to close the secondary defect (Figure 13-17C). This pushes the flap into place. Usually the flap tip is trimmed to fit the primary defect.

4. The remainder of the flap is sutured in a layered fashion (Figure 13-17D).