Chapter 243. Excisional Surgery and Repair, Flaps, and Grafts

The goal of any excisional surgery is to remove the lesion with appropriate margins and leave the least noticeable scar possible. In order to consistently attain aesthetically pleasing results, time must be taken long before the first incision to appropriately plan the procedure. While excisional surgery is as much an art form as it is a science, there are many principles to keep in mind when planning the surgical excision and closure. Wounds should be closed under minimal tension, with scars placed along cosmetic unit junctions or skin tension lines, without distorting critical anatomic structures and landmarks (eyelid, eyebrow, nose, lip, hairline, etc.). Biologically, the closure must be such that the mobilized skin and associated adenexal structures are viable, and there is maximal preservation of sensory and motor nerve function.

Knowledge of underlying anatomy is critical in both the design and execution of the excision (see Chapter 242).

The planning and execution of dermatologic surgery procedures varies from case to case. A skilled surgeon evaluates the risks and benefits of various options in each patient and anticipates potential complications. Key elements of dermatologic surgery procedures include proper patient selection and preparation; comprehension of risks and necessary precautions; obtaining effective local anesthesia; use of sterile or clean technique; informed procedure design and meticulous technique in performing the incision and repair; diligent postoperative wound care and patient education.

It is important that both the patient and practitioner be aware of the risks of dermatologic surgery. In fact, professional standards dictate that these risks be documented for proper patient consent.1 The main risks of excisional surgery include pain and discomfort; bleeding, bruising, and hematoma formation; nerve damage; wound infection; wound dehiscence; and undesirable scar or contracture.

• While the injection of local anesthesia is not without pain, there are several ways to minimize the discomfort. Some of the most effective ways to diminish pain on injection is the addition of sodium bicabonate to the anesthetic agent, using small-gauge needles, inserting the needle into the skin through a pore, and injecting very slowly and into the subcutaneous tissue. In addition, starting at the proximal aspect of the neural innervation and working distally will help minimize discomfort. Postoperative pain is typically minimal and controlled with over-the-counter analgesics such as acetaminophen. Meticulous operative technique will also help minimize postoperative pain. More severe pain may require the prescription of narcotics.
• Excessive bleeding, subsequent bruising, and possible hematoma formation are also risks. Most dermatologic surgeons now recommend that medically necessary anticoagulation, including aspirin, clopidogrel, heparin, and warfarin, be continued perioperatively.2 Herbal supplements such as ginseng or garlic, vitamin E, aspirin, and nonsteroidal anti-inflammatory agents that are not prescribed by a physician should be discontinued 2 weeks prior to surgery if possible.2 The consumption of alcohol should also be restricted immediately before and after the procedure. Meticulous hemostasis with electrocautery or coagulation, ligation of larger arteries, and the application of a compression bandage minimize the risk of bleeding.
• Risk of infection exists whenever the skin barrier is breached. Wound infection is relatively uncommon3 and occurs more frequently in particular patient populations, such as those who are diabetic, smokers, or immunosuppressed, and at certain surgical sites, such as the ear or lower leg.4 Sterile technique and atraumatic tissue handling minimizes this risk. Prophylactic antibiotics may be administered for high-risk patients, or if the wound base or suture perforates into nonsterile areas, such as the nasal or oral cavities. Guidelines for antibiotic usage are outlined in Table 243-1).
• Wound dehiscence occurs in wounds under high tension, or in cases of poor wound healing or infection. This risk is reduced by proper planning of the closure, the use of buried subcutaneous sutures, fascial plication to relieve tension on wound edges where indicated, and minimizing activity and immobilization of the wound edges for 1 to 2 weeks after surgery.
• Undesirable scars are always a possibility. While many steps can be taken to minimize the appearance of the final scar, it is important for the patient to understand that all excisional surgery will result in the formation of some form of a scar. Many factors must be considered with respect to formation. Free margins must be respected and never distorted. Closures are best hidden when they are placed on along cosmetic unit junctions and contained in as few cosmetic units as possible. The long axis of the excision and/or design of a repair should be placed in the direction of rhytides or relaxed skin tension lines. It is best to plan an excision with the patient in an upright position, and animation using the underlying muscles of facial expression may also be helpful. On the trunk or extremities, the direction of skin tension may be tested by moving/pinching the area. The incision should be made perpendicular to the skin surface, and an even depth of resection and undermining across the base of the wound should be maintained. Remove standing cones of redundant tissue. Buried vertical mattress sutures should be placed to attain good wound eversion and minimize the tension on the wound edges as it heals. Wounds heal under the optimal conditions of a clean, occluded environment.

Procedure Room

• Basic: mechanical table, overhead procedure lights, electrocautery, vital signs monitor, Mayo stand (1 or 2), receptacle for contaminated waste.
• Optional: depending on the location and scope of the procedure, suction may be needed.

Surgical Tray

The specific instruments selected depend on the scope of the procedure and personal preference of the surgeon. It is helpful to set up the basic elements on the tray in the same layout each time. Consistency in placement of sharps prevents inadvertent injury with contaminated instruments to the surgeon or the assistant.

A basic excisional surgery tray (eFig. 243-0.1) contains:

• Instruments: curette, No. 3 or No. 7 Bard-Parker scalpel handle with a No. 15 or No. 10 blade (or a Beaver blade in some cases), small forceps (e.g., Bishop-Harmon) and/or smooth-toothed Adson forceps, delicate standard skin hook or double-prong skin hook, curved iris scissors, blunt-tipped undermining scissors, hemostat, towel clamps, needle holder, suture scissors. For larger procedures, such as flaps, additional hemostats or hooks may be needed. Special procedures will need other instruments added to this tray (e.g., split-thickness skin grafts require a dermatome).
• Disposable material: marking pen, gauze sponges, cotton tip applicator sticks, scratch pad for electrocautery tip, electrocautery handpiece and tip, surgical drapes, foam or magnetic pad for discarded needles
• Suture

Before starting a surgical procedure, it is important to review the patient's medical history, drug allergies, and current medications, including over-the-counter medications. The entire procedure should be explained in detail, and the patient must sign an informed consent. Vital signs should be taken and recorded.

The patient should be positioned in a manner that allows maximum exposure of the surgical site and is comfortable enough that the patient can remain still for the procedure. It is also important to be sure the patient is positioned in an optimally ergonomic way for the surgeon. Patients should be positioned so that the surgeon and assistance are comfortable and not leaning excessively over the table. A back flexion angle of greater than 15° increases the risk of significant back injury. Likewise, the patient should be elevated to a height that is comfortable for the surgeon. While many occupational therapists suggest working at a height that is in line with the elbow, most find bringing the working surface up higher to reduce the angle of the surgeon's neck to be significantly more comfortable. Operating with a cervical neck angle greater than 15° can lead to serious neck injuries and disabilities (eFig. 243-0.2).

If hair removal is deemed necessary, it may be trimmed. The operative field is cleansed in a sterile fashion with one of several scrubs, including chlorhexidine (with or without isopropyl alcohol), iodophors, or triclosan.5 The boundaries of the skin prep should be much wider than the planned incision and take into account the path of suture material in the surgical field. For procedures on the face, the patient should be advised to keep the eyes closed and caution should be used not to get any of the prep into the eyes. Sterile towels or a sterile drape should be placed around the edges of the field. In addition, draping the eyes may add additional comfort to the patient by helping avoid the glare of the operative lights.

Most excisions are performed with local anesthesia only.6 The most common agent utilized is 1% or 2% lidocaine, injected in a ring around the involved area. Other anesthetics used include bupivicaine, mepivicaine, or articaine. The addition of epinephrine 1:100,000 causes local vasoconstriction and helps increase the amount of total anesthesia that may be safely administered, increases the duration of anesthetic activity,7 and decreases intraoperative bleeding. Plain lidocaine should be used when the administration of epinephrine is contraindicated, such as in patients with known cardiac arrhythmias, unstable angina, and narrow-angle glaucoma. It should be used with care in patients who are hypertensive, pregnant, or with known anxiety disorders.

The administration of local anesthetic is painful, particularly on sensitive sites such as the perioral and perinasal areas. There are several ways to decrease this discomfort.8 Lidocaine is slightly acidic, and the addition of sodium bicarbonate 1:10 raises the pH of the solution closer to physiologic levels. Liquid injected at room temperature or warmer is less uncomfortable than that delivered at cooler temperatures. At the injection site, the application of ice or vibration may also decrease the sensation of pain. Placement of the needle through an enlarged pore, especially on the nose, may also limit discomfort. Superficial dermal injection induces anesthesia more quickly than that injected into the deep dermal-subcutaneous tissue region, yet since the tissue is less distensible, it is uniformly more painful. Therefore, lidocaine should first be delivered to the deep dermal-subcutaneous tissue and then more superficially as the needle is withdrawn. Anesthesia should be delivered slowly through a small caliber needle. A 30-gauge needle typically is used in these circumstances. The surgical site should also be anesthetized from the proximal to the distal aspect of the local sensory nerve if possible. For example, when injecting around a lesion on the forehead, start the injections at the inferior aspect and move more superiorly with subsequent injections. In this manner, by the time the superior injections are performed, the area may already be numb since the supraorbital nerve had been anesthetized from the inferior injections.

For larger procedures, nerve block anesthesia is helpful because a large area can be anesthetized with a limited volume of anesthesia. Tissue distortion is also limited with nerve block anesthesia, and the vascular perfusion of the flap is not impaired.

Ellipical Excision

Excisional surgery is one of the most frequently performed dermatologic surgery procedures. Specifically, the elliptical or fusiform excision allows for a linear, side-to-side closure. Mastery of elliptical excision and closure is fundamental to more advanced procedures, including variations on the ellipse itself and planning and executing more complex flaps. An elliptical excision is indicated for the removal of small- to moderate-sized benign or malignant neoplasms as well as for excisional biopsy and scar revision.

Planning the Ellipse

In planning the excision, the lesion to be excised should first be identified and confirmed by the patient. Using an appropriate marker a circle is drawn around the lesion with the appropriate margins. The size of the surgical margin is dependent on the nature of the lesion.9,10

Once the margins of the lesion have been marked, the ellipse is planned. When planning a fusiform excision with linear closure, one must consider several factors, including the impact of the procedure on form and function. Free margins are of primary concern. Any distortion of a free margin will be aesthetically unacceptable. Closures should be planned such that tension vectors are perpendicular to free margins so no distortion occurs. For optimal cosmetic results, the long axis of the fusiform excision should be oriented along the relaxed skin tension lines, which are generally perpendicular to the direction of the pull of the underlying muscle (Fig. 243-1). These lines should be identified while the patient is sitting upright, and may be highlighted by asking the patient to make certain facial expressions. If the relaxed skin tension lines are not obvious, the direction of laxity may be identified by manipulating tissue manually. Relaxed skin tension lines rarely follow published diagrams, and closures should mimic the subtle arcs in the facial lines of expression. When possible, excisions should be restricted to one of the major cosmetic units (e.g., forehead, nose, periorbital area, lips and perioral area, chin, and cheeks) (Fig. 243-2). Placing the incision line at the junction of the cosmetic units may also minimize the appearance of the resultant scar. An adequate reservoir of surrounding tissue or skin laxity must be present. When the elliptical excision and closure that has been designed cannot include these conditions consideration must be given to other forms of repair such as flaps, grafts, partial purse sting closures, or healing by second intention.

The simple ellipse is based on an optimal length to width ratio of 3.5:1 to minimize the formation of redundant tissue at the apices, otherwise known as “dog-ears,” “puckers,” or “standing cones skin.” The ratio may be increased to 4:1 or greater in locations with less tissue distensibility or decreased to 3:1 in areas where the tissue is more lax. The apical angle between the two arciform incisions ranges from of 37°–74°, depending on the length to width ratio.11 As the ratio becomes larger, the apical angle decreases; thus, for a ratio of 5:1, which may be needed for scalp surgery, the apical angle approaches 30° (Fig. 243-3).

It is important to note that as a wound is closed in a linear fashion, the length of the resultant scar will be longer than the distance between the two distal points drawn out in the preoperative design of the ellipse. The arc of the two sides of the closure that are brought together is necessarily longer than a straight line drawn between the distal points of the ellipse. Mathematically, with the angles used in excisional surgery, the arcs are roughly 20% longer than the straight line drawn down the middle of the ellipse. In most cases this becomes irrelevant as there is contraction along the long axis of a scar and the tissue around the closure distends and absorbs this small difference without any noticeable distortion. In areas such as the upper lip, however, this small difference may be enough to distort the lip margin and be disfiguring. Lengthening the elliptical closure and bringing it around the lip to the wet mucosal margin will often help hide this potential distortion.

Technique

After the ellipse is planned and drawn, the field is anesthetized, prepped, draped, and the first incision is made using a scalpel (Fig. 243-4). In most instances, a number 15 blade is used to score the epidermis or to cut through to the fat on the first pass; however, thick back skin may require the use of a No. 10 blade. The surgery begins with the point of the blade at the apex distal from the surgeon's position. As the incision progresses toward the arc of the ellipse, the belly of the blade is held perpendicular to the skin surface, preventing a beveled incision. As the opposite apex of the incision is approached, the blade rocks back up onto its tip, which allows the surgeon to clearly see the apex of the incision under the advancing hand. This prevents extending the incision beyond the planned apex. To prevent bunching of the tissue ahead of the pressure exerted by the blade, traction on the surrounding skin is held with the nondominant hand; in addition, an assistant may aid with traction. The depth of the excision is, again, dependent on the nature of the neoplasm being excised. When a side-to-side closure is planned, the depth of the incision must be full thickness, or into the superficial subcutaneous fat. The proximal apex of the ellipse is grasped gently with a toothed forceps to elevate the tissue. The base of the specimen is dissected in an even plane with a scalpel or scissors. The depth at the apices should be the same as the depth at the center; there is a tendency to remove the specimen with the depth at the apices more superficially. When the depth of the excision is not uniform, a more noticeable standing cone of tissue may surround the tips as the wound is closed.

Closure

Undermining is performed to increase mobility of the surrounding tissue, aid in wound eversion, decrease tension on the wound edges, and diffuse scar contraction.12 The subcutaneous tissue is undermined at the same level around all edges of the wound, including the apices, utilizing iris or blunt-tipped scissors. The tissue may be snipped or bluntly dissected by inserting the tip of the scissors and spreading. The plane of undermining will vary depending on body site but should be uniform in depth at all edges. Knowledge of anatomy is extremely important and careful attention must be given to surrounding vital structures. Patients receiving anticoagulants or with reduced platelet number or function may benefit by limiting the extent of undermining as the risk of bleeding and hematoma formation is decreased.

Electrocoagulation or electrocautery is employed to attain meticulous hemostasis of the bed of the wound. A skin hook is used to elevate the wound edges to expose vessels that were injured during the excision or undermining. Blood that accumulates in the wound must be cleared with gauze or cotton swabs to allow for visualization of pinpoint bleeding and to allow for a relatively dry field. The cautery tip may be applied directly to the vessel until bleeding ceases. Alternatively, indirect coagulation is achieved by using small forceps to grasp the vessel and applying the cautery tip to the forceps. Indirect cautery limits the residual thermal damage surrounding the cauterization and may speed wound healing. Theoretically it could reduce the risk of infection but in facial skin, where much dermatologic surgery is performed, the excellent blood supply often minimizes the risk of infection. No matter which method is used, care should be taken to stop all significant bleeding while minimizing cautery char. Larger, more high-pressured arteries may require ligation with absorbable suture.

Suturing technique (see Chapter 242) reduces and redistributes wound tension, everts the skin edge, eliminates dead space, and maintains or restores natural anatomic contours, while minimizing the formation of permanent suture marks on the skin surface. Most wounds are closed in two layers: (1) absorbable deep sutures and (2) nonabsorbable superficial sutures. Deeper wounds or those with significant dead space may benefit from a third, deep layer in the subcutaneous fat or fascia.

Ideally, the wound is closed by first placing the deep sutures using the rule of halves to minimize the formation of dog-ears (Fig. 243-5). The first suture is placed in the center of the wound. Each half of the remaining defect is closed in a similar manner, which is repeated until a suitable numbers of sutures have been placed. A wound gains only 7% of its final strength after 2 weeks.13 As most skin sutures are removed within 1 to 2 weeks of placement, absorbable buried sutures are an important part of a layered wound closure.14 Buried sutures typically dissolve over the course of months and provide support for the wound until epidermal tensile strength has increased sufficiently to prevent wound dehiscence.

Buried vertical-mattress sutures aid significantly in wound eversion by reducing or eliminating tension on the wound edge and producing thinner less noticeable scars (Fig. 243-6). This type of buried suture should be used in nearly all closures. Subcutaneous sutures help minimize or eliminate dead space and align deep structures such as skeletal muscle or fascia. They can also be used to anchor overlying tissue to underlying fixed structures, such as periosteum, to prevent distortion of free margins or maintain proper facial contour and function. This is exemplified by anchoring a melolabial flap to the maxillary periosteum. When tying a buried suture, it is important not only to keep both free ends of the suture on the same side of the loop created, but also to tie the suture in such a manner that draws the knot down on the same side so it will tuck up under the loop and not get hung up on it (Fig. 243-7). Buried sutures should align the wound edges such that they are perfectly approximated with good wound eversion before the placement of epidermal sutures.

Epidermal sutures are placed to approximate the margins of the skin edge. They should be evenly spaced and placed at roughly the same distance from the wound as the combined dermal epidermal depth. Therefore, sutures placed on the eyelid will be much closer together than those placed on the thick skin of the back. Most practitioners use a running nonabsorbable minimally-reactive monofilament suture, such as polypropylene, that requires subsequent removal.15 Alternatives include running absorbable fast-acting gut16, absorbable or nonabsorbable running subcuticular sutures17, simple interrupted nonabsorbable sutures, and polymethylmethacrylate tissue glue. Simple interrupted sutures are more time-consuming to place and remove than a running suture. In settings, where wound healing may be impaired due to the patient's advanced age or underlying disease, interrupted sutures compared with running sutures may be preferred, as interrupted sutures may have, with all other factors being equal, greater tensile strength and less potential to cause edema, induration, and impaired microcirculation.18

Suture Removal

The risk of crosshatch marks across the suture line can be minimized by removing the sutures within a week of placement, before the formation of epithelial suture tracks develop. On the face and ears, most skin sutures are removed within 5 to 7 days. Neck sutures should be removed in 7 days and scalp sutures in 7 to 10 days. On the trunk and extremities, risk of wound dehiscence mandates that epidermal sutures may be left in place longer, typically 10–14 days, to provide additional support. In repairs under high tension or when dehiscence is likely, sutures may be left in place for 3–4 additional days. However, if sufficient buried sutures have been placed and the wound as well approximated at 7–10 days, epidermal sutures can be removed. The use of a running subcuticular suture for well-approximated wounds will prevent the formation of suture tracks and should be used in most cases that require sutures be left for more than 7 days.

Excision Without Closure

There are certain locations and situations where allowing a wound to heal by second intention is the preferred method of closure. Wounds in patients who are poor surgical risks for reconstructive surgery, where there is relatively minimal tissue mobility (scalp, distal lower extremities), and where there is a high risk of infection healing by second intention may be indicated. (eFig. 243-7.1).

Wounds located in concave areas such as the medial canthus, ear concha, alar crease (if small), temple region, and postauricular sulcus lend themselves well to healing by second intention.19 Wounds allowed to heal by second intention contract significantly and may decrease in size as much as 50% or more.20 Superficial wounds heal with less wound contraction, because there is less deposition of collagen. Therefore, a very superficial wound, even on a convex surface such as the forehead or the nose, can potentially heal well. Because all wounds contract to some degree, it is important that there be no free margin along one side of the wound that can be elevated during wound contracture and cause distortion at the site. This may be encountered along the eyelid margins, ear margins, eyebrow, nasal ala, and lip vermillion border. These areas are almost always better managed with appropriate reconstructive surgery.

When a lesion is excised with the intention of allowing the wound to heal by second intention, appropriate margins should be included and the resulting defect will typically be circular in nature. The incision through the skin is beveled inward to provide exposure of the base of the wound. The depth need not reach the subcutaneous fat if the lesion can be removed satisfactorily by transecting the dermis.

Wounds that are allowed to granulate are more resistant to infection and do not form a hematoma. In addition, the size of the final scar is kept to a minimum by negating the need to remove standing cones. These wounds, however, require more time to heal than those that are closed primarily and exhibit increased contracture. In some cases there is an unpredictable cosmetic result.20 Employing a purse string suture can significantly decrease the size of the wound and abbreviate the healing time considerably.

Revision of Standing Cones of Tissue

Under certain circumstances, a circular excision may be performed when the orientation of the ellipse is difficult to anticipate. This may occur when the precise direction of relaxed skin tension lines and least tension is difficult to determine, when the length of the ellipse for an optimal outcome is unclear, or when alternative repairs may be considered, such as a local flap. Nonelliptical defects require revision of the cones or dog-ears. First, the wound is closed with a few centrally placed sutures; bilateral standing cones of excess tissue form on either side of the central closure. In addition, tissue redundancies may persist at one or both ends of a planned fusiform excision if the apical angle is too wide, if the sides are of unequal lengths, or on convex surfaces and the techniques for addressing these redundancies are similar under both clinical circumstances 21 Skillful repair of the redundant standing cones extend the incision line by removing an additional triangle of tissue at the tip (Fig. 243-8). The apex of the standing cone is lifted with forceps or a skin hook and manipulated to determine where to place the incision that releases the redundant tissue. The incision is made with a scalpel and the dog-ear is undermined. The free end of the cone is pulled over the incision and the remaining incision is made such that the resultant wound edges lie flat.22 The freed cone is termed a Burow's triangle. This technique results in a linear extension of the scar. Variations on the revision of tissue cones include a curved extension, an angled extension, and an M-plasty.

Variations of the Ellipse

Curved Ellipse

The classic fusiform excision creates a linear scar. At times, it is aesthetically preferable to create a curvilinear scar. The curvilinear repair is useful on the cheek and around the chin. The curved ellipse is created by intentionally designing it with one side longer than the other. The wound is closed by the rule of halves.

S-Plasty

An S-shaped repair is useful on convex surfaces such as the extremities where a linear repair may result in persistent standing cones or indentations. The tension vectors of a standard elliptical incision are perpendicular to the long axis of the ellipse. Since wounds contract along their long axis, designing the closure with an S-plasty, displaces the tension over a greater length and a variety of angles (Fig. 243-9) and does not create a contracting in one direction with resulting indentation over a convex surface such as an extremity.

M-Plasty

An M-plasty allows the length of a scar to be shortened. Rather than extending the end of an ellipse or removing a Burow's triangle, the redundant tissue may be excised inward, forming a M-shaped scar. The long axis of the incision is reduced by the length equivalent to the inverted triangle which makes the center of the M. This technique is useful for confining a scar to a single cosmetic unit, that is, the chin, or when an incision approaches a free margin. The scar may be camouflaged in locations where rhytides bifurcate, such as the crow's feet in the periorbital area or around the lips. It is important to advance the inverted triangle up into the rest of the ellipse to take full advantage of the scar-shortening effect.

Partial Closure

Partial closure is used when more extensive repairs are limited by lack of local tissue reservoirs or the patient's health or coagulation status. The wound is closed from the ends toward the center. When wound tension prevents further closure, the area remains open to heal by second intention. The final scar is usually linear and may resemble a spread scar in the middle. Alternatively, a purse-sting suture is placed around the wound and tissue is drawn together circumferentially. The purse-string suture is closed just to the point of minimal tissue buckling. Additional guiding sutures may then be placed across the partially closed wound to attain better alignment and even further closure.

Serial Excision

In some cases, the length of an ellipse required to excise a lesion with a 3 or 4:1 ratio is too long for an acceptable cosmetic or functional outcome. In such instances, the lesion may be removed with a series of staged excisions. A partial excision is performed, ideally an ellipse that accommodates the full length of the lesion, with primary linear closure. During the following months, the surrounding tissue stretches and the tension in the area decreases. Additional excisions are performed in a similar manner, removing the remaining lesion as well as the scar or scars created from the first steps of the procedure. This is typically used to minimize the length of the final scar in large circumference neoplasms that are benign or low risk.

When simple primary closure cannot be done because a wound is too large, there is excessive tension, or an unacceptable functional or cosmetic result would ensue from a linear scar, a tissue-movement procedure, such as a flap or a graft, should be considered. A local skin flap is a portion of full-thickness skin and subcutaneous tissue transferred from an adjacent donor site into the surgical defect. The flap maintains its blood supply via a vascular pedicle that remains connected to the donor site.

Random pattern flaps, the most widely used in dermatologic surgery, are supported by the small arterioles and capillaries of the subdermal vascular plexus found in the mid-to-superficial fat. Therefore, undermining and flap mobilization must be done at or below this level to ensure adequate blood supply. If undermining occurs too superficially, the intradermal vaculature alone will often not be able to support a flap. In certain areas other than the face, the perfusion pressure of even the subdermal vascular plexus is often not sufficient to support a random pattern flap. Fortunately, the blood supply of the face is rich, estimated to be ten times greater than necessary to support the skin's basic metabolic needs so it can support a wide variety of random pattern flaps.

The vascular perfusion pressure, that is the force of blood flow through a vessel, is greatest at the proximal end of a vessel and decreases steadily as it travels more distal into the flap. To ensure flap survival, the perfusion pressure must be great enough to keep the distal capillaries of the flap open. If the pressure falls below a certain critical level, the capillaries close and insufficient blood is supplied to the distal end of the flap.

For years, it was believed that the viable length of a flap was directly proportional to the width of the pedicle. In 1970, Milton discovered that axial flaps in a pig model under the same conditions of blood supply survive only to a finite length regardless of width.23 Daniel and Williams, as well as Stell confirmed Milton's findings and concluded that there was an upper limit of flap length that cannot be increased by increasing the pedicle width.24,25 The maximal flap length is determined by vascular supply, not simply pedicle width. The greater the perfusion pressure in the flap pedicle, the longer the flap can be without undergoing necrosis.26 In addition, the greater the perfusion pressure in the pedicle, the narrower the pedicle may be. Axial pattern flaps have the highest perfusion pressure at the base and therefore can support very narrow long flaps (generally greater than 4:1 length to width ratio). Musculocutaneous flaps have the next greatest vascular perfusion pressure, followed by fasciocutaneous flaps, and finally random pattern flaps. Stell discovered the greatest length of a viable axial flap was 60% greater than that of a random pattern flap. In general, random pattern flaps on the face should have a maximal length to width ratio of 3:1.27,28 This is however only a rough guideline and individual patient characteristics such as tobacco use, sebaceous nature of skin, prior radiation or surgical procedures, and precise location all affect vascular perfusion. To help ensure flap survival the pedicle length-to-width ratios should not exceed 2:1 on the trunk and extremities.

The two movements involved in repairing a defect with a flap are the primary movement, which is the action of placing the flap into the defect and the secondary movement of tissue in the donor area, which closes the secondary defect and facilitates primary flap movement. Both movements are important in terms of distributing tension in the proper direction and over a larger area so as to minimize tension on the flap itself, which might compromise its survival.29 Flaps are commonly classified according to their primary movement—advancement flaps, rotation flaps, transposition flaps, and interpolation flaps. This classification underplays the reality that many flaps have more than one primary movement, e.g., a rotation flap usually has a component of advancement to fill the distal portion of a wound. Therefore, another way to classify flaps is by whether the primary movement is sliding, which displaces tissue redundancy at a site distant from the defect (advancement and rotation) or lifting, where a flap is moved over intact skin, reorienting wound tension (transposition and interpolation).

As with elliptical excisions, the flap should be planned paying attention to the concepts discussed above, such as free margins, skin laxity, relaxed skin tension lines, cosmetic units, and attention to function. The flap and possible resultant Burow's triangles should be drawn out with a marking pen while the patient is in an upright position. It is advisable to plan the flap prior to administering anesthesia, as the injected volume may distort the tissue and alter its movement.

Flap incisions should be made perpendicular to the skin and the recipient wound edges should similarly be squared off. The thickness of the flap should be uniform and should approximate the thickness of the wound edge. The area around the flap should be widely undermined.

Advancement 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.

Single Advancement

The simplest example of a pure advancement flap is the U-plasty, whereby double, parallel incisions are made tangential to what is most often a round defect. The flap is undermined, advanced into the defect, and secured with sutures, creating a U-shaped scar (eFig. 243-9.1). Redundant tissue cones may be sewn out using the rule of halves or removed as Burow's triangles at the base of the flap. While the U-plasty is occasionally used to make the majority of lines in the repair of a forehead defect run in the horizontal direction with the natural skin tension lines; the fact that it does not alter tension vectors and does not significantly free tissue up limits its usefulness.

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. 243-10). Tissue redundancy is created on the side of the defect opposite the flap incision and must be removed. While this type of advancement flap may tap into some distant laxity, it is generally minimal. Advancement flaps also do not change the tension vectors of the closure. 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. 243-11). The incision may be 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 and prevent unnatural webbing. When a defect involves both the cheek and the ala, a cheek advancement flap may be used to cover the defect on the cheek and a full-thickness skin graft may be used to repair the alar part of the defect (Fig. 243-12). This will keep the cosmetic units separate and place the scar lines along the cosmetic unit junctions.

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 intact30 (conceptually analogous to the L-plasty) (Fig. 243-13). 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.

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 on the forehead and upper lip to hide incision lines along relaxed skin tension lines and cosmetic unit junctions.

Another commonly employed bilateral advancement flap is an O-to-T flap, also termed an A-to-T or a T-plasty (eFig. 243-13.1), analogous to a bilateral L-plasty. This flap is essentially a bilateral O to L flap. The standing cone is removed from one end of the defect, creating a triangle, or transforming on “O” into an “A”. Single incisions extend from the base of this triangular defect, and the two sides of the triangle slide together along this baseline. The T-plasty is best performed with the broad base along a free margin or cosmetic unit junction (e.g., lip, eyebrow).

Crescentic Advancement Flap

The crescentic advancement flap utilizes the removal of small crescent of tissue along an advancement flap to either better hide the scar line or increase the length of the line to prevent distortion. This flap is particularly useful for the repair of upper lip and perialar defects. The superior standing cone is removed in a crescentic shape around the ala such that the superior scar line is placed in the perinasal sulcus (Fig. 243-14).31 For defects on the upper cutaneous lip, the inferior cone is removed along relaxed skin tension lines and extended through the vermilion border and around to the wet mucosa to prevent a downward distortion of the vermilion. A modification of the crescentic advancement includes the repair of a small, perialar defect of the medial cheek where both cones are removed around the ala, and the entire scar line is placed in the nasal sulcus, similar to the cheek advancement. Another modification includes incorporating a crescent along the vermilion border to an advancement flap closing a defect just superior to the vermilion border. Removing a crescent here increases the length of flap and helps minimize the differences in length between the flap and the total length of the closure (flap + defect). This will take some of the horizontal tension off the flap and minimize distortion of the lip and modeolus (Fig. 243-15).

Island Pedicle Flap

A subcutaneous island pedicle flap, also referred to as a V-to-Y advancement flap, may be considered as a variation of an advancement flap that has had all of its connections to the epidermis and dermis severed, maintaining its blood supply through a subcutaneous tissue pedicle (eFig. 243-15.1).32 The flap is designed within cosmetic units when possible and, as with all repairs, it is optimal for the incision lines to run along cosmetic junctions. The island pedicle flap is frequently used on nasal and perioral closures where free margins are at risk for distortion. The tension vectors of an island pedicle flap are primarily in the same direction as that of a primary closure; however, they are displaced distal to the wound (i.e., superior to the nasal tip, superior or lateral to the vermilion border) and help avoid distortion of the area around the defect.

An island pedicle flap is created by extending two nonparallel tangential incisions to meet at an approximate 30° angle, similar to when planning a Burow's triangle. The difference is that the incision lines stay parallel for a short distance before converging, creating a slightly larger triangle than would be created with a Burow's triangle. This extra length gives tissue that closely approximates the size of the defect and minimizes local distortion. The triangle may be designed larger or smaller depending on how much tension sharing is desired. The incisions are made just to the superficial subcutaneous tissue. The tip and sides of the flap are undermined widely extending outward from the flap in the subcutaneous plane. The triangular flap is also undermined slightly to help mobilize it. The flap is then advanced into the defect and sutured into place. In order for the flap to fit properly into a circular defect, either the corners of the flap must be trimmed or the defect squared off. The flap must be undermined with attention both to the mobility of the tissue as well as to the maintenance of a subcutaneous vascular pedicle. While the initial design should have a broad pedicle, if mobility is limited the pedicle may be progressively diminished (particularly at the trailing tip of the flap).

When closing defects on the nasal dorsum and tip, a muscular flap is often created laterally on one or both sides. For this musculocutaneous island pedicle flap, undermining is performed both above and below the nasalis muscle. If there is not enough laxity to close the defect without upward tension on the nasal tip, the muscular flap is released horizontally at the superior and inferior edge to create a muscular sling that advances with the flap into place. The muscular attachment gives a robust blood supply to the flap and helps ensure its survival.

Rotation Flaps

In a rotation flap, skin moves into the defect by rotating around a pivot point (Fig. 243-16). This is classically used to close relatively large defects on the cheek, temple, or scalp. The design of the traditional rotation flap uses a curvilinear incision along an arc adjacent to the primary defect. Adjacent lax tissue is recruited while the closure tension is redirected in multiple directions away from the primary defect. The flap is designed with attention to its length and curvature.33 Rotation flaps often require long incision lines, as a larger arc of the rotation vector allows closure with minimal tension on the flap's tip while simultaneously decreasing the width of the secondary defect. The ideal arc of a rotation flap extends up to five times the width of the defect and makes up approximately one quarter of the circumference of a circle.

As the flap is raised and undermined, the adjacent tissue laxity allows the flap to rotate into the primary defect. The stiffness about the pivot point may hinder the flap's movement,33 and undermining the area of pivotal restraint improves flap mobility. If restraint of motion keeps the tip from moving into the distal defect, a back cut can increase tissue movement in areas of limited tissue laxity, such as the nose. The back cut cannot extend so far across the base of the flap that it interferes with blood flow into the flap.

Dorsal Nasal Rotation Flap

Also known as the Rieger flap, this flap is employed to repair nasal defects involving the distal dorsum or tip.34 The tissue reservoir of the nasal root and glabella allows for the movement of the dorsal nasal skin superior to the defect. A long, sweeping arc is created that extends into the nasofacial sulcus and terminates in the glabella. A back cut in the glabella improves the rotational mobility of this flap and is termed a hatchet flap (Fig. 243-17). If the arc of this flap is not long enough or there is too much tension on the leading edge of the flap, elevation of the nasal tip will result. Wide undermining at the level of the perichondrium is required.

Bilateral Rotation Flap

At times, the size of the defect or the tension on the flap mandates a bilateral rotation flap, in which tissue is rotated into a defect from two opposite sides. The vectors of rotation may be mirror images of each other, recapitulating the premise of the A–T advancement flap. This may be utilized for large defects on the scalp and larger defects on the lower lip (Fig. 243-18). The vectors of movement may also be in opposition, creating an O-to-Z flap.

Transposition Flaps

A transposition flap is a random pattern flap, which borrows skin laxity from an adjacent area in order to fill a defect in an area with little or no skin laxity. In its travel from the donor site to the recipient site, the flap is lifted or “transposed” over a segment of intervening tissue. When the secondary defect is closed, the transposition flap pushes tissue into a defect rather than pulling it, as with the advancement and rotation flaps. While moving to the recipient site, the flap actually follows a rotational path and must be designed so it does not rotate too far and pull too tightly on its pedicle.

Transposition flaps have several advantages over other closures. Their primary function is to redistribute and redirect tension. This is useful in the closure of defects, which would otherwise close under high tension or distort a nearby anatomical structure leading to functional or aesthetic impairment. Transposition flaps are usually smaller in size than advancement and rotation flaps. The resulting scars are geometric broken lines that may be less noticeable than longer linear closures in certain areas. This geometric broken line scar, however, may also be thought of as a disadvantage because such a scar is difficult to completely place along a relaxed skin tension line or cosmetic unit junction. One of the major advantages of transposition flaps are that they utilize adjacent skin and provide an excellent color and textural match.

The most common transposition flaps in cutaneous surgery include rhombic flaps (and their variations), bilobed flaps, and banner flaps such as the nasolabial flap. Knowledge of the tissue dynamics used in these three basic transposition flaps can be carried over to the planning and execution of the numerous variations of these flaps.

Rhombic Flap

First described by Lindberg in 1963, the classic rhombic flap was designed to create a secondary defect perpendicular to the primary defect.35 When closed, it would not only provide tissue to the primary defect, but also redirect the tension vector by 90°. This allowed the primary defect to be closed under almost no wound edge tension. Subsequent modifications by DuFourmental and Webster provide more tension sharing between the primary and secondary defects. These modifications are useful in situations where some laxity around the primary defect is available.36

The classic Lindberg rhombic flap is designed by conversion of the primary defect into a four-sided parallelogram with each side of equal length and tip angles of 60° and 120°.35 This rhombus forms the recipient site for the flap as well as the template on which to plan the flap incisions. In its classic configuration (Fig. 243-19), the incisions are designed by extending a line (line a-b) outward from one of the obtuse tips for a length equal to that of one side of the rhombus. From the free end of the extended line (point b), a second line (line b-c) is drawn. The tip angle in this configuration is 60°. The flap is lifted and transposed into place. The tension vector is redirected from that of closing the primary defect, to that of closing the new secondary defect created in the design of the flap. This allows the tension vector to be shifted and redirected by 90°.

There are four possible flap designs off of the short axis of any rhomboid defect (Fig. 243-20). Which of these four flap configurations is selected depends on several factors that affect the final outcome. These factors include adjacent anatomic structures, adjacent skin type, and where the scar line will be best hidden. Though the classic rhombic transposition flap can be designed and executed off of the long axis of the rhombus, there are two advantages to designing it off of the short axis of the defect. First, it keeps the flap as small as possible while filling the defect completely. Second, it minimizes the arc through which the flap must rotate to fit into the defect.

In designing the flap from the circular defect, the length of the line extended out from the defect should be drawn longer than the diameter of the circular defect. This will account for the fact that the diameter of the circular defect is shorter than the short axis of a rhombus drawn around the defect. A second line of the same length is drawn, keeping the tip angle at 60° to complete the flap. The triangle of tissue redundancy created by the rotation of the transposition flap is removed by trimming a Burow's triangle at the pivot point. The transposed tissue may be rounded to fit the circular defect, or the defect may be squared off to accommodate the angular flap. This choice can be made based upon which option yields the best aesthetic result.

As with any closure, understanding the tension forces is essential to the planning, execution, and outcome of the repair. There are two main tension forces associated with the classic rhombic flap. The first set of tension forces are realized during the approximation and closure of the secondary defect. The second set of tension forces are generated at the tip of the flap when moving it into the primary defect. These forces are due to the resistance to rotation at the flap's pedicle as well as shortening of the length of the flap during rotation into the recipient site. Dzubow describes these forces as pivotal restraint.33 Securing the flap into the recipient site under high tension is not advised because it may lead to tip ischemia and necrosis. Two modifications in design can be utilized to assist in minimizing the shortening of the flap and subsequent tension at the flap tip.

• By lengthening both the leading edge and the secondary limb of the flap, the flap can be enlarged and lengthened. This lengthening can compensate for the shortening resulting from pivoting at the base, thus, reducing tension at the tip when secured in the recipient defect.
• An alternate method to lengthen the flap is by designing the flap with a slightly more obtuse (greater than 120°) flap angle. Widely undermining around the flap also assists in the redistribution of tension vectors as well as redistribution of contractile forces during the healing phase.

The Dufournmental Flap

The DuFournmental flap modification differs from the classic rhombic transposition flap (Fig. 243-21) in that it utilizes a narrower flap tip angle and a shorter arc of rotation, allowing easier closure of the secondary defect, and some sharing of the tension between the primary and secondary defects. Given that there is generally some tissue laxity at the site of the surgical defect, the DuFourmental modification is utilized by this author more than any of the classic rhombic flap.

As with the classic rhombic flap, it is designed by extending the first line from the short axis of the rhomboid defect. However, the angle at which the first line is extended differs from the classic rhombic flap in that it bisects the angle formed by the first line of the classic rhombic flap (which extends straight out from the short axis of the rhombic defect) and the line formed by extending one of the sides of the rhombus from the same corner of the rhombus. The length of the first line is equal to that of a side length of the rhombus. The second line originates from the free end of the first line, and is drawn parallel to the long axis of the rhombus. This second line's orientation results in a slightly widened pedicle, a decrease in the tip volume, and a decrease in the degree of rotation necessary to execute the flap. The tissue redundancy at the base of the leading edge of the flap can be removed by taking a slightly larger Burow's triangle.

The 30° Angle Webster Flap

The 30° angle Webster modification of the classic rhombic flap utilizes a more acute angle than other rhombic transposition flaps allowing for even greater tension sharing between the primary and secondary defects. A Webster 30° angle flap is planned similarly to the DuFourmental flap; however, its distal tip angle is designed to be 30° (Fig. 243-22). This gives the flap a slimmer design and narrower pedicle. The flap area is only 50% of the area of the primary defect; therefore, it only relieves half of the tension from the primary defect. This modification is used in situations where a fair amount of laxity exists in the horizontal axis of the rhombic shaped defect. Since this design places more tension on the primary defect, care must be taken not to close with too much lateral tension or distort adjacent anatomic structures.

Rhombic transposition flaps are very versatile and may be used to reconstruct a variety of defects. Transposition flaps are generally used when there is insufficient laxity in the immediate surrounding area of closure and/or the tension vectors need to be redirected. This is particularly important when repairing defects near free margins such as the eyelids and the nose. The most common areas they are employed include the nasal dorsum, nasal sidewall, medial and lateral canthus, lateral forehead, temple, cheek, perioral region, inferior chin, and the dorsal hand.

The Banner Flap

Banner type flaps are random pattern finger-shaped cutaneous flaps that, like other transposition flaps, tap into adjacent skin to borrow laxity and fill a defect.37 This flap is most commonly planned as a melolabial transposition to repair defects of the nasal ala or from the pre- or postauricular area to close defects on the ear. For an optimal cosmetic result, the scar is generally placed at the junction of two cosmetic units, providing excellent camouflage (in the nasolabial fold or preauricular sulcus) (Fig. 243-23).

The fundamental design of the banner flaps consist of a finger-shaped flap drawn with a width that is equal to the width of the defect and a length equal to the distance from the pivot point to the far edge of the defect. The flap is transposed and rotated in an arc around the pivot point to fill the defect. Since this is a long random pattern flap with a narrow pedicle, the risk of vascular compromise may be high if the entire length of the flap is used and its pedicle originates from an area of minimal vascularity. To minimize risk of vascular compromise, the flap is typically designed to rotate through an angle of 60 to 120° instead of the originally described 180°. Additionally, when designing the backcut and removing the redundancy at the base of the flap, it should be designed in a direction away from the pedicle of the flap to avoid further narrowing of the pedicle thereby maximizing flap viability. Typical locations for use of Banner type flaps include the nasal ala, the superior helix of the ear, and the medial anterior ear.

Bilobed Flap

The bilobed flap used today is a highly evolved transposition flap. The bilobed flap was first described by Esser in 1918. It became a workhorse flap only after the modifications described by Zitelli were published in 1989 (Fig. 243-24). The design of the bilobed flap actually consists of two transposition flaps executed in succession, which follow the same direction of rotation over intervening tissues. The basic premise of this flap is to fill the defect with the primary lobe, while filling the secondary defect with the secondary lobe, leaving a triangle-shaped tertiary defect to be closed primarily. This series of transposition flaps allows the surgeon to further the reach of the flap, and borrow laxity from donor sites at a greater distance from the defect while decreasing the arc of rotation of the pedicle.

The Zitelli modification of the bilobed flap is designed by placing the lobes over a 90° arc from the center of the defect, with the primary lobe rotating from a pivot point that is created by removing a Burow's triangle at one pole of the defect.38 The width of the primary lobe should be equal to the width of the defect and should be long enough to just extend past the edge of the defect. The secondary lobe must be trimmed to match the secondary defect left by the transposition of the primary lobe.

As with the rhombic flap, the bilobed flap redirects the principal tension vector and takes advantage of tissue laxity of the donor site. This flap is predominantly used for small-to-medium sized defects of the lower nose as the tension is redirected to a near vertical vector, preventing distortion of the alar rim (eFig. 243-24.1, Fig. 243-25).

Interpolation Flaps

Interpolation flaps are more complex repairs that import pedicle-based tissue from a site distant to the defect. They are typically utilized on defects that are either too wide or too deep to reconstruct with local flaps or grafts. Many interpolation flaps may be classified as axial flaps if their vascular pedicle is based on a large, named artery. They are also commonly referred to as staged flaps as more than one stage is required to complete the repair. Interpolation flaps require careful planning, substantial time in executing, and significant, albeit temporary, disfigurement of the patient.

The first stage of an interpolation flap involves the design and creation of the flap, including repair of the secondary defect. The flap is designed around a substantial artery and therefore is able to support a larger mass of tissue than random flaps. Because the flap is used to repair defects distant from the donor site, the vascular pedicle must temporarily be left in place to ensure adequate blood supply. The distal end of the flap is thinned to match the depth of the defect and sutured in place. The area is bandaged and kept moist. The second stage generally takes place 2- to 3-weeks later, by which time the flap has established a local blood supply from the donor site. The pedicle is then divided from the donor site and the proximal portion of the flap is secured into the original defect. Due to granulation tissue formation, this portion of the flap may need to be thinned out subcutaneously to approximate the depth of the defect. The pedicle is also separated from the donor site which will then require further steps for complete repair.

Paramedian Forehead Flap

The paramedian forehead flap is useful to repair large, deep nasal defects that may or may not require cartilage grafts. Tissue is mobilized from the forehead, based on one of the supratrochlear arteries, and transposed to repair large distal nasal defects with the pedicle remaining attached in the glabellar region (Fig. 243-26). The supratrochlear artery is located at the medial border of the eyebrow, approximately 1.5–2 cm from the midline.

The aesthetics of the repair are often improved when the defect is enlarged to include the total cosmetic subunit. The portion of the flap that will fill the defect is the superior portion closest to the hairline; the width here should be equal to the widest portion of the defect, although the pedicle itself need be no wider than 1–1.5 cm. Its height must be equal to the distance from the base of the flap to the distal edge of the defect. In designing the flap, it is important that the vertical height of the forehead is able to accommodate the necessary length of the flap. The tissue is rotated approximately 180° around its pedicle and should be rotated medially as to minimize obscuration of the medial visual field of the ipsilateral eye; therefore, the flap will require less rotation if it is harvested from the forehead supplied by the supratrochlear artery contralateral to the defect.

The donor site is undermined and closed primarily as far superiorly as it will close. The distal aspect of the flap is debulked to the depth of the defect and secured at the distal margin with sutures. The proximal margin, by design, cannot be secured until the pedicle is divided. The donor site is repaired with a side-to-side closure, resulting in a long linear scar. The superior portion of the defect will be the widest, as it is here that the width of the defect must be accommodated, and thus, generally this portion of the wound is too tight to be closed and is left to heal by secondary intention. The pedicle should be circumferentially wrapped with Vaseline or Xeroform gauze or Surgicel to prevent desiccation.

The second stage takes place 3 weeks subsequently. The pedicle is separated from the brow, the wound edges are freshened, and the donor defect is closed. After the pedicle is separated from the defect, the tissue is further debulked and trimmed, and the remaining edge is secured.

Nasolabial Interpolation Flap

This flap is utilized to repair complex defects of the ala, particularly in instances when cartilage grafting is also required to restore the structural integrity of the alar rim. The flap is harvested from the medial cheek and nasolabial fold and is based on branches of the angular artery (Fig. 243-27).

The aesthetics of the repair is often improved when the defect is enlarged to include the entire alar lobule. The flap is designed around a pedicle that will be placed at the alar groove, extending as an ellipse that will be easily closed in the nasolabial fold. Through-and-through nasal defects will require the repair of the mucosa, and thus, the width of the flap must take this into account. This myocutaneous flap is dissected from the donor site, rotated downwardly, debulked and trimmed, and secured to the widely undermined defect.

As with the paramedian forehead flap, the pedicle may be wrapped with Vaseline or Xeroform gauze or Surgicel. Three weeks later, the pedicle is separated, the wound edges are freshened, and the donor defect is closed. After the pedicle is separated from the defect, the tissue is further debulked and trimmed, and the remaining edge is secured.

The reverse nasolabial flap, also known as a Spear's flap, is employed when the defect involves the alar groove. The motion of this flap is an upward rotation, opposite of the traditional nasolabial interpolation flap.

Abbé Flap

The Abbé flap is also known as the lip-switch flap and is reserved for repair of large, deep defects, typically of the upper lip. It is particularly useful for defects that involve up to half of the lip without crossing the midline and those that penetrate into the muscularis. The Abbé flap is harvested from the ipsilateral lower lip and is based on the inferior labial artery. This artery is located deep to or within the orbicularis oris muscle and runs along the mucosal aspect of the vermillion border.39

The vermillion border and flap design must be properly marked out. The defect should be full thickness (including muscularis and oral mucosa) and may be enlarged to encompass the total cosmetic unit, which includes the ipsilateral upper cutaneous lip. The flap, also designed to be full-thickness to fill the enlarged defect, is rotated upon a vascular pedicle that makes up the lateral aspect of the flap. The inferior labial artery will be visualized as it is transected at the mobilized (medial) edge of the flap. The pedicle itself should be about 1 cm thick, containing the robust blood supply.

The donor site is undermined and closed first to facilitate the movement of the flap. It should be closed in layers as in the repair of a lip wedge resection: mucosa, muscularis, subcutaneous, then cutaneous. The flap is rotated superiorly and also inset with a layered closure. Careful attention should be given to aligning the vermillion borders at the donor site and defect.

The pedicle of the Abbé flap should not be circumferentially wrapped, but kept moist with occlusive ointment. As with other interpolation flaps, the pedicle will remain in place for at least 3 weeks. During this time, the oral aperture will be significantly distorted, and the patient must be counseled. The pedicle is divided and the final repair takes place, again with careful attention to the placement of the vermillion borders.

Retroauricular Flap

The retroauricular flap is a two-staged interpolation flap useful for large defects of the helix. Defects in this location typically involve the perichondrium and are not suitable for grafts. This flap is considered a random flap as it is not based on a large named artery. It is harvested from the richly vascularized skin of the postauricular scalp and is advanced over intervening intact skin to fill the helical defect; the pedicle remains attached to the posterior scalp (Fig. 243-28). The flap should be thinned to match the depth of the defect and carefully sewn into place. The pedicle is circumferentially dressed, and the patient is warned of likely postoperative bleeding and discomfort. The donor site is not repaired until pedicle take-down and often, due to its inconspicuous location, is allowed to heal secondarily.

Skin grafts are transplanted skin from a donor to recipient site with the goal of closing a surgical defect or wound. They are typically used in reconstruction after removal of a cutaneous malignancy; however, they are also used in the treatment of chronic skin ulcerations, full-thickness burns, epidermolysis bullosa, and vitiligo. Grafts are completely detached from the donor site and receive all nutrients from the wound bed of the recipient site. The three basic types of skin grafts are full-thickness skin grafts (FTSG), split-thickness skin grafts (STSG), and composite grafts. FTSGs consist of epidermis with full-thickness dermis, while STSGs consist of epidermis with partial-thickness dermis. Composite grafts are full-thickness skin grafts with cartilage attached to the graft. Skin grafts are also categorized by their donor origin. These include autografts (donor = recipient), allografts (human to human), and xenografts (animal to human).

Full-Thickness Skin Grafts

FTSGs are useful for defects in which complex linear closures or a flap would not be suitable, where close monitoring of the site is advisable, and in certain areas where they provide optimal aesthetic reconstruction. When possible, FTSGs are chosen over STSGs because of their similarity in thickness and texture to surrounding skin and their relative lack of significant wound contraction. Since STSGs generally result in a depressed, hypopigmented, scar without normal epidermal texture, they are reserved for larger wounds that cannot be covered with FTSGs. When wounds are too deep for even a FTSG to cover without creating a depression (when the depth of the wound exceeds the thickness of a graft), second intension healing may be employed for a period of time to build the base of the wound up to the point where a FTSG would completely fill the defect.

FTSGs have essential nutrient requirements and, therefore, should not be placed at a site where the vascular supply is poor. FTSGs will not survive if transplanted directly over bone, cartilage, or tendon.

Determining Donor Site

When planning your graft, there are many factors to be taken into consideration. The donor site should be well matched to the skin surrounding the defect in terms of thickness, texture, sun exposure, and adnexal structures.40 Donor sites can be differentiated by thickness, for example, thin (eyelids, postauricular sulcus), medium thickness (preauricular, conchal, cervical), and thick (supraclavicular, clavicular, nasolabial fold, forehead).41 However, examining for tissue similarity, such as adnexal structures and sun exposure, is also pertinent.

Common sites for FTSGs for nasal defects include preauricular, postauricular, nasolabial fold, forehead, and conchal bowl skin. Preauricular skin can be used to repair most nasal defects, has similar sun exposure and skin quality and heals with minimal scar visibility.42,43 Conchal bowl grafts are particularly well matched for nasal tip and alar defects due to the similarity in texture and concentration of sebaceous glands (Fig. 243-29) as well as the ability to allow the donor site to heal by secondary intention.44 Nasolabial fold and forehead skin offer excellent matches but leave secondary scars in more visible areas.

Harvesting

Once the donor site has been established, the graft can be harvested. To ascertain the size and shape of the graft needed to fill a given defect, many surgeons will create a template using a nonstick dressing, pressing it against defect. The template is cut out and then traced with a marking pen onto the donor skin. Although some authors have recommended grafts be designed 3% to 5% larger than the defect to accommodate contraction of the graft skin once it is removed45; oversizing grafts can lead to unsightly pincushoining. For this reason, the authors size their grafts at or just under the size of the defect. If the donor site is to be closed primarily, an ellipse is planned around the designed graft (see Section “Excisional Surgery”).

Defatting the graft before securing it to the recipient bed is critical. The subcutaneous tissue is poorly vascularized and, therefore, hinders graft survival. Defatting can be performed with an iris scissors by trimming away the yellow fat to expose the shiny white dermis. If the area being repaired is uneven, thin areas of fat may be left on the graft to more closely approximate the natural contours. Alternatively, at times, it may be necessary to thin the dermis slightly to ensure similar thickness between graft and donor tissue. If this is the case, minimal thinning is recommended to avoid structural damage of adnexae. Once the graft has been prepared, it should be placed in the recipient bed as soon as possible. The recipient bed should have good hemostasis without devitalizing the tissue with overuse of cautery.

Grafts generally need to be trimmed at the edges to ensure a perfect match to the donor site. Survival of the graft is also dependent on the surgical technique during placement. The graft must be manipulated and grasped gently.

Small caliber nonabsorbable or fast-absorbing cat gut sutures are commonly utilized for FTSGs on the face. Insertion of sutures should be from graft to recipient tissue to minimize graft movement and best approximate wound edges. It is helpful to place the initial four sutures at intervals of approximately 90° from each other to ensure proper placement and to secure the graft. These are followed by interrupted sutures or, at times, running sutures to complete closure. When grafts are large or placed over concave areas, basting sutures help keep good graft to bed contact. This will stabilize the graft and minimize sheering forces. Several authors recommend the use of bolster dressings. While bolster dressings may assist in prevention of hematomas and seromas they also compromise vascularity and can increase the risk of necrosis.

For larger defects or those with exposed bone or cartilage at the periphery, a purse-string approach may be introduced. A purse-string suture is placed subdermally along the defect edges, then tightened to advance edges into the defect circumferentially. This technique helps protect exposed tissue as well as reduce the defect size, thereby allowing the surgeon to use a smaller graft.

Sutures should be removed in one week for grafts on the face. Healthy grafts are pink in color. Although a purple color indicates relative hypoxia, most grafts with this color will survive. A white color on the surface of a graft generally represents maceration and may do fine when no longer occluded. If the white color is full thickness, it may represent necrosis. Black grafts are necrotic. Gentle wound care without debridement is the best treatment for graft necrosis. The necrotic graft will act as a biologic wound dressing, promote dermal healing, and generally avoid contraction. Antibiotics should also be started to minimize the risk of infection.

Burow's/Regional Graft

Burow's or regional grafts essentially use the Burow's triangle or dog-ear, often from a partial linear closure, to act as an FTSG (eFig. 243-29.1). This utilizes removed skin that might otherwise have been thrown away and eliminates the need for removing tissue from a separate donor site. Because these are often local grafts, the tissue match is generally excellent.46 Since a circular defect has a much larger surface area than a standard triangle taken in an elliptical closure, the triangle must be designed more like that of an island pedicle with a wider and longer body.

Stages of Wound Healing

• First 24 hours: plasmatic imbibition or ischemia: the graft affixes to the recipient bed via fibrinous material
• 48–72 hours: anastomosis and proliferation of vessels
• 4–7 days: reestablishment of full circulation

Stress on the wound should be avoided to provide the best results. Overstimulation of the patient may lead to increased blood flow to graft site leading to fluid overload and disruption of vascularity. The patient should be advised not to undergo strenuous activity for at least 1–2 weeks.

Composite Grafts

Composite grafts consist of one or more adjacent tissues, often involving a typical FTSG with underlying cartilage.47 Small full-thickness defects of the nasal ala and helical rim most commonly require such a graft. Donor sites for composite grafts frequently include the helix and conchal bowl. It is desirable to harvest the graft in a manner that allows the underlying cartilage to extend beyond overlying tissue. This extension allows for the cartilage to insert under the surrounding defect margins. Two small pockets are generally made across from each other at a level below the dermis in the recipient site to accommodate the cartilaginous wings on the composite graft. The cartilage may or may not be sutured, and the remaining FTSG is sutured and secured as described earlier in this section. After being sutured into place, a composite graft with cartilage at its base receives its blood supply from its lateral margins only. Therefore, composite grafts should remain less than 2 cm2, as a larger graft will not receive sufficient nutrients to allow its central portion to survive.48

Free Cartilage Grafts

Free cartilage grafts consist of cartilage and perichondrium. This type of graft assists in structural support (e.g., prevent nasal valving) and retention of natural facial contours (e.g., ala and helical rim). Elastic cartilage from the ear, versus hyaline cartilage from the nose, is the best for recontouring. A strip or disc of cartilage is usually harvested through an incision in the postauricular sulcus or conchal bowl. As is done with a composite graft, the strip of cartilage harvested is slightly longer than the size of the defect and the edges are inserted into pockets made under the dermis. The cartilage is sutured lightly into place with absorbable sutures. The site is then typically closed with a flap. Full-thickness skin grafts may be placed over very thin cartilage struts but as the size of the cartilage increases, the vascular supply to the graft becomes increasingly compromised and decreases graft survival. The addition of cartilage helps with structural support such as preventing collapse of the nasal valves which results in disruption of air flow. It also helps retain the patient's original facial contours and prevents concavity and/or contraction of the repair.

Split Thickness Skin Grafts

STSGs are composed of epidermis and partial dermis. Because these grafts are much thinner than FTSGs, they have a less rigorous demand for vascular support and have an increased survivability profile. Unfortunately, since they lack the full thickness of dermis and dermal appendageal structures, STSGs appear more like scar tissue than skin; they are depressed, hypopigmented and have a shiny texture. They are used to cover large defects unable to be closed by other methods, to allow better wound bed surveillance, to line tubed pedicle flaps, or to resurface mucosa.49 STSGs are often harvested from the upper inner arm, thigh, or buttock. If small, STSGs may be harvested with a blade by hand. When they are larger STSGs are harvested with a dermatome, which provides a more precise width and depth. Once the graft is obtained, it is placed in sterile saline on the meshing plate. Meshing is beneficial since it expands the donor tissue, allows wound exudate to drain preventing seroma and hematoma formation, and has been found to increase graft survival. Increased wound contraction and decreased cosmesis, however, are associated with meshing. After harvesting is complete, STSGs are placed over the defect and secured similarly to FTSG. For larger defects, surgical staples are often used to secure the graft.

STSGs size can vary. They are categorized as thin (0.013–0.033 cm), medium (0.033–0.046 cm), or thick (0.046–0.076 cm). The amount of dermis present determines the chance of survival of the graft on a poor vascular bed. Generally, the thinner the graft, the higher the “take rate” but the poorer cosmesis. The donor site re-epithelializes rapidly and relatively painlessly with the use of bio-occlusive dressings.

The main advantage of an STSG is that it survives even in locations with poor vascularization, such as over bone or cartilage. It also allows for early detection of tumor recurrence. Cosmetically, the final outcome of this graft is suboptimal with absent appendages, poor color match, and frequent wound contracture under the graft. For this reason, second intention healing and skin substitutes are often employed for defects once covered with STSGs. These methods avoid the wound care and generally unsightly appearance of the STSG harvest site.

Punch and Pinch Grafts

A subset of STSGs includes punch and pinch grafts. These are useful for accelerating the healing phase of a chronic ulcer. Several grafts are harvesting from a donor site and placed in the wound bed. Instruments used are a 4-mm punch for punch grafts or a scalpel (Weck knife) for pinch grafts. The rate of survival of these grafts is good if the site has meticulous postoperative care; however, the cosmetic outcome is suboptimal due to the variable thickness throughout the wound.

Skin Substitutes

Tissue which has been cultured or processed prior to grafting is known as a skin substitute. There are a few different types: autologous epidermal, allogenic dermal, and xenogenic and allogenic bilayered.

Epidermal skin substitutes are derived by culturing the patient's own skin. These are good for covering a wound and stimulating the healing process.

Dermal skin substitutes are allografts developed from cadaver skin. They often consist of neonatal foreskin-harvested allogenic fibroblasts with an overlying silicone epidermis. These are helpful in replacing the dermis in a defect and can be covered by a STSG. There are several different types available commercially including Alloderm, Integra, Trancyte, and Dermagraft.

Bilayered skin substitutes are made from allogenic neonatal foreskin-derived fibroblasts and keratinocytes and bovine collagen. They are useful for protection of large wounds where donor tissue is insufficient to cover. Commercially available products include Apligraf and Orcel.

Meticulous postoperative wound care is necessary to ensure an optimal outcome. Attention must be made to limit postoperative bleeding of all surgical wounds, particularly flaps and grafts, as hemorrhage or hematoma formation may jeopardize tissue survival and increase the risk of infection. Meticulous intraoperative hemostasis and good postoperative compression dressings are very important in minimizing postoperative bleeding. A pressure dressing should be applied and left intact for 24–48 hours. This dressing includes a layer of ointment applied directly to the wound, a nonstick bandage such as Telfa, gauze for pressure, and surgical tape. Finally, elastic dressing materials, such as Flexinet or Coban, may be helpful for wounds on the scalp or extremities.

For the aforementioned procedures, it is important that the wound be kept clean, moist, and covered until suture removal. This will eliminate desiccation and promote re-epithelialization,50 reduce bacterial contamination, and aid in hemostasis. Verbal and written instructions regarding home wound care should be reviewed and then provided in writing to the patient. After removal of the pressure dressing, the wound should be cleaned once or twice daily with attention to gently removing any crust and debris that may form. This is followed by a layer of ointment. A bland, nonmedicated ointment, such as petrolatum or Aquaphor is preferred over topical antibiotics such as Neomycin. The use of these topical antibiotics following cutaneous surgery increases the risk of contact dermatitis51 without imparting a significant reduction in infection rates.52 The patient should be advised to limit activity for 1 to 2 weeks after surgery, particularly, movement that stretches or adds tension to the wound area and may result in wound dehiscence or a widened scar.

The signs and symptoms of hemorrhage and wound infection should be reviewed as early intervention can reduce serious complications. To better prepare patients, it is helpful to educate him or her about what to expect during normal wound healing. The patient should be provided with the physician's contact information and should be encouraged to call with any questions or concerns.

Early complications of all forms of cutaneous surgery and closure are bleeding, pain, and infection. Bleeding typically occurs in the first 24 hours after surgery and must be addressed promptly. Low flow ooze may be treated by compression. Patients should be instructed to apply direct pressure for at least 20 minutes without peeking to see if it is working. Frank arterial hemorrhage or large hematoma formation will require partial or complete suture removal, evacuation of clot, and exploration of the wound to allow visualization and closure of the bleeding vessel. Patients should be instructed to call if they see an enlarging mass below or around the wound.

Pain is usually manageable with non-narcotic pain relievers such as acetaminophen. Acetaminophen may be administered at the time of surgery and continued for 24 hours to reduce the risk of postoperative discomfort. It is generally easier to get ahead of pain than it is to catch up to it. Patients should be instructed to avoid non-prescribed nonsteroidal anti-inflammatory medication for up to 48 hours postoperatively to reduce bruising and bleeding from platelet dysfunction. While more severe pain may require the administration of prescription pain medication, it should be investigated to be sure more significant issues such as infection or hematoma are not occurring.

Signs of infection usually will occur within the first week after surgery and include increased pain, erythema, and heat around the wound, purulent and sometimes foul-smelling drainage, and fever. When wound infection is suspected, a culture must be obtained for pathogen identification and antibiotic susceptibility, and treatment with a broad-spectrum antibiotic should be initiated. Common pathogens on skin and mucosal surfaces are Gram-positive cocci, notably staphylococci or, less commonly, streptococci. However, Gram-negative aerobes and anaerobic bacteria contaminate skin in the groin/perineal areas. Gram-negative bacilli may also be cultured from ear and lower leg wounds, particularly in diabetic patients. Methicillin resistant Staphylococcus aureus (MRSA) infections are increasing dramatically in frequency and should be vigilantly watched for.53

An expected consequence of surgery is the formation of a scar. While the goal of reconstructive surgery is to minimize the appearance of the resultant scar, at times they may widen, or even become hypertrophic. With time, hypertrophic scars tend to flatten and soften. Their course may be hastened with the administration of intralesional steroids and laser treatment. In areas under tension and or motion, such as the upper back and arms over the deltoids, scars may spread or become atrophic. While scar spread may become less noticeable with time as the initial dark pink color fades, the width generally does not change significantly. Erythema and telangiectasia often form around scars during the healing phase and may persist for extended periods of time. Highly vascular areas (rosacea) and those under high tension are more likely to develop persistent erythema and telangiectasia. This can be effectively treated with lasers, such as the pulsed dye laser, KTP, or intense pulsed light.

Spitting sutures or suture granulomas from buried sutures may occur. Placing the buried dermal sutures in the appropriate plane will help minimize the occurrence. If the spitting suture becomes visible it may be trimmed out, but it is unadvisable to aggressively go after these as a scar may result.

In the case of a flap repair, additional complications may be encountered. In the early postoperative period, partial or complete flap necrosis may occur. This may be due to inadequate blood supply from the wound bed, which is more commonly encountered in smokers, or when an underlying hematoma is present. Flap design may also lead to vascular compromise and flap necrosis, as when the pedicle is too narrow to support the mass of the flap, when there is too much torque, or when there is too much tension at the flap's leading edge. Areas of partial necrosis will heal secondarily and may lead to a less appealing scar, which can be revised after wound healing is complete. Later in the postoperative period, a trapdoor deformity may occur in which the center of the flap becomes elevated and the suture line becomes depressed. It may resolve spontaneously over a period of 6–12 months. However, if the trapdoor effect or pin-cushioning persists, it may respond to intralesional steroids, flap elevation with flap thinning, and/or dermabrasion. The trapdoor effect may be prevented with wide undermining around the primary defect, proper thinning of the flap, proper size of the flap, and the use of a geometric shape for the flap.

Complications of grafting include graft failure in the early postoperative period and results from inadequate nutrient supply to the tissue. This is often due to poor vascular health of the wound bed as encountered in smokers or diabetics, inadvertent shearing forces or trauma to the graft, hematoma formation, or infection. Later complications typically are attributed to the cosmetic appearance of the graft, usually related to mismatch of thickness, color, or texture. Contraction may be considerable, particularly with thinner grafts, which may result in the distortion of free margins.

If nonabsorbable epidermal sutures are placed, the patient should return for suture removal at the appointed time. If the defect has been left to heal secondarily, the wound should be checked in approximately 4 weeks. The surgical site should then again be evaluated 3 to 4 months postoperatively to ensure wound healing is progressing as expected. Patients who have been treated for malignancy should be counseled regarding proper follow-up for full skin examination to monitor for new or recurrent skin cancers.