Pedicle/Interpolation Flaps Treatment & Management
- Author: Michael L Ramsey, MD; Chief Editor: Dirk M Elston, MD more...
Forehead flap, or paramedian forehead flap
The postsurgical nasal defect is examined first to determine if further excision should be performed to remove remnants of any significantly involved anatomic subunits, shown in the images below. These subunits include the nasal tip, columella, sidewalls, alae, and soft triangles. If more than 50% of the subunit is missing, removing its remaining portion prior to the repair often enables a better aesthetic result; however, if the defect occurs on the nasal dorsum, leaving this skin intact is important because the thick skin of the forehead is not a good match for the thin skin of the nasal dorsum. Likewise, the alar rim should be left intact. A template of the final defect is made by using foil or another suitable material. The template should be fashioned prior to removing an entire subunit because the widening of the defect causes the template to be larger than necessary.
The location and course of the supratrochlear artery is identified by using Doppler ultrasonography, as shown in the images below. Precise location of the artery allows the use of a narrower pedicle with greater mobility of the flap; however, some surgeons choose to rely on previously described landmarks to mark the artery. The artery passes just medial to the eyebrow and then pierces the frontalis muscle, passing over the remainder of the forehead in a subcutaneous plane 1.5-2 cm from the midline.
A strip of gauze is placed, with its inferior (caudal) end at the planned base of the pedicle, which can be on either side of the forehead. The tube is twisted down and draped over the nasal defect as shown in the first image below. The length of the gauze touching the most distal aspect of the defect is marked, and the tube is returned to its original vertical position over the forehead. The distal point of the planned pedicle is marked on the forehead and represents the portion to be transposed to the most inferior aspect of the defect, as shown in the second image below. If vertical placement will result in harvesting hair-bearing scalp skin, a cross-paramedian forehead flap may be used. In this technique, the forehead flap is based contralateral to the nasal defect, with the proximal 75% of the flap running vertically and then the distal 25% crosses the forehead obliquely to achieve a greater length of optimal skin.
The template is marked on the forehead, and a 1- to 1.5-cm-wide pedicle is planned to course from the template to the origin of the supratrochlear artery at the medial aspect of the eyebrow. The skin is locally anesthetized, the incision is made, and the flap is elevated in a plane under the frontalis muscle. See the images below.
The distal third of the flap is thinned almost to the dermis and trimmed to precisely fit the defect. Meticulous hemostasis is obtained, and the sides and distal end of the flap are sutured into the defect in a layered manner, as shown below. The pedicle covering the superior portion of the defect is thinned at the time of division.
The forehead donor defect is closed primarily, and if the wider superior portion of the defect cannot be closed completely, it may be allowed to heal secondarily, usually with good cosmetic results. In some instances, a full-thickness skin graft may be applied, but this skin graft is usually not necessary or preferred.
Petroleum gauze is wrapped around the pedicle trunk, and nonadherent dressing material is placed over any exposed tissue edges or suture lines. An absorbent gauze dressing is loosely applied around the area for 24-48 hours to collect any drainage, which commonly occurs early in the postoperative period. Monsel ferric subsulfate solution can be applied to the exposed edges of the pedicle to reduce the postoperative oozing, without a risk of vascular compromise. Alternately, oxidized cellulose gauze (Surgicel absorbable hemostat) may be applied to the pedicle to decrease postoperative bleeding. The patient should return in 1 week for a dressing change. An intermediate stage to thin the distal pedicle is sometimes necessary at week 2, particularly if the patient uses tobacco products. By the second week, the flap is usually ready for division and inset.
The flap is incised close to the base, and it can be set back into the eyebrow area in a V shape, as shown below; however, this may result in a protuberant scar. Usually, excising the entire base in a fusiform fashion and closing the resulting defect primarily is possible and preferable (see the second image below). The remainder of the pedicle is incised 5-10 mm proximal to the edge of the defect. Granulation tissue in the recipient site is debrided, and the wound edge is incised perpendicular to the skin surface to allow precise placement of the flap. The flap is trimmed and thinned so that it fits the wound exactly and with only slight tension.
The flap may be secured with simple interrupted or running sutures and without deep sutures. Sutures may be removed in 4-7 days. Future scar revision is usually performed no sooner than 6 weeks after surgery. Revision may consist of surgical thinning and planing, dermabrasion, or a combination of these procedures.
A study by Blázquez-Sánchez et al supported the efficacy of the paramedian forehead flap in reconstruction of the external nose, with the cosmetic results of the surgery reported as acceptable or excellent in 90.2% of the study’s 41 patients. Early and late postoperative complications occurred in 14.6% and 31.7% of patients, respectively, including trapdoor effect and hair transposition.
Cheek interpolation flap
The medial cheek skin is an excellent color and texture match for defects on the caudal third of the nose. Based superiorly, the cheek interpolation flap can be based on a cutaneous pedicle or a subcutaneous pedicle. The subcutaneous pedicle has greater mobility and vascular supply than the cutaneous pedicle. For small-to-medium alar defects, an inferiorly based flap can also be used to avoid transfer of facial hair.
Foil or nonabsorbent surgical dressing is used to make a template of the surgical defect to be repaired. Gauze is rolled into a tube, and one end is held in place in the area of the planned flap base, in and lateral to the melolabial crease. While the proximal end is held in place, the remainder of the gauze tube is turned to overlap the wound without tension.
The most distal portion covering the wound is marked, and the gauze is swung back into the melolabial crease. A mark is made on the skin, corresponding to the mark on the gauze and signifying the distal aspect of the flap. The template is placed on the cheek with its superior edge placed medially and touching the melolabial crease. The portion of the template representing the lateral wound edge furthest from the flap is placed most inferiorly (or distally) on the cheek, touching the mark previously placed on the cheek, as shown below. A tapered incision is planned distal to this tissue and parallel to the melolabial crease to allow closure without a dog-ear defect. This tissue is included in the initial flap elevation and is not removed until the flap is finally trimmed and fit in the defect.
An incision is made through the full thickness of the skin, and the flap is elevated in a subcutaneous plane and progressively deeper toward the base of the pedicle to ensure an adequate vascular supply. Little undermining is necessary to close the donor defect on the cheek in a standard layered fashion.
The flap is draped over the surgical defect. After ensuring that the designed flap covers the defect without tension, the surgeon can excise and discard the distal triangle of excess tissue. The flap can be trimmed and thinned to precisely fit into the defect, shown below. The nasal defect can be deepened if additional thinning of the flap would require the removal of all the subcutaneous fat and its vessels. The skin surrounding the defect is undermined to minimize potential pincushioning, and after hemostasis is obtained, the flap is sutured into place in a layered fashion.
Petroleum gauze is loosely wrapped around the flap pedicle, and nonadherent dressing material is applied over the sutured areas. Fluffed gauze or similar material is placed over these dressings to absorb the expected serosanguineous drainage from the pedicle and exposed base. The sutures can be removed in 3-7 days, but often, the most convenient time for suture removal is when the patient returns for the first weekly dressing change.
The flap is usually divided and inset after 3 weeks, although some surgeons perform these steps as early as 2 weeks. To ensure that engraftment has occurred, the color of the flap can be assessed after constriction at the base of the pedicle with a hemostat. If the color does not change, engraftment has occurred.
The base of the pedicle is severed, and it can be inset back into the cheek in a V shape. However, excision of the base in a fusiform manner and primary closure of the wound are usually preferred (see the first and second images below). The remaining portion of the pedicle is removed, leaving some excess flap tissue near the nasal defect. The flap is thinned, with some subcutaneous fat carefully left intact, and the wound base is cleared of granulation tissue. The rounded exposed edge of the wound is incised perpendicular to the wound base for precise apposition with the flap. The flap is further trimmed to perfectly fit the defect with slight tension, and interrupted cutaneous sutures are placed (see the third image below).
The flap can be revised by surgical thinning or dermabrasion approximately 6 weeks after flap placement, if indicated.
The postauricular flap involves the use of skin from the posterior ear, retroauricular sulcus, and mastoid area to repair defects of the middle third of the auricular helix and adjacent skin. This random flap has a broad vascular pedicle, and donor scars remain well hidden behind the ear.
Reconstruction begins by making a template of the helical defect with foil, Telfa, neurosurgical cottonoid, or other suitable material. The template is placed behind the ear with its leading (anterior) edge over the loose portion of the posterior ear; the template is outlined with a surgical marker. Lines are drawn toward the hairline, gradually tapering outward as they approach the hairline (see images below). Burow triangles can be drawn lateral to the base of the pedicle, but the actual excision of the triangles is usually not necessary.
Incisions are made through the skin along the planned lines, and the flap is elevated. The surrounding tissue is undermined for a short distance to allow greater tissue mobility, decrease pincushioning, and allow better placement of subcutaneous sutures. The flap is draped over the defect to ensure that coverage of the anterior portion of the defect does not cause excessive tension, and the Burow triangles can be excised if necessary.
Electrocoagulation is used to obtain meticulous hemostasis before the sutures are placed. A few interrupted, subcutaneous, absorbable sutures can be used to securely anchor the flap into place, and superficial sutures are placed for fine approximation (see the images below). A few basting sutures can be placed through the flap into the cartilage to recreate the helical sulcus, if desired.
The exposed flap pedicle is loosely wrapped with petroleum or iodoform gauze, and an absorbent dressing is placed over the wound and allowed to remain in place for 1 week. Moderately heavy serosanguineous drainage is expected in the first few days after surgery, and the patient should be informed of this likelihood. In the author's practice, the entire dressing is changed weekly until the third postoperative week, when the flap is divided and inset, as shown below.
Incision of the flap is performed at a point that allows adequate tissue to cover the posterior portion of the defect. The granulating wound is cleaned and debrided to provide a suitable base for placement of the remaining flap, which has been thinned and trimmed to provide precise fit and contour. The flap can be sutured to the posterior edge of the ear defect with interrupted sutures. Absorbable gut or synthetic suture can be used so that further manipulation of the ear to remove the sutures is not necessary. The remaining portion of the pedicle can be advanced to help repair the donor defect, and placement of a full-thickness skin graft may be considered; however, in most instances, donor defects heal secondarily with excellent cosmetic results.
A study by Sleçuk et al indicated that full-thickness defects of the upper and middle third of the ear, including the helix, can be successfully reconstructed using a postauricular chondrocutaneous flap pedicled with the superior auricular artery. The study, which involved eight patients, reported a good cosmetic result with no effect on ear height or projection and no serious postoperative complications.
Preoperative evaluation and planning are essential components of dermatologic surgical care. The patient should be informed about planned procedures, and the patient should be involved in choosing his or her care. The surgery and any subsequent surgical procedures should be thoroughly discussed with the patient. Diagrams and photographs can make this task easier for both the physician and the patient.
A pertinent medical history should be taken, as with any more complex skin surgery. Patients should be questioned regarding any prior reactions to drugs or commonly used agents, including anesthetics, sedatives, analgesics, antibiotics, iodine, and latex. In addition, a history of hypertrophic scars or keloids should be sought.
The history should also include the patient's use of medications that may influence the surgical risk. Anticoagulant agents and aspirin increase the risk of intraoperative or postoperative bleeding, and these agents should be stopped if the prescribing physician approves. Warfarin should be stopped approximately 5 days prior to surgery and can be resumed 24-48 hours after the operation. Extra attention should be given to meticulous hemostasis and the careful application of pressure dressings.
Aspirin should be discontinued at least 1 week, or preferably 2 weeks, prior to surgery; aspirin can be resumed after 1-2 days. Although most physicians usually allow patients to discontinue their use of aspirin, circumstances exist in which this approach may be imprudent. Flap surgery can be performed in patients taking aspirin. The surgeon should be aware that intraoperative bleeding is likely to be significantly increased; however, the bleeding is controllable. Physician-prescribed anticoagulant therapy should be stopped only with the approval of the prescribing physician.
The degree of risk with the use of epinephrine in patients who are also taking nonselective beta-blockers (eg, propranolol) is controversial. The literature describes a small number of patients who received intradermal epinephrine while taking propanolol; these patients had malignant hypertension and cardiovascular collapse. The mechanism is believed to result from unopposed alpha-receptor stimulation by epinephrine after complete beta blockade. Risk of this effect is believed to be low, but physicians should keep this potential problem in mind.
A history of congenital or valvular heart disease is an important consideration in deciding whether to treat a patient with antibiotics to prevent bacterial endocarditis. The 2007 guidelines from the American Heart Association recommend antibiotic prophylaxis for procedures on infected skin, skin structures, or musculoskeletal tissue only for patients with prosthetic cardiac valves, previous infective endocarditis, congenital heart disease and cardiac transplantation recipients who develop cardiac valvulopathy. Prophylaxis in these high-risk patients is also recommended when breaching the oral mucosa. Contacting the patient's physician regarding his or her individual needs is prudent. This policy is appropriate in patients with prosthetic joints, who have an increased risk of prosthetic joint infection, especially those with prostheses placed in the past 2 years.
Cigarette smoking is the bane of skin flap and skin graft survival, and an honest history from the patient is important in planning the procedure and in tempering the patient's expectations. Less thinning of a flap might be considered in a patient who smokes, and the patient who smokes must understand that the risk of flap necrosis is significantly greater than that of an individual who does not smoke.
Interpolation flaps can be performed in a variety of settings. Some surgeons prefer to perform these procedures, especially forehead flap procedures, with the patient under general anesthesia. However, all of the flap procedures can be successfully performed in an outpatient setting, either with conscious sedation in an ambulatory care center or with local anesthesia in an outpatient clinic.
Flap procedures with local anesthesia alone are best performed by surgeons who have enough experience to efficiently complete the procedure and minimize the patient's time on the operating table. Patients tolerate lengthier procedures better with sedation or general anesthesia.
Surface irregularities or areas with excessive skin thickness may be addressed in the weeks after surgery. Depressed incision lines can be revised with dermabrasion or narrow excision of the depressed incision line and reapproximation. Areas of noticeable thickening can be improved by incising the skin, lifting the affected area, and sharply trimming the excess deep dermal or subcutaneous tissue, followed by precise repositioning and suturing of the skin edges. Incisions can be made along the original incision lines or, alternately, along the lines of the anatomic subunit junctions. If combined with undermining of the surrounding skin, the use of the junction lines can result in an excellent cosmetic outcome. Erythematous or hypertrophic scars can be treated with pulsed dye laser therapy.
Sterile, nonadherent, absorbent dressings are applied postoperatively, and patients are instructed to leave the bandages in place until their next visit. The author usually follows up with the patients on a weekly basis, cleaning the area and replacing the dressing on each visit.
Patients are provided with rolls of paper tape to reinforce the dressings if they start to loosen. Usually, forehead flaps are divided and inset after approximately 2 weeks, and the same is completed for cheek interpolation flaps and postauricular flaps after 2-3 weeks. After flap division and inset, the patient is instructed to remove the dressings daily and gently clean the area with soap and water. Sterile ointment (eg, mupirocin, petrolatum) and a nonadherent dressing are applied to the wound and secured with paper tape. The author prefers to avoid ointments containing neomycin or bacitracin due to the significant incidence of allergic reactions with their use.
Sutures are removed on the next visit in 5-7 days. If the surgical site appears to be healing well, a follow-up visit is scheduled 4-6 weeks later, when the repair is evaluated for possible revision. If dermabrasion, thinning, or other procedures are indicated, they are scheduled for the near future. Otherwise, the patient is scheduled to return in 4-6 months for rechecking, or the patient can return to the referring physician for follow-up care.
The author often prescribes antibiotics to patients who are undergoing interpolation flap surgery. These procedures tend to be lengthy, and in the author's clinic, the flap procedures are performed after one or more stages of Mohs surgery. In addition, the operations are performed on the nose and ear, where the risk of postoperative infection is greater than in most other areas of the skin. In patients with nasal defects, the author usually prescribes oral cephalexin 1-2 g before surgery or oral cephalexin 500 mg 3-4 times per day for several days after surgery. In patients who are allergic to penicillin or cephalosporin, clindamycin may be substituted. Oral ciprofloxacin or cephalexin may be used in patients with defects of the ear.
Potential complications are those associated with virtually any skin surgery.
Some degree of discomfort, pain, or tenderness is common after any skin surgery, but increasing severity may indicate infection, hematoma, or seroma. Meticulous intraoperative hemostasis and the use of pressure dressings can minimize risk of hematoma and seroma. In most instances, the pressure dressing does not need to be removed in 24 hours. With proper application, the dressing can often be left in place for as long as 1 week.
Patients should be asked about any history of bleeding disorders or the use of anticoagulants such as aspirin or warfarin. Bleeding disorders should be discussed with the patient's physician or hematologist prior to surgery. Likewise, the prescribing physician should be consulted before any anticoagulant medications are discontinued. The risk of postoperative bleeding can also be minimized with careful electrocoagulation and the use of sturdy pressure dressings.
The flap should be sized to allow its placement without undue tension. Sutures should be tightened just enough to approximate the skin edges and not cause visible blanching of the tissue. In addition, the flap should not be overly thinned, especially near the proximal base of the pedicle.
Although not ideal, paramedian forehead flaps and cheek interpolation flaps may contain scalp hair or cheek hair, respectively. Laser hair removal, electrolysis, or depilatory creams may be used to remove this unwanted hair. Although the author has not used this technique, some surgeons cauterize each hair follicle at the time of pedicle transfer or division.
Regarding hypertrophic scars and keloids, the likelihood of individual scarring can be estimated by examining the rest of the skin for areas of previous trauma, such as pierced ear holes. In patients with dark skin and in individuals with areas of previous excessive scarring, the likelihood of hypertrophic scars and keloids is greater than in others.
To prevent infection, the skin should be thoroughly prepared by using antibacterial agents before surgery, and sterile technique should be used. Although antibiotic therapy is not routinely necessary in most skin flap operations, it should at least be considered before and after interpolation flap procedures. The likelihood of infection increases with the length of surgery, and these flaps are somewhat more complex and time-consuming than simple repairs. In addition, the creation of interpolation flaps is often preceded by more protracted procedures such as Mohs surgery or staged excisions.
The ear and nose are more prone to infection than most other areas of the skin. The effects of infection can be severe and include flap loss, bacterial chondritis, and perichondritis. Pseudomonas organisms commonly colonize the ear, as do various Staphylococcus and Streptococcus species, and Staphylococcus aureus colonizes the nose in a significant percentage of individuals.
Partial or total flap necrosis is a risk with any cutaneous flap surgery. Causes include wound tension, bacterial contamination, bleeding, improper surgical technique, and nicotine use. Delay techniques may be used in those believed to be at elevated risk of necrosis. Fortunately, risk of necrosis remains very low when performing interpolation flaps.
Outcome and Prognosis
Outcomes, both functional and cosmetic, are generally good to excellent with these flaps. Cosmetic revision may be performed in selected patients, but often, none is required.
Future and Controversies
Medical and legal pitfalls
Preparation for an interpolation flap requires that the patient be fully informed about the procedure, the somewhat lengthy interval between its start and completion, and the potential risks. Photographs and diagrams of each step of the process may be obtained from textbooks or previous patients; these can be helpful in explaining the procedure.
Risks, such as infection, bleeding, flap necrosis, and scarring, should be discussed before the patient signs the consent form.
The possibility of future revision procedures, such as thinning of the flap or dermabrasion, should be discussed prior to flap surgery. If revision is needed later, the patient will understand that this is a common touch-up procedure and not a failure of the surgeon's technique or the patient's wound care.
Photographic documentation of the postoperative defective and repair should be kept with the patient's medical record. A careful surgeon should include the patient in decision making, keep the patient informed, and remain accessible to the patient; these measures greatly decrease the medical and legal risks.
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