Local skin flaps provide a sophisticated approach to closing large skin defects produced by trauma or removal of lesions from the skin. The fusiform (elliptical) excision is the technique most commonly employed for lesion removal, but nearby structures (e.g., nose, ear) can preclude use of this technique. Nearby skin generally better approximates the needed color and texture to close a defect than skin brought in from a distant site (i.e., skin graft). Local skin flaps can provide excellent functional and cosmetic outcomes.
Advancement flaps represent some of the simplest and most commonly used flap techniques. Advancement flaps move adjacent tissue to close a defect without rotation or lateral movement. The skin is stretched unidirectionally (i.e., single advancement flap) or bidirectionally (i.e., bilateral advancement flap) to close the defect. Unidirectional pull on tissue can be useful when a certain type of skin is needed for closure. For instance, after removal of a tumor from the outer portion of the eyebrow, the defect should be replaced with hair-bearing skin of the medial eyebrow to prevent a shortened and cosmetically abnormal-appearing eyebrow.
The blood supply for a single advancement flap comes from the base of the flap. If a long advancement flap is needed to stretch skin for closure, the blood supply may be compromised to the flap tip. When closing a 1-inch diameter defect on the face, the single advancement flap should be no longer than 3 inches. Single advancement flaps on less vascular areas of the body do better if limited to a length-to-width ratio of 2.5 to 1. One way to avoid long single advancement flaps is to pull skin from both directions; the bilateral advancement flap generally has less chance of flap tip necrosis. The long arms for single or bilateral advancement flaps are designed to align with the lines of least skin tension to improve the final cosmetic result.
When removing skin cancer, it is best to ensure clear margins before performance of flap closure. Wide excision around a cancer may provide high rates of cure, but the excessive removal of tissue may limit the cosmetic outcome. Histologic confirmation by Mohs' surgery or frozen sections is essential before closure, when removing cancers at high risk for recurrence (e.g., morpheaform or sclerosing basal cell carcinomas).
Preventing complications is an important aspect of performing flap surgery. Strict sterile technique is necessary to avoid wound infections. Excessive stretching of skin should be avoided because necrosis will ensue. Wide undermining of
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the lateral tissue around a flap aids the closure. Do not pull on the skin edges with forceps because careful handling prevents excessive scarring. Blood accumulations beneath flaps can interfere with oxygen delivery to the tissue, and excellent hemostasis is required. Bleeding vessels should be clamped or suture-ligated before the flap is sutured, and pressure bandaging is advocated following the procedure.
INDICATIONS
Single Advancement Flap
Bilateral Advancement Flap
RELATIVE CONTRAINDICATIONS
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PROCEDURE
The single advancement flap technique is performed after administration of anesthesia (e.g., field block). The lesion is removed with a rim of normal-appearing skin, and the defect is squared (Figure 1A). The flap arms are incised, paralleling the lines of lest skin tension, approximately two times the original defect's diameter (Figure 1B). The flap and surrounding skin are undermined with a horizontally held scalpel blade (Figure 1C).
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(1) The single advancement flap technique. |
Attempt to slide the flap to cover the defect using skin hooks on the flap. If the defect cannot be covered by the flap, the flap can be lengthened. Anchor the flap in place with one or two sutures (Figure 2A). If there is tension on the sutures, vertical mattress sutures can be placed (see Chapter 16). Notice that the skin bunches up (i.e., dog ears) near the base of the flap when the flap is moved. These dog ears are eliminated by excising triangular pieces of skin (i.e., Burrow's triangles) (Figure 2B).
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(2) Using skin hooks, attempt to slide the flap to cover the defect. |
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After removal of redundant tissue, the corners lie flat. Corner sutures can be placed for the four corners, and interrupted suture is used to complete the flap.
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(3) Place corner sutures on the four corners and interrupted sutures along the sides of the flap. |
After removal of a tumor in the lateral eyebrow, hair-bearing skin is used to close the defect (Figure 4A). After removal of a tumor in the temple, hair-bearing skin is brought down from the scalp to close the defect (Figure 4B).
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(4) Applications of the single advancement flap. |
A square defect is created around the tumor, and the flap arms incised to about 1.5 times the diameter of the defect.
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(5) The bilateral advancement flap. |
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The centers of the flaps are joined with anchoring sutures, and corner sutures are used to join the flap corners (Figure 6A). The dog ears formed are smaller with bilateral advancement flaps and sometimes may not require excision. Smaller triangles are excised (Figure 6B), and the completed flap is illustrated (Figure 6C). A pressure bandage can be applied using gauze and elastic tape.
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(6) The centers of the flaps are joined with anchoring sutures, and corner sutures are used to join the flap corners. |
The middle eyebrow (Figure 7A) and the forehead (Figure 7B) can be closed using this technique.
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(7) Applications of the bilateral advancement flap. |
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CODING INFORMATION
These codes encompass excision or repair, or both, by adjacent transfer or rearrangement, including Z-plasty, W-plasty, V-Y plasty, rotation flaps, advancement flaps, and double-pedicle flaps. When applied to laceration repair, the defect must be developed by the surgeon, and these codes should not be used for direct closure of a defect that incidentally results in the configuration of one of the flaps or plasties. If the configurations result incidentally from the laceration shape, closure should be reported using simple repair codes (see Chapter 14). All of the following codes are for adjacent tissue transfer or rearrangement, and they refer to defects in the trunk or the following sites: scalp, arms, or legs (SAL); forehead, cheeks, chin, mouth, neck, axillae, genitalia, hands, or feet (FCCMNAGHF); and eyelids, nose, ears, or lips (ENEL).
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INSTRUMENT AND MATERIALS ORDERING
Surgery tray instruments are listed in Appendix A. Consider adding two skin hooks to gently handle the skin flaps. Have at least three fine (mosquito) hemostats to assist with hemostasis while developing large skin flaps. Suggested suture removal times are listed in Appendix C, and a suggested anesthesia tray that can be used for this procedure is listed in Appendix G. All instruments can be ordered through local surgical supply houses.
BIBLIOGRAPHY
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Grabb WC. Classification of skin flaps. In: Grabb WC, Myers MB, eds. Skin flaps. Boston: Little, Brown, 1975:145–154.
Grigg R. Forehead and temple reconstruction. Otolaryngol Clin North Am 2001;34:583–600.
Harahap M. The modified bilateral advancement flap. Dermatol Surg 2001;27:463–466.
Shim EK, Greenway HT. Surgical pearl: repair of helical rim defects with the bipedicle advancement flap. J Am Acad Dermatol2000;43:1109–1111.
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Stegman SJ, Tromovitch TA, Glogau RG. Basics of dermatologic surgery. Chicago: Year Book Medical Publishing, 1982:82–84.
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Whitaker DC. Random-pattern flaps. In: Wheeland RG, ed. Cutaneous surgery. Philadelphia: WB Saunders, 1994:329–352.
Zuber TJ. Advanced soft-tissue surgery. The AAFP illustrated manuals and videotapes of soft-tissue surgery techniques. Kansas City: American Academy of Family Physicians, 1999: 62–72.