Skin Flaps(Eng)

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Skin Flaps, Design

IReconstruction of facial defects is a challenging endeavor. The results are observed andjudged daily by everyone who sees the patient. Poor results can be devastating, both

functionally and aesthetically. Successful reconstruction requires a thorough

understanding of skin anatomy and physiology, careful analysis of the defect, thoughtfulconsideration of multiple options for donor tissue, and skillful and meticulous soft tissue

handling techniques.

Cutaneous defects in the head and neck can be reconstructed with grafts or flaps.

Vascularized grafts are transferred with a named artery and vein to the given angiosome.Nonvascularized grafts depend on imbibition, inosculation, and neovascularization from

surrounding tissue for survival. The most commonly used nonvascularized grafts for

facial reconstruction are skin grafts (ie, split thickness, full thickness, dermal) orcomposite grafts (ie, full-thickness skin with perichondrium, with or without cartilage). A

complete description of grafts is beyond the scope of this article.

Local and regional skin flaps provide the foundation for reconstructive surgery of the

face. When planned and executed properly, skin flaps enable rapid reconstruction whenthe color and texture matches well and when it has a reliable and adequate blood supply.

The subunit principle is well recognized as the starting point in the analysis of facial

defects (see Image 1). With the subunit principle, skin color, skin texture, skin thickness,

hair growth, and surrounding contours at subunit junctions are considered; these featurescan provide optimal camouflage for incisions and transition. The subunit principle is only

a starting point, but it is the foundation for adequate reconstruction of facial defects.

No single flap is optimal for every defect. Each defect must be individually analyzed fordepth, distortion of surrounding subunits, and normal tissue available for reconstruction.On the basis of this analysis, the appropriate flap or combination of flaps is chosen.

Facial plastic and reconstructive surgeons must be aware of the entire armamentarium of

local flaps so that they can more easily visualize the various combinations of flaps andpredict their success. Mastery of the use of local flaps requires the ability to predict long-

term results and anticipate inevitable scarring and contracture.

Lokal Flap : Anatomy dan Fisiology

The microcirculatory system of the skin is composed of the deep vascular plexus at the

junction of the subcutaneous fat and reticular dermis and the superficial plexus in thesuperficial dermal papillae in the papillary dermis. The superficial plexus of capillaries

supplies the more metabolically active epidermis by means of diffusion. Parallel to the

skin surface, the 2 dermal and subdermal plexuses are supplied through numerouscollaterals. These, in turn, are supplied by deeper septocutaneous and musculocutaneous

arteries, which are perpendicular to the skin surface. This network provides a redundant

rich source of blood supply to the skin.
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Both the sensory and the sympathetic nervous systems innervate the skin. The sensory

nerves are distributed in a segmental fashion. The sympathetic nerves control the

arteriolar preshunt sphincters and are mediated by the release of norepinephrine. Incisionsat the borders of the flap interrupt the parallel superficial and deep cutaneous plexuses,

inevitably resulting in decreased perfusion pressure to the skin. Sympathetic nerves are

severed; as a result, norepinephrine is released from the nerve terminal andcatecholamine reuptake is eliminated. This surgical sympathectomy further decreases the

blood flow to the flap.

Many physiologic factors affect flap survival, but the common denominator involves 2

basic factors: (1) blood supply to the flap through its base and (2) formation of newvascular channels between the flap and the recipient bed. The surviving length of the

random portion of a skin flap depends primarily on the perfusion pressure of the

supplying blood vessels. In the past, random skin flaps were thought to have a strictnumeric length-to-width ratio: the wider the base, the longer the flap. However, if the

wider base simply involves additional vessels with the same perfusion pressure, the

length of surviving flap is unaltered.

Neovascularization of the flap usually occurs 3-7 days after transfer. This vascularizationoccurs through 2 processes, namely, direct ingrowth and inosculation. With an

angiogenic stimulus, the vessels at the edge of the flap become dilated, and the basement

membrane thins considerably. Endothelial cells then migrate from the adjacent vascularlumen toward the vascular stimulus. Behind the advancing front of migrating endothelial

cells, endothelial cell replication leads to the formation of a capillary sprout, which

elongates toward the angiogenic source. Nearby capillary sprouts form anastomoses with

each other, forming capillary loops and then new blood vessels. Inosculation refers todirect ingrowth of surrounding recipient capillaries into preexisting vessels in the flap.

Certain clinical scenarios worth noting call for reconstruction with flaps that have been

delayed. Although a detailed description is beyond the scope of this article, the delayphenomenon alters flap vasculature and results in a reorganization of the vessels along

the long axis of the flap. Choke vessels become dilated, and the zone of necrosis is

shifted toward the tip of the flap. Vascular endothelial growth factor seems to play a role

in this phenomenon.

Klasifikasi

Flaps may be classified by using different features, as follows:

Arrangement of the blood supply (ie, random versus axial)

Configuration (ie, bilobed, rhombic, pinwheel)

Location (ie, local, regional, distant)

Method of transfer


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Surgeons must be familiar with the vascular supply of a local flap, either random

(supplied by the dermal and subdermal vascular plexuses) or axial (supplied by a named

artery and vein). Most axial flaps have some random blood supply at their distal ends.

Efforts for simplifying the classification of local flaps according to sliding or lifting

tissue movements are applauded; however, for teaching purposes, the authors prefer toclassify local flaps according to classic transfer methods. In reality, as discussed in

Reconstruction of Specific Facial Subunits, many local flaps actually are combinations ofthese classifications.

Flaps include advancement, pivotal, transpositional, rhombic, and bilobed flaps.

Advancement flaps

Advancement flaps have a linear or rectangular configuration. Advancement flaps aresubclassified as simple, single pedicle, bipedicle, and V-Y flaps.

Single-pedicle advancement flaps

These flaps are created by making 2 parallel incisions extending from the defect, ideally

along relaxed skin tension lines (RSTLs). The flap and its pedicle are then advanced intothe defect. Undermining around the defect minimizes tension and promotes better

scarring along the incisions. The advancement creates a length discrepancy (ie, the length

of advancement), which creates standing cone deformities. Three following options for

removing standing cones exist:

If the flap is long enough, the principle of halves can be used to evenly distribute

the relative excess in length and to use sutures to eliminate a standing cone. Burow triangles may be used to remove standing cone deformities, which may be

excised anywhere along the longer side. Deformities are usually excised at a sitethat promotes good scar camouflage.

Bilateral z-plasties may be performed at the base of the flap, provided that the

pedicle is wide enough to support the length of the flap.

An island advancement flap is a special type of single-pedicle advancement flap. Theskin island is designed to match the defect and is incised through only the dermis to

preserve the underlying subcutaneous tissue. As the skin island is advanced into the

adjacent defect, the subcutaneous pedicle is preserved, and the donor defect is closed in a

V-Y fashion.

Bipedicle advancement flaps

These flaps are designed to allow advancement into the adjacent defect in a vector that is

perpendicular to the flap axis. These flaps are generally used to close a defect in an areaof high visibility by moving the defect into an area of low visibility (eg, from the
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forehead to the scalp). Bipedicle advancement flaps are used infrequently because

simpler more aesthetically favorable options for reconstruction usually exist.

The V-Y advancement flap

This flap is unique among advancement flaps in that it is pushed rather than stretched intothe defect. The donor flap, which usually is triangular, is advanced, and the resulting

donor defect is closed in a straight line. This approach results in a suture line with a Y

configuration, although the ultimate result more closely resembles a lollipop.

Pivotal flaps

Pivotal flaps are moved about a pivotal point from the donor site to the defect. Pivotal

flaps include rotation, transposition, and interpolation flaps.

Rotation flaps

These flaps are designed so that the leading edge of the flap also is a border of the defect.Rotation flaps are usually based inferiorly to promote lymphatic drainage. The border

perpendicular to the axis of rotation usually is curvilinear and designed to contact at the

junction of 2 facial subunits for optimal scar camouflage. The border of the flap must belonger than the border of the defect perpendicular to the axis of rotation of the flap by a

ratio of 4:1 (see Images 2-3). A standing cone deformity is almost inevitable when a

rotation flap is used. This deformity should be addressed in a second stage rather than by

narrowing the base of the flap at this stage.

Transposition flaps

A transposition flap is created so that the donor site is remote from the defect. The flap is

moved about the pedicle and transposed over the intervening tissue into the defect.

Transposition flaps are versatile and offer a choice of flaps of similar color and texturefrom various donor sites, which make them the most commonly used flaps for defects in

the head and neck. The classic rule requires a 3:1 length-to-width ratio for random

transposition flaps; however, in the head and neck, the vascularity is rich enough toenable development of flaps in which the length-to-width ratio exceeds 3:1.

Z-plasty (see Image 4) is a technique of creating 2 transposition flaps with identical

angles to the direction of the defect and transposing them in opposite directions. This

technique has many applications in facial reconstruction. Z-plasty is used to lengthen acontracted scar, change the direction of the scar into a more favorable orientation (ie,

along RSTLs), and/or interrupt scar linearity (see Images 5-7).

Interpolation flaps

The interpolation flap is similar to the transposition flap in that the flap is moved about

the pedicle and transposed across intervening tissue; however, with an interpolation flap,
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the pedicle rests over the intervening tissue. The pedicle must be divided and inset at a

second stage after neovascularization occurs. The most common interpolation flap is the

forehead flap.

Rhombic flaps

Limberg originally described the rhombic flap (seeImages 8-10), which is a specially

designed transposition flap used to correct a rhombus-shaped surgical defect. The classic

rhombus defect has sides of equal length, with 2 opposing 60 angles and 2 opposing120 angles. This configuration creates a short diagonal (which bisects the 120 angles)

of the same length as that of the sides of the rhombus.

Every rhombic defect has 4 potential closure flaps. To determine which flap is optimal toclose a particular defect, the lines of maximum extensibility (LMEs) surrounding the

defect first must be determined. The LMEs are oriented perpendicular to the RSTLs. Two

parallel lines are drawn along the LMEs and adjacent to the defect. Two additional

parallel lines are drawn to create the 60 and 120 angles. The short diagonal is thenextended by the length of the sides of the rhombus. A cut is made from each of the 2

extensions of the short diagonal back to the lines along the LMEs and parallel to the sides

of the rhombus. Thus, 2 flaps are created, and the surgeon must determine which bestmatches the skin and camouflages the scar.

The Dufourmentel flap is a variation of the classic Limberg rhombic flap. This flap is

designed to close rhombic defects with any 2 opposite angles rather than the 60 and 120

angles.

Bilobed flaps

The bilobed flap (see Images 11-15) is another variation of the transposition flap. The

flap actually is 2 transposition flaps that share a common pedicle. The first transposition

flap is used to reconstruct the defect, and the second flap is used to repair the donor sitefor the flap. The angle between each flap is 90, with a total transposition of 180, which

frequently causes standing cone deformities and increases the likelihood of

pincushioning. Zitelli introduced a modification to reduce the standing cone deformitiesand pincushioning. This modification reduces the angles between the flaps to 45,

limiting the total transposition to approximately 90. The key to the success of the

bilobed flap is the distribution of tension over both limbs of the flap.

In designing the flap, one must consider the tissue elasticity, potential deformation ofsurrounding structures, and RSTLs. Not infrequently, dermabrasion is planned as a

second stage to minimize scarring associated with this flap. For a bilobed flap, the upper

limit in size of the defect is approximately 1.5 cm. The bilobed flap works best withdefects involving the lower third of the nose, namely the ala and the tip.
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The major criticisms of the bilobed flap are that the scars created in designing the flap are

difficult to camouflage in the RSTLs and that a simpler flap can usually be used with a

better aesthetic outcome.

Rekonstruksi spesifik dari sub unit wajah

Choosing the optimal reconstructive method for a specific defect is a complex process.

Generally, reconstruction should be accomplished with the simplest effective method

possible. Rather than discuss the entire reconstructive ladder for each defect, certain flapsare described, with pertinent pearls and pitfalls.

Two important pearls can be applied to all local flaps:

Before deciding on the flap, draw the surrounding subunits, including and

adjacent to the defect. Close the donor site for the flap before the flap is sutured in position. This

maneuver decreases tension on the flap and makes closure easier.

Nose

Because of its prominent position on the face, the nose is commonly injured in trauma

and burns. When properly executed, adherence to the principle of separate 3-layeredreconstruction of full-thickness defects generally preserves function and minimizes the

effect of contraction. The effect of scar contracture is most prominent at the nasal alar

subunit and can cause major deformity. The nasal subunits provide a good foundation for

planning reconstruction. A general rule is that if more than 50% of the subunit isremoved, all of the subunit should be removed for optimal camouflage of the

reconstruction.

Reconstruct defects of the superior two thirds of the nose that involve the dorsal and/orsidewall subunits with thinner less sebaceous skin than that used in the inferior third of

the nose. The paramedian forehead flap (interpolation flap) provides abundant tissue,

with excellent color and texture matching, and it can reliably be used to resurface theentire nasal surface (see Images 16-19). This flap is axially oriented relative to the

supratrochlear artery, which travels superiorly in the subcutaneous-subdermal plane from

a point 1 cm above the level of the eyebrow. Differential sculpting of the undersurface of

the flap to match the contours of the defect allows great flexibility in the use of this flapanywhere on the nose. The major disadvantages of the flap are the vertically oriented

forehead scar and the limited length in nonhair-bearing forehead skin.

Another option in the reconstruction of defects of the middle third and junction of the

middle third and lower third of the nasal dorsum is the dorsal nasal flap, or Reiger flap.Marchac describes modification of the flap, defining an axial pedicle for the flap based
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on the angular artery. This modification creates greater flexibility and a more reliable

blood supply.

The lower third of the nose, with its complex contours and thicker, more sebaceous, andless elastic skin, is more challenging to reconstruct. For defects smaller than 1.5 cm in the

greatest dimension, the Zitelli bilobed flap, when properly designed, is an excellent flap(see Images 11-15). Defects less than 10 mm from the lateral alar margin should not be

reconstructed with the bilobed flap because this procedure can result in notching andretraction of the ala. When the entire tip subunit requires reconstruction, the authors

prefer to use a paramedian forehead flap. For subtotal tip defects, a full-thickness skin

graft or composite auricular skin/perichondrium/cartilage graft is another option.

The alar subunit requires cartilage support between the internal and external linings to

prevent upward contracture. If the defect is confined only to the alar subunit, the best

choice of local flaps for the external lining usually is a melolabial flap. If the defect

includes the adjacent tip subunit, a paramedian forehead flap often is the best choice. A

frequent reconstructive problem is scarring across the alar-facial crease. This problem ismost easily and successfully reconstructed with a well-planned Z-plasty (seeImages 4-7)

or a laterally based cheek advancement flap into the alar-facial crease combined with aforehead flap.

Cheek

Cheek defects are complex because of their depth and the difficulty in adequately

matching the contour of the surrounding tissue. The skin of the cheek is relatively thickand has good elasticity. In elderly patients, great laxity and redundancy is usually present;

therefore, primary closure along RSTLs is the simplest and best reconstructive option for

small defects. However, for medium-to-large defects, local flap coverage is required.

Rhombic and other simple transposition flaps can be used with some success in thecheek, but care must be taken to avoid placing incisions perpendicular to the RSTLs of

the cheek. These flaps are generally limited to the lateral aspect of the cheek and to the

superior aspect of the cheek near the lower eyelid.

The most common local flaps used for cheek reconstruction are advancement rotationflaps. When carefully planned, large amounts of tissue can be recruited from the cheek

and cervical skin to cover large defects, without causing significant secondary deformity.

The secondary deformity of most concern is lower eyelid ectropion. This deformity must

be considered in any cheek reconstruction. The lower medial area of the cheek near thealar-facial junction frequently is amenable to repair with island pedicle flaps (see Images

20-21).

Lip

The upper and lower lips are the focal points of the lower part of the face. Goals of lipreconstruction include maintenance of oral competence, including both motor and
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sensory innervation and preservation of an adequate gingival-labial sulcus without

distortion of surrounding structures. The first step in reconstruction is consideration of

the complete sphincter formed by the orbicularis oris muscle, which is the foundation forlip reconstruction. If restoration of the complete sphincter is unattainable, reconstruction

of the lower lip takes precedence because the lower lip is slightly more important to oral

competence; that is, the upper lip functions more like a curtain, while the lower lipfunctions more like a dam.

Reconstruction of the red lip should involve tissue from the red lip or buccal mucosa.

Small defects are repaired with V-Y advancement flaps or Z-plasty. Larger defects may

require vermilionectomy with buccal mucosal advancement.

Small full-thickness (


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reconstruction of full-thickness defect or scarification of the eyelids requires

consideration of each lamella.

Partial-thickness (anterior lamella) lower lid defects that are not amenable to primaryclosure may be reconstructed with advancement rotation flaps or upper lidtolower lid

transposition flaps (see Image 32). Partial-thickness (posterior lamella) upper or lower liddefects are generally reconstructed with grafts. (The authors use either hard palate

mucosal or septal composite grafts.)

Full-thickness defects involving less than 25% of the eyelid may be reconstructed by

using primary closure. Defects involving 25-50% of the eyelid require cantholysis.

Larger defects involving the upper and lower eyelids require specialized flaps.

The most common flap for total and subtotal lower lid defects is the Hughestarsoconjunctival flap, which provides a vascularized posterior lamella on which an

anterior lamella flap or graft may be placed. The Hughes flap has a pedicle at its superior

aspect, and its width matches the width of the defect. The inferior horizontal border mustbe at least 4 mm superior to the lid margin to prevent upper lid malposition and severing

of the marginal arcade. The pedicle is divided at 4-6 weeks. The major disadvantage of

this flap is that the lid is closed over the visual axis, while the pedicle is intact. In 1995,

Patel et al described the creation of a buttonhole in the flap at the time of primarysurgery, thereby preventing the temporary loss of vision.

Forehead

Reconstruction in the forehead facial unit most commonly involves advancement or

rotation flaps. The usual goals of preserving sensory and motor nerve function and

carefully placing incisions for optimal camouflage apply here with a single exception; ameticulously executed vertical scar in the midline of the forehead that crosses the RSTLs

at right angles is cosmetically acceptable. In the midline and paramedian areas of theforehead, the bellies of the frontalis muscle are dehiscent; therefore, the cephalocaudal

action is minimized, and this effect ostensibly minimizes the distortion created by vertical

scars in this area. The adjacent hairline and brows also offer potential hiding places for

well-conceived flap incisions. Particular care must be taken with incisions around thebrow so that brow asymmetry is not created with movement and contracture of

surrounding tissue.

H-plasty is one of the most commonly used methods for closing forehead defects. In this

procedure, bilateral lateral-to-medial advancement flaps are used to close square or rounddefects, and the incisions are placed in existing forehead furrows (seeImage 35). Other

similar repairs use the O-T, A-T, and O-Z closures, all of which are variations of bilateral

advancement flaps.

Scalp
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The workhorse flap for scalp reconstruction is the rotation advancement flap. Often used

for central or vertex defects that measure less than 3-4 cm, 2 rotation advancement flaps,

coming from opposite directions, can be used to close the defect. For larger defects, theOrticochea flap is preferred. Originally described as a 4-flap technique, Orticochea

modified this several years later to a 3-flap technique, capitalizing on larger flap bases

and a greater blood supply. Defects of up to 10-12 cm have been closed using thismethod.

NTRODUCTIN

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Skin Flaps(Eng)