FLAPS

I. General

A. Definition and terms

1. A flap is a segment of tissue that contains a network of blood vessels that may be

transferred from a donor site to reconstruct a secondary defect.

2. The base of the flap contains the blood supply is called the pedicle

B. Flaps can be categorized according to several criteria

1. According to the blood supply

a. Ramdom – pattern flaps : have no dominant blood supply

b. Axial flaps : have a dominant feeding vessel

c. Reverse – flow flaps (also known as distal pedicle flaps or reverse axial

pattern flaps) : The proximal blood supply is divided, leaving the flap to survive

on the intact distally based vessels (e.g, reverse radial forearm flap, reverse

superficial sural artery flap)

2. According to the proximity to the defect

1. Local : the flap shares a side with the defect (e.g., rhomboid flap)

2. Regional : the flap is near, but not immediately adjacent to the defect (e.g,.

paramedian forehead flap)

3. Distant : the flap is not near the defect (e.g., groin flap)

4. Free flap : free tissue transfer

3. According to the method of transfer

a. Advancement

b. Transposition

c. Rotation

d. Interpolation

e. Jumping

f. Waltzing

g. Free

4. According to the tissue contained

a. Cutaneous

b. Fasciocutaneous

c. Musculocutaneous

d. Osteocutaneous

e. Osteomusculocutaneous

f. Omentum / bowel

C. Monitoring of flaps

1. Clinical evaluation is the best method of flap assessment

a. Temperature : should be body temperature

b. Color : should be pink, neither white nor blue / purple

c. Capillary refill : should be approximately 2 seconds

d. Point bleeding : upon introduction of a fine-gauge needle, bleeding should be

present. Blood should be red, not purple/blue

e. Firmness : should be soft, but with some appreciable turgor

2. Signs of insufficient arterial supply

a. Cool

b. Pallid (white)

c. Capillary refill slower than 2 seconds.

d. Slow or absent point bleeding.

e. Softer.

3. Signs of insufficient venous return (venous congestion)

a. Wanner than expected.

b. Blue to purple hue.

c. Capillary refill faster than 2 seconds (blood pooled in venous system returns

rapidly).

d. Brisk point bleeding, with dark blood.

e. Tense, swollen.

4. Factors leading to flap vascular compromise

a. Tight dressings

b. Tight sutures.

c. Pressure from positioning.

d. Hematoma, causing increased tissue pressure, impeding inflow/out flow.

e. Kinking of the flap or pedicle or both.

f. Cool ambient room temperature.

g. Nicotine, caffeine, or other vasoconstricting agents

h. Microvascular technical issues (see Chapter 6).

5. Formal tests (rarely necessary),

a. Doppler studies.

b. Fluorescein dye.

c. Sensors for O.,, pH, temperature.

D. Crane principle

1. A pedicled flap is used to lift, transport, and deposit subcutaneous tissue from one

place to another.

2. After 10 to 21 days, angiogenesis is sufficient from the recipient bed to support the

deeper layer of the overlying flap. The top (superficial) one-half to three-fourths of

the flap is then raised and returned to the original donor site.

3. A viable subcutaneous layer is left behind, which may be covered by a split skin

graft.

4. This technique provides coverage to a local or regional area, without significant

donor site morbidity.

E. Angiosome concept

1. An angiosome is a composite unit of skin and underlying tissue supplied by a

source vessel.

2. The entire surface area of the body is composed of angiosornes.

3. An angiosome consists of an arteriosome and a venosome.

4. Ansiosomes connect either by true anastomoses or by choke vessels (reduced-

caliber vessels.) that may dilate up to true anastomoses under certain

circumstances, such as flap delay (see "Delay phenomenon").

5. Explains how a flap could support more than one angiosome area under certain

conditions.

F. Delay phenomenon

1. A flap is partially eievated and reset in a separate procedure or procedures before

definitive fiap elevation and transfer.

2. This allows the harvest of a larger flap because of the survival of a random

cutaneous component distal to the boundaries defined by the original vasculature.

3. Benefits of delay are thought to be due to the following.

a. Changes in sympathetic ton.

b. Increased number of vessels in the flap (angiogenesis).

c. Dilation of previously present choke vessels.

d. Metabolic changes in the flap, increasing toleionce.

4. Time recommended between delay procedures varies, but usually 7 to 14 davs

between delavs is sufficient.

Fig .4-1 The reconstructive ladder (from place M. herber S, and Hardesty R.Basic technique and principles in plastic surgery. In

Grabb and Smith’s Plastic Surgery,5th ed. Aston SJ, Beasley RW, Thorne CH (eds). Philadelphia, Lippincott-Raven, 1997. With

permission.

G. Reconstructive ladder (Fig. 4-1)

1. A systematic approach that facilitates decision making when reconstructing a

defect.

2. Progresses from simple to complex choices

a. Healing by secondary intention.

b. Direct closure.

c. Skin graft.

d. Local tissue transfer A flap raised immediately adjacent or near to the defect

(the flap and the defect share an edge).

e. Regional flap: A flap raised near the defect (the flap and the defect do not

share an edge).

f. Distant tissue transfer. A flap raised some distance from the primary defect.

g. Free tissue transfer.

3. Reconstructive "elevator": Often the best solution to a reconstructive dilemma is

not the simplest, necessitating a jump up the "ladder."

H. Factors in flap decision making

1. Location of defect

2. Size of defect

3. Underlying or exposed structures

FREE TISSUE TRANSFERS

DISTANT TISSUE TRANSFERS

LOCAL TISSUE TRANSFERS

SKIN GRAFT

DIRECT TISSUE CLOSURE

ALLOW WOUND TO HEAL BY SECONDARY INTENTION

4. Potential donor sites

5. Donor site defects or disability

6. Viability of surrounding tissue

7. Shape and contour of the potential reconstruction

8. Surgeon's experience

9. Surgical goals

10. Patient's medical history

11. Patient s expectations v

12. Potential complications

13. Outcome evaluation

14. Cost of care

II. Cutaneous flaps

A. Indications

1. Reconstruction of a local defect with similar, adjacent tissue.

2. Need for full-thickness tissue to cover relatively less vascular tissue such as

bone or tendon without periosteum/paratenon intact (skin graft is insufficient).

B. Blood supply to the skin

1. Direct cutaneous arteries

2. Fasciocutaneous arteries

3. Musculocucaneous arteries

C. Types of skin flaps

1. Random-pattern flaps

a. Designed on a random vascular supply.

b. Roughly dependent on a length-to-width ratio of about 2:1 in the lower

extremity and 4:1 in the head and neck. Hap ischemia is expected when

these guidelines are exceeded without flap delay.

2. Axial-pattern flaps

a. Designed along a named artery (angiosome)

b. Can be much longer and robust than random-pattern flaps.

3. Advancement flaps (Fig. 4-2)

a. Single-pedicled flap: The flap is raised as a square or rectangle, and is

undermined and advanced to fill the defect. Small triangles (Burow's

triangles) may be made at the base of the flap to facilitate advancement.

b. Bipedicled flap: An incision parallel to the defect allows the flap to be

undermined and advanced. Useful for longitudinal defects of extremities.

c. V-Y advancement flap: A flap is raised in a "V shape, and advanced to fill the

defect and closed as a “Y”. Useful on the face and for finger tip

reconstruction. A variation of this is the Y-V flap.

4. Rotation flaps (Fig. 4-3)

a. The basic rotation flap is raised in a semicircle. It is particularly useful for

scalp defects and sacral pressure sores.

b. Bilobed flap: Two flaps are raised 45 to 50 degrees apart, adjacent to the

defect. The first flap is rotated in to fill the primary defect The second flap fills

the donor site of the first. The donor site of the second flap is closed

primarily. Useful for defects on the nose, where superior skin laxity can be

stepwise transferred to the inferior (e.g., tip) region, where laxity is sparse.

This flap moves the ultimate donor site to a distant position, where primary

closure is possible.

5. Transposition flaps (Fig. 4-4)

a. Z-plasty: Interpolation of two adjacent triangular flaps, which has the effect of

moving lateral tissue in to increase tissue length longitudinally. It classically

consists of a central component with adjacent limbs oriented at 60 degrees.

All three lines are of equal length. Angles may be 30 degrees to 90 degrees.

Increasing the angle increases the percent gain in length (Table 4-1).

Multiple Z-plasties may be done in series. Clinical examples: Lengthen scar

contractures, change scar direction, release epicanthai folds or constricting

bands.

b. Limberg or rhomboid flap: Used to close a rhombic-shaped (equilateral

parallelogram) defect, with angles of 60 degrees and 120 degrees. To create

the flap, the short diagonal of the rhombus is extended a distance equal to its

length. Complete the flap by drawing a line parallel to the nearest limb of the

flap. Four flaps can be drawn around the various sides of the defect.

c. Dufourmentel: A variation of the Limberg flap. Used for rhomboid-like defects

that have angles other than classic 60 and 120 degrees. Draw a line from the

short diagonal of the rhomboid. Continue the line of one of the sides to

intersect the line already drawn. Bisect these lines to get the limb of the flap,

which should be equal in length to the side. Complete the flap by drawing a

line parallel to the long horizontal.

d. Interpolation : Also called an island flap. A skin paddle is elevated dis-tally

on a vascular pedicle proximally. The flap is then transposed into a nearby

defect either over or under a skin bridge.

III. Fasciocutaneous flaps

A. These are flaps that include the deep fascia, winch incorporates a rich vascular

network-the fascial plexus. Branches from this plexus reach the skin as direct or

indirect perforators.

1. The arc of rotation is determined by the distance from the pedicle base to the

maximal safe length of the elevated flap.

2. The pedicle of a fasciocutaneous flap may be lengthened by tracing the

perforators of the flap back to the source vessel

3. A cutaneous nerve may be incorporated into the flap, making it sensate.

4. Can be used as local, regional, or free tissue transfer flaps.

B. Classification of fasciocutaneous flaps (Table 4-2)

C. Workhorse pedicled fasciocutaneous flaps (Table 4-3)

Table 4-1. Theoretical gain in length for Z-Plasty with different angles

Angle of Z-Plasty (degree)% Theoretical Gain in Length of

the central Limb

30

45

60

75

90

25

50

75

100

120

IV. Muscle and musculocutaneous flaps

A. Indications

1. Need for bulk.

2. Eradication of dead space and infection (e.g., sternal and lower extremity

reconstruction).

3. Restoration of function (e.g., gracilis transfer to the upper extrenmaty or face).

B. Advantages

1. Bulk to fill depth of defects.

2. Conform to fit an irregular wound.

3. Highly vascular.

4. May include bone in the transfer.

5. May be transferred with motor or sensory nerve.

C. Disadvantage: Sacrifice of a functional muscle

D. Classification of musculocutaneous flaps (Table 4-4 and Fig. 4-5)

E. Workhorse muscle and musculocutaneous flaps (Table 4-5)

V. Flap modifications

A. Free flaps tsee Chapter 6, "Microsurgery")

B. Supercharging

1. The process of enhancing the blood supply of a pedicled flap by performing a

microvascular anastomosis to a secondary pedicle in the flap.

2. Example: A pedicled transverse rectus abdominis (TRAM) flap-addition of

anastomosis or anastomoses of the deep inferior epigastric vessels to vessels in

the axilla, neck, or chest.

C. Flap prefabrication

1. The transfer of a new vascular pedicle into an area of tissue that will later be

raised as a flap.

2. The flap, based on new vasculature. can be raised after approximately 6 weeks.

3. Rarely used because of the availability of numerous alternative options.

D. Prelamination

1. The introduction of additional tissue layers into the flap prior to transfer.

2. A twos tased procedure: Stage 1 modifies the donor flap with the introduction of

additional tissue. Stage 2 raises the flap.

3. Allows custom-made flaps for specialized areas such as the face. Clinical

example: Prelammate a forehead flap or forearm flap with cartilage and skin

graft for nasal reconstruction.

E. Vascularized bone flaps

1. The most commonly transferred bones

a. Radius: Based on the radial artery

b. Fibula: Based on the peroneal artery.

c. Scapula: Based on either circumflex scapular or thoracodorsal artery.

d. Iliac crest: Based on the deep circumflex iliac artery.

2. Toe (or partial toe/joint) transfer

a. Great toe : based on the first dorsal metatarsal artery

b. Second toe : also based on the first dorsal metatarsal artery

Table 4-2. Nahai – Mathes classification system for fasciocutaneous flaps

Type Vessel Description Examples

A

B

C

Direct cutaneous perforator

Septocutaneous perforator

Musculocutaneous Perforator

Temporoparietal Fascial Flap

Radial artery forearm flap

TRAM flap

Table 4-3 Workhorse Pedicled Fasciocutaneous Flaps

NameAre of Rotation

(standard Flap)

Pattern of

Circulation

Maximum Size

(cm)Source Vessels Sensory Nerve

Groin Flap

Reverse Superficial

Sural

Radial Forearm

Scapular/

Parascapular

Temporoparietal

fascia flap

Lateral arm

Posterior interosseus

Paramedian forehead

flap

Abdominal wall,

perineum, hand,

forearm.

Foot and Heel

Anterior posterior,

Forearm, elbow,

upper arm

Shoulder, axilla,

thoracic wall

Ear, ipsilateral face,

FOM

Anterior, posterior

shoulder

Elbow antecubital

fossa, proximal volar

forearm

Nose, midface,

forehead

Type A

Type A

Type B

Type B

Type A

Type B

Type B

Type C

25X10

8X12

10X40

20X7

12X9

15X8

18X8

6X8

Superficial circumflex iliac

Median superficial Sural

Radial

Circumflex scapular

(transverse and descending)

branches

Superficial temporal

Posterior radial collateral

Posterior interosseus

Supratrochlear, supraorbital

Lateral cutaneous T12

Insensate

Medial and Lateral ante

Brachial cutaneous

Cutaneous of intercostals 3,

4,and 5

Auriculotemporal

Posterior brachial

cutaneous

Medial, dorsal antebrachial

cutaneous

Supratrochlear supraorbital

F. Perforator flaps : the perforating vessel or vessels are dissected down to deeper

vessels, leaving the intervening tissue intact and not included in the flap. This allows

thinner flaps to be harvested and potentially reduces donor site morbidity. For

example, a deep inferior epigastric perforator (DIEP) flap versus a free TRAM flap,

leaving the rectus muscle intact.

G. Innervated flaps

1. Motor : possible functional free tissue transfers

a. Latissimus

b. Serratus

c. Pectoralis minor

d. Gracilis

2. Sensory flaps most commonly used

a. Lateral arm flap with posterior brachial cutaneous nerve

b. Radial forearm flap with medial and lateral antebrachial cutaneous nerves

c. Dorsalis pedis flap with deep peroneal nerve in the first web and superficial

peroneal nerve in the remainder

H. Delayed flaps (see “delay phenomenon)

I. Tissue expansion (see chapter 5 “tissue expansion”).