DEFINITION

A flap is a composite of tissue (ie, skin, fascia, muscle, bone, or combination) that is moved from its original location to another location in or on the body.5

Several different types of flaps exist, defined by their blood supply.

Random flaps (eg, Z-plasty, cross-finger flap) depend on preserving enough of the subcutaneous and dermal vascular plexus for flap survival. There are very few “random flaps.” Because of the extensive research on cutaneous circulation, the knowledge of vascular perforators, and understanding of angiosomes, this term is rarely used (FIG 1A).

 

FIG 1 • A. Random flap. The distal skin flap is not supplied directly by the underlying vessels but relies on circulation from the dermal and subdermal plexus for nutrition. B. Axial flap. The entire flap is carried over an underlying vascular pedicle. C. Advancement flap. This is a direct tissue advancement. This figure also shows Burow triangles, which will decrease the dog-ears at the corners. D. Rotational flap. The flap rotates into the adjacent defect. The radius of the flap decreases with the rotation. A backcut can be used to extend the arc of coverage. E. Transposition flap. This flap is similar to a rotational flap, but the flap is moved across normal tissue to fill the defect.

Axial flaps depend on the blood supply from a single consistent (usually named) blood vessel; examples of this include the radial forearm flap and dorsal metacarpal artery flap (FIG 1B).

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Free flaps depend on the division and microsurgical anastomosis of the artery and vein to reestablish blood flow to the flap in a different location.

Flaps also can be defined by how the tissue is moved.

Advancement flaps are elevated and advanced in a linear direction away from the base of the flap (FIG 1C).

Rotational flaps are elevated adjacent to the defect and re-inset within the same bed10 (FIG 1D).

Transpositional flaps are elevated and moved across normal tissue to a new defect site (FIG 1E).

Island flaps are elevated on their vascular pedicle and moved to a different location; mobility is limited by the pedicle length.

Grafts are differentiated from flaps in that there is no native blood supply to the tissue. A skin graft survives initially by osmosis (imbibition) before it obtains vascular ingrowth (inosculation). This process works only for fairly thin tissue grafts.3,4

 

ANATOMY

 

A thorough understanding of the anatomy of the area injured and the donor area of the flap is necessary for safe elevation and insetting of these flaps.

 

A full description of the anatomy of the forearm and hand is beyond the scope of this chapter, but the key points of the relevant anatomy will be addressed in the separate sections.

 

The skin and soft tissue covering the forearm and hand vary by location, and this variation must be accounted for when considering coverage.

 

The palm (volar surface) of the hand consists of very thick dermis and epidermis that is structurally anchored to the underlying tissues by numerous vertical fascial connections.

 

 

The glabrous skin of the palm should be used to cover palmar defects, if possible.

 

The dorsum of the hand has thin dermis and subcutaneous fat covering gliding extensor tendons.

 

 

Coverage here should be as thin as possible to match the lost tissue.

 

Fingertip sensation and durability should be given consideration when deciding on the type of coverage for fingertip injury.

 

The forearm has thin soft tissue coverage.

 

 

Proximally there is muscle, which often can be covered with a skin graft.

 

Distally there is tendon on the palmar and dorsal surfaces. Trauma to the soft tissue often disrupts the paratenon and the exposed tendons will subsequently require flap coverage.

 

PATHOGENESIS

 

The mechanism of injury has a considerable effect on the need for flap coverage.

 

 

Sharp injuries can usually be closed primarily without the need for flap coverage.

 

Abrasive injuries commonly occur as a result of motor vehicle accidents. These usually involve one surface of the hand, and the extent of injury is usually relatively apparent. However, the level of contamination often is high, and extensive débridement of contaminated and devitalized tissue is necessary.

 

Crush injuries can lead to necrosis of skin, tendon, bone, and muscle. The zone of injury often is large and can be underestimated on initial inspection.

 

Other systemic injuries may delay treatment of extremity injuries. However, treatment for compartment syndrome and gross contamination must not be delayed any longer than necessary.

 

NATURAL HISTORY

 

The natural history of a wound depends greatly on the type of injury. The degree of original injury is the primary factor contributing to the prognosis for function of the hand.

 

A large wound involving the bones, tendons, or joints often has a profound negative effect on future function of the hand.

 

Early coverage can decrease total inflammation of the injured area and can limit the detrimental effect of the injury on the return to function.

 

Many wounds will heal by second intention without the need for coverage. Secondary healing can lead to acceptable results in some locations but also may lead to very poor results in others. These factors must be taken into account when deciding type of coverage.

 

 

Small wounds (<1 cm) on the fingertips, without exposed bone or tendon, will likely heal well on their own. This secondary healing often gives the strongest soft tissue coverage with the best sensibility and is the preferred treatment for most wounds of this type.

 

If dorsal hand wounds secondarily heal or “granulate” over tendons, the tendons tend to scar, which limits gliding and impairs finger motion.

 

Exposed bones, tendons, nerves, or vessels usually should be covered with a flap. Secondary healing or skin grafts will result in more scarring or unstable coverage.

 

Skin grafts are best for wounds that have no exposure of tendons, nerves, or vessels. However, in certain circumstances, a skin graft can provide temporary coverage over most viable tissue. Skin grafts will not survive on bone or tendon when the periosteum or paratenon is absent.

 

A well-performed flap will provide stable, durable coverage over any viable wound bed. This will allow earlier therapy and motion.

 

PATIENT HISTORY AND PHYSICAL FINDINGS

 

After a traumatic injury, a complete history and physical examination are performed.

 

The mechanism of the injury is important. Contaminated or crush injuries often require more than one procedure for adequate irrigation and débridement.

 

Any past medical history of diabetes, smoking, heart disease, peripheral vascular disease, or hypercoagulability will impact the healing of any flap, but none of these is an absolute contraindication to coverage procedures.

 

Examination of the wound and extremity should be comprehensive:

 

 

 

Assessment of vascular status Imaging for fracture

 

 

Motor and sensory examination to evaluate for nerve, tendon, or muscle injury Examination for compartment syndrome in severe injuries

 

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IMAGING AND OTHER DIAGNOSTIC STUDIES

 

Radiographs of the hand should be obtained to evaluate for bony injury.

 

 

Advanced imaging, such as computed tomography (CT) scan or magnetic resonance imaging (MRI), may be warranted for fracture pattern delineation, but these studies rarely are needed to assess the indications for flap coverage.

 

Questionable blood flow or limb perfusion warrants further evaluation, such as angiography.

 

 

Adequate blood flow to the extremity must be restored before considering flap coverage.

 

TYPES OF FLAPS

Radial Forearm Flap

 

This is a useful flap to cover upper extremity wounds. This flap can be used as a pedicle or free flap and provides excellent thin soft tissue coverage.9

 

The donor site is the major area of morbidity.

 

 

The volar forearm donor site is relatively conspicuous.

 

If a skin graft is needed to close the donor site, the donor morbidity is decreased by using nonmeshed split-thickness skin grafts applied carefully.

 

The radial artery is divided during isolation of the flap. Therefore, ulnar artery patency is critical. This must be confirmed with an Allen test or with direct Doppler evaluation of the hand with the radial artery occluded with manual pressure.

 

 

The flap can be elevated with a proximal (anterograde) or distal (retrograde or reversed) pedicle. The anterograde flap is useful for coverage of the elbow, as either a pedicled flap or a free flap.

 

The reverse radial forearm flap can cover the volar and dorsal hand to and can reach the tips of the fingers.

 

The reversed radial forearm flap has arterial flow through the ulnar artery and palmar arches and back through the radial artery. The venous return is compromised due to valves in the vein but occurs through interconnections in the vena comitans that bypass the valves.

 

Advantages

 

 

 

 

Thin pliable tissue Reliable anatomy Fair color match

 

 

Can be elevated under tourniquet control Disadvantages

 

 

Possible unsightly donor site Requires patent ulnar artery

 

 

Reversed flap may appear swollen and slightly congested (but loss of flap is rare) Relevant anatomy

 

The brachial artery divides in the proximal forearm to form the radial and ulnar arteries. The ulnar artery is the dominant arterial blood supply to the hand in most people.

 

The radial artery courses distally just deep to the interval between the brachioradialis (BR) and the flexor carpi radialis (FCR) muscles. In the proximal forearm, the superficial branch of the radial nerve is adjacent to the radial artery.

 

The radial artery has paired venae comitantes that are important for venous egress from the flap once it is elevated.

 

 

 

FIG 2 • Cross-section showing the relevant forearm anatomy for a radial forearm flap. The septum lies between the BR and FCR. The skin and subcutaneous tissue and fascia above the volar forearm musculature are elevated as a unit with the radial artery and septum with perforating vessels.

 

 

There is a loose tissue septum between the FCR and BR. Within this septum, there are perforating branches of the radial artery to the skin that provide blood supply to the overlying skin. These are meticulously preserved to perfuse the flap (FIG 2).

 

Groin Flap

 

 

The groin flap is another commonly used pedicled flap for coverage of larger soft tissue avulsions of the hand. This fasciocutaneous flap is based on the superficial circumflex iliac artery (SCIA) and is located on the anterior thigh, just below the inguinal ligament.8

 

It can be taken as a free flap but more commonly used as a pedicled flap and a two-stage operation.

 

 

In the first stage, the flap is elevated laterally and inset onto the injured area. It is still attached medially by the

pedicle originating from the femoral vessels.

 

In the second stage (2 to 3 weeks later), the pedicle is divided, freeing the arm from its connection to the groin.

 

Advantages

 

 

The flap is thin.

 

 

It is nearly hairless, which may or may not be an advantage, depending on the recipient site. It is very reliable.

 

Flap elevation is relatively quick.

 

The donor site can be closed primarily with widths up to about 10 cm.

 

Disadvantages

 

 

Mandatory two-stage operation

 

The injured hand is dependent and connected to the patient's groin for 2 to 3 weeks while waiting for vascular ingrowth.

 

Poor color match

 

Postoperative numbness in the lateral femoral cutaneous nerve is common.

 

Relevant anatomy

 

 

The SCIA arises off the femoral artery about 3 cm inferior to the inguinal ligament and deep to the deep fascia of the thigh (FIG 3).

 

SCIA travels superolaterally beneath the deep fascia.

 

As the SCIA crosses the sartorius, it supplies branches to the muscle.

 

About 6 cm from the femoral artery, the SCIA travels superficial to Scarpa fascia.

 

 

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FIG 3 • Relevant groin flap anatomy. The SCIA arises from the femoral artery 3 cm distal to the inguinal ligament. It then travels laterally, anterior to the thigh musculature, parallel and inferior to the inguinal ligament.

 

Kite Flap

 

The kite flap, or first dorsal metacarpal artery flap, is a reliable flap taken from the dorsum of the index finger over the proximal phalanx.

 

Its most common use is for reconstruction of palmar thumb defects. Both soft tissue coverage and sensibility can be provided if the dorsal branches of the radial nerve are moved with the flap.1

 

 

It also can be used for web space reconstruction or covering smaller defects on the dorsum of the hand or wrist. The flap can be 2 × 4 cm in size.

 

Relevant anatomy

 

 

The radial artery travels through the anatomic “snuffbox,” then onto the dorsum of the thumb, before diving between the two heads of the first dorsal interosseous muscle. This artery has three main branches:

 

 

The dorsal carpal arch

 

 

The princeps pollicis artery to the thumb The first dorsal metacarpal artery

 

The first dorsal metacarpal artery extends dorsally out along the surface of the first dorsal interosseous muscle to the dorsum on the index finger (FIG 4).

 

The venous drainage of the flap is from the dorsal venous system of the finger.

 

The radial nerve provides sensation to the dorsum of the radial hand and fingers distally. These small branches can be preserved and included with the flap, if desired.

 

Posterior Interosseous Flap

 

The posterior interosseous flap, a fasciocutaneous flap, is a less commonly used flap taken from the dorsum of

the forearm.11 This flap can be based proximally to cover the elbow or distally to cover the dorsum of the hand or can be harvested as a free flap.

 

 

 

FIG 4 • Anatomy of the dorsal metacarpal artery.

 

 

The reversed flap, if used to cover the hand or wrist, relies on retrograde venous and arterial flow. The valves within the veins are bypassed by interconnections between the paired venae comitantes.

 

The donor site on the dorsal forearm is more visible and subsequently less desirable than the radial forearm flap.

 

The flap is based on the perforating arteries coming from the posterior interosseous artery.

 

 

The posterior interosseous artery travels on the posterior side of the interosseous membrane and arises from either a common interosseous artery or the ulnar artery.

 

Septocutaneous perforators travel in the septum between the extensor digiti quinti (EDQ) and extensor carpi ulnaris (ECU) to the skin.

 

The posterior interosseous artery connects with the anterior interosseous artery near the distal radioulnar joint (DRUJ) and also will get retrograde flow through the dorsal carpal arch. This site is the location of the distal pivot point of the flap.

 

Proximally, the posterior interosseous artery enters the posterior compartment of the forearm at the junction of the proximal and middle thirds of the forearm (FIG 5).

 

Advantages

 

 

 

Thin pliable tissue with good match to dorsal hand tissue Preservation of both the ulnar and radial arteries

 

Can be closed primarily if flap width is less than 5 cm

 

 

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FIG 5 • The posterior interosseous flap is elevated with the posterior interosseous artery in a retrograde fashion. Perforating vessels are present within a septum that lies between the EDQ and ECU. The skin, subcutaneous tissue, fascia, and septum are all elevated with the artery.

 

 

Disadvantages

 

 

Technically difficult dissection due to the proximity of the posterior interosseous nerve

 

The anatomy does not always allow safe dissection of the flap, and the surgeon should have a plan for an alternate flap if necessary.

 

Flap repair is contraindicated with wrist trauma due to disruption of the dorsal wrist vascular arcade.

 

Z-Plasty

 

Although Z-plasty is not often used during immediate reconstruction, it is a useful adjunct for secondary reconstruction due to scar contracture.

 

This method lengthens or redirects a scar by transposing two triangular flaps to bring normal tissue within a scarred area.

 

A prerequisite is good tissue on either side of the area to be lengthened because this tissue is interposed in the place of the original scar.

 

NONOPERATIVE MANAGEMENT

 

As with all reconstructive procedures, if nonoperative management is possible, it should be considered and may be preferred.

 

Small wounds often will heal secondarily with good results.

 

 

Fingertip injuries that do not expose bone or tendon usually heal with good results and with good sensibility. These wounds should be débrided and cleaned, then dressed appropriately and allowed to heal over 2 to 3 weeks.

 

Wounds on the distal forearm and hand often have exposure of tendon, bone, nerve, or vessel. Except in rare circumstances, these should all be covered with good tissue.

 

 

Primary closure is the ideal, but with tissue loss, this may not be possible.

 

Skin grafts provide good coverage for muscle or clean wounds of the hand but often do not offer the best coverage for future function of the hand.

 

 

A skin graft will heal on bone or tendon if the periosteum or paratenon is intact, but this may create a thin, unstable wound. Skin grafting over tendons is prone to scarring and may decrease tendon excursion.

 

Skin grafts will heal over nerves or vessels but can result in hypersensitivity with nerves or thin coverage over vessels increasing the chance of bleeding.

 

 

In many cases, early flap closure with a good gliding surface (for tendon movement) may be better than delayed healing with increased scar tissue.

 

SURGICAL MANAGEMENT

 

The wound should be débrided back to viable tissue before it is covered.

 

 

If there is gross contamination, the débridement often can be done in several stages to obtain a clean wound. The wound depth and size must be taken into consideration.

Preoperative Planning

 

If there is tendon or bone involvement of the injury site, the selected reconstruction should consider these factors.

 

 

The affected area should be well perfused when the patient is brought to the operating room for flap coverage. Only rarely should flaps be performed on an emergent basis in an unhealthy patient.

 

Flap coverage should be performed over a stable skeleton, and devitalized or contaminated tissue should not be

covered.

 

Positioning

 

The arm usually is placed on an arm board at a 90-degree angle. The operating table is positioned to allow the surgeon and the assistant to sit on either side of the arm.

 

This positioning gives excellent access to the palmar and dorsal forearm, arm, and hand.

 

If a skin graft is considered, the ipsilateral groin or thigh is prepped to allow for full- or split-thickness grafting, respectively.

 

Small full-thickness grafts can be obtained from the antecubital fossa, the ulnar forearm, or the ulnar side of the palm (for thick glabrous skin).

 

Approach

 

For all procedures, a padded tourniquet is used on the patient's arm and inflated for the duration of the débridement of the wound and for flap elevation.

 

 

 

At the end of the flap elevation, the tourniquet is released and bleeding controlled with bipolar electrocautery. Easily visible vessels are divided with clips or ties while the tourniquet is inflated.

 

The wound site is always well débrided back to good tissue. Any foreign material is removed, and the wound irrigated with saline. Pulse lavage irrigation is used for heavily contaminated wounds.

 

Careful handling of the tissue is imperative. Avoid handling the skin edges with pickups because the corners of flaps are particularly susceptible to trauma. Use retention sutures and skin hooks as much as possible.

 

 

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TECHNIQUE

• Radial Forearm Flap

A template of the defect is made (TECH FIG 1A).2

The position of the radial artery is established using Doppler ultrasound and marked on the forearm (TECH FIG 1B).

The template is placed over the radial artery on the volar forearm and marked in place.

If a reversed flap is to be used for hand coverage, it usually is obtained from the proximal forearm. If antegrade flap is to be used, it is obtained from the distal forearm.

The proximally based flap can pivot at the bifurcation of the radial and ulnar arteries. The distally based flap will pivot at the level of the radial styloid.

An incision is made distal to the flap to identify the radial artery.

Then, starting on the ulnar aspect, the skin and subsequently the forearm fascia are incised. The flap is elevated deep to the forearm fascia.

Care must be taken when approaching the radial artery not to cross and divide the septum between the FCR and BR (see FIG 2).

The perforating vessels that perfuse the skin paddle lie within this septum.

 

 

 

 

TECH FIG 1 • A. After resection of a recurrent sarcoma, this patient had a large dorsal defect with exposure of bone and tendon. B. The radial forearm flap is planned on the proximal forearm overlying the radial artery. Distal to the flap, the incision is drawn over the radial artery to extend the pedicle length. C. The flap is elevated from the proximal forearm, and once freed from its bed, the pedicle dissection is completed to the wrist. D. After the flap is elevated, it is inset in the excised wound. The flap defect is covered with a split-thickness skin graft.

 

 

Once the radial artery is identified along the course of the flap on the ulnar aspect, the radial aspect of the flap is elevated in a similar fashion.

 

The radial artery exposure is facilitated by lateral opposing traction on FCR and BR, which can be provided by a self-retaining retractor.

 

The radial artery is then divided proximally (or distally) and the flap elevated (TECH FIG 1C).

 

It is imperative that the venae comitantes be preserved with the flap during the dissection and elevation of the radial artery. These will provide venous outflow for the flap.

 

As the flap is elevated over the tendons of the FCR and palmaris longus, the paratenon must be preserved because this will provide the vascular bed for the skin graft that will cover the donor site.

 

Once flap elevation is complete, the flap is inset in the defect and the donor defect covered with a skin graft (TECH FIG 1D).

• Groin Flap

   

  A template of the defect is made (TECH FIG 2A).

   

   

  The inguinal ligament is marked from the anterior superior iliac spine to the pubic tubercle (see FIG 3). The origin of the SCIA is about 3 cm below the inguinal ligament and off the femoral artery.

   

  A second line is drawn parallel to the first, 3 cm inferior to it, indicating the SCIA.

   

  The flap can be as large as needed up to the following guidelines—any larger and the donor site may not close primarily. The flap margins are marked as follows6:

   

   

  Superior margin: 2 to 3 cm above the inguinal ligament Inferior margin: 7 to 8 cm below the inguinal ligament

   

   

   

  Lateral margin: 8 to 10 cm lateral to the anterior superior iliac spine The flap is then elevated from lateral to medial (TECH FIG 2B).

  P.1277

   

  The skin is incised laterally, and the flap is elevated at the level below the superficial fascia (Scarpa fascia).

   

  When the lateral border of the sartorius is encountered, the dissection proceeds beneath the deep fascia, just on top of the muscle fascia.

   

  The penetrating branches to the sartorius are ligated and divided.

   

  When the medial border of the sartorius is encountered, the dissection stops (for the pedicled flap).

   

  The donor site is then closed over a drain. Near the origin of the flap, care is taken not to strangulate the flap with the closure.

   

   

   

  TECH FIG 2 • A. This patient had a traumatic amputation of his thumb, leaving reasonable bony length, but no soft tissue coverage. B. The groin flap is elevated from lateral to medial. Lateral to the sartorius, the superficial fascia is elevated with the flap. At the lateral border of the sartorius, the deep fascia is elevated and the perforating branches are ligated. Elevation stops at the medial border. C. After elevation and inset of the flap, the thumb is well covered. D. After 3 weeks, the flap had matured well in place. The pedicle is divided in the operating room. E. Three months after pedicle division, the flap is doing well. The preserved

  length of the thumb allows for a good post for opposition. The bulk of the flap can be reduced operatively over time.

   

   

   

  The proximal portion of the flap is then tubed if possible; however, there cannot be any tension on the tube. The flap is then inset on the hand, usually over a Penrose drain (TECH FIG 2C).

   

  The flap may then be divided 2 to 3 weeks later (TECH FIG 2D,E). Perfusion of the flap can be tested before division by temporarily occluding the pedicle with a circumferential Penrose drain and assessing flap perfusion.

   

  P.1278

• Kite Flap: First Dorsal Metacarpal Artery Flap

   

  A template of the defect is made (TECH FIG 3A).

   

  The template is transferred to the dorsum of the index finger overlying the proximal phalanx, on the radial aspect.

   

  The flap is marked, then a proximal incision is marked in a zigzag or curvilinear fashion to extend to the takeoff of the first dorsal metacarpal artery (TECH FIG 3B).

   

  The flap is incised along the sides and distally down to the level of the extensor apparatus. Care is taken to preserve the paratenon of the extensors.

   

  The first dorsal interosseous artery will be elevated, with the subcutaneous tissue lying above it. The skin above the artery is left in its original location.

   

  The skin incision is made proximal to the flap. The incision around the proximal border of the flap needs to remain shallow, at the subdermal level as the venous drainage is through the small veins in the subcutaneous tissue.

   

   

   

  TECH FIG 3 • A. This wound of the volar thumb has exposed tendon and will not heal without a vascularized skin flap. B. The flap is planned on the dorsoradial aspect of the index finger. The proximal incision is for pedicle dissection. C. The first dorsal metacarpal artery flap is a vascularized skin flap from the dorsum of the index finger over the proximal phalanx. The dissection will give a flap that is good for small dorsal defects of the volar thumb. D. The flap is inset on the wound. E. The defect is closed. A small skin graft is needed to assist in closure. F. At 3 weeks postoperatively, the donor defect is healed. G. At 6 months postoperatively, the flap is well healed and allows for full tendon excursion.

   

   

  The skin proximal to the flap is elevated on the radial and ulnar side of the artery. The skin is elevated off the fat at the subdermal level.

   

  The pedicle should be elevated, with a total width of about 1 cm. On the ulnar side, the pedicle border is the middle of the metacarpal. On the radial side, the pedicle border is 5 to 10 mm radial to the artery (TECH FIG 3C).

   

  The artery lies on top of the fascia of the first dorsal interosseous muscle. To help preserve the artery and subcutaneous tissue, the muscle fascia is elevated with the pedicle.1,7,11

   

  Once the dissection of the pedicle has reached the radial artery proper, as it dives palmar to the deep palmar arch, the elevation typically ends.

   

   

  This should allow enough pedicle length for coverage of many volar thumb defects and some dorsal hand defects (TECH FIG 3D-G).

   

• Posterior Interosseous Flap

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  The operation is performed under tourniquet control, but without Esmarch exsanguination, to maintain visibility of the small vessels.

   

  The wound is débrided and irrigated, and then a template is made (TECH FIG 4A).

   

  A line is drawn from the lateral epicondyle to the DRUJ. The line approximates the position of the posterior interosseous artery (TECH FIG 4B,C).

   

  The template is placed over the line marking the pedicle. It can be placed proximally as close as 6 cm from the lateral epicondyle of the humerus.

   

  An incision is made along the flap outline proximal to the pivot point. Dissection is carried between the EDQ and ECU to look for the posterior interosseous artery (see FIG 4).

   

  If the artery is found at this location, it is generally consistent with favorable anatomy. If the artery is not satisfactory, the operation is aborted.

   

  Once the artery has been determined to be acceptable, the radial incision is made. The skin flap is elevated below the level of the muscular fascia. The EDC, extensor indicis proprius, and EDQ muscles are all retracted radially to facilitate exposure of the septum.

   

   

   

  TECH FIG 4 • A. This traumatic wound has exposure of the extensor tendons. B,C. The posterior interosseous flap is located proximally over the posterior interosseous artery. The flap is centered over a line from the lateral epicondyle to the DRUJ. D. After elevation, the flap is inset on the wound. E. The wound is well healed.

   

   

  The muscular branches of the posterior interosseous artery are carefully divided, exposing the posterior interosseous artery along the septum.

   

  Once one good septocutaneous perforator is located, the posterior interosseous artery is divided proximal to this branch. Further dissection to obtain more perforators is discouraged because of the proximity to the posterior interosseous nerve and potential damage to this nerve.

   

  After locating the major perforator and dividing the posterior interosseous artery proximally, the ulnar incision around the flap is made. This side is also elevated at a subfascial level.

   

  The flap is then elevated from proximal to distal. This dissection is facilitated with ulnar retraction of the ECU. A generous cuff of surrounding tissue is taken with the posterior interosseous artery to help preserve its vena comitans.

   

   

  A superficial vein may be preserved in the elevation for distal reanastomosis to help with venous drainage (TECH FIG 4D,E).

   

• Z-Plasty

  P.1280

   

  The angle of the flaps in Z-plasty is most commonly 60 degrees (TECH FIG 5A), but it can be varied to give more or less lengthening, depending on the quality of the adjacent tissue. Theoretically, 60-degree flaps will provide a lengthening of 75%.

   

  The central incision is designed along the tight scar. This scar often is excised during this part of the procedure (TECH FIG 5B).

   

  The two limbs are designed at opposing ends of the scar on opposite sides of the central member. These limbs are placed at about 60 degrees from the central incision (TECH FIG 5C).

   

   

   

  TECH FIG 5 • A. With a Z-plasty, two triangular flaps are elevated and transposed to interpose normal tissue into a contracted scar. The angle of the flaps usually is 60 degrees. B. This small finger has a contracted scar on the volar radial border. As it crosses both interphalangeal joints, the scar decreases the finger's ability to extend fully. C. The Z-plasty is designed. D. After the flaps are elevated and transposed, the scar is lengthened, allowing full extension of the finger.

   

   

  The flaps created are then elevated at a subcutaneous level. Then, the two triangular flaps are transposed and sutured into place.

   

  Once the two flaps are elevated, they often “fall” into the correct position and are easily sutured in place.

   

   

  This usually gives an obvious and considerable lengthening immediately after flap transposition and insetting (TECH FIG 5D).

   

  PEARLS AND PITFALLS
  	Indications ▪ A thorough physical examination must be completed before reconstruction of any defect.     Flap ▪ Flap elevation must be done with care and precision, with attention to preservation elevation of the feeding blood vessels. The small vessels perfusing the flaps are vital to flap survival.

  • The choice of reconstruction is guided by the reconstructive ladder. Less invasive operations should be considered before more invasive procedures, but, ultimately, the expected outcome of the type of operation will direct the choice.

  • Before any wound is covered, it must be clean, with no foreign material or dead tissue. Delaying reconstruction a few days until these goals are met is worthwhile.

  • Frequent use of Doppler ultrasound facilitates vessel identification.

   

   

  Radial forearm flap

• The dissection is safest when the fascia is elevated first from the ulnar side. The septum rises obliquely under the BR.

• Preservation of the paired venae comitantes and the septal perforators is critical to survival of the flap.

• The reversed flap needs a patent palmar vascular arch.

   

  Groin flap ▪ The patient must be prepared to have the hand connected to the groin and must understand that a second operation is mandatory.

  • This flap and the radial forearm flap are the workhorse flaps for large soft tissue flaps of the hand.

     

    First dorsal metacarpal artery flap

• Reliable coverage for volar thumb or small dorsal hand defects

• Sensation can also be preserved with this flap through branches of the superficial radial nerve.

• The dissection is somewhat complex due to the small caliber of the vessels.

 

Posterior interosseous flap

• This flap is not typically a first choice.

• It is used when there is not a patent palmar arch (ie, when a radial forearm flap is contraindicated) and when there is a reason not to use a groin flap.

 

 

 

POSTOPERATIVE CARE

 

 

The postoperative care largely depends on the flap that has been used. For all of the operations, some of the same principles are followed.

P.1281

 

Postoperative antibiotics often are indicated because the wounds have been open for some time, have been contaminated, or have associated open fractures. The choice of antibiotic is individualized for each patient.

 

The operative site usually is splinted to allow for healing of the flap without movement. If there is no bony injury, this is usually for 7 to 10 days, but the length of time may vary.

 

The arm should be elevated above the level of the heart as much as possible. This will help decrease both edema within the flap and patient discomfort.

 

The radial forearm flap should be monitored in the hospital for 2 or 3 days.

 

 

When distally based, this flap may be susceptible to venous congestion.

 

 

Care should be taken during the operation to meticulously preserve the vena comitans.

 

If the cephalic vein has been preserved with the flap, it can be anastomosed to a vein in the field of the flap, but this is rarely necessary with the reversed flap.

 

Care should be taken not to make the splint or dressing too tight.

 

 

If a skin graft is placed during the operation, the bolster dressing is removed at 5 to 7 days and the skin graft is dressed daily with petrolatum-infused gauze or a nonadhering dressing until fully healed.

 

Sutures around the flap are removed at 10 to 14 days.

 

Early active motion of the fingers is encouraged to promote tendon gliding and lessen edema, unless contraindicated after coverage.

 

Hand therapy is initiated in most patients at 1 to 2 weeks following surgery.

 

 

COMPLICATIONS

Short-term complications include those related to flap survival and healing of the wound.

Long-term complications result from undesirable scarring relating to both the primary injury and the method of closure.

Complete flap loss due to flap ischemia is uncommon. More often, a small area of the flap margin may not heal to the native skin margin due to inadequate débridement of the skin edges or rough handling of the flap skin.

As the flaps heal, the function of the hand depends on subsequent scarring, which, if it occurs, leads to poor tendon gliding. Persistent tendon scarring requires later tenolysis. After 3 months, loss of the flap by inadvertent pedicle division is rare, but late flap loss has been reported.

If scarring from the flap margin creates a contracture across a joint, a Z-plasty may be necessary.

Overall, the complications related to flap closure are less than complications related to secondary healing. The long-term outcome will be better with flap coverage compared to secondary healing because secondary intention creates an abundance of scar tissue, which can impair function of the hand.

 

REFERENCES

1. Foucher G, Baun JB. A new island flap transfer from the dorsum of the index to the thumb. Plast Reconstr Surg 1979;63:344-349.

    

    

2. Foucher G, van Genechten N, Merle M, et al. A compound radial artery flap in hand surgery: an original modification of the Chinese forearm flap. Br J Plast Surg 1984;37:139-148.

    

    

3. Mathes SJ, Nahai F. Introduction: a systematic approach. In: Mathes SJ, Nahai F, eds. Reconstructive Surgery: Principles, Anatomy, and Technique. New York: Churchill Livingstone, 1997:3-15.

    

    

4. Pederson WC, Lister GD. Skin flaps. In: Green DP, Hotchkiss RN, Pederson WC, et al, eds. Green's Operative Hand Surgery, ed 5. Philadelphia: Elsevier Churchill Livingstone, 2005:1648-1703.

    

    

5. Place MJ, Herber SC, Hardesty RA. Basic techniques and principles in plastic surgery. In: Aston SJ, Beasley RW, Thorne CH, eds. Grabb and Smith's Textbook of Plastic Surgery. Philadelphia: Lippincott Williams & Wilkins, 1997:13-16.

    

    

6. Serafin D. The groin flap. In: Serafin D, ed. Atlas of Microsurgical Composite Tissue Transplantation. Philadelphia: WB Saunders, 1996:57-65.

    

    

7. Sherif MM. First dorsal metacarpal artery flap in hand reconstruction: I. Anatomical study. J Hand Surg Am 1994;19:26-31.

    

    

8. Smith PJ, Foley B, Mcgreggor IA, et al. The anatomic basis of the groin flap. Plast Reconstr Surg 1972;49:41-47.

    

    

9. Song R, Gao Y, Song Y, et al. The forearm flap. Clin Plast Surg 1982;9:21-26.

    

    

10. Spector JA, Levine JP. Cutaneous defects: flaps, grafts, and expansion. In: McCarthy JG, Galiano RD, Boutros SG, eds. Current Therapy in Plastic Surgery. Philadelphia: WB Saunders, 2006:11-21.

     

     

11. Zancoli EA, Angrigiani C. Posterior interosseous island flap. J Hand Surg Br 1988;13:130-135.