Radial forearm flap

Part E

Upper extremity

Chapter

25

Radial forearm flap David S. Soutar

Introduction The radial forearm flap is often nicknamed “the Chinese flap.” Cadaveric injection studies performed in Shenyang Military Hospital in 1978 by Drs Yang Guofan and Gao Yuzhi led to the identification of the forearm flap and its subsequent description in a series of 60 clinical cases in 1981 in the Chinese literature. Initially this flap was described as a large flap incorporating most of the circumference of the forearm and was used as a free flap to release burns contractures, mainly in the head and neck. In 1980 a delegation of German surgeons visiting China saw this flap and subsequently introduced it to the western world. Further developments showed that the flap could be used as a free flap of varying size and also as an island flap pedicled distally for reconstruction of hand defects. The almost constant vascular anatomy and reliability of this vast territory of forearm led to numerous modifications in design. The skin is thin and pliable enough to be fabricated into a tube for pharyngoesophageal reconstruction or even a double tube for penile reconstruction and reconstruction of the urethra. The medial and lateral cutaneous nerves offer the possibility of transferring a sensate flap. Further tissue modifications include adipofascial flaps, osteofasciocutaneous flaps including a segment of radius, vascularized tendons in the fascia and in addition the vessels can be used as a conduit or interpositional graft on both the arterial and venous side. The forearm is also a very suitable site for flap prefabrication.

Regional anatomy (Figures 25.1–25.3) Topographically the forearm extends from a line three fingerbreadths below the level of the elbow distally to the crease of the wrist. The plane joining the radius and ulna divides the forearm into an anterior or volar region and a posterior or dorsal compartment. The forearm muscles are separated into three groups. The radial group comprises muscles arising from the lateral humeral epicondyle and includes the brachioradialis, extensor carpi radialis longus, and extensor carpi radialis brevis muscles. The flexor or pronator group arises from the medial epicondyle and epicondylar ridge and comprises pronator teres muscle and the flexors: flexor carpi radialis, flexor digitorum superficialis and profundus, palmaris longus, and flexor carpi ulnaris. The posterior compartment contains the extensor muscles. The radial artery

lies in the fascia between the radially placed brachioradialis, radial extensors, and the pronator teres and flexor muscles.

Arterial anatomy of the region (see Figures 25.1, 25.2)

The forearm is supplied by the brachial artery, which divides approximately 2 cm distal to the elbow crease into the radial artery and the ulnar artery (see Figure 25.1). These two vessels communicate distally through the superficial and deep palmar arches. Proximally the ulnar artery gives off the common interosseous trunk, from which arises the posterior interosseous artery, which supplies much of the posterior compartment of the forearm. The radial artery at the level of the bifurcation can be found deep to the bicipital aponeurosis and arises in the condensation of the deep fascia, termed the lateral intermuscular septum, which separates the flexor and extensor compartments of the forearm. In the proximal third of the forearm, the radial artery lies between the brachioradialis and pronator teres muscles, much of the vessel being covered by this latter muscle. More distally, the vessel comes to lie between the brachioradialis and flexor carpi radialis muscles. Distal to the insertion of the ­pronator teres, the radial artery is not covered by muscle and is therefore palpable, particularly in the distal third nearing the wrist. Also distal to the insertion of the pronator teres, the lateral intermuscular septum is attached to the periosteum of the radius. At the wrist the radial artery passes posteriorly underneath the tendons of abductor pollicis longus and extensor pollicis brevis to enter the anatomical snuffbox. It then passes through the space between the first and second metacarpal bones and forms the deep palmar arch by joining the deep branch of the ulnar artery. Proximally the radial artery gives off the radial recurrent artery. Slightly more distally, there is a large perforator which arises approximately 4 cm below the interepicondylar line. This vessel has been termed the inferior cubital artery and gives origin to a perforator flap named the anticubital flap. As the radial artery courses down the lateral intermuscular septum, it provides branches through the deep fascia to the overlying subcutaneous tissue and skin, and branches to the flexor muscles, nerves, and, through the lateral intermuscular septal attachment, to the underlying periosteum of the distal radius (see Figure 25.6). Proximally fasciocutaneous perforators are well spaced and fairly large, whereas

S ection TWO Conventional workhorse flaps Biceps brachii muscle

Ulnar nerve Median nerve Brachial artery Medial intermuscular septum

Brachialis muscle Lateral antebrachial cutaneous nerve (cut) (from musculocutaneous nerve)

Pronator teres muscle (humeral head) (cut and reflected)

Radial nerve Deep branch Superficial branch

Medial epicondyle Flexor carpi radialis and palmaris longus tendons ( cut)

Biceps brachii tendon Anterior ulnar recurrent artery

Radial recurrent artery

Flexor digitorum superficialis muscle (humeroulnar head) Radial artery

Ulnar artery

Supinator muscle

Common interosseous artery Pronator teres muscle (ulnar head) (cut)

Brachioradialis muscle

Anterior interosseous artery Flexor carpi ulnaris muscle Flexor digitorum superficialis muscle

Pronator teres muscle (cut) Flexor digitorum superficialis muscle (radial head) Flexor pollicis longus muscle Palmar carpal ligament (continuous with extensor retinaculum) with palmaris longus tendon (cut and reflected)

Ulnar artery Ulnar nerve and dorsal branch Median nerve Palmar branches of median and ulnar nerves (cut) Pisiform Deep palmar branch of ulnar artery and deep branch of ulnar nerve

Flexor carpi radialis tendon (cut)

Superficial branch of ulnar nerve Superficial palmar branch of radial artery

Flexor retinaculum (transverse carpal ligament)

Brachialis muscle Musculocutaneous nerve (becomes) Lateral antebrachial cutaneous nerve Lateral intermuscular septum Radial nerve Lateral epicondyle Biceps brachii tendon (cut) Radial recurrent artery Radial artery Supinator muscle Posterior and anterior interosseous arteries Flexor digitorum superficialis muscle (radial head) ( cut) Pronator teres muscle (cut and reflected) Radial artery Flexor pollicis longus muscle and tendon ( cut) Radius

Ulnar nerve Median nerve Brachial artery Medial intermuscular septum Pronator teres muscle (humeral head) (cut and reflected) Anterior ulnar recurrent artery Medial epicondyle of humerus Flexor carpi radialis, palmaris longus, flexor digitorum superficialis (humeroulnar head), and flexor carpi ulnaris muscles (cut) Posterior ulnar recurrent artery Ulnar artery Common interosseous artery Pronator teres muscle (ulnar head) (cut) Median nerve (cut) Flexor digitorum profundus muscle Anterior interosseous artery and nerve

Pronator quadratus muscle Brachioradialis tendon (cut) Radial artery and superficial palmar branch Flexor pollicis longus tendon (cut) Flexor carpi radialis tendon (cut) Abductor pollicis longus tendon Extensor pollicis brevis tendon 1st metacarpal bone

Ulnar nerve and dorsal branch Palmar carpal branches of radial and ulnar arteries Flexor carpi ulnaris tendon (cut) Pisiform Deep palmar branch of ulnar artery and deep branch of ulnar nerve Hook of hamate 5th metacarpal bone

A

322

Figure 25.1  Regional anatomy. (Reprinted from Netter Anatomy Illustration Collection. © Elsevier Inc. All Right Reserved.) (continued)

Radial forearm flap

25

Posterior view

Anterior view

Lateral supraclavicular nerve

Medial Intermediate Lateral

Supraclavicular nerves (from cervical plexus)

Acromial branch of thoracoacromial vein

Acromial branches of thoracoacromial vein

Superficial branches of posterior circumflex humeral vein

Medial brachial cutaneous nerve

Intercosto brachial nerve

Intercostobrachial nerve

Medial brachial cutaneous nerve

Superior lateral brachial cutaneous nerve (from axillary nerve)

Superior lateral brachial cutaneous nerve (from axillary nerve)

Cephalic vein

Posterior brachial cutaneous nerve (from radial nerve)

Inferior lateral brachial cutaneous nerve (from radial nerve)

Inferior lateral brachial cutaneous nerve (from radial nerve)

Posterior antebrachial cutaneous nerve (from radial nerve)

Posterior antebrachial cutaneous nerve (from radial nerve)

Branches of medial antebrachial cutaneous nerve

Accessory cephalic vein

Basilic vein

Branches of medial antebrachial cutaneous nerve

Lateral antebrachial cutaneous nerve (terminal part of musculocutaneous nerve) Median cubital vein Intermediate (median) antebrachial vein Basilic vein Perforating veins Cephalic vein BB

Branches of lateral antebrachial cutaneous nerve (terminal part of musculocutaneous nerve) C

Figure 25.1  Continued.

in the distal third of the forearm the perforators are much smaller, more numerous, and grouped together. The vascular territory of the radial artery supplies the entire volar forearm skin and the radial border as well as one-third of the radial posterior surface of the forearm. The junction between the anatomic distribution of blood supply between the radial and ulnar arteries is in the midline of the volar forearm.

Venous anatomy of the region The radial artery in the intermuscular septum is accompanied by two venae comitantes. They communicate at f­requent intervals in a ladder-shaped fashion. The comitantes contain valves but the frequent interconnections allow bypassing

of these valves, and this perhaps in part explains retrograde venous flow required, for example, in distally pedicled flaps. The venae comitantes drain into the median cubital vein via a constant branch near the elbow. The superficial forearm veins drain into the cephalic, basilic, and median cubital veins (see Figure 25.3). The deep venae comitantes communicate with the superficial veins via the common branch, going into the median cubital vein proximally and via a network of veins in the region of the radial styloid process distally. This allows the venous drainage of the forearm to be equally effective using either the deep venae comitantes or superficial veins. The median cubital vein connects the cephalic and basilic systems. The basilic vein is the dominant drainage for the dorsum of the hand and passes proximally in the medial bicipital groove. The cephalic vein is superficial

323

S ection TWO Conventional workhorse flaps Medial antebrachial cutaneous nerve Biceps brachii muscle

Ulnar nerve

Brachial artery and median nerve

Triceps brachii muscle Lateral antebrachial cutaneous nerve (terminal musculocutaneous nerve)

Medial intermuscular septum Ulnar artery

Brachialis muscle Biceps brachii tendon

Medial epicondyle of humerus Common flexor tendon

Radial artery

Pronator teres muscle Bicipital aponeurosis Brachioradialis muscle Extensor carpi radialis longus muscle Extensor carpi radialis brevis muscle

Flexor carpi radialis muscle Palmaris longus muscle

Superficial flexor muscles

Flexor carpi ulnaris muscle Flexor digitorum superficialis muscle

Flexor pollicis longus muscle and tendon Palmaris longus tendon Radial artery

Dorsal branch of ulnar nerve

Median nerve Palmar carpal ligament (continuous with extensor retinaculum)

Ulnar artery and nerve

Pisiform Palmar branch of median nerve

Thenar muscles Palmar aponeurosis Figure 25.2  Regional anatomy of the forearm.

Hypothenar muscles

between the brachioradialis and biceps at the elbow. The cephalic vein can in fact be dissected out proximally as far as the deltopectoral groove, giving an enormous length of venous pedicle (see Figures 25.1B, 25.3).

Flap anatomy Arterial supply of the flap (see Figures 25.1A, 25.2; Figures 25.4, 25.5)

324

Nerves in the region

Dominant: radial artery

(see Figures 25.1B,C, 25.3)

Length: 18 cm (range 15–22 cm)

The radial nerve is supplied by branches from the radial artery but because of its importance it is not used as a donor nerve. Cutaneous nerve supply of the forearm is supplied by medial and lateral cutaneous (medial and lateral antebrachial cutaneous) nerves. The medial cutaneous nerve of the forearm accompanies the basilic vein as it exits the deep fascia in the distal third of the arm and divides into an anterior and posterior branch. The anterior branch accompanies the basilic vein at the elbow and then passes distally over the medial half of the volar surface of the forearm. The lateral cutaneous nerve is a continuation of the musculocutaneous nerve and enters the forearm accompanying the cephalic vein and can be identified in the groove between brachioradialis and biceps muscles. The nerve courses down the forearm together with the cephalic vein and supplies the skin of the lateral half of the volar surface of the forearm (see Figure 25.3).

Diameter: 3 mm (range 2.5–3.5 mm) Nine fasciocutaneous branches from the radial artery (range: 4–14) supply the skin of the forearm, four (range: 0–10) in the proximal forearm arising between the brachioradialis and pronator teres muscles and nine in the distal forearm arising between the brachioradialis and flexor carpi radialis muscles. The proximal vessels arise from the radial artery deep to the brachioradialis muscle and course around the muscle to supply the skin 4 cm below the elbow flexion crease. Average diameter of the skin vessels is approximately 0.5 mm.The largest vessel coming off the radial artery is the inferior cubital artery, which occasionally arises from the radial recurrent artery. A large skin vessel coming off the radial artery is located in the distal forearm 7 cm proximal to the wrist crease. With the exception of the antecubital vessel proximally, the perforators from the radial forearm flap that supply

Radial forearm flap

the surrounding tissue are unnamed. In the proximal third of the forearm the perforators tend to be large and well separated (see Figure 25.4). In the midportion of the forearm there are very few, whereas in the distal third there are large numbers of perforators grouped closely together and of small caliber. These perforators supply a network of

Lateral cutaneous nerve of forearm Median cubital vein

Medial cutaneous nerve of forearm

25

vessels on the superficial surface of the deep fascia and form a v­ascular plexus which supplies almost all the skin of the forearm (see Figure 25.5). Interestingly, this vascular plexus can equally be supplied by the ulnar artery and its perforators and forms the basis of the ulnar fasciocutaneous flap. The perforators from the radial artery pass superficially in the lateral intermuscular septum and lie superficial to the deep fascia. Here they interconnect in a network or arcade fashion. It is therefore not essential to include the deep fascia on the undersurface of the whole of the flap. It is only necessary to preserve a cuff of fascia close to the lateral

Basilic vein

Cephalic vein

Median vein of forearm

Figure 25.3 Venous anatomy and cutaneous nerves of the forearm.

Figure 25.4  Cadaveric injection showing proximal perforators supplying the fascial plexus.

Figure 25.5  Cadaveric injection showing the extent of the vascular network in the forearm.

325

S ection TWO Conventional workhorse flaps

intramuscular septum to preserve the perforators. It is also possible to completely isolate a portion of skin on a perforator such as the antecubital vessel or, more commonly, on a group of perforators without having to harvest or include the radial artery.

Venous drainage of the flap Primary: venae comitantes of the radial artery Length: 18 cm (range 15–22 cm) Diameter: 1.5 mm (range 1–2 mm) Veins accompany the radial artery and its branches. There are two venae comitantes which intercommunicate at regular intervals in a ladder-type network and eventually drain into the medial cubital vein.

Secondary: cephalic vein Length: 20 cm (range 16–24 cm) Diameter: 3 mm (range 2.5–4 mm) The skin is also drained by named and unnamed superficial subcutaneous veins, notably the large cephalic vein radially. This vein can in fact be dissected proximally the whole length of the arm up to its insertion into the axillary vein through the groove between pectoralis major and deltoid muscles. Similarly, the basilic vein can be used to augment

venous drainage and can be dissected in the forearm in the medial bicipital groove. The superficial and deep systems communicate at the elbow proximally and around the radial styloid process distally.

Flap innervation (see Figures 25.1B,C, 25.3) Sensory Lateral antebrachial cutaneous nerve: innervates the lateral half of the volar surface of the forearm. l Medial antebrachial cutaneous nerve: innervates the medial half of the volar surface of the forearm. l

Motor Although a muscle component can be harvested with this flap, it is not indicated due to the functional importance of forearm muscles. It may find an indication in cases with upper extremity paralysis.

Flap components This is a true septocutaneous flap with a main vessel lying in the septum, giving perforators superficially to supply the fascia fat and skin and deeper branches to supply underlying tendons, muscles, nerves, and bone (Figure 25.6). Specialized

Superficial vein Lateral cutaneous nerve of forearm Septocutaneous vessels Deep fascia Mesoneurium

Radial nerve

Arteria nervosa Radial artery Venae comitantes

Lateral intermuscular septum

Periosteal feeding vessels Segment of radius

A

Septocutaneous perforators

Septocutaneous vessels Pedicle vessels 326

B Figure 25.6 Radial forearm flap components.

Cutaneous island

Fascial base

Radial forearm flap

flaps can be designed, such as adipofascial flaps, composite flaps including tendons of palmaris longus brachioradialis and flexor carpi radialis or o­steofasciocutaneous flaps incorporating a segment of distal radius. The importance of the flexor muscle compartment for function of the hand means that this flap is not suitable for any muscle transfer.

Advantages The forearm has a relatively constant and reproducible vascular anatomy based on large vessels. l Often allows for a two-team approach to reconstruction. l Long pedicle with large-diameter vessels. l The artery and veins of the flap can serve as conduits or interpositional grafts, along with soft tissue coverage. The flap can easily be used as a flow-through flap. l It has superficial and deep venous systems which communicate, allowing flexibility of venous anastomosis. l It can be used as either a free or pedicled flap, pedicled either proximally or distally, and offers a combination of tissues. l Allows for variation in size, shape, and design with tissue that is thin, pliable, and often hairless. l Can be harvested under regional block. l

Disadvantages The donor site has functional and cosmetic disadvantages (see Untoward outcomes, below). l The donor site can only be closed primarily if less than 2–3 cm cutaneous flap is harvested, the remainder requiring some form of large local rotation or advancement flap or skin grafting. l When harvesting bone, the radius is weakened and therefore there is a risk of subsequent fracture. l Unless the radial forearm flap is harvested based on perforators from the radial artery, this flap requires sacrifice of a major artery of the arm.

25

Preoperative preparation An Allen test must be performed preoperatively to ensure that the vascularity of the hand can be maintained following division of the radial artery. This test should be repeated on one or two occasions preoperatively. Clinical examination should also include identification of any previous injuries to the forearm which might have damaged or altered the vascularity, such as self-inflicted wounds. It must be remembered that the radial artery can be significantly affected by atheroma, which may increase the risk of failure. In severe cases this can be felt clinically on palpation of the radial artery proximal to the wrist crease. It is common practice to choose the donor site from the non-dominant upper limb. However, in cases where there is a questionable clinical examination, the opposite limb, i.e. the dominant hand, should be fully examined. Frequently there are differences, particularly in the elderly and in those with vascular disease or where there has been a history of previous trauma. Vascular compromise following harvesting of a radial forearm flap is so rare that there is no indication for MRA or angiography. If there is doubt with regard to tissue viability following occlusion of the radial artery and full clinical examination, then a different donor site should be chosen. If bone is to be harvested as an osteocutaneous flap, then x-rays of the forearm should be taken preoperatively to assess the size and shape of the radius and to ensure there is no pathology such as an old fracture.

l

1

2

3 4

5 6 7

8

9 10

Flap design Anatomic landmarks (Figure 25.7)  Virtually all the skin in the forearm from the elbow to the wrist can be taken as a radial forearm flap. However, this would be inadvisable as it would severely disrupt the lymphatic drainage of the hand. In practice, a strip of skin of at least 3 cm width overlying the posterior extensor compartment of the forearm and the ulnar subcutaneous border 11

121314 15

X X

28 27 26 25 24 23 22 21 20 18 19 17 16 Figure 25.7  Anatomic landmarks. 1. Acromion. 2. Greater tubercle (tuberosity). 3. Deltoid. 4. Axillary nerve. 5. Biceps brachii. 6. Radial nerve. 7. Cephalic vein. 8. Lateral epicondyle. 9. Head of radius. 10. Brachioradialis. 11. Radial artery. 12. Styloid process of radius. 13. Scaphoid. 14. Thenar eminence. 15. Lunate. 16. Hypothenar eminence. 17. Triquetrum. 18. Styloid process of ulna. 19. Proximal wrist crease. 20. Ulnar artery. 21. Ulnar nerve. 22. Median cubital vein. 23. Median epicondyle. 24. Basilic vein. 25. Median nerve. 26. Triceps. 27. Brachial artery. 28. Pectoralis major. The dashed line marks the

327

S ection TWO Conventional workhorse flaps

should be maintained intact. This is also the area which has the poorest vascularity based on the radial artery and the volar draining veins. The course of the radial artery can be marked by drawing a line from a point 1 cm below the center of the antecubital fossa and the tubercle of the scaphoid. This marks the course of the lateral intermuscular septum which incorporates the radial artery and venae comitantes. The artery is easily palpable in the distal third of the arm and its course can be mapped out more proximally using a Doppler. Proximal pressure above the elbow provides a degree of venous occlusion which can help identify veins. The cephalic on the radial side is readily recognized and unnamed veins can be identified in the subcutaneous tissue on the volar surface of the forearm.

General thoughts about flap design Very large flaps can be harvested incorporating almost the whole circumference of the arm except for a posterior strip on the ulnar subcutaneous border, as mentioned previously. With smaller flaps it should be noted that the skin distally at the wrist is significantly thinner than that more proximally over the muscle bellies of the forearm. Small flaps are best designed distally where the perforators are numerous. A suprafascial dissection can be performed but the deep fascia close to the lateral intermuscular septum where the perforators originate must be elevated with the flap. Such suprafascial dissection protects the tendons from exposure and simplifies skin grafting when required. Distally designed flaps allow for direct wound closure using an ulnar transposition flap and flaps up to 7  4 cm can be successfully managed in this way. The advantage of distal flaps is that they provide thin, pliable skin with a very long vascular pedicle. More proximally designed flaps are thicker, having more subcutaneous fat. It is simpler to use a subfascial dissection throughout to preserve the perforators which are more widely spaced. There is also no requirement for a suprafascial dissection since grafting onto exposed muscle is highly successful. There is generally no opportunity for direct wound closure in the proximally designed flaps and the antegrade vessel pedicle is much shorter. There is a possibility of using the lateral intermuscular septum with the radial artery and the venae comitantes distally to provide a long retrograde vascular pedicle.

328

3

5

4

2 6 1

Figure 25.8  Radial forearm flap for penile reconstruction. A radial forearm flap with a width of about 13 cm and a length of about 10 cm is raised with its sensory nerves. The outer surface is divided into urethra, de-epithelialized skin, and penile skin. A small skin tongue flap is designed on the middle of its distal edge to form the orifice of the urethra. 1, Urethra; 2, de-epithelialized strip; 3, penile skin; 4, radial artery and vein; 5, cephalic vein and lateral cutaneous nerve of forearm; 6, basilic vein and medial cutaneous nerve forearm. Redrawn from Strauch B, Yu H-L. Atlas of microvascular surgery, 2nd edn. Thieme Medical Publishers, 2006.

In designing flaps from the center of the forearm, it should be remembered that this is an area with few perforators arising from the radial artery. In such situations it is advisable to take a wide cuff of fascia, either proximally or distally, to ensure capture of sufficient perforators to supply the skin flap. When performing the flap as a pedicled flap, problems can arise with venous drainage. For this reason, it is advisable to preserve soft tissue on the pedicle rather than isolating it on its artery and veins. This is particularly true in distally pedicled flaps where broad tissue attachments should be maintained around the radial styloid. This preserves the multiple small venous branches that c­ommunicate between the superficial and deep systems. The same procedures should be adopted for proximally pedicled flaps. When taking bone, only the distal part of the radius is accessible and well vascularized. This is the segment between the pronator teres and the radial styloid and in an adult the maximum length of bone that can be harvested is approximately 12 cm. Alterations in design therefore may be required when harvesting the osteocutaneous forearm flap, paying particular attention to providing cover for the exposed radius following harvest.

Special considerations

Differences in design when performing the flap as pedicled or free

The cutaneous element of this flap is open to great variations in size, shape, and position. Flaps which are going to be used as a skin tube need to be broad and usually incorporate all of the volar aspect of the forearm. Used for reconstruction of the cervical esophagus, it is helpful to angulate the upper and lower ends of the design so that, when tubed, both ends become very wide or cone shaped. Flaps for penile reconstruction need to be very broad so that they can be separated into three areas: one is tubed for the urethra, which measures approximately 3 cm in width; the second is a de-epithelialized area approximately 1 cm in width; and the third is an area 8–10 cm in width, forming the outer surface of the penis (Figure 25.8).

Distal flaps are almost identical whether they are used as free or pedicled flaps. It is of course possible to raise the venous pedicle of the forearm flap well above the elbow, whereas this is not necessary in free tissue transfer. The more proximal forearm flaps are most commonly used as pedicled flaps to reconstruct defects in the hand, using the total length of the radial artery and the venae comitantes in a retrograde flow through connections distally from the ulnar artery. Although the veins are valved, they do allow retrograde flow, which is probably a combination of pressure and shunting due to the communications between venae comitantes and communication with the superficial venous system at the wrist.

Radial forearm flap

25

particularly if a local flap is being used, and this should be designed as part of the skin incision.

Patient positioning

Bone Small distal flap with V-Y ulnar flap for closure Larger flap design

The patient is placed lying on their back with the arm extended to 90° on a hand table. It is easiest to have the hand fully supinated to expose the whole of the volar aspect of the arm. The radial forearm flap can be harvested in almost any position, including the ipsilateral decubitus and prone positions. However, care must be taken to minimize traction on nerves in both the axilla and elbow regions.

Anesthetic considerations This flap can be harvested under regional anesthesia such as an axillary or subclavian nerve block. This is particularly useful when used as a distally pedicled flap for reconstructing defects of the hand.

Technique of flap harvest (Figure 25.10)  Distally positioned radial forearm flap

Figure 25.9  Flap markings. Black outline shows distal flap with planned ulnar transposition flap and cutback. Red markings show larger flap suitable for skin resurfacing. Blue markings show boat-shaped segment of radius.

Flap dimensions Skin island dimensions Length: 12 cm (range 4–30 cm) Maximum to close primarily: 3 cm Width: 5 cm (range 4–15 cm) Maximum to close primarily: 2 cm Thickness: 1 cm (range 0.5–2 cm) Very small flaps, particularly distal flaps of 4  2–3 cm, can be raised.

Bone dimensions Length: 10 cm (range 6–14 cm) Width: 1 cm (range 0.7–1.5 cm) Thickness: 1 cm (range 0.7–1.5 cm)

Flap markings (Figure 25.9)  The cutaneous element of the flap can be designed as appropriate. The radial artery is identified and superficial veins that might be suitable for superficial venous anastomosis are identified and marked on the skin surface. Identification of the cephalic and basilic veins can help identify the medial and lateral cutaneous nerves in subsequent dissection. It is best to commit to a method of closure,

The flap is raised under tourniquet control after exsanguination by elevation. This does not completely empty the flap and aids identification of the superficial veins. The margins of the flap are incised down to subcutaneous fat and any proximal subcutaneous veins and nerves to be preserved are identified. It is easiest to start elevation of this flap in a subfascial plane at the ulnar border. Incision is carried through the deep fascia on to the muscle bellies proximally and the tendons distally. Elevation of the flap is on the muscle surface proximally and on the paratenon of the tendons distally. Elevation proceeds superficial to the palmaris longus, dividing the intermuscular septae and vessels which pass deeply to supply muscles, nerves, and deeper structures. At this point it is useful to identify the distal end of the radial artery and venae comitantes to ensure that the vessels are in a safe position. Attention now focuses on the radial incision. A decision has to be made whether to preserve the cephalic vein or use it as part of the venous drainage of the flap. The free border of brachioradialis muscle and tendon is identified and retracted to give access to the lateral intermuscular septum. It is important to identify the cutaneous branch of the radial nerve and where possible preserve this intact to avoid subsequent loss of sensation or painful neuromas. Retraction of brachioradialis reveals the lateral intermuscular septum along its length from the styloid process to the insertion of pronator teres. This septum can be divided deep to the vascular pedicle, taking care to secure branches that pass to the periosteum of the radius and to flexor muscles of the forearm. The flap is now separated from its deep structures but remains attached by its proximal and distal pedicle and by the proximal subcutaneous tissue. Proximally an extension is made on the ulnar side of brachioradialis. This allows access to the subcutaneous tissue proximally to dissect out any superficial veins and nerves that are to be elevated with the flap. Retraction of brachioradialis allows the proximal

329

S ection TWO Conventional workhorse flaps

330

A

B

C

D

E

F

G

Figure 25.10  Technique of flap harvesting. (A) Skin marking identifying two skin paddles, segment of bone, and proximal incision to dissect out pedicle. (B) Dissection commences at the ulnar border in a suprafascial plane. (C) Fascia has been divided to enter the subfascial plane and incorporates the palmaris longus tendon. (D) Small draining superficial subcutaneous veins are identified and preserved. (E) The radial incision is completed, identifying the superficial branches of the radial nerve. (F) Retraction of brachioradialis reveals the radial artery pedicle with its venae comitantes. (G) The distal end of the radial artery pedicle is identified. Division allows the flap to be raised from a distal to proximal direction. (continued)

Radial forearm flap

H

I

J

K

25

Figure 25.10  Continued. (H) To harvest bone, flexor pollicis is incised on the volar surface with the arm in full supination. (I) The volar osteotomy is completed. (J) The arm is placed in full pronation and the radial osteotomy marked. (K) Composite flap elevation incorporating skin paddle, palmaris longus, and segment of radius.

vascular pedicle, comprising the radial artery and venae comitantes, to be identified. At this stage it is easiest to divide the pedicle distally and perform a distal to proximal dissection, mobilizing the proximal vascular pedicle and any superficial veins and nerves.

Flap modification/flap handling Reverse forearm flap In this situation the skin flap is situated proximally in the forearm. Some of the proximal perforators will be divided, notably the antecubital vessel. It should also be remembered that in the mid forearm there are very few direct perforators from the radial artery. In this regard the reverse forearm flap differs from the standard flap in that it is essential to ensure a wide fascial attachment to the radial artery, particularly distally. It is in this area that the multiple perforators supplying the fascial plexus arise. It is also essential to maintain sufficient soft tissue distally to ensure adequate venous drainage. The multiple veins round about the medial styloid which communicate between the superficial and the deep systems should be preserved. The reverse forearm flap therefore has a significant amount of soft tissue surrounding its distally based pedicle.

Suprafascial flap With experience it is possible to raise much of the radial forearm flap in a suprafascial layer. Preservation of the fascia,

particularly in distal flaps, helps protect the paratenon and therefore the integrity of the flexor tendons and simplifies subsequent skin grafting, should this be required. Suprafascial dissection therefore can be performed, commencing again at the ulnar border but in the subcutaneous tissue. Dissecting radially over palmaris longus, the dissection plane deepens into the subfascial layer so that a cuff of fascia surrounding the vascular pedicle is maintained intact and the perforators included. Suprafascial dissection does not result in a significantly thinner flap. It is primarily aimed at improving the donor site defect. Elevation of this flap is therefore identical to that previously described except for the initial dissection which is above the deep fascia until the radial side of palmaris longus is reached.

Musculo- and tendinocutaneous flaps Other variations include the use of the palmaris longus and its sheath as a vascularized tendon transfer. When raising the palmaris longus tendon, it is advisable to divide the distal end of the tendon from its insertion into the palmar aponeurosis and this aids elevation of the tendon within its sheath. The plane of dissection is deeper than that previously described and lies on the fascia overlying pronator quadratus and flexor pollicis. Further elevation allows the proximal attachment of palmaris longus to be divided. The remainder of the dissection proceeds as previously described. The composite flap therefore contains a tendon within its sheath and is most useful for facial reconstruction

331

S ection TWO Conventional workhorse flaps

when a fascial sling is required. This includes complex defects affecting the angle of the mouth or lower lip.

Osteocutaneous flap Where bone is to be included, the attachment of the lateral intermuscular septum to the periosteum of the radius must be preserved. Available bone extends from the insertion of the pronator teres to the distal styloid where there is no muscle attachment on the radial border. This gives a length of about 10–12 cm in an adult. Dissection proceeds as previously described, but, at the radial border of palmaris longus, the plane is deepened to expose flexor pollicis longus and pronator quadratus. These are incised close to their attachment to the radius but deep to the lateral intermuscular septum. This septum with a small cuff of flexor muscle maintains the attachment of the vascular pedicle to the underlying bone. The plan is to remove a wedge of bone widest at its periosteal surface and narrowest at the center of the radius. This is best achieved by placing the arm in full supination and making an osteotomy cut through the incision in flexor pollicis longus and pronator quadratus. This cut should be boat-shaped to prevent overcuts at both proximal and distal ends of the radius and facilitate harvesting (Figure 25.11). The arm is then put into full pronation. The brachioradialis is retracted, exposing the free radial border of the radius. The lateral osteotomy can be made under direct vision, connecting to the previous proximal and distal bone cuts. A wedge of very rigid cortical bone can be harvested with a wide periosteal attachment maintaining its blood supply (Figure 25.12). Osteotomies can be performed when it is necessary to contour this straight bone. Our preference is to restrict this to a single osteotomy so as not to disrupt the blood supply. The osteotomy is performed on the internal surface of the radius, using a cutting burr which takes out a small portion of bone. The outer periosteal surface is maintained intact. The effect is to create a wedge-shaped osteotomy which closes when the bone is contoured and aids fixation. The osteotomy can readily be performed after flap harvest when the bone is being trimmed and contoured to fit the bony defect.

Flexor pollicis longus (origin)

Pronator teres (insertion)

Boat-shaped bone segment

Pronator quadratus Brachioradialis Figure 25.11  Boat-shaped osteotomies in the radius.

Tissue expanded flap

332

This procedure requires two stages. It has the advantage of providing a larger flap as well as providing a better possibility of closing the donor defect primarily. In the first procedure, the flap is outlined based on the size required and the landmarks discussed earlier. A subfascial dissection is performed on the ulnar, radial or both sides of the intermuscular septum. Once the septum is visualized, expanders are placed and the incisions are closed. In the second procedure, the same incisions are made, the expanders are removed, and the procedure proceeds as in the standard dissection technique. Tissue expanders may be used secondarily after a radial forearm flap donor site has been skin grafted. This can allow for an eventual linear scar at the donor site.

forearm, which occupies a more central forearm position. The sensory nerve of the flap is coapted to a sensory nerve at the recipient site.

Sensate flap

Split flap

When a sensory flap is being taken, subcutaneous dissection proximally is required to identify and dissect out either the lateral cutaneous nerve of the forearm, which accompanies the cephalic vein, or the medial cutaneous nerve of the

By including a large portion of fascia, the skin can be divided into separate islands either by de-epithelialization (see Figure 25.8) or by complete division through the skin into the subcutaneous tissue but preserving the fascia intact. Alternatively,

Figure 25.12  Harvesting a wedge of bone. Redrawn from Strauch B, Yu H-L. Atlas of microvascular surgery, 2nd edn. Thieme Medical Publishers, 2006.

Radial forearm flap

after clearly identifying and visualizing the intermuscular septum, the perforators supplying the overlying skin can be assessed. Each perforator or group of perforators can supply a skin island; therefore, the flap can be split into several segments based on the septocutaneous perforators.

Fascial and adipofascial flaps An incision is made over the course of the radial artery, and skin flaps are elevated in the subcutaneous plane radially and ulnarly as far as the size of the flap required to reconstruct the defect. The thickness of the skin flaps left in the arm should not be less than 4 mm. The dermis, subdermal plexus, and a thin layer of fat are preserved to insure adequate blood supply at the donor site. The raised skin flaps are retracted to expose the fat and/or fascia. The flap is marked to include the radial artery. The marking does not require centering the flap over the artery. Care is taken to avoid and preserve the radial sensory nerve. The flap is incised on the ulnar side and dissection is carried in a subfascial plane towards the radial artery. The rest of the procedure is similar to the standard elevation technique. Fascial and adipofascial flaps can be elevated in the same regions described for the standard flaps. Such flaps can be used as soft tissue fillers as free flaps where the tissue is buried or as pedicled flaps, either proximally or distally, and the flap skin grafted. A useful alternative for the distally based flaps used in hand reconstruction is to base the adipofascial flap on the distal perforators, which are numerous. This has the advantage of preserving the radial artery intact. A further m­odification is to base a turnover adipofascial flap on a single perforator. The only vessel large enough to be reliable is the dorsal superficial branch of the radial artery. This in fact is a perforator-based adipofascial flap supplied by this named branch of the radial artery and includes tissue over the extensor surface of the forearm.

Perforator-based flaps The majority of branches from the radial artery are too small to be dissected out individually as perforator flaps. As stated previously, the proximal vessels are certainly larger and one vessel, the inferior cubital vessel, can be raised as a perforator flap, which is termed the antecubital flap. The only other sizeable branch is the one mentioned above, the dorsal superficial branch of the radial artery, which supplies a turnover flap for hand reconstruction. Other flaps such as the split flaps mentioned above are based on a group of small unnamed perforators.

Conduit flap Both the artery and vein can be used as vascular conduits to provide throughflow. This is useful in revascularization of limbs and also to piggy-back a second free flap.

Donor site closure and management The majority of standard flaps require skin grafting with either split-thickness or full-thickness skin grafts. Full-thickness grafts tend to give a better cosmetic appearance. The grafts can be sutured in place and the arm dressed with gauze wool and bandaged. Since the arm is decompressed, no drain is required. Alternatively, the defect can be closed with a local

25

skin flap based on the ulnar artery and its perforators. A V-Y advancement flap is a useful example for closing distal defects. The proximal incision which has been used to elevate the proximal vascular pedicle of the flap can be extended towards the elbow and a backcut made to allow V-Y advancement. It is advanced subfascially and contains perforators from the ulnar artery. A variation of this technique is to use a bilobed flap, again based on perforating vessels from the ulnar artery. In such flaps a suction drain is inserted and the wound bandaged as before. The drain is usually removed after 24 hours. In the V-Y advancement the wrist is kept flexed for 5–7 days to avoid tension on the distal suture line. When bone is harvested it is important to immobilize the arm to avoid the risk of fracture. A plaster cast should be applied above the elbow to prevent supination and pronation. This can be reduced to a below-elbow plaster after 3 weeks. Some form of protective splinting should be maintained for a total period of 6 weeks.

Technical tips to optimize outcomes and avoid complications This is a donor site where the design of the flap can be made very accurately to match particular defects. Included in the design, attention should also focus on the method of closure to be used, e.g. graft, direct wound closure or ulnar transposition flap. l It is essential that preoperative testing insures that the hand can not only survive but also function well with good vascularity once the radial artery is divided. l In large flaps it is useful to include part of the superficial venous system as well as the venae comitantes as large flaps often require drainage from both the superficial and deep systems. l In females the venae comitantes can be small, making venous anastomosis technically more difficult and here it is advisable sometimes to think in terms of using a subcutaneous superficial vein. l It is important to preserve the paratenon intact to minimize any effect of tethering of the tendons or failure of graft take. A suprafascial dissection can aid this and help minimize donor site morbidity. l When harvesting bone it is important to insure that the arm is positioned correctly. Increased angulation can result in too much radius being removed. It is therefore important to harvest bone both in full supination and full pronation where it is easier to angle the osteotomies. l No more than 25% of the circumference of the radius should be removed; otherwise, there is a risk of subsequent fracture. l In cases where too much radius has been removed, primary bone grafting should be performed using cancellous bone chips harvested from either the tibia or the hip. Where there is significant or feared risk of fracture, the surgeon should consider plating the radius at the time of flap harvest. It is imperative to minimize the risk of subsequent fracture, particularly any displacement of a fracture. l Redo the Allen test prior to dividing the radial artery. l Consider grafting the radial artery with a vein graft after the harvest. l Do not fully exsanguinate the arm. l

333

S ection TWO Conventional workhorse flaps

Flap usage Pedicled The radial forearm flap can be pedicled distally for soft tissue defects of the hand or proximally to reconstruct defects of the antecubital fossa, elbow, and upper arm. It may be used as a fasciocutaneous flap but more commonly as an adipofascial flap with grafting. Particularly in hand reconstruction, this latter method gives a better contour and avoids the necessity of having to thin the cutaneous flap. Using the standard design isolating the radial artery pedicle, these flaps have an arc of rotation of 360°. Pedicled distally, a segment of radius can be incorporated as an osteo­ fasciocutaneous flap for reconstruction of the phalanges, particularly the thumb. Additionally, there are two perforator flaps which can be raised, preserving the radial artery intact. Proximally there is the antecubital flap, based on the inferior cubital artery, and distally the radial artery perforator flap, based on the dorsal superficial branch of the radial artery. The dimensions and arc of rotation of these two flaps are more limited than those based on the radial artery.

Free flap The radial forearm flap has become a popular free flap because of its thin pliable nature.

Head and neck Free flap for oral and oropharyngeal reconstruction to replace mucosa. l Composite flap for oral reconstruction incorporating a segment of radius for mandibular reconstruction. l Tubed flap for pharyngeal and cervical esophageal reconstruction. l Skin resurfacing of face and neck. l Adipofascial free flap for facial augmentation. l Prefabricated flap for complex facial reconstruction, e.g. nasal reconstruction or prelamination of oral mucosa. l Conduit flap, to piggy-back a second free flap in complex facial reconstruction. l

Trunk Penile reconstruction: double tubed flap to reconstruct both urethra and penis. l Upper extremity: mainly used as a pedicle flap for hand reconstruction. l Lower extremity: as conduit flap to provide vascular continuity in limb salvage and reconstruction. l

This flap has become popular because of its thin pliable nature and for many years was the mainstay of mucosal replacement in oral and oropharyngeal reconstruction. This position has been somewhat overshadowed by the advent of the anterolateral thigh flap, but in many western countries this latter flap remains too thick.

Composite flaps

Free radial forearm flap There are four major indications for the use of the free radial forearm flap:

1. Soft pliable tissue. The forearm provides thin pliable tissue with great variability in size. It is therefore often used to replace oral or oropharyngeal mucosa, to resurface the thin skin of the neck and face, and to provide a tube for pharyngoesophageal and penile reconstruction. Although the flap can be made sensate, it has not earned a major place in sensory cutaneous flap reconstruction. The thin pliable skin is not really suited for weight-bearing surfaces such as in plantar foot reconstruction. Sensate flaps are, however, sometimes used in oral and oropharyngeal reconstruction. Alternatively the flap can be raised without the over­ lying skin as an adipofascial flap useful in recontouring complex defects for providing a thin surface which can be skin grafted. 2. Composite tissue transfer. The radius remains a source of bone and is certainly useful for reconstruction of horizontal defects of the mandible to improve stability, also pedicled distally to augment the thumb. The bone stock, however, is limited and it is difficult to manage to prevent fracture of the donor site. Tendon is incorporated, notably palmaris longus as a vascularized tendon sling, useful in reconstructing defects that involve the corner of the mouth or lips. 3. Vascular pedicle. The constant reliability of the vascular pedicle is advantageous in the following situations: where a long vascular pedicle is required, and when a vascular conduit is required either as an arterial and/or venous interposition graft or to piggy-back a second free flap in complex reconstructions. 4. Prefabrication. The extensive fascial network of vessels and vascularity of the radial forearm flap make it ideal for prelamination or prefabrication of flaps. Prelamination using oral mucosa for subsequent transfer is a well-recognized method of intraoral reconstruction. A pocket is created superficial to the deep fascia and a mucosal graft applied. A silicone sheet has to be inserted between the mucosa and the overlying skin and subcutaneous tissue to isolate the construct. After 3–4 weeks the mucosal graft has taken on the fascial vascularity and this composite can be raised on the radial artery pedicle in a similar fashion to an adipofascial flap. The nose has been prefabricated in the forearm. Again by raising a suprafascial pocket, a skeletal structure of bone can be inserted and also the skin contoured and shaped to allow the insetting of grafts to simulate nostrils. Once the overall shape has been obtained on the forearm, it can subsequently be transferred as a ready-made “nose” on the radial artery/arterial pedicle.

Postoperative care

Including skin, fat, nerve, tendon, bone, and fascia.

General

Prefabricated flaps

Three common uses for the radial forearm flap are in head and neck reconstruction, limb reconstruction, and penile reconstruction. The specialized care in each is markedly different. As a general rule, we use antibiotics for a short period

Prelamination of oral mucosal flaps. Complex facial reconstruction, e.g. nasal reconstruction.

l

334

Typical indications for the use of this flap

l

Radial forearm flap

depending on the recipient site and do not use any antithrombotic agents except routine DVT prophylaxis in the form of subcutaneous Clexane (enoxaparin). The radial forearm flap donor site allows early mobilization of the patient and a relatively pain-free donor site.

Outcomes

Recipient site

The radial forearm flap is a very reliable flap because of its constant vascularity and relatively large-sized vessels. Overall survival and reliability of the radial forearm free flap in different sites are in excess of 96%. The excellent vascularity of this flap promotes healing. This can be seen in skin mucosal junctions such as in the oral cavity or oropharynx where the incidence of orocutaneous fistula is exceedingly low. Similarly, it does appear to form watertight closure when forming a tube such as in esophageal and penile reconstruction. The vascularity of this flap has further been tested and proved to be effective by its ability to withstand early postoperative radical radiotherapy in head and neck cancer cases.

The majority of free flaps are used for head and neck reconstruction. Here nursing care and postoperative stay are dependent on the extent of surgery. Where the flap is used for external resurfacing or for facial augmentation as an adipofascial flap, recovery is usually rapid and the hospital stay 5–7 days. Where the upper aerodigestive tract is involved and the flap used for oral or oropharyngeal or esophageal reconstruction, recovery is often dependent on the extent of surgery. This involves the necessity to carry out neck dissection and to protect the airway with a tracheostomy. Antibiotics in such cases are used for 5 days and often incorporate cephalosporin or Augmentin (amoxicillin and clavulanate) and metronidazole. Early mobilization is encouraged and feeding performed, using either a nasogastric or PEG tube. A tracheostomy is usually in situ for a period of 5–10 days to protect the airway, and swallowing usually commences by the oral route after 10 days. When used for limb reconstruction, early mobilization is usually the rule, with early referral to physiotherapy for rehabilitation. Antibiotics are used depending on the concomitant injuries such as bony injuries or soft tissue infection. For penile reconstruction, a catheter is inserted into the urethra and maintained in position for 4–6 weeks. The hospital stay is usually 14–21 days and antibiotics are given for a period of 7 days. Postoperative monitoring of flaps is routinely performed by frequent clinical examination by experienced nursing staff. For free flaps this is recorded every 15 minutes for the first 6 hours, and then every 30 minutes until the next day. Any change in appearance of the flap warrants urgent exploration.

Donor site The donor site is usually bandaged or put in some form of plaster cast. When the wound is closed directly or when an ulnar transposition flap is used, the arm is padded and bandaged and the wrist held in a flexed position with a back slab plaster. This takes the tension off the distal wrist wound. A suction drain is usually inserted and removed at 24 hours. At 5–7 days the wounds can be inspected and the wrist extended gradually to the neutral position. The hand is monitored every hour for temperature and capillary refill. If the donor site is closed primarily, signs and symptoms of compartment syndrome are looked for. Where a skin graft is used, it is essential to prevent shearing of the underlying tendons and therefore tendon movement has to be eliminated. This again requires the arm to be in a plaster cast for a period of 5–7 days. Where bone is harvested, the arm should be placed in an above-elbow cast to prevent flexion and extension and also supination and pronation. The arm8 should be x-rayed at 3 weeks and the plaster cast usually reduced to a below-elbow cast for a further 3-week period. It is important to monitor healing of the radius and insure that there is no fracture and any subsequent displacement. Where this occurs, a decision should be made to reduce the fracture and fix with either external fixators or internal plating. If the fracture can be successfully reduced, function can be restored.

25

Expected outcomes General

Untoward outcomes Donor site A major problem with the radial forearm flap relates to its donor site and the effects on function and cosmesis. Cosmetic deformity can be minimized by confining the flap design to the true volar aspect of the forearm and avoiding the free radial border. Where a skin graft is used, improved results can be achieved by using full-thickness in preference to split-thickness grafts while suprafascial dissection aids graft take and minimizes the contour defect. If the paratenon is breached, there is a risk of tethering of the underlying tendon or of delayed wound healing when skin grafts are used. Such delayed wound healing can further tether the tendons and give a very unsightly appearance. As mentioned previously, when bone is harvested great attention to detail is required to prevent and minimize risk of fracture. Potentially the most devastating problem with this flap is sacrificing the radial artery and therefore diminishing the blood supply to the hand. Damage to the superficial sensory branch of the radial nerve at the distal part of the forearm can give rise to painful neuromata as well as loss of sensation in the area of the anatomica snuffbox. It is important in the lateral part of the dissection therefore to identify and preserve this branch as it curves under brachioradialis.

Long-term outcomes The radial forearm flap has exceptional vascularity and has been shown to be durable and tolerate full-dose postoperative radiotherapy in the head and neck. Often the skin within the oral cavity or oropharynx adopts an appearance very similar to mucosa. However, investigations have shown that this flap does not mucosalize and that the appearance change is due to inflammatory changes in the dermis. In cases that have undergone postoperative radiotherapy, c­andidal infection is often a cause. Sensory recovery of this flap can occur without reinnervation of the cutaneous sensory nerves and is to a large extent dependent on the recipient site. Sensory recovery in reinnervated flaps, particularly in the head and neck, is largely dependent on the donor nerve used for anastomosis.

Donor site As mentioned previously, the cosmetic defect remains a longterm problem and particularly so in female patients. Sensory

335

S ection TWO Conventional workhorse flaps

disturbances due to damage to branches of the radial nerve are also a permanent feature when they occur. Loss of or diminution in hand function has been exceptionally rare in our

experience, except in cases where there has been a displaced fracture of the radius. In this latter situation, functional loss is the rule, particularly when there is angulation of the radius.

Case examples Case 1: Squamous carcinoma of the lips (Figure 25.13)

 A 75-year-old man who had undergone radiotherapy presented with recurrent squamous carcinoma of the lip. He underwent resection of the cancer and reconstruction with a radial forearm flap incorporating palmaris longus

tendon. The forearm flap was folded on itself to provide oral lining and skin cover. The palmaris longus tendon was fixed to the zygomatic arch to maintain right commisure position and to provide oral competence.

A

B

C

D

Figure 25.13  (A) A 75-year-old man with recurrent squamous carcimoma of the lips following radiotherapy. (B) Extent of full-thickness excision. (C) Radial forearm flap incorporating palmaris longus tendon. (D) Forearm flap folded on itself to provide oral lining and skin cover. Palmaris longus tendon fixed to zygomatic arch to maintain right commmisure. Oral competence is maintained.

336

Radial forearm flap

25

Case 2: T4 squamous carcinoma of the lower alveolus (Figure 25.14)  A 72-year-old man presented with a T4 squamous carcinoma of the right lower alveolus. He underwent reconstruction with a radial forearm osteocutaneous flap.

A

B

C

D

E

Figure 25.14  (A) A 72-year-old man with T4 squamous carcinoma of the right lower alveolus. (B) Composite radial forearm flap showing vessels supplying periosteum of radius. (C) Orthopantogram showing fixation of radius. (D) Intraoral appearance at 1 year. (E) Facial symmetry is maintained at 1 year.

337

S ection TWO Conventional workhorse flaps

Case 3: Distally based radial forearm flap for dorsal hand defect (Figure 25.15)  The patient presented with an injury to his hand, with resultant extensor tendon injury and skin loss. He was reconstructed with a distally pedicled radial forearm flap

used to provide cover for secondary repair of traumatic extensor tendon and skin loss.

Figure 25.15  Distally pedicled radial forearm flap used to provide cover for secondary repair of traumatic extensor tendon and skin loss.

Conclusion The radial forearm flap is a very versatile flap and is at its best as a cutaneous flap. It is ideally suited where complex patterns and designs are required and it is a relatively easy flap to manipulate in a variety of different dimensions. It can be formed into a tube or a double tube or split into several skin paddles for complex facial reconstruction. The

rich vascular network lends itself to prefabrication either using the local tissue or incorporating distant tissues such as mucosa as grafts. As a pedicled flap, it retains a role in the management of complex hand injuries and, as a free flap, its major use is in head and neck surgery.

Further reading

338

Badran D, Soutar DS, Robertson AG et al. Behaviour of radial forearm skin flaps transplanted into the oral cavity. Clin Anat 1998; 11: 379–389. Bardsley AF, Soutar DS, Elliot D, Batchelor AG. Reducing morbidity in the forearm flap donor site. Plast Reconstr Surg 1990; 86: 284–287. Biemer E, Stock W. Total thumb reconstruction. A one stage reconstruction using an osteocutaneous forearm flap. Br J Plast Surg 1983; 36: 52–55. Boutros S, Yuksel E, Weinfeld AB, Alford EL, Netsher DT. Neural anatomy of the radial forearm flap. Ann Plast Surg 2000; 44: 375–380. Chang TS, Hwang WY. Forearm flaps in one stage reconstruction of the penis. Plast Reconstr Surg 1984; 74: 251–258. Harii K, Ebihara S, Oho I. Pharyngooesophageal reconstruction using a fabricated forearm free flap. Plast Reconstr Surg 1985; 75: 463–476. Hsieu CH, Kuo YR, Yao SE, Laing CC, Jeng SF. Primary closure of radial forearm flap donor defects with a bilobed flap based on the fasciocutaneous perforator of the ulnar artery. Plast Reconstr Surg 2004; 113: 1355–1360. Hwang K, Hwang JH, Jung CY, Sun Wan H, Chung H. Cutaneous perforators of the forearm. Ann Plast Surg 2006; 56: 284–288.

Inoue Y, Taylor GI. The angiosomes of the forearm: anatomic study and clinical implications. Plast Reconstr Surg 1996; 98: 195–210. Kim JT. New nomenclature concept of perforator flap. Br J Plast Surg 2005; 58: 431–440. Koshima I, Moriguchi T, Etoh H, Tsuda K, Tamaka H. The radial artery perforatorbased adipofascial flap for dorsal hand coverage. Ann Plast Surg 1995; 35: 474–479. Lauder G, Schimming R, Gellrich NC, Schmelzeisen R. Prelaminating the fascial radial forearm flap by using tissue engineered mucosa: improvements of donor and recipient sites. Plast Reconstr Surg 2001; 108: 1564–1572. Lutz BS, Wei FC, Sophia CN et al. Donor site morbidity after suprafascial elevation of the radial forearm flap: a prospective study in 95 consecutive cases. Plast Reconstr Surg 1999; 103: 132–137. Mamoon R, Sarwar SR. Avulsion injuries of the male external genitalia: classification and reconstruction with the customised radial forearm free flap. Br J Plast Surg 2005; 58: 585–592. Mateev M, Beermandu K, Subanova L, Novikova F. Reconstruction of soft tissue defects of the hand using the shape-modified radial forearm flap.

Scand J Plast Reconstr Surg Hand Surg 2004; 38: 228–231. Muhlbauer W, Herndle E, Stock W. The forearm flap. Plast Reconstr Surg 1982; 70: 336–340. Sinclair A, Johnstone E, Badran DH et al. Histological changes in radial forearm skin flaps in the oral cavity. Clin Anat 2004; 17: 227–232. Song R, Gao Y, Song Y, Yu Y, Song Y. The forearm flap. Clin Plast Surg 1982; 9: 21–28. Soutar DS, Widdowson WP. Immediate reconstruction of the mandible using a vascularised segment of radius. Head Neck Surg 1986; 2: 232–246. Soutar DS, Scheker LR, Tanner NSB, McGregor IA. The radial forearm flap: a versatile method for intraoral reconstruction. Br J Plast Surg 1983; 36: 1–8. Timmons MJ. The vascular basis of the radial forearm flap. Plast Reconstr Surg 1986; 77: 80–92. Wolff KD, Ervens J, Hoffmeister B. Improvement of the radial forearm donor site by prefabrication of fascial-split-thickness skin grafts. Plast Reconstr Surg 1996; 98: 358–362. Yang G, Chen B, Gao Y et al. Forearm free skin flap transplantation. Natl Med J China 1981; 61: 139–142.