Perforator flaps are frequently used for defect coverage for the whole body. There are strong indications for the use of perforator flaps in the upper extremity. This article demonstrates the possibilities for defect coverage with perforator flaps as well as their anatomic and technical considerations. Lateral arm, posterior interosseous artery, ulnar artery, radial artery perforator flaps, and intrinsic hand flaps are described.
Perforator flaps are frequently used for defect coverage for the whole body. There are strong indications for the use of perforator flaps in the upper extremity. This article demonstrates the possibilities for defect coverage with perforator flaps as well as their anatomic and technical considerations.
The following perforator flaps are described: lateral arm perforator, posterior interosseous artery perforator, ulnar artery perforator, radial artery perforator, radial artery fascial perforator, and intrinsic hand. General aspects of perforator flaps, including the anatomy at the upper limb are enumerated below.
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At the forearm, most of the blood supply comes from fasciocutaneous (direct) perforators that arise from the radial, ulnar, anterior interosseous, and posterior interosseous arteries. There are only few musculocutaneous (indirect) perforators.
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Radial artery, ulnar artery, and anterior and posterior interosseous arteries supply the lower arm and the hand. In Fig. 1 the individual areas are drawn in. Fig. 2 shows important perforators of different forearm arteries.
Fig. 1
Vascular territories of the forearm. AIA, anterior interosseous artery; BA, brachial artery; PIA, posterior interosseous artery; PURA, posterior ulnar recurrent artery; RA, radial artery; RRA, radial recurrent artery; UA, ulnar artery.
Fig. 2
Important perforators of the forearm. Palmar ( A ) and dorsal ( B ) aspect of the forearm.
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The palmar aspect of the hand is supplied predominantly by the ulnar artery through the superficial palmar arch. The dorsal part of the hand is supplied by the radial artery through the dorsal metacarpal arteries, which have communicating branches with the palmar arch. The digital arteries are arising from the arches in the hand and supply the fingers and thumb.
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Transversal anastomoses between perforators emerge from different main arteries, but mostly the longitudinal anastomoses realized between perforators emerge from the same principal artery are significant from the vascular point of view.
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The distal third of the forearm has a rich supply of smaller caliber arterial perforators compared with the proximal two thirds of the forearm. The proximal forearm, having larger perforators that branch to cover a larger surface area, is a source available for large flaps based on a single perforator. In the distal forearm, the perforators are of smaller caliber and would, therefore, tend to support smaller flaps.
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Depending on their composition, the flaps can be cutaneous, subcutaneous, fasciosubcutaneous, and fascial.
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Perforator vessels supply not only the skin, but also the anatomic sector spanning between the skin and bone; these sectors are well known as angiotomes or angiosomes and represent the anatomical base of composite flaps in the forearm.
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Perforator flaps can be used in three major ways:
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Pedicled flaps
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Transposition flaps
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Free flaps.
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Although for the pedicled flaps, due to their large rotation axis, the major indication is represented by coverage of defects located on the dorsal aspect of the hand, on the first web space, and on the thumb, the transposition flaps can cover tissue forearm and elbow defects.
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It is easier to detect proximal perforators with Doppler examination because of smaller perforators in the distal area because they are more superficial and can interfere with the Doppler signal.
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Each arterial perforator is accompanied by one or two venae comitantes with communicating branches between them to build a very rich venous plexus that drains into the superficial and the deep systems of veins.
Lateral arm perforator flap
The first description of the lateral arm flap was by Song and coworkers 1982 as a free microvascular flap for defect coverage in head and neck.
Vascular Anatomy
The intermuscular septum perforators originate from two main branches in the middle of the upper arm between the acromion and the lateral epicondyle from the profunda brachial artery. These main branches are the anterior and posterior radial collateral arteries. The posterior radial collateral artery is the nourishing artery for the lateral arm flap. The posterior radial collateral artery originates in the radial groove of the humerus and has a diameter of 2 mm at its proximal origin. Along its course within the lateral intermuscular septum, the posterior radial collateral artery gives rise to four to five septocutaneous perforators (1–15 cm proximal to the lateral epicondyle). The most constant perforator can be found about 9 cm above the lateral epicondyle. The posterior radial collateral artery communicates with a rich vascular plexus that extends well into the proximal forearm for the extended lateral arm flap.
Flap Harvesting
The longitudinal flap is centered over a line running from the deltoid insertion to the lateral epicondyle of the humerus. This axis runs along the lateral intermuscular septum of the upper arm where the dominant pedicle of the flap—the posterior radial collateral artery with its two venae comitantes—is found. The lower lateral cutaneous or the posterior cutaneous nerve of the forearm can also be harvested with the flap and used as a vascularized nerve graft.
The lateral arm flap can be used as an adipofascial or free fascial flap when very thin and pliable coverage is required. Also, the flap can harvested as an osteocutaneous flap with parts of the lateral humerus. One or two branches of the posterior collateral artery directly and constantly supplying the bone between 2 to 7 cm proximal to the lateral epicondyle can be included in flap harvest. Depending on flap positioning, the overall pedicle length can reach up to 11 cm with the artery having a diameter of 2 to 2.5 mm at its proximal origin from brachial artery.
Inclusion of the distal plexus allows the lateral arm flap to be extended up to 12 cm beyond the lateral epicondyle or the proximal forearm skin. Depending on the patient’s body habitus, the donor site can be closed primarily in the majority of cases if flap width is limited to 6 to 7 cm. A case presentation figured out with a perforator flap for covering a forearm tumor defect is demonstrated ( Fig. 3 ).
