Flag flap - Kite flap Dorsal metacarpal flap

Abstract

The flag flap is a pedicled dorsal digital flap, combining a skin paddle (the ''flag'') and a vascular pedicle (the flag ''pole''). Its vascularisation depends on the dorsal metacarpal arteries (DMCA). It has been described in 1963, by Holevitch [1] with harvest of a cutaneovascular pole; it has been brilliantly modified in 1979 by Foucher et al. [2][3][4] under the form of a unipedicled ''kite'' flap, although we would like to point out that Vilain has been using it since 1952 [5]. Usually harvested from the dorsum of the metacarpophalangeal region of the index finger, this flap is reliable, but it is more uncertain and less movable at the level of the other digits. Owing to its small size, it proves useful in hand traumatology because it does not sacrifice any major vascular axis. The kite flap is considered as a sensory flap (presence of a nerve supply) with a two-point discrimination, which can be assessed from 11 to 16 mm [1-6]. IndicationsHarvested at the level of the index finger, owing to its pedicle measuring on average 5 cm, its indications are mainly:-extended losses of substances of thumb. However, it does not represent the ideal solution for the thumb pulp, because it only has a discriminatory sensitivity of 11 to 16 mm (6-7). Moreover, to ensure its restoration, the thumb should be flexed, entailing a risk of articular stiffening (8-12);-the cover of the palmar aspect of the first phalanx of the index finger;-the reconstruction of the first or second web space. A distally based variation allows the cover of the palmar aspect of the proximal phalanx.A distal bone fragment from the second metacarpal can be incorporated in the flap and thus used in some forms of pseudarthroses or necroses of wrist bones [13].At the level of the other digits, it can be harvested for a web space or palm reconstruction. AnatomyAs a general rule, the dorsal vascularisation of the first phalanges of the digits depends on the dorsal metacarpal arteries (DMCA); the first one of them originating from the radial artery and in most cases, from the dorsal metacarpal arch for the three others. These arteries (of a diameter of 0.5 to 0.7 mm), associated with satellite veins, are located in contact with the aponeuroses of the dorsal interosseous, below the plane of the extensor tendons, with the exception of the first one [14].These DMCA course longitudinally from the base of the interosseous spaces through to the level of their respective web space, to form a tree structure at the level of the dorsum of the metacarpophalangeals and of the first phalanx of the digits.At the base of the intermetacarpal spaces, they are supplied by the dorsopalmar perforators, and, opposite the necks of metacarpophalangeal joints, they acquire anastomoses with the palmar arterial system (creating a periarticular ring). Along their courses, these arteries ensure the vascularisation of the neighbouring structures and in particular, they supply the periosteal branches.However, there are numerous variations in this delicate dorsal vascularisation system: ...