Page 60 - WSAVA2017
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An Urban Experience
L. Findji1
1Fitzpatrick Referrals, Oncology and Soft Tissue surgery, Guildford, United Kingdom
Skin reconstruction. Advanced techniques
Climbing up the “ladder” of reconstruction techniques (cf. “Skin reconstruction. Basic techniques”), when simple primary closure is not possible and no local flaps are available to cover a wound, axial pattern flaps should be considered. If no axial pattern flap is deemed suitable, appropriate distant flaps and free skin grafts should next be sought. This second part will focus on axial pattern flaps, distant flaps and free skin grafts.
Axial pattern flaps
Skin flaps are either subdermal (relying on the subdermal vascular plexus) or axial (relying on a direct cutaneous artery).
Axial pattern flaps are determined by the area of
skin vascularised by a major direct cutaneous artery (angiosome), after which it is named (Figure 1a). Many direct cutaneous arteries which can be used to perform axial flaps have been described. Provided this artery
is preserved, such flaps are more robust and survive
on greater lengths compared to equivalent subdermal flaps. They can even be islanded, i.e. entirely cut out from the donor site apart from their vascular pedicle (Figure 1b). However, axial flaps cannot be elevated in any direction: their design has to follow the description of the cutaneous area vascularised by the chosen direct cutaneous artery. The anatomical landmarks of each axial pattern flap is provided in their original description and in textbooks. The most commonly used axial flaps include the caudal superficial epigastric, thoracodorsal, omocervical, deep circumflex iliac and caudal auricular flaps.
Figure 1: Vascularisation of axial flaps. Peninsular flap (a), island flap (b)
Skin flaps, either subdermal or axial, are transposed with their own vascularisation and can survive on poorly vascular beds or over cavities.
Distant flaps are subdermal flaps which can be used for reconstruction of wounds on limb extremities (distal to the elbow or stifle). Ideally, the wound, or at least
part of it, is lateral. Extensive, circumferential wounds (degloving injuries) are very good indications. With these flaps, the wound is taken to the excess skin rather than the other way round, like in other flaps. With distant flaps, the reconstruction is by necessarily staged, as their principle is to give enough time for a vascularised portion of skin to heal on the wound to reconstruct, sufficiently to be secondarily detached from the trunk and survive on its neovascularisation from the wound. These flaps include hinge and pouch flaps, depending on whether
a monopedicular or a bipedicular subdermal flap is elevated on the trunk. Pouch flaps (“tunnelisation”) are safer both because of their double pedicle and because they immobilise the leg better. The disadvantages of these flaps are to require that the patient tolerate having the treated leg maintained against the trunk during the first phase of the reconstruction. Very heavy patients or patients with severe orthopaedic issues of the remaining limbs may not be good candidates for this technique. In any case, a degree of ankylosis is expected when the leg is released, but is usually resolves spontaneously or with minimal physiotherapy.
To perform a distant flap, the leg to treat is brought to the trunk and a skin flap is elevated from the trunk to cover the wound. This is left to heal 7-18 days depending on the age of the dog and whether the flap is released from the trunk progressively or not. If a circumferential wound is to be covered, enough skin is harvested from the trunk to be wrapped around the released leg and cover the medial aspect of the wound. If the wound to reconstruct is large, closure of the donor site may itself require the use of skin flaps.

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