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L. Findji1
1Fitzpatrick Referrals, Oncology and Soft Tissue surgery, Guildford, United Kingdom
Skin reconstruction. Basic techniques
Having to close a large or challenging wounds is common in small animal surgery, whether it be after tumour resection or in traumatised patients. Simple primary closure, combined when needed with tension- relieving techniques, allows closure of most wounds
in small animals, thanks to the laxity of their skin. Frequently, however, the skin surrounding the wound edges needs to be undermined to free the loose skin around the wound and allow such simple primary closure. Whenever simple primary closure is not possible, reconstructive techniques should be considered. As a rule, the safest, simplest and cheapest option should
be preferred, equating to choosing the lowest available technique on the “ladder” of reconstruction techniques. The 5 steps of this ladder, from the lowest to the highest are simple closure, local  aps, axial pattern  aps,
distant  aps / free grafts, and microvascular  aps / other advanced techniques. This  rst part will focus on vascular anatomy and local  aps.
Vascular anatomy of the skin
Understanding the organisation of the cutaneous vasculature is critical for skin reconstruction.
In dogs and cats, the skin is vascularised by 3 plexi:
the subpapillary, cutaneous and subdermal plexuses. The two most super cial plexuses depend on the subdermal plexus, which is therefore the most important to preserve. This subdermal plexus lies in depth of the hypodermis. In regions of the body where a panniculus muscle is present (trunk, neck), the subdermal plexus runs immediately deeply and super cially to it. As a practical consequence, when the skin is undermined for primary closure or performance of a skin  ap, it must
be elevated in depth of the panniculus muscle. In areas where no such muscle is present, the skin must be elevated as close as possible from the underlying fascial or muscular plane.
Local  aps
Skin  aps are either subdermal (relying on the subdermal vascular plexus) or axial (relying on a direct cutaneous artery). Subdermal  aps are subdivided in local and distant  aps.
Subdermal  aps are sometimes referred to as “random”  aps, as they rely on the random subdermal plexus to vascularise the elevated skin. This means that these  aps can be harvested in any location and direction. However, the perfusion pressure of the elevated skin has to be estimated as an empirical statistical notion, as the potential presence and direction of direct cutaneous arteries supplying the elevated skin are unknown (Figure 1a). As
a consequence, these  aps can only be elevated on a limited length, and their base need to be at least as wide as their free end. As an empirical rule, subdermal  aps should only be 1.5 to 2 times longer than they are wide.
Figure 1: Subdermal  aps. a: vascularisation; b: advancement  ap; c: rotation  ap; d: transposition  ap
Local  aps include advancement (Figure 1b), rotation (Figure 1c), transposition (Figure 1d) and interpolation  aps, depending on the way the excess (loose) skin
is transferred to the wound. These  aps are elevated from skin adjacent to the wound. The interpolation  aps involve a staged reconstruction on the same principle than that of distant  aps (see later). It is used when the  ap pans over a portion of intact skin which is preferred left untouched rather than split by a bridging incision.
The choice of the type of subdermal  ap to use depends on the relative orientation and position of the skin in excess to be transferred and the wound to be covered.
The axillary and inguinal skin folds can be used to create a wide range of subdermal skin  aps. These skin folds are attached in 4 places, 2 (medial and lateral) on the trunk and 2 (medial and lateral) on the limb. Any
3 of these can be severed for the  ap to be created, remaining attached by the 4th one.
An Urban Experience

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