Skin grafts

Definition

These are living or preserved tissue transfers from a donor to a recipient site without their blood supply. The first record of a successful skin graft in humans was credited to Sir Astley Cooper (1817) even though the technique of free skin grafting may have originated some 3000 years ago in India.

CLASSIFICATION

Can be divided into autografts (same person), isografts (genetically identical e.g. twins), allografts (same species) or xenografts (different species). Can be further classified into split-thickness (SSG) (epidermis with partial-thickness dermis), full-thickness (FTSG) (epidermis with entire dermis) and composite (composed of two or more tissues e.g. skin and fat). They are indicated in cases where there is lack of adjacent tissue for coverage and are the third option on the reconstructive ladder (see Figure 156). Choice of donor site is influenced by scar visibility and skin colour match.

GRAFT HEALING

Known as graft ‘take’ this has five phases: adherence [fibrin mediated] (immediately), serum imbibition [graft nourished from serum nutrients] (1–2 days), inosculation [capillary re-anastomosis] (after 2 days), revascularization (3–7 days) and remodelling (weeks–months). Graft failure may arise because of: inadequate recipient site vascularization (avoid irradiated skin, exposed bone, cartilage or over-necrotic tissue), infection (especially β-haemolytic streptococci), fluid collection between the graft and the recipient surface (e.g. due to a haematoma or a seroma), shearing forces, co–morbidity (e.g. smoking, diabetes, vascular disease) and poor surgical technique (e.g. graft placed upside down). Other complications of skin grafting include skin colour mismatch and secondary contracture (especially with SSG).