57.1 Different kinds of graft

If a wound or a burn removes the whole thickness of a patient’s skin, the natural way for his epidermis to cover it is by growing slowly inwards from the edges. If his wound is less than about 2 cm across, this is usually easy. But if it is larger than this, healing will take a long time. If you cannot bring the skin edges of a wound together by suturing them, you can close his wound in one of these three ways.

(1) You can slice the superficial part of some skin (a split skin graft) from another part of the patient’s body (the donor area) and lay this on his wound (the recipient site). It will probably , ’take’ (live). The donor site will heal, because the whole of his epidermis can regenerate from the deeper parts of his sweat glands and hair follicles which you have left behind.

(2) You can take the whole thickness of some skin from another part of his body (a full thickness graft) and sew this into his wound. If the skin at the donor site is loose and the graft small, you can usually suture the edges of the donor site together to cover the gap. Or, you can cover it with a split skin graft.

Both split skin and full thickness grafts are completely deprived of their former blood supply. They are free grafts and have to be revascularised from the wound.

(3) You can move the whole thickness of his skin, complete with its blood supply, and sew it over his wound (flaps and pedicle grafts). These are difficult and only the simpler kinds of flap (57.11) which move skin over a small distance are described here. Tubular pedicle flaps, in which the skin is moved widely about the body, are a job for an expert, with the possible exception of a groin flap for the back of the hand (75.27).

Split skin grafts

are much the most useful kind of graft: (1) They can cover large areas of the body. (2) They take well. (3) They are easy to cut. (4) They resist infection moderately well, so you can put them on granulations which are not completely sterile. But they do have some disadvantages: (1) When they have healed, they don’t look good or resist trauma well. (2) Because the dermis is missing, they shrink. (3) They also give a worse colour match than a full thickness graft. But in spite of all this, split skin grafting is one of the most useful methods in surgery, in the form of either immediate primary grafting (54.2), delayed primary grafting (54.4), or secondary grafting (54.6). To leave graftable wounds ungrafted is a major surgical disgrace, because it can do much to reduce suffering and disability.

Full thickness grafts:

(1) Produce skin of much better colour and texture. (2) Resist pressure better. (3) Shrink less. But they have some great disadvantages: (1) They can only be small—usually only a few square centimetres. (2) They are a very sensitive to infection. (3) They are more difficult to apply. So they have a useful but much more limited role, mainly on the hands and face. Some surgeons consider that they have no place in a manual like this.

The equipment for cutting split skin grafts is simple—here it is:

• KNIFE, skin graft, Humby, modified by Blair and Watson, (a) knife only. (b) Set of 50 spare blades for the above, five sets only. Sterilize only the knife, the blades are disposable and already sterile. Autoclaving will blunt them.

• SKIN GRAFT KNIFE, miniature, as developed by H. L. Silver of Toronto, to use ordinary safety razor blades. The advantage of this is that you can get the blades anywhere, its disadvantage is that it can only cut a narrow strip of skin.

• RAZOR, for skin grafting, Gillette, modified as in Fig. 57-9, local adaptation, one only. This modification is not yet made commercially so you will have to make it yourself.

• HOOKS, skin, single point, Gilles, stainless steel, 200 mm, four only. These are the least traumatic way of handling skin. They are not essential, and you can use fine dissecting forceps instead.

• SKIN GRAFT BOARD, teak, with bevelled edge, 6 $\ensuremath{\times }$ 100 $\ensuremath{\times }$ 200 mm, two only. These are rectangular hardwood boards with rounded edges. When you cut a graft, the skin must be held under tension in the line of the cut between two small boards, as in A Fig. 57-5. You can use any conveniently shaped board, or even a wooden spatula.

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Figure 57.1: EQUIPMENT FOR SKIN GRAFTING. A, different kinds of graft. B, a skin hook. C, making a skin hook from a syringe. D, is the standard instrument. E, the advantage of this is that you can get the blades anywhere; its disadvantage is that it can only cut a narrow strip of skin. F, you can use almost any board, or even a spatula. With the kind permission of James Smith.