The presence or absence of damaged tissue determines whether or not a wound needs to be excised. It is axiomatic that all dirt and other for-eign material must be removed, and when the dirt is ingrained this may entail the vigorous use of a sharp spoon or wire brush to ensure that removal is demonstrably complete. The apparent coarseness of the methods involved may seem inappropriate, but total removal of grit and dirt at this stage takes priority.
Where the cosmetic result is of paramount importance, as in the face, a conservative policy to excision of wound margins is desirable, only obviously non-viable tissue being removed, the limited objective being to replace structures in their normal position and suture them there. This policy is particularly necessary in the more extensive wounds.
It recognises that an optimum result cannot be expected from the healing of such a wound, and accepts at the out-set the probable need for subsequent revisional surgery. It also permits the salvage of tissue whose viability is felt to be in doubt, and which might otherwise be excised, tissue which may be of considerable value later. It is often important to know when a piece of traumatised tissue is viable and should be con-served or whether it should be excised.
The deci-sion is made on the basis of evidence of an active circulation. The relevant signs are the presence of blanching of the skin on pressure with return of the original colour on release, and the presence of bleeding from the cut edge of the tissue con-cerned. Where there is doubt, the anatomy of the region and its known vascularity, together with the size and content of the pedicle, help in mak-ing a decision. The problem arises most acutely in the face, ear and scalp.
The vascularity of these sites is on the side of survival, and flaps with even a small pedicle should not be excised lightly. In the case of the scalp and the ear, the poss-ibility exists of a totally detached flap being replanted using microvascular techniques, but for success immediate referral to a Unit with the necessary expertise is essential.
Quite apart from its use in judging viability in the context of trauma, skin colour. has to be assessed frequently and accurately in most plastic surgical procedures, and for this reason the agents chosen for skin cleansing and sterilisation should be ones which do not stain the skin or tissues. Satisfactory from this point of view are cetrimide and an aqueous solution of chlor-hexidine (Hibitane).