The perinecrotic zone in burns and its influence on healing

Abstract

THREE well defined zones can be discerned in a typical thermal burn of the skin; these have been characterized by Sevitt (1949) and Jackson (1953). Contact of the skin with sources of heat frequently causes immediate coagulation of tissue protein (Moritz, 1947) and this zone of coagulation is surrounded by a region of capillary stasis and this, in turn, is bounded by an area of hyperaemia (Fig. 1); these zones which can often be discerned on the surface (Fig. 2) also occur in depth (Fig. 3). Heat coagulation of tissue protein due to burning can almost certainly be regarded as irreversible whereas hyperaemia, on the other hand, possibly represents minimum tissue damage and rarely presents any local problem other than pain, though pigmentation sometimes occurs and this may be permanent. There are also changes in capillary permeability within this region which may persist for 2 days or sometimes longer (Sevitt, 1957). Until recently the tissue damage associated with the capillary stasis that develops following a burn was considered irreversible (Jackson, 1969). The development of stasis and its subsequent pathology has been described by Sevitt (1949, 1957); the condition develops within a short time of burning and persists for some days. During this time the trapped blood ceils and the surrounding tissue become necrotic and eventually indistinguishable from coagulated tissue. Thus, if the zone of stasis penetrates below the plane of the deepest epithelial structures (hair follicles, sweat glands, etc.) the burn will be full skin thickness in depth (see also Fig. I). Many full skin thickness burns require surgical intervention to facilitate healing; surgery may either be performed early by excising all damaged tissue and applying skin grafts to the obviously viable bed thus exposed or grafting is delayed until necrotic tissue has formed a slough and granulation tissue has appeared below the burn eschar. Some years ago Janzekovic (1968) showed that some burns did not require as complete an excision as hitherto supposed in order to provide