Histological assessment of tangentially excised burn eschars.

BACKGROUND The burn eschar serves as a medium for bacterial growth and a source of local and systemic infection. To prevent or minimize these complications, it is important to debride the eschar as early as possible. OBJECTIVE To identify the presence of viable skin within the excisions by examining tangentially excised burn eschars. METHODS A total of 146 samples of burned human tissue were removed during 54 routine sharp tangential excision procedures (using dermatomes). The samples were histologically examined to identify the relative thickness of the dead, intermediate and viable layers. RESULTS The mean (± SD) thickness of the excised samples was 1.7±1.1 mm. The sacrificed viable tissue (mean thickness 0.7±0.8 mm) occupied 41.2% of the entire thickness of the excision. In 32 biopsies (21.8%; 95% CI 16.0 to 29.3), the excision did not reach viable skin. Only eight biopsies (5.4%; 95% CI 2.8 to 10.1) contained all of the necrotic tissue without removing viable tissue. CONCLUSIONS The thickness of a single tangentially excised layer of eschar is not much greater than the actual thickness of the entire skin and often contains viable tissue. Because surgical debridement is insufficiently selective, more selective means of debriding burn eschars should be explored.