Immediate tangential excision accelerates wound closure but does not reduce scarring of mid-dermal porcine burns

Current evidence supports the use of excision to remove eschar from deep dermal and full-thickness burns. However, the role of excision of mid-dermal burns remains unclear. This study aimed to develop a porcine model that could produce reproducible middermal thermal burns that undergo tangential excision; and investigate the effects of immediate tangential excision (30 minutes postburn) on healing and scarring. An aluminum bar preheated in hot water (70°C) was applied for 20 or 30 s to produce a total of sixteen mid-dermal burns per pig on each of six pigs. Thirty minutes after burn creation, half of the burns were tangentially excised. Four partial-thickness wounds per pig were created as controls. Depth of burn injury (1 and 24 h), reepithelialization (7 and 10 d) and scar depth (28 d) were assessed microscopically. Total scar surface area was grossly evaluated on day 28. Exposure of porcine skin to a preheated aluminum bar at 70 °C for 20 or 30 sec resulted in reproducible mid-dermal burns, where immediate excision enhanced complete wound closure as judged by complete re-epithelialization, but did not reduce initial depth of injury, scar contraction and scar depth. Immediate surgical intervention is sufficient to enhance wound closure, but not to mitigate mid-dermal burn scar formation. This work provides a suitable animal model to evaluate novel therapies that may be used to inhibit burn progression, accelerate wound closure and decrease scarring, especially those therapies unable to penetrate burn eschar.