Development of a porcine excisional wound model

Objectives: To develop a porcine model for cutaneous tangential excisional wounds. Methods: This was a prospective, longitudinal, blinded experiment on four isoflurane-anesthetized swine. Forty standardized excisional wounds (1 square inch each) were created with an electric dermatome set at a depth of 300, 600, 750, or 900 μm. Full-thickness wounds were created with a surgical blade (n = 8 for each depth). Wounds were treated with polyurethane film. Full-thickness punch biopsies were taken after one, two, three, four, five, and 14 days for blinded histopathological evaluation. The main outcome was the percent wound reepithelialization (REP) calculated by dividing the length of neoepidermis in cross-section by the specimen's diameter (interobserver correlation = 0.99). Analysis of variance was used to compare percent REP among wound depths. This study had 80% power to detect a 33% difference in REP across groups (two-tailed α = 0.05). Results: There were significant differences in percent REP across wound depths for days 2-5 (p < 0.001 for all days). The more superficial wounds (300 to 600 μm) were mostly reepithelialized by day 4, whereas wounds ranging in depth from 750 to 900 μm were mostly healed by day 5. Full-thickness wounds had no evidence of REP even after 14 days. Conclusions: The authors describe an excisional wound model in swine. Rapid reepithelialization occurs within three to five days in wounds <900 μm deep.