Fascial incisions heal faster than skin: A new model of abdominal wall repair

Background. Optimal healing of the fascial layer is a necessary component of complete abdominal wall repair. The majority of acute wound healing studies have focused on the dermis. We designed a model of abdominal wall repair that, to ur knowledge, for the first time simultaneously characterizes differences in the would healing trajectories of the fascia and skin. Methods. Full-thickness dermal flaps were raised on the ventral abdominal walls of rats, and midline fascial celiotomies were completed. The dimensions of th flap were developed so as to have no detrimental effect on skin healing. The dermal flaps were replaced so that the fascial incisions would heal separately from the overlying skin incisions Animals were killed 7, 14, and 21 days after operation and fascial and dermal wounds were harvested and tested for breaking strength. Fascial and dermal wounds were also compared histologically for inflammatory response, fibroplasia, and collagen straining. Results. Fascial wound breaking strength exceeded dermal wound breaking strength at all time points (9.16 +/- 2.17 vs 3.51 +/- 0.49 N at 7 days, P < .05). Fascial wounds also developed greater fibroblast cellularity and greater collagen staining 7 days after the incision. There was no difference in wound inflammatory response. Conclusions. Fascial incisions regain breaking strength faster than simultaneous dermal incisions. The mechanism for this appears to involve increased fascial fibroplasia and collagen production after acute injury.