Full thickness abdominal wall defect in growing rats as a model for congenital diaphragmatic hernia prosthetic repair.

Background: Large congenital diaphragmatic hernia may require prosthetic correction. Acellular collagen matrices were introduced to avoid complications owing to the use of synthetic patches. We tested 3 different ACM for reconstruction of an abdominal wall defect in an animal model that mimics the fast growth during infancy.

Methods: Pelvisoft® (CR Bard, Covington, GA) and 2 investigational ACM were used for primary reconstruction of a full thickness abdominal wall defect. 3months-old rats (n=26) were allowed to survive for 90days after implantation. Anatomical, tensiometric and histological analyses were performed. Based on good outcomes, we did the same with 1month-old rats (n=54). Unoperated rats were used for obtaining reference tensiometric values of selected native tissues.

Results: Major wound complications were exclusively observed in 1month-old rats. All explants in both groups thinned significantly (p<0.03) and had an elastic modulus increasing over time, far above that from native tissues at 90days of life. Both investigational ACM induced a more vigorous foreign body reaction than Pelvisoft(®).

Conclusions: The shift from 3 to 1month-old rats was associated with wound complications. Pelvisoft® showed a better biocompatibility than the 2 investigational ACM. Passive biomechanical properties of all explants were still not comparable to that of native tissues.