Allograft dermal implant (AlloDerm) in a previously irradiated field

Objective: To evaluate the integration of AlloDerm (LifeCell Corp., The Woodlands, TX) in a field exposed to external-beam radiation (EBR) by analyzing graft thickness, fibroblast recellularization, and neovascularization. Study Design: Randomized control. Methods: Thirty-six male Sprague-Dawley rats (n = 36) were randomly assigned to four groups. One hind leg of each rat was exposed to 20 Gy of EBR; the other limb served as the nonirradiated control. Two weeks after irradiation, AlloDerm was implanted into both hind legs. Grafts were harvested at 3, 4, 6, and 14 weeks after implantation and underwent histological analyses, Results: There was no statistically significant difference in graft thickness, fibroblast count, or neovascularization between the grafts placed in the irradiated bed and the controls (n = 33, P =.332, P =.336, and P =.057, respectively). However, at week 3, fibroblast counts in the graft placed in the field ex posed to EBR were significantly lower than those of controls (P =.019), although at week 14 the counts in the experimental limb were higher than those of the controls (P =.002), Graft thickness (P =.001) and fibroblast count (P <.004) were lower at week 14 than at earlier time periods for both the experimental and control grafts, Conclusions: In the rat model, graft thickness and neovascularization of the AlloDerm dermal implant do not appear to be adversely affected by a field that has received EBR. Fibroblast ingrowth may be hindered in the early postimplantation period but appears to normalize in the long term. Furthermore, overall graft thickness and fibroblast counts decrease over time, regardless of irradiation status.