Revascularization of acellular human dermis (alloderm) in subcutaneous implantation

Background Although autogenous soft tissue graft materials, such as fat, fascia, and dermis, are commonly used for subdermal and subcutaneous augmentation, their inherent disadvantages continue to inspire a search for an alternative biomaterial. Objective This study investigated revascularization after subcutaneous implantation of Alloderm, an allograft derived from acellular human dermis, in a rabbit model. Methods Alloderm was implanted under the skin in the ears of 8 adult female white rabbits. Harvesting took place after 3, 7, 14, and 28 days. Serial sections were stained and examined under light microscopy to assess vascular ingrowth, as determined by the number of vessels and their location of entry. Results Postoperatively, minimal vessel ingrowth extending from all sides of the implantation site was visible in the grafts at 3 days. By 7 days, scattered vessels could be seen within the collagen bundles of the grafts. Further vessel ingrowth with nearly complete through-and-through vascularity was evident at 14 days. By 28 days, single-layer grafts were structurally intact, with identifiable vessels throughout the collagen bundles and no volume loss. Conclusions Acellular human dermis is capable of complete revascularization within weeks after implantation. The orientation of the basement membrane has no impact on vascular ingrowth. The extent of revascularization in more complex grafts awaits further study.