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Graft adherence may be divided into two distinct phases: Phase I, which is fibrin dependent and Phase II, which begins after 72 hours with fibro-vascular ingrowth or vascular anastomosis with the graft material. Adherence values for autograft, homograft, heterograft, silicone membrane and a modified collagen membrane were evaluated during the fibrin-dependent Phase I period at 5 and 72 hours on dermal, fascial and granulating surfaces on rats. Modified collagen membrane demonstrated a superior adherence at both times tested on dermal and fascial surfaces, while autograft and homograft were significantly more adherent on granulating surfaces at 72 hours. The inert silicone membrane was consistently the least adherent. Granulating surfaces produced the highest adherence values at 5 hours and fascial surfaces at 72 hours. The higher values found with collagen indicate that future research directed toward the production of a synthetic wound dressing or skin should be directed toward biologically derived materials, rather than inert materials. The data supports the concept of the role of fibrin as the bonding factor in Phase I adherence and implies that collagen, rather than elastin, is primarily responsible for early graft adherence.

Modified collagen membrane when compared to autograft, homograft, heterograft and silicone polymer membrane, demonstrated a superior adherence on split and full-thickness surfaces, but proved to be an inferior covering for granulating surfaces. Water vapor transport was found to be adequate and adaptable to modification. It was found to be permeable to most commonly used topical antibiotics, and no significant antigenicity could be demonstrated. In a controlled animal burn study, modified collagen membrane proved superior to homograft and heterograft in regard to mortality, time to grafting, bacteriology and autograft take. These studies provide a background for further laboratory and clinical studies now in progress.