Comparison of the Characteristics of Three Acellular Dermal Matrices Subjected to Distinct Processing Methods Using Five Types of Histochemical Staining.

BACKGROUND: Acellular dermal matrix (ADM) is treated using various devitalization and aseptic processing methods. The processing effects on ADM were evaluated by histochemical tests. METHODS: From January 2014 to December 2016, 18 patients [average age, 43.0 (range, 30-54) years] who underwent breast reconstruction with an ADM and tissue expander were prospectively enrolled. During the permanent implant replacement, a biopsy of the ADM was performed. We used three different human-derived products, namely, Alloderm®, Allomend®, and Megaderm®. Hematoxylin and eosin, CD68, CD3, CD31, and smooth muscle actin were used to evaluate the collagen structure, inflammation, angiogenesis, and myofibroblast infiltration. Each ADM was semi-quantitatively analyzed. RESULTS: Significant differences in collagen degradation, acute inflammation, and myofibroblast infiltration were observed among the ADMs. Collagen degeneration (p<0.001) and myofibroblast infiltration (smooth muscle actin-positive, p=0.018; CD31-negative, p=0.765) were the most severe in Megaderm®. Acute inflammation, represented by CD68, was most severe in Alloderm® (p=0.024). Both radiation and freeze-drying treatment physically damaged the collagen structure. Collagen degeneration was most severe in Megaderm®, followed by Allomend® and Alloderm®. Since Alloderm® is treated using chemicals, an assessment of the chemical irritation is warranted. CONCLUSIONS: The biopsy results were inconclusive. Therefore, to better interpret processing, more large-scale, serial, histochemical studies of each ADM are needed. LEVEL OF EVIDENCE IV: This journal requires that authors 38 assign a level of evidence to each article. For a full 39 description of these Evidence-Based Medicine ratings, 40 please refer to the Table of Contents or the online 41 Instructions to Authors www.springer.com/00266 .