LAUSR

INTRODUCTION Free flap-based soft tissue reconstruction comes at the price of donor-site morbidity. Providing an opportunity to overcome this issue, the arteriovenous loop (AVL) technique allows for the de novo generation of axially vascularized soft tissue flaps from vein grafts embedded into different matrices. Thus far, the application of the AVL technique has been limited by insufficient long-term volume retention and poor tissue stability. Therefore, we investigated the suitability of a novel human dermal scaffold to improve volume retention and tissue stability. METHODS AVLs were created in 28 immunocompetent rats and embedded in either decellularized human dermal scaffolds (experimental group, n=14, Epiflex) or bovine collagen/elastin matrices (control group, n=14, MatriDerm) in subcutaneous polytetrafluoroethylene chambers. The weight and volume of engineered tissues, as well as the extent of angiogenesis and proportion of proliferating cells were compared between both groups on postoperative days (POD) 21 and 28 via immunohistochemistry and micro-computed tomography (μCT). RESULTS On POD 28, both groups displayed homogeneous microvascular networks upon histopathology and µCT. Mean microvessel counts and surface areas as well as the percentage of proliferating cells did not differ between both groups. However, the experimental human scaffold group displayed significantly smaller volume loss and significantly less extent of tissue degradation compared to bovine matrix controls (volume retention: 102±5% vs. 27±7% on POD 21, 79±12% vs. 12±7% on POD 28; p<0.0001, respectively). CONCLUSIONS Compared to bovine matrices, decellularized human scaffolds allow for superior volume retention and tissue stability of de novo engineered soft tissue AVL flaps in rats.