Augmentation of random-flap survival by implantation of vascularized fascia allografts and temporary immunosuppression: implications for flap fabrication.

Abstract

The purpose of this study was to explore the possible use of an allogeneic vascular source for flap fabrication. Epigastric fascia with its superficial epigastric vessel pedicle was harvested from the donor rat and microsurgically revascularized in the recipient rat across a major histocompatibility barrier. ACI rats (Rtl-a) served as donors, and Lewis rats (Rtl-1) served as recipients. The recipient rat was immunosuppressed with a daily dose of 2 mg/kg cyclosporin A plus 5 mg/kg prednisone for 4 weeks. Three experiments were performed for skin, muscle, and bone studies. In experiment 1 (20 Lewis rats), placement of the allotransplanted fascia underneath the epigastric skin significantly improved the survival of a random epigastric skin flap raised 3 weeks later (7.35 +/- 0.65 cm2 versus 6.09 +/- 0.90 cm2, p < 0.05). Immunosuppression was discontinued 10 days after flap elevation with no observable additional skin necrosis. In experiment 2 (13 Lewis rats) and experiment 3 (14 Lewis rats), segments of isogeneic muscle and bone were grafted successfully on the allotransplanted fascia, respectively. The survival of these grafts was confirmed by metabolic bone activity, bone labeling, microangiography, and histologic studies and further confirmed 2 weeks after cessation of immunosuppression. An allotransplanted fascia as a vascular source proved in this model its capability to improve the survival of a random skin flap and to accept a free bone or muscle graft with temporary immunosuppression. These findings hold promise for possible use of an allogeneic vascular source in flap fabrication.