Use of abdominal wall allotransplantation as an alternative for the management of end stage abdominal wall failure in a porcine model

Background: We describe a novel approach for treating end stage abdominal wall failure using isolated abdominal wall allotransplantation in a porcine model. Methods: Full thickness abdominal wall transplants were performed in 13 pairs of genetically mismatched pigs. All recipients received daily immunosuppresion after transplantation. Rejection was assessed by visual inspection and skin biopsies. At the end of the 28 d study period, thickness, stiffness, and tensile strength of the transplanted rectus muscle was measured and compared with native rectus muscle. Results: Eight grafts were viable and showed no signs of herniation. Four grafts failed within the first week secondary to vascular thrombosis. One animal had viable graft but was euthanized due to an incarcer-ated inguinal hernia. Rejection was minimal in six of the eight recipients. At necropsy, the gross thickness of the transplanted muscle flap was reduced compared with the native muscle (4.3 mm versus 7.7 mm, P < 0.001). Histologically, the diameter of the muscle fiber decreased from 0.15 mm to 0.09 mm (P < 0.0001). While the stiffness measurements between the transplanted and native muscles were comparable, the transplanted muscles had significantly lower tensile strength than the native muscles. Conclusion: This study demonstrates the feasibility of isolated abdominal wall allotransplantation to provide a potential solution for end stage abdominal wall failure. Based on the model set forth, future work will evaluate the biomechanical properties of the composite allograft to provide a suitable dynamic abdominal wall replacement.