Twenty years of experience with composite tissue allograft models is presented. First, the experimental models of microcirculatory response to ischemia and reperfusion injury and surgical trauma are discussed, with presentation of the intravital microscopy system for direct in vivo observation of the microcirculation of the composite tissue allograft transplants. The intravital microscopy system presents responses to hemodynamic changes, leukocyte en-dothelial interactions, and permeability of the grafts under different ischemic conditions and under the trauma of transplantation surgery. These studies served as a baseline for establishment of treatment protocols for composite tissue allograft transplants. As a result, the meticulous surgical techniques and shortening of ischemia time and reperfusion injury, were considered in development of the experimental models for composite tissue transplantation. The model of rat hind limb transplantation, across major histocompatibility barrier, is presented as a standard model for evaluation of graft rejection, and for testing of tolerance induction, under different immunosuppression and immunomodulation protocols. The outcome of the treatment protocols for induction of tolerance and chimerism is discussed. The evolution of composite tissue allograft models from limb transplantation to groin transplantation and face transplantation, is discussed.
The models of full face transplantation, hemi-face transplantation, and composite facial- cranial, and facial-maxilla transplantation, are presented with different immunosuppression protocols. Finally, in preparation for face transplantation, cadaver studies evaluating the technical feasibility of a full face transplant and evaluation of the surface area for face and scalp transplantation, are discussed. These 20 years of research in the field of composite tissue allograft transplantation are presented as the basis for the first IRB approval for facial allograft transplantation in humans, leading to the first face transplantation surgery performed in the United States, in December 2008. Objectives:
1. At the end of the session, the participant will be able to understand background information regarding the need for facial transplantation.
2. At the end of the session, the participant will be able to understand experimental animal studies and cadaver studies performed in preparation for facial transplantation.
3. At the end of the session, the participant will be able to understand that
the first IRB approval for facial allograft transplantation in humans was based on over 20 years of extensive research in the field of composite tissue allograft transplantation.

Keywords: experimental models