[Study of revasularization of tracheal graft in a canine autotransplantation model--a novel technique to promote blood supply to a long graft].

The success of tracheal transplantation largely depends on the revascularization process of the graft. We studied blood supply to the graft with 7 tracheal rings in an autotransplantation model; Group I, II and III. Then, a technique to promote blood supply to the graft with 14 tracheal rings was evaluated; Group IV and V. In group I, autotransplantation of the graft with 7 tracheal rings to the intact host trachea was performed. In group II, peritracheal sheath was dissected from the host trachea in the length of 2 tracheal rings prior to autotransplantation of the same graft. In group III, omentopexy was added to the graft of group II. In group IV, two circular incisions into the tissue between the 4-5th cartilage from the host trachea except the posterior wall were made in the graft with 14 tracheal rings. Omentopexy was added to the graft was autotransplanted to the intact host trachea. In group V, a procedure similar to that of group IV was performed without circular incisions in the graft. The rate of successful transplantation in group I, II, III, IV and V was 82.1%, 0%, 72.7%, 76.8% and 16.7% respectively. In the successful groups with transplantation (I, III, IV), establishment of blood supply through the newly developed blood vessels on the mucosal and outer surface of the anastomotic site was observed between 4 and 7 postoperative day. At that time, recanalization of the native vessels in the graft via new vessels was observed. The omentopexy enhanced the blood supply at the anastomotic sites, but it showed no improvement of the blood supply in the middle portion of the graft with intact sheath. The circular incisions in the long graft had additional effect on enhancement of blood supply to the middle portion of the graft. In conclusion, preservation of the host peritracheal sheath, omentopexy, in general, and the circular incisions in the long graft were the keys for successful tracheal transplantation.