EXPERIMENTAL-STUDY OF TRACHEAL ALLOTRANSPLANTATION WITH CRYOPRESERVEDGRAFTS

Objective: Tracheal reconstruction is necessary in patients with exten sive tracheal stenosis caused by neoplasm, trauma, and congenital dise ase. We investigated the possibility of tracheal allotransplantation w ith cryopreserved grafts in a canine model. Methods: A seven-ring sect ion of thoracic trachea was removed in 19 adult mongrel dogs. In group A (n = 4), a five-ring tracheal autograft was implanted. In group B ( n = 6), a five-ring allograft was implanted with immunosuppression. In group C (n = 9), a five-ring cryopreserved tracheal allograft was imp lanted without immnnosuppression, Omentopexy wrapping around the graft s and both anastomotic sites was used in all animals, Results: All gra fts survived without any evidence of atrophy or stenosis in group A. A ll animals in group B died of severe airway obstruction within 1 month , and postmortem examination of these grafts showed epithelial defect and necrotic tracheal cartilage in the scar tissue. In group C, no ani mals died of asphyxia caused by severe stenosis of the grafts. The gra ft epithelium was no longer present 20 days after transplantation, and the graft was covered with regenerated epithelium within about 60 day s after the operation. Conclusion: These findings show that cryopreser ved tracheal allografts cam be transplanted by means of omentopexy wit hout immunosuppression and that cryopreservation may reduce tracheal a llogenicity.