RECONSTRUCTION OF TRACHEA AND CARINA WITH IMMEDIATE OR CRYOPRESERVED ALLOGRAFTS IN DOGS

Background. Grafting is required when primary reconstruction of a trac heocarinal defect is not feasible. To determine the viability of and t he nature of the healing process occurring in the cryopreserved graft, we performed tracheocarinal transplantation in dogs. Methods. We perf ormed 32 tracheocarinal reconstructions in dogs using autotransplanted , immediately transplanted, or cryopreserved allografts. The viability of each graft was evaluated serially by fiberoptic macroexamination a nd by measurement of the tracheal mucosal blood flow using a hydrogen clearance method. In group A (n = 8), the tracheal carina was removed and reimplanted immediately. In group B (n = 8), the tracheocarina was allotransplanted immediately after harvest. In group C (n = 8), allot ransplantations were performed using grafts cryopreserved for 1 to 3 w eeks by freeze-drying. In group D (n = 8), we attempted to achieve imm unosuppression-free transplantation with the cryopreserved allografts. Results. Sufficient viability and good healing (6/8, 75%) occurred in the dogs with cryopreserved tracheocarinal allotransplants. Three of 8 dogs (38%) with cryopreserved allotransplants survived for 25 to 57 days without immunosuppression. Conclusions. The cryopreservation of t racheocarinal allografts for 3 weeks without the use of a preservative solution was shown to be feasible. Cryopreservation prolonged the sur vival of nonimmunosuppressed allotransplants in dogs.