Tubes of vascularized cartilage used for replacement of rabbit cervical trachea

This study was performed to evaluate the healing process of vascularized cartilage tubes after reconstruction of circumferential tracheal defects in rabbits. Vascularized cartilage was obtained by applying ear cartilage to a vascularized fascia flap in the lateral thoracic area in 10 animals. Five animals (control group) were used to evaluate the viability of the vascularized cartilage after 2 weeks. Circumferential tracheal defects were reconstructed in 5 animals by means of tubes of vascularized cartilage with preservation of the established blood supply around the grafts. The experimental animals were followed until signs of dyspnea became apparent. After follow-up and euthanasia, cartilage viability and regeneration of respiratory epithelium were evaluated. A viable plate of cartilage that was intensely attached to the vascularized fascia flap was found in the control animals. The animals from the experimental group showed dyspnea after a mean follow-up period of 22.6 days because of cartilage necrosis with loss of airway support. Cartilage graft revascularization and remucosalization were limited to 18.1% of the initial surface area of the cartilage tube. Mucosal coverage was seen at the anastomoses, whereas the middle part of the cartilage tube underwent necrosis. We conclude that tubes of autologous cartilage show problematic healing when placed inside the airway. Migration of vascularized connective tissue, migration of respiratory epithelium, and preservation of the viability of the cartilaginous graft were limited to a short segment at the anastomotic sites.