Successful Circumferential Free Tracheal Transplantation in a Large Animal Model

ABSTRACT

Background: Long segment tracheobronchial stenoses are associated with high morbi-mortality rates and difficult treatment. Transplantation hasn't proved to be useful yet. Currently, the successful results achieved in small animal models couldn't be satisfactorily accomplished or extrapolated in large mammals. We aimed to evaluate the viability of orthotopic tracheal autoimplantation in an ovine model. Methods: All animals underwent tracheal transplantation of 4 cm (5–7 rings) of the cervical trachea and were divided randomly in two groups: isolated autoimplantation (Group A/6) and autoimplantation with omental wrapping (Group B/6). Clinical follow up and weekly bronchoscopical examinations were performed. The grafts were macroscopically, histologically, and bacteriologically analyzed. Results: In group A, four animals achieved their planed survival and were sacrificed up to 60 days after transplantation with viable grafts. In group B, only two sheep had successful results. Graft failure with infection, necrosis and severe stenosis was observed in the rest of the animals from both groups. Pseudomonas aeruginose was isolated in all cases. The main complication of the omental pedicle was vascular congestion and peritracheal hemorrhage. Conclusions: Contrary to the data reported to date, we found that tracheal transplantation is viable in a large mammal like the sheep. The main complication observed in this animal model was graft infection. The use of an omental pedicle with the technique applied worsened the grafts survival. The encouraging results obtained in this investigation justify further research in order to manage graft infection, leading us to establish a suitable large animal model for allotransplantation.

Keywords: :

• animal model
• autograft
• infection
• revascularization
• trachea

ACKNOWLEDGMENTS

We thank the Veterinary Doctors María Inés Besansón, Pedro Iguaín, and Marta Tealdo for taking care of the animals during surgical and anesthesiological procedures. In addition, we thank Julio Martínez and Fabián Gauna for their technical assistance as well as Juan Ocampo, Juan Carlos Mansilla, and Osvaldo Sosa for daily care of animals.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.