Heterotopic Tracheal Transplantation Model	Orthotopic Tracheal Transplantation Model
Advantages	+ Easy to perform + Luminal obliteration with complete airway occlusion after 28 days + No physical affection of animals by OAD	+ Physical ventilation of the graft + Inhaled drug administration possible + Strong immunological reactions such as alloreactive IgM antibody production + Physiological thoracic milieu + Tracheal-tracheal anastomosis imitates the clinical setting
Disadvantages	- No ventilation of transplanted trachea - No evaluation of inhaled pathogens possible - Inhibition of mucociliary clearance and retained secretions - Peritoneal microenvironment instead of thoracic milieu	- Surgical training necessary - Luminal obliteration with luminal occlusion app. 45% after 60 days - Animals may develop symptoms of OAD