METHODS: Ex vivo porcine tracheas were harvested from the cricoid to the carina (average length was 11cm). These full-length tracheal specimens were sectioned into two equal segments with each section approximately 5.5cm long (containing at least 5 cartilaginous rings). The tracheal segments were tested for their maximal positive intraluminal pressure, axial lengthening, and degree of rotation. To measure intraluminal pressure, each end of an ex vivo tracheal segment was sealed with a custom designed and 3-dimensional (3D) printed cap and a pressure transducer was placed through one end to measure the intratracheal pressure. Tracheal length was evaluated by stretching the tracheal segments on their axis between two clamps and using ImageJ software (National Institutes of Health, Bethesda, MD) for measurements. Similarly, tracheal rotation was evaluated by rotating the tracheas between two clamps.