A method for estimating the Young's modulus of complete tracheal cartilage rings.

Cartilage is primarily responsible for maintaining the stability of the large airways; yet very little is known about the mechanical properties of airway cartilage. This work establishes a technique whereby average values for the equilibrium modulus of excised tracheal cartilage rings can be obtained. An apparatus was designed to apply preset deformations to a tracheal segment and to monitor the deforming force. Segments of four human tracheae obtained postmortem and containing three rings were mounted in the apparatus after being stripped of posterior membrane. The load-deformation behavior was analyzed with a model on the basis of thin curved beam theory. Agreement between predicted deformed shapes and those observed was good in three of the four cases and in the case of a short length of longitudinally split rubber tube. The technique is suitable for comparing mechanical properties of cartilage before and after an intervention.