• airway stent
• atraumatic removal
• in-vivo molding

The following master's thesis describes and explains the design and testing of a new pediatric in-vivo moldable airway stent that will prevent tracheal collapse for children affected by a destructive disease called Tracheobronchomalacia (TBM). Tracheobronchomalacia is the most common congenital defect of the central airways and has been identified in up to 15% of infants and 30% of young children undergoing bronchoscopic examination for respiratory distress. Increased compliance and intrinsic weakness of the airway lead to collapse during expiration resulting in air trapping and poor gas exchange.
The ultimate goal of this research is to present a suitable alternative to existing treatments, thus overcoming and avoiding the risks and costs of positive air pressure ventilation, which is how neonates and infants are typically treated. Along with the stent and the delivery and removal tools, an in-vivo molding process was developed to quickly and inexpensively produce a customized stent, inside the patient’s airway, that would perfectly fit the lumen. The effective functionality of the device and of the newly designed procedures was first tested through ex-vivo benchtop experiments and was subsequently evaluated in
a porcine, in vivo experiment. A flexible silicone stent, filled with a UV-curable polymer resin, was molded in situ to the shape of the animal’s trachea within less than a minute and, at the end of the experimentation, was atraumatically removed.
Personalized stents can be vital for neonates and infants given the variability in airway anatomy associated with TBM and the vulnerability of adjacent cardiovascular structures.
In addition, the value of custom stents has been demonstrated in patients for which existing stents will not remain in position. The newly designed moldable stent described herein allowed mucus flow, resisted migration inside the airway while facilitating easy insertion and removal.