3D Printed Airway Splints: Pre-clinical and Clinical In Vivo Degradation and Tissue Response

Abstract Tracheobronchomalacia (TBM) in children is a congenital or acquired deficiency of tracheobronchial cartilages that causes dynamic airway collapse, respiratory difficulties, and, in severe cases, acute life-threatening events and death. A previous study tested a bellowed 3D printed polycaprolactone (PCL) airway splint (denoted Airway Support Device – ASD) to treat TBM with a solid arch under fatigue in vitro, in a Yucatan swine in vivo model for 1 and 2 years, and lastly to treat patients with TBM under FDA Expanded Access clearance. Both in vitro fatigue and in vivo results demonstrated that this design had a risk for fracture under growth, and in addition restricted airway growth in the pre-clinical animal model. The goal of this proposal is to 1) develop new flexible ASD designs that allow radial and longitudinal growth while reducing fracture risk and 2) develop a new computational simulation combining growth, degradation and PCL elastic-plastic damage models to predict airway growth and ASD damage both in a pre-clinical model for Aims 2 and 3 as well as for a clinical model in Aim 4. It is hypothesized that a new auxetic design will allow more airway growth and show less damage than the current ASD designs. It is also hypothesized that the new growth/degradation simulation will correctly predict the effects of ASD design on airway growth and device damage. Both hypotheses will be tested using a 6-month and 2-year large pre-clinical animal study. Patient implantation to treat TBM will be continued under expanded access. Finally, data obtained in this study will be used to support an Investigational Device Exemption (IDE) to the FDA.