ASPO005 - Quickshot: Mechanical Properties of 3D Printed Polycaprolactone Intraluminal Airway Stents
Friday, April 29, 2022
1:10 PM – 1:30 PM CT
Location: Landmark C
Joshua A. Stramiello, MD1, John-Paul Pham, AS2, Andrew Steward, AS2, Micah Tattao, AS2, Kendra Worthington, AS2, Matthew T. Brigger, MD, MPH1;
Otolaryngology-Head and Neck Surgery, Univ. of California, San Diego, San Diego, CA, 2School of Engineering, Univ. of California, San Diego, San Diego, CA.
Resident Physician University of California, San Diego San Diego, California
Introduction: Pediatric tracheomalacia is a complicated, patient-specific disease that requires a multidisciplinary approach to treat. Surgical interventions, external splinting and nondegradable intraluminal stents have high ratesconsiderable of morbidity. Polydioxanone is the only bioresorbable, intraluminal, tracheobronchial stent material reportedly used in pediatric subjects and has a short degradation time with structural integrity compromise in 4-8 weeks of placement. Other materials such as polycaprolactone (PCL) have been investigated in animal models with promising results. We present the mechanical properties of novel, patient-specific, 3D printed, intraluminal, PCL airway stents.
Methods: Diamond-lattice PCL (FacilanTM PCL 100) stents of two sizes (large 1cm diameter (D) x 2.5cm length (L) and small 0.5cm D x 1.4cm L) were designed using computer-assisted software (Solidworks 2020). The stents were 3D-printed via additive layering (Prusa MK3S) and molded to shape. A tensile test machine (Instron 3400) measured radial compression forces with a PLA cylindrical sleeve adaptor and linear compression testing with piston adaptors aligned at various locations. Stress-strain curves were derived for 4 stents (n=2 for each size) using MATLAB.
Results: Radial compression tests show an average Young’s modulus of 55.68 kPa for large stents and 45.83 kPa for small stents. Linear compression tests mimic physiological forces, and per compressed surface area of 22 mm2, large stents can resist 0.3kg of weight (133.49 kPa stress) at the seam (S) and 0.21kg (94.91 kPa) at cell intersections (I) at 50% compression. For small stents, weights of 0.15kg (68.58 kPa) (S) and 0.17kg (76.35 kPa) (I) were resisted at 50% compression.
Conclusion: The mechanical property test results show PCL has a Young’s modulus comparable to metallic stents used for intraluminal pediatric airway stenting. Linear force tests confirm large stents can support over half the weight of a newborn’s heart (20 g) imposed on one-sixth of its surface area. This study represents the first step towards developing practical methods for 3D printed, bioresorbable materials to treat a continually growing tracheobronchial airway with cartilaginous deficiencies while simultaneously reducing the morbidity of open surgery.