Steroid eluting biocompatible stent for subglottic stenosis

Abstract

Objective: Develop a prototype steroid eluting stent suitable for endoscopic treatment of subglottic stenosis.

Methods: Rectangular-shaped spoke design stents thermally molded into horseshoe-shaped stents were developed using AutoCAD program, and printed on a Lulzbot 3D printer with polycaprolactone (PCL). Kenalog saturated AEROSIL 200 was embedded in the PCL filament. Horizontal radial force measurements were measured at baseline, 1 day, and 1 month when deformation switched from bending to compression. Amount of Kenalog eluted after 1 day, 1 week and 1 month were measured using HPLC.

Results: Horizontal pressure applied to the PCL stent corresponding to a 5-0 ET were 1.27 ± 0.38 lb. at baseline, 1.79 ± 0.045 lb. at 1 day, 1.94 ± - 0.22 lb. at 1 week and 2.07 ± 0.11 lb. at 1 month. The horizontal pressure applied to PCL stent corresponding to an 8-0 ET tube were 0.82 ± 0.018 lb. at baseline, 1.008 ± 0.045 lb. at 1 day, 0.95 ± - 0.064 lb. at 1 week and 1.078 ± 0.021 lb. at 1 month. The amount of Kenalog eluted increased from 5.78 µg/mL at 1 day to 15.01 µg/mL at 1 week to 19.35 µg/mL at 1 month.

Conclusion: This proof-of-concept project is an initial step to demonstrate and create a novel stent in the treatment of subglottic stenosis that applies expansile force on the trachea, elutes steroids and dissolves. Over time the expansile force along the trachea increases allowing the PCL to mucosalize, while it dissolves and continues to elute steroids. The limitations of this in vitro study necessitate experiments on animal models, such as rabbit tracheas to observe for complications and histologic changes.

Level of evidence: This proof-of-concept project is a Level 5 mechanism-based reasoning study.

Keywords: Dissolvable; Endoscopic intervention; Subglottic stenosis; Tracheal stent.