Investigating the Challenges of Managing Coexisting Subglottic Stenosis and Bronchopulmonary Diseases Medically Using Computational Modeling.

Abstract

Subglottic stenosis (SGS) coexists with bronchopulmonary disease, complicating topical therapy given the distinct anatomical targets. Optimizing inhaled medication delivery to both regions remain a therapeutic challenge. This study evaluates the ability of orally inhaled aerosol particles to achieve dual‑site deposition in SGS and bronchopulmonary regions. Computational modeling of orally inhaled drug particle delivery. Academic Medical Center. Digitally modified airways simulating 8 SGS variants, combining McCaffrey Stage I (5 mm) and II (15 mm) subglottic lengths with Cotton‑Myer Grade I (10%, 30%), Grade II (60%), and Grade III (90%) luminal constrictions. Oral inhalation at 15 L/min and particle transport were simulated for fluticasone propionate (FP; mean aerosol velocity 9.19 m/s, particle size range 1-8 μm) and ciclesonide (CIC; mean aerosol velocity 4.26 m/s, particle size range 1-4 μm) inhaler characteristics, and 6 particle‑size distributions M₁(1-5 μm), M₂(6-10 μm), M₃(1-10 μm) while maintaining the respective parent (CIC and FP) mean aerosol velocity. In the normal airway, CIC and FP inhalers achieved >80% bronchial deposition but ≤0.02% subglottic delivery. Among modified devices, M₂CIC optimized dual targeting, providing the highest subglottic deposition (0.09%) with preserved bronchial efficiency (69.46%). In SGS models, M₂CIC and M₂FP consistently achieved the most balanced delivery, with maximum deposition of M₂CIC = 8.4% and M₂FP = 7.86% at subglottic region, and M₂CIC = 69.89% and M₂FP = 61.02% at bronchial site. M₃ variants offered intermediate dual deposition at advanced and Grade III stenosis stages. M₂CIC and M₂FP inhaler modifications optimized dual-site supporting tailored device strategies for SGS with coexisting bronchopulmonary disease.