Ideal Particle Sizes for Inhaled Steroids Targeting Vocal Granulomas: Preliminary Study Using Computational Fluid Dynamics. (21st November 2017)

• Record Type: Journal Article
• Authors: Perkins, Elizabeth L.; Basu, Saikat; Garcia, Guilherme J. M.; Buckmire, Robert A.; Shah, Rupali N.; Kimbell, Julia S.
• Is Part Of: Otolaryngology--head and neck surgery. Volume 158:Number 3(2018)
• Page Start: 511
• Page End: 519
• Publication Date: 2017-11-21
• Subjects: computational fluid dynamics (CFD) -- inhaled corticosteroids -- vocal fold granuloma; Head -- Surgery -- Periodicals; Neck -- Surgery -- Periodicals; Otolaryngology -- Periodicals; 617.51
• DOI: 10.1177/0194599817742126
• Languages: English
• ISSNs: 0194-5998

Abstract

Abstract : Objectives: Vocal fold granulomas are benign lesions of the larynx commonly caused by gastroesophageal reflux, intubation, and phonotrauma. Current medical therapy includes inhaled corticosteroids to target inflammation that leads to granuloma formation. Particle sizes of commonly prescribed inhalers range over 1 to 4 µm. The study objective was to use computational fluid dynamics to investigate deposition patterns over a range of particle sizes of inhaled corticosteroids targeting the larynx and vocal fold granulomas. Study Design: Retrospective, case‐specific computational study. Setting: Tertiary academic center. Subjects/Methods: A 3‐dimensional anatomically realistic computational model of a normal adult airway from mouth to trachea was constructed from 3 computed tomography scans. Virtual granulomas of varying sizes and positions along the vocal fold were incorporated into the base model. Assuming steady‐state, inspiratory, turbulent airflow at 30 L/min, computational fluid dynamics was used to simulate respiratory transport and deposition of inhaled corticosteroid particles ranging over 1 to 20 µm. Results: Laryngeal deposition in the base model peaked for particle sizes 8 to 10 µm (2.8%‐3.5%). Ideal sizes ranged over 6 to 10, 7 to 13, and 7 to 14 µm for small, medium, and large granuloma sizes, respectively. Glottic deposition was maximal at 10.8% for 9‐µm‐sized particles for the large posterior granuloma, 3 times the normal model (3.5%). Conclusion: As the virtual granuloma size increased and the location became more posterior, glottic deposition and ideal particle size generally increased. This preliminary study suggests that inhalers with larger particle sizes, such as fluticasone propionate dry‐powder inhaler, may improve laryngeal drug deposition. Most commercially available inhalers have smaller particles than suggested here.