Comparative study of inhaled corticosteroid deposition in pediatric mouth-throat airway with tonsil hypertrophy

Pediatric tonsillar hypertrophy (TH) represents one of the most prevalent and frequently diagnosed respiratory conditions in children, in severe cases, it can precipitate obstructive sleep apnea (OSA), thereby increasing the potential risk of neurocognitive impairment and severely affecting the patient's psychological well-being and quality of life. Tonsillectomy is currently the primary therapeutic intervention. However, the formulation of treatment strategies largely depends on the clinician's experience. In this study, we developed a computational fluid-particle dynamics (CFPD) approach and conducted an investigation involving three cases (4, 5, and 7 years old respectively) of severe oropharyngeal obstruction caused by pediatric tonsillar hypertrophy (TH). This study examines the impact of oropharyngeal obstruction on airflow dynamics and the transport of medicinal aerosols within the MT airway. Utilizing models of MT obstruction exceeding 75 %, we created post-operative models after virtual tonsillectomy and meticulously compared the airflow dynamics and ICS particle deposition characteristics in the original pathological (pre-operative model) and post-operative healthy (post-operative model) MT airway models. Quantitative data supporting our findings demonstrate significant improvements: a 42.65 % reduction in pressure drop across the obstructed airway segments, a 92.94 % reduction in wall shear stress (WSS), and a 18.09 % reduction of Maximum DE in aerosol deposition efficiency following the intervention. These results underscore the profound influence of anatomical variations on treatment efficacy and highlight the significant impact of oropharyngeal obstruction on airflow dynamics and the transport of medicinal aerosols in the MT airway. Furthermore, the analysis of regional particle deposition reveals that post-surgical intervention (tonsillectomy) enhances the delivery efficiency of nebulized ICS particles in the oropharynx by restoring a normal flow field. Most significantly, the post-operative MT model demonstrates enhanced airflow and particle deposition in distal tracheal airway region, suggesting a broader applicability of nebulized ICS therapy for pulmonary diseases. These research findings establish a scientific foundation for developing tonsillectomy plans and nebulized inhalation treatments via the MT airway for intrathoracic respiratory tract conditions, including pediatric asthma, with the potential to significantly enhance current clinical treatment outcomes.