Numerical study of the effect of nasopharynx airway obstruction on the transport and deposition of nanoparticles in nasal airways

Although there is abundant literature for both experimental and numerical studies of respiratory aerosol exposure in nasal airways, research efforts concentrating on diseased nasal cavities undergoing pathological changes remain significantly less. This paper presents a comparative study of pre- and post-operative nasal airway models based on a 3-year-old nasal cavity model with severe nasopharynx obstruction due to the presence of adenoid hypertrophy. By numerically comparing the airflow dynamics and nanoparticle deposition characteristics in original diseased and post-operative healthy nasal airway models, our results demonstrated that nasopharynx obstruction can induce significantly biased flow distribution in the main nasal passage, despite the obstruction site is located downstream of the nasal airway. In addition, the regional particle deposition analysis revealed that the affected area can receive better nanoparticle aerosol delivery after receiving surgical treatment (adenoidectomy) due to restored normal flow fields. More importantly, ventilation and particle deposition improvements were achieved for the olfactory region in the post-operative nasal model, which indicates a more promising olfactory drug delivery using nanoparticles. Research findings are expected to provide scientific evidence for adenoidectomy planning and intranasal aerosol therapy, which can substantially improve present clinical treatment outcomes.