Yuanyuan Tang

Objective: To review the existing literature on the application of computational fluid dynamics methods to study nasal particle deposition and to summarize and analyze the factors affecting nasal particle deposition in order to provide theoretical references for the development of future transnasal drug delivery devices and the prevention of respiratory‐related diseases.Data Source: PubMed and CNKI databases.Methods: A search of all current literature (up to and including February 2023) was conducted. Search terms related to the topic of factors influencing nasal particle deposition were identified, and queries were conducted to identify relevant articles.Results: Both the properties of the particles themselves and the environmental conditions external to the particles can affect particle deposition in the nasal cavity, with particle deposition showing a positive correlation with particle size, particle density, and airflow velocity, with increasing subject age leading to a decrease in deposition, and with the relationship between airflow temperature and humidity still requiring more research to further explore.Conclusions: With the popularity of computational fluid dynamics, more and more scholars have applied computational fluid dynamics technology to explore the influence of different parameters on particle deposition. By summarizing and analyzing the influence law of various factors on deposition, it can provide a theoretical basis for the future development and application of transnasal drug delivery devices and the prevention of respiratory‐related diseases, which makes a significant contribution to the optimization of clinical disease prevention and treatment.Level of Evidence: NA.

To build a finite element numerical model of the nasal and nasopharyngeal cavities in healthy subjects and analyze the particle deposition characteristics of the nasal and nasopharyngeal cavities under different conditions, in order to investigate the influencing factors of particle deposition in the nasal and nasopharyngeal cavities of healthy subjects from the perspective of biomechanics, and to provide reference for the potential predisposing factors of clinical nasal and nasopharyngeal diseases and transnasal drug delivery methods. The nasal multi-layer spiral CT data of a healthy adult male volunteer was collected, and a three-dimensional numerical model was reconstructed based on the obtained image data (the model included nasal cavity, nasopharyngeal cavity, and pharyngeal cavity), and then numerical simulations were performed for particle deposition under different airflow rate, particle size and particle density conditions. In the reconstructed model, the nasal threshold, the nasal vestibule, the anterior part of the inferior and middle turbinates, and the posterior wall of the nasopharyngeal apex are the most likely areas for particle settling. When the airflow rate was 30L/min and 60L/min, the deposition efficiency(DE) of the reconstructed model was more than 80% with different particle diameters and particle densities. When the particle diameter is 10um and 15um, the deposition efficiency of the reconstructed model can reach more than 90% under different airflow rate and particle density. When the particle density and airflow rate were constant, the deposition efficiency of particles in the posterior wall of the nasopharynx decreased as the particle diameter became larger. A numerical model of nasal and nasopharyngeal cavity biomechanics can be established to explore the important influencing factors of particle deposition in the nasal and nasopharyngeal cavities from a biomechanical perspective. It was found that: 1. particle deposition mainly at the nasal threshold and nasal vestibule in the nasal cavity, and mainly at the posterior wall of the nasopharyngeal apex in the nasopharyngeal cavity; 2. airflow velocity, particle size and density all had effects on particle deposition rate, among which particle size had the greatest effect on particle deposition, followed by airflow rate, and the effect of particle density changes on particle deposition was not significant; 3. when particle density and airflow rate were constant, the smaller the particle diameter, the the more particle deposition in the nasopharyngeal cavity, the larger the particle diameter, the more particle deposition increases in the anterior part of the nasal cavity, and the less particle deposition in the nasopharyngeal cavity; 4. As the particle diameter increases, the particle deposition in this reconstructed model increases.

Background Nasal vestibular cyst is a non-dental cystic mass that occurs under the skin at the base of the nasal vestibule. The primary treatment is a transnasal endoscopic excision of the cyst wall at the base of the nose to open the cyst wall at the base of the nasal cavity, namely, marsupialization. Methods We present a patient with bilateral nasal vestibular cysts with sinus tract formation. This patient underwent marsupialization under general anesthesia because of the presence of facial swelling and other symptoms. Results After a 4-year follow-up, our studied case show a significantly improved radiological outcome and clinical prognosis. Conclusions Compared to unilateral lesions, bilateral nasal vestibular cysts are more likely to be underdiagnosed due to the deceptive nature of the bilateral anatomy observed from the radiological findings. With this rare clinical case reported in this study, we hope our experience in diagnosis and treatment will provide a reference for otolaryngologist surgeons managing similar patients.