Intranasal medication is commonly used for nasal disease. However, there are no clear specifications for intranasal medication delivery after functional endoscopic sinus surgery.

A three-dimensional model of the nasal cavity was constructed from computed tomography scans of an adult Chinese male who had previously undergone functional endoscopic sinus surgery in the right nasal cavity. Computational fluid dynamic simulations modelled airflow and particle deposition, based on discrete phase models.

In the right nasal cavity, more particles passed through the upper dorsal region, around the surgical area, and streamed into the right maxillary sinus region. In the left cavity, particles were distributed more regularly and uniformly in the ventral region around the inferior turbinate. A lower inspiratory airflow rate and smaller initial particle velocity assisted particle deposition within the right maxillary sinus cavity. In the right nasal cavity, the optimal particle diameter was approximately 10−5 m for maxillary sinus cavity deposition and 3 × 10−6 m for bottom region deposition. In the right nasal cavity, altered back head tilt angles enhanced particle deposition in the top region of the surgical area, and altered right side head tilt angles helped enhance maxillary sinus cavity deposition.

This model indicates that a moderate inspiratory airflow rate and a particle diameter of approximately 10−5 m should improve intranasal medication deposition into the maxillary sinus cavity following functional endoscopic sinus surgery.