Liquid volume and squeeze force effects on nasal irrigation using Volume of Fluid modelling

For various sinonasal conditions, including chronic rhinosinusitis, saline irrigation is an accepted standard-of-care treatment. This study was aimed at determining the effect of increased irrigation volumes and greater squeeze force on mucosal irrigation. A sinonasal cavity computational model was reconstructed from high-resolution CT scans of a healthy, unoperated 25-year old female. Seven combinations of irrigation volumes (70, 150, 200, and 400 mL) and squeeze forces (ramp time 0.1, 0.5, and 1.0 s) at a fixed head tilt of 0 degrees to the horizontal (Frankfort position) were performed. Velocity, pressure, and wall shear stress, together with mapping of surface coverage and residual volumes at specific locations and time were demonstrated. Higher volume irrigation (400 mL) and greater squeeze force (ramp time 0.1 s) improved irrigation coverage on the ipsilateral and contralateral sinonasal surfaces and increased shear force (approximately 140 Pa). An increase in irrigation volume from 70 to 150 mL approximately doubled sinus surface coverage and from 70 to 200 mL tripled sinus surface coverage. A faster squeeze also contributed to increased sinus surface coverage but its effect was less influential. We infer that the greater irrigation volume and squeeze force improve therapeutic benefit in terms of lavage and distribution of topical medications.