Magnetic drug targeting in post-operative human paranasal sinuses: a CFD–DPM study

BACKGROUND: Topical drug delivery to the paranasal sinuses remains challenging in chronic rhinosinusitis (CRS), even after functional endoscopic sinus surgery (FESS). This study evaluated magnetic drug targeting (MDT) for enhancing aerosolized drug delivery to post-operative sinuses. RESEARCH DESIGN AND METHODS: A computational fluid dynamics-discrete phase model was developed using two patient-specific post-operative sinonasal geometries: frontal drill-out (FDO) and full-house FESS (FHFESS). Sixty-six simulations assessed the effects of magnetic field strength, magnetic nanoparticle volume fraction, and magnetic source position on particle deposition. The primary outcome was deposition efficiency in the frontal sinuses (FS) and left maxillary sinus (MSL). RESULTS: A magnetic field of approximately 0.22 T increased FS deposition efficiency by up to 16-fold in the FDO model and 36-fold in the FHFESS model compared with non-magnetic conditions. Stronger fields caused premature nasal deposition. Increasing nanoparticle volume fraction reduced sinus deposition as particle inertia increased. In the MSL, selected magnetic configurations increased deposition efficiency by approximately 3-fold and 2.5-fold in the FDO and FHFESS models, respectively. CONCLUSIONS: MDT substantially improved post-operative sinonasal drug delivery when magnetic field strength, particle loading, and source placement were optimized. Limitations include the computational nature of the study and the use of two patient-specific geometries.