Acoustic Rhinometry and Paranasal Sinuses: A Systematic Study in Models, Anatomic Specimens, and In Vivo

Abstract Objective/Hypothesis: Acoustic rhinometry (AR) evaluates the cross‐sectional areas (CSA) of the nasal cavity through acoustic reflections. The aim of this study was to test whether the paranasal sinuses are a cause for the measurement of increased CSA in the posterior cavum of the nose. Study Design: Experimental study to evaluate the influence of paranasal sinus volume on AR measurements in two anatomic nose models, an anatomic specimen, and seven individuals. Methods: The paranasal sinus volume was systematically reduced by filling of the maxillary sinus with saline. The paranasal sinus ostia were enlarged in the models and the anatomic specimen by infundibulotomy and supraturbinal fenestration, with AR repeated thereafter. Results: No modification of the posterior area‐distance curve was found in the models, the specimen, and the individuals after changing the volume of the maxillary sinus with unmodified anatomy of the paranasal sinus ostia. The apparent CSA measured in the posterior cavum after infundibulotomy and supraturbinate fenestration in the models and the specimen increased with the volume of the paranasal sinuses. Conclusion: Regular anatomy provided, AR reveals reproducible measurements that correspond with the actual CSA up to the ostia of the paranasal sinuses. Untypical large openings to the paranasal sinuses (e.g., after paranasal sinus surgery) appear to contribute to the inaccuracy of AR by overlapping paranasal sinus CSA with the posterior part of the area distance curve.