Assessment of Cottle's areas through the application of a mathematical model deriving from acoustic rhinometry and rhinomanometric data.

OBJECTIVES: Each nasal area, as defined by Cottle, has a different influence on the nasal airflow. The longitudinal distribution of resistances in nasal cavities was calculated by the anterior rhinomanometry and acoustic rhinometry data. DESIGN: Dynamic study of Cottle's areas in normal subjects was carried out by rhinomanometry and acoustic rhinometry. SETTING: Study by the Department of Otolaryngology of the University of Rome-La Sapienza. PARTICIPANTS: Twenty-seven Caucasian adults in local and general healthy conditions took part and completed this study, with a total of 54 nasal cavities included because of negativity at ENT-examination and clinical history, with normal respiratory parameters at the rhinomanometry and acoustic rhinometry. MAIN OUTCOME MEASURES: We determined nasal and acoustic resistances, nasal volumes and cross-sectional surface areas, as defined by Cottle, using nasal endoscopy. The longitudinal distribution of nasal resistances was obtained by integrating experimental surface areas using a novel mathematical model. The estimation of the longitudinal nasal resistance variations as a result of a theoretical reduction of the surface areas. RESULTS: The reduction of the 2-3-1 areas (in this order of importance) showed the greatest influence on the nasal resistances with coefficients of determinations greater than 0.98, this being quite different from that of the areas 4 and 5 for quite smaller area reduction percentages. CONCLUSIONS: The areas 2-3-1 control the overall nasal resistance so the surgical procedures on these areas greatly influence the dynamics of nasal airflow. The mathematical model developed here gives useful information to nasal functional surgery and may be applied to other schemes of nasal cavity.