Acoustic rhinometry: rationale and perspectives.

Acoustic rhinopharyngometry provides a new, non-invasive access to upper airways geometry. In this experimental and clinical study the diagnostic value of acoustic rhinopharyngometry was investigated. In vitro measurements showed adequate accuracy, reliability and spatial resolution within the range of nasal and epipharyngeal dimensions. Clinical measurements confirmed reasonable reproducibility for the evaluation of nasal (NV) and epipharyngeal (EV) volume. Decongestion with xylometazoline resulted in a 36% enlargement of nasal volume on average. The alteration of pharyngeal soft tissues due to maxillomandibulary advancement of 10 mm correlated to an increase of the EV-index of 6 cm3. Acoustic rhinometry identifies location and amount of nasal obstruction and in addition allows differentiation between obstruction due to mucosal hypertrophy and that due to skeletochondral deformity. Changes in the epipharyngeal volume following maxillary and mandibular osteotomies can be estimated in comparison with the preoperative situation.