Airway geometry and rhinomanometric measurement methods.

A: To measure airway geometries of all cases in the same condition, X-ray computed tomography (X-CT) scanning measurements were conducted using the Frankfort horizontal plane (white line) so that it was perpendicular to the floor in a maximal intercuspal position, with mouth closed, the tongue pressing against the palate (white circle); B: The extracted airway geometry data were transformed into text files of Stereolithography (STL) format; C: Rhinomanometric measurements (i.e., nasal patency inspection) were also conducted before and after surgery operations in accordance with the anterior-mask method.