Intraglottal pressures in a static physical hemilarynx model

Intraglottal air pressures during oscillation of a single vocal fold against an immobile opposing structure are of interest to surgery after unilateral vocal fold removal and the validity of pressure data in hemi‐laryngeal bench studies. Intraglottal pressures and flows within a static hemilarynx were studied using Plexiglas model M5 with removable vocal folds and FLUENT, a commercial code using the control‐volume technique. For a minimal diameter of 0.04 cm, an axial glottal length of 0.3 cm, and a vertical static opposing wall, data were collected for converging and diverging angles of 5, 10, and 20 (and 0) deg. Pressure distributions were obtained for transglottal pressures of 3 to 40 cm water. For divergent, zero, and smaller converging angles within the physical model, greater intraglottal velocities could be coaxed to favor one side or the other and were typically stable. The side of faster flow for divergent angles had lower pressure in the downstream third of the glottis ranging from approximately 5% to 20% of the transglottal pressure, which would produce asymmetrical forces acting on the opposing vocal folds. FLUENT results are in good agreement with the measured pressures. [Work supported by NIH R01DC03577.]