Synchronous 3D Imaging of the Medial and Superior Vocal Fold Surface in an Excised Human Hemilarynx

Objective: This study investigates relationships between the oscillation behavior of the medial and superior vocal fold (VF) surfaces during sustained phonation in a human cadaver hemilarynx. Methods: An experimental test stand synchronously captured the medial and superior VF surfaces of a human ex vivo hemilarynx during sustained phonation using two high-speed camera setups in 24 experimental settings. The 3D coordinates of the medial VF surface were reconstructed by triangulation of sewn-in marker points, while laser-based reconstruction was used for the superior VF surface. Correlation analysis and linear regression were used to quantify the connections of the mean and maximal vertical and lateral VF displacements and the VF velocities. Additionally, stepwise linear regression was used to analyze the impact of the measurement variables mean flow rate, adduction and elongation. Results: Strong linear relationships between all of the tested corresponding parameter pairs of the superior and medial VF surfaces were found (p<.001). Mean and maximum vertical displacements of the medial surface were both approximately 50% of the superior surface. The mean lateral displacements for the medial surface were 12% below the superior surface but 12% higher for the maximum values. The mean and maximum VF velocities were 32% and 36% lower for the medial surface. Conclusion: The suggested multi-modal test stand allows efficient, comprehensive analysis of human hemilarynges and provides promising information about the interaction of the different VF areas and opens up the systematic analysis of multiple hemilarynges. Significance: In future, our results could integrate into ENT diagnostics using 3D laryngoscopy where the hidden medial VF surface dynamics may be predicted from the observable superior surface.