Author(s)
Gregory R. Dion, MD
Jean-Francoi Lavoie, PhD
Paulo Coelho, DDS, PhD
Milan R. Amin, MD
Ryan C. Branski, PhD
Affiliation(s)
Brooke Army Medical Center; Biomomentum, Inc., New York University
Abstract:
Objectives/Hypothesis: Various animal models have been employed to investigate vocal fold (VF) and phonatory function. However, biomechanical testing techniques to characterize vocal fold structural properties vary and have not compared critical properties across species. We adapted a non-destructive, automated indentation mapping technique to simultaneously quantify VF structural properties (VF cover layer and intact VF) in commonly used species based on the hypothesis that VF biomechanical properties are largely preserved across species. Study Design: Ex vivo Methods. Canine, leporine, and swine larynges (n=4 each) were sagittally bisected, measured, and subjected to normal indentation mapping (indentation at 0.3mm; 1.2mm/s) with a 2mm spherical indenter to quantify normal force along the VF cover layer, structural stiffness, and displacement at 0.8mN; 2-D maps of the free VF edge through the conus elasticus were created for these characterizations. Results: Structural stiffness was 76.34mN/mm (1.47-730.59) for leporine, 24.30mN/mm (1.96-409.15) for canine, and 14.21mN/mm (5.49-44.69) for swine. For each species, the lowest values were along the free VF edge (mean ± SD; leporine: 3.90±2.08mN/mm, canine: 11.15±4.83mN/mm, swine: 8.72±2.79mN/mm). Similar results were obtained for the cover layer normal force at 0.3mm. On the free VF edge, mean (SD) displacement at 0.8mN was 0.24mm (0.05) in leporine, 0.12mm (0.05) in canine, and 0.13mm (0.03) in swine. Conclusions: Automated indentation mapping yielded reproducible biomechanical property measurement of the VF cover and intact VF. Divergent VF structural properties across canine, swine, and leporine species were observed.