Impact of medialization laryngoplasty on dynamic nanomechanical vocal fold structure properties

Dion, Gregory R.; Benedict, Peter A.; Coelho, Paulo G.; Amin, Milan R.; Branski, Ryan C.

doi:10.1002/lary.26963

Cited by 9 publications

(20 citation statements)

References 19 publications

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“…Due to material nonlinearity, stretching of the vocal folds around the implant would significantly increase vocal fold stiffness in the transverse plane. This may explain the stiffness increase reported in a recent indentation study [19]. Previous studies have shown that increasing transverse stiffness may increase phonation threshold pressure and reduce the vertical phase difference and thus the closed quotient of vocal fold vibration [20], which may be undesirable, but may also suppress vocal instabilities [21].…”

Section: Discussionmentioning

confidence: 82%

Three-dimensional vocal fold structural change due to implant insertion in medialization laryngoplasty

Zhang

Gray

et al. 2020

PLoS ONE

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Glottal insufficiency due to vocal fold paralysis, paresis, or atrophy often leads to degraded voice quality. One of the primary surgical intervention procedures to treat glottal insufficiency is medialization laryngoplasty, in which an implant is inserted through a lateral window on the thyroid cartilage to medialize the vocal folds. While the goal of medialization is to modify the vocal fold structure to restore normal phonation, few studies have attempted to quantify such structural changes of the vocal folds. The goal of this study is to quantify the three-dimensional structural changes of the vocal folds due to implant insertion in medialization laryngoplasty, and evaluate its potential effect on voice production. Medialization laryngoplasty were performed in excised human larynges using implants of different stiffness. Magnetic resonance images of the larynges were obtained with and without implant insertion. The results showed that implant insertion significantly changed the original body-cover structure of the vocal folds, with the implant taking over the large space used to be occupied by the original body layer and the vocal fold being stretched into a thin layer wrapped around the implant. The medial-lateral dimension of the vocal fold was significantly reduced from about 4 mm to 1 mm, and the vocal fold was stretched in the coronal plane by about 70%. It is hypothesized that use of implants with stiffness comparable to that of the vocal folds is beneficial because the degree of medialization can be adjusted without much negative effects on phonation frequency, phonation threshold pressure, or vibration amplitude.

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Section: Discussionmentioning

confidence: 82%

Three-dimensional vocal fold structural change due to implant insertion in medialization laryngoplasty

Zhang

Gray

et al. 2020

PLoS ONE

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“…[1][2][3] Indentation biomechanical testing techniques show promise in both animal models and engineered vocal fold products to objectively assess material stiffness and elasticity. [4][5][6][7][8] Comparison between excised human and canine vocal fold cover layers identified similar stiffness and elastic properties measured via Young's modulus. 5 These preliminary studies provided useful biomechanical information, but are time-consuming and traditionally require significant tissue dissection or disruption.…”

Section: Introductionmentioning

confidence: 77%

“…Unique laryngeal geometry and pliability of vocal fold tissues create a challenging environment for biomechanical testing approaches . Indentation biomechanical testing techniques show promise in both animal models and engineered vocal fold products to objectively assess material stiffness and elasticity . Comparison between excised human and canine vocal fold cover layers identified similar stiffness and elastic properties measured via Young's modulus .…”

Section: Introductionmentioning

confidence: 98%

“…Conversely, rheologic and force elongation measurements, earlier pioneered biomechanical tests, do not provide perpendicular displacement measurement of the vocal fold structure. Previous work from our lab illustrated the potential for micrometer scale measurements of intact vocal fold elastic and stiffness properties through dynamic nanomechanical analysis . Results were limited by the length of time necessary to complete the study and the complexity of adequately securing the specimen in the testing system exactly perpendicular to the indenter tip during testing.…”

Section: Introductionmentioning

confidence: 99%

“…Previous work from our lab illustrated the potential for micrometer scale measurements of intact vocal fold elastic and stiffness properties through dynamic nanomechanical analysis. 7,8 Results were limited by the length of time necessary to complete the study and the complexity of adequately securing the specimen in the testing system exactly perpendicular to the indenter tip during testing. Between each test position on each sample, the specimen requires manual repositioning.…”

Section: Introductionmentioning

confidence: 99%

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Automated Indentation Mapping of Vocal Fold Structure and Cover Properties Across Species

et al. 2018

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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 7.79gf/mm (0.15–74.55) for leporine, 2.48gf/mm (0.20–41.75) for canine, and 1.45gf (0.56–4.56) for swine. For each species, the lowest values were along the free VF edge (mean ± SD; leporine: 0.40±0.21gf/mm, canine: 1.14±0.49gf/mm, swine: 0.89±0.28gf/mm). Similar results were obtained for the cover layer normal force at 0.3mm. On the free VF edge, mean (SD) displacement at 0.08gf was 0.14mm (0.05) in leporine, 0.11mm (0.03) in canine, and 0.10mm (0.02) 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. Level of Evidence N/A

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Quantifying vocal fold wound‐healing biomechanical property changes

et al. 2019

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Objectives Development of novel vocal fold (VF) therapeutics is limited by a lack of standardized, meaningful outcomes. We hypothesize that automated microindentation‐based VF biomechanical property mapping matched to histology permits quantitative assessment. Study Design Ex vivo. Methods Twelve anesthetized New Zealand white rabbits underwent endoscopic right VF injury. Larynges were harvested/bisected day 7, 30, or 60 (n = 4/group), with four uninjured controls. Biomechanical measurements (normal force, structural stiffness, and displacement at 1.96 mN) were calculated using automated microindentation mapping (0.3 mm depth, 1.2 mm/s, 2 mm spherical indenter) with a grid overlay (>50 locations weighted toward VF edge, separated into 14 zones). Specimens were marked/fixed/sectioned, and slides matched to measurement points. Results In the injury zone, normal force/structural stiffness (mean, standard deviation [SD]/mean, SD) increased from uninjured (2.2 mN, 0.64/7.4 mN/mm, 2.14) and day 7 (2.7 mN, 0.75/9.0 mN/mm, 2.49) to day 30 (4.3 mN, 2.11/14.2 mN/mm, 7.05) and decreased at 60 days (2.7 mN, 0.77/9.1 mN/mm, 2.58). VF displacement decreased from control (0.28 mm, 0.05) and day 7 (0.26 mm, 0.05) to day 30 (0.20 mm, 0.05), increasing at day 60 (0.25 mm, 0.06). A one‐way ANOVA was significant; Tukey's post hoc test confirmed day‐30 samples differed from other groups (P < 0.05), consistent across adjacent zones. Zones far from injury remained similar across groups (P = 0.143 to 0.551). These measurements matched qualitative histologic variations. Conclusion Quantifiable VF biomechanical properties can be linked to histology. This technological approach is the first to simultaneously correlate functional biomechanics with histology and is ideal for future preclinical studies. Level of Evidence NA Laryngoscope, 130:454–459, 2020

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Impact of medialization laryngoplasty on dynamic nanomechanical vocal fold structure properties

Abstract: NA. Laryngoscope, 128:1163-1169, 2018.

Cited by 9 publications

References 19 publications

Three-dimensional vocal fold structural change due to implant insertion in medialization laryngoplasty

Three-dimensional vocal fold structural change due to implant insertion in medialization laryngoplasty

Automated Indentation Mapping of Vocal Fold Structure and Cover Properties Across Species

Quantifying vocal fold wound‐healing biomechanical property changes

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