Mechanical stresses in the vocal folds during phonation are caused in part by impact forces associated with collision between the vibratory surfaces. These stresses may be responsible for the formation of nodules, polyps and cysts. The objective of this study was to investigate a method for measuring impact stress non-invasively. High-speed images of porcine larynges were studied using Digital Image Correlation (DIC), a method used to measure strain fields by tracking random speckle pattern deformations. Impact stresses may be estimated from the resulting data through the use of a Hertzian impact model and the elastic properties of the tissue. Methods to improve the speckling pattern for excised tissue were developed. Two dyes were found to produce speckles with a desirable Gaussian greyscale distribution, and good adhesion to the tissue. Superior surface strain results were obtained for two porcine larynges. The strain values obtained in a few regions of the superior surface were found to be comparable with previous results from a mechanical silicone model. Further work with animal models is needed in order or perfect the speckling procedure and to obtain more uniform results over the superior surface. Although challenges still exist before a similar method can be used with human subjects, these preliminary results suggest that DIC displays some potential for future clinical use. / Les contraintes mécaniques dans les replis vocaux durant la production vocale sont causées en grande partie par les forces d'impact entre les surfaces vibrantes. Ces contraintes peuvent causer l'apparition de nodules, polypes, or des cystes. Le but de cette etude était le développement d'outils pour la determination non-intrusive des contraintes d'impact à partir d'analyse des images obtenues par l'entremise d'une camera video-endoscopique. Des larynx de porc furent utilisés. Les cordes vocals furent recouvertes de substances permettant la vaporisation d'un nuage de peinture noire sur fond pale afin d'obtenir le champs de déformation a partir de correlations d'images digitales. Les résultats obtenus furent limités à quelques points sur la surface. Néanmoins, ces résultats sont en assez bon accord avec des mesures faites dans le cadre d'un etude précédante sur un modèle de silicone. Des applications éventuelles en milieu clinique sont envisageable, après des travaux supplémentaires de mise au point.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.107611 |
| Date | January 2012 |
| Creators | Young, Jonathan |
| Contributors | Luc Mongeau (Internal/Supervisor), Sam Joseph Daniel (Internal/Cosupervisor2) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Otolaryngology - Head and Neck Surgery) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | Electronically-submitted theses. |
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