HYDRATION RECOVERY OF CANINE THYROARYTENOID MUSCLE TISSUE AFTER VARYING LEVELS OF DEHYDRATION

We observed and calculated the solid and liquid volumes and mass parameters of canine vocal fold thyroarytenoid (TA) muscle at tissue dehydration levels of 30% and 70% followed by a complete rehydration to examine the effects of hydration recovery with respect to biphasic properties of the TA muscle in relation to the vocal fold lamina propria. Twenty samples of TA muscle were harvested from 10 canine larynges. Each sample group was subjected to either 30% or 70% dehydration. Following dehydration, the samples rehydrated until the tissue mass stabilized. The solid volume and mass fraction, liquid volume and mass fraction, liquid–solid volume and mass ratios, and degree of hydration recovery were calculated. Median liquid–solid volume ratios were significantly different between the 30% and 70% groups after rehydration and between the medians of 30% and 70% liquid–solid mass ratios after rehydration. The means of solid mass fraction, liquid mass fraction, solid volume fraction, and liquid volume fraction all displayed statistically significant differences. Irreversible tissue damage undergone via severe dehydration of the TA muscle indicates the anatomical and physiological similarity between the TA muscle and the lamina propria. The results imply the significance of the biphasic theory in the construction of biomechanical models.