Regional blood flow to the canine vocal fold at rest and during phonation

Recent reports have suggested that blood flow to the vocal fold decreases during phonation. However, these studies relied on indirect measures of blood flow, such as tissue oxygen tension. Among the differing methods of measuring blood flow, one of the most sensitive is the microsphere surface technique. This technique has been effective in assessing the overall and regional blood flow to a number of different organs, including the cochlea. Employing an in vivo canine model, we injected microspheres into the left atrium. From there, they were distributed and became entrapped in the tissues in proportion to blood flow. We measured the blood flow to the entire vocal fold, as well as the lamina propria and muscularis layers. The results revealed a statistically significant (p less than .002) increase in blood flow on phonation. The increase, however, was due to increased flow to the muscularis layer. The flow to the lamina propria remained unchanged during phonation.