Quantitative representation of Eustachian tube component movements during swallowing.

OBJECTIVE: Describes a method of dynamic video-endoscopy of the Eustachian tube (ET) orifice at the nasopharynx to quantitatively represent ET component movements during swallowing using a graphic function and analyze their importance to its opening mechanics.

METHODS: This was a pilot study of relational event capture using a polar coordinate system applied to trans-nasal video-endoscopic recordings of the ET during 3 swallows in 5 adults. After topical anesthesia of the nose, a 45° telescope was introduced unilaterally and focused on the ipsilateral ET orifice. For each recording, consecutive still-frame images were analyzed by identifying 4 fixed-point locators; the luminal apex, lateral and medial walls and the torus. A frame-normal, horizontal line was constructed through the apex and, then, the medial angles defined at the intersection of the horizontal line and the lines from apex to each point locator were measured. The magnitudes of these angles were plotted as a function of time (i.e. successive frames) for each swallow.

RESULTS: The resulting graphs captured the "in plane" relational movements for the locator points during a swallow. Complex interactions among the ET components were resolvable and the patterns were reproducible across swallows. Individual peculiarities observable on review of the corresponding "movies" such as double-swallows, delayed swallows and ET luminal constriction were easily identified in the graphic representation.

CONCLUSION: This methodology is potentially useful for summary presentations of the ET mechanics of individual patients and for quantifying differences in those mechanics between groups defined by their history of middle-ear disease.