Objective: To describe for the first time a method of recording of Eustachian tube (ET) function by simultaneous and synchronous endoscopy and sonotubometry and explore its advantages compared with the performance of these tests independently.
Study design: Observational study.
Setting: Academic tertiary medical center.
Patients: Eighteen healthy subjects.
Intervention: Endoscopic nasopharyngoscopy with simultaneous, synchronous sonotubometry. Each subject performed three maneuvers: pronouncing the constant "k", swallowing and yawning.
Main outcome measures: The number of ET opening as a fraction of all efforts to open the tube, the duration of each opening and the sound intensity recorded by sonotubometry.
Results: Six (35.3%) of 17 subjects used for data analysis did not open their ET during swallowing. Excluding nonopeners, the ET opened in 3 of 4 of the swallows. The average duration of opening of the ET during swallowing was 0.44 seconds. The ET does not open every time the endoscopic view notes dilation. A negative sound pressure wave was recorded in a number of instances, immediately preceding a swallow-related opening. Contraction of the tensor veli palatini muscle was essential for ET opening.
Conclusion: Simultaneous synchronous endoscopy and sonotubometry may improve the accuracy of either performed separately as an ET function measurement tool. Sonotubometry may prevent a false-positive endoscopy (ET viewed as open but no functional patency achieved). Endoscopy can lower the threshold considered as positive for sonotubometry. A negative pressure wave recorded by sonotubometry may reflect the ET role of clearing the middle ear of secretions toward the nasopharynx. This novel measurement technique provided additional evidence that the tensor veli palatini muscle provides the final opening action of the ET.