Biomechanics of the Eustachian Tube: An In Situ Study

HYPOTHESIS: The goal of this research is to gain deeper insight into the Eustachian tube mechanics using sheep cadaver to improve clinical management of ET diseases. BACKGROUND: Sheep are widely used to study the mechanics of the ET. However, the anatomic suitability of using sheep to study the human ET is poorly characterized. The aim of this study is to measure ET opening in cadaveric sheep specimens to understand its mechanics and compare the sheep ET anatomy to the human anatomy. METHODS: Five fresh-frozen sheep cadavers were used to study the ET mechanics. Using an in situ testing approach coupled with a µCT X-ray scanner, a muscle group was incrementally loaded. Results were compared with an unloaded human cadaver specimen to assess translatability. RESULTS: In all five sheep specimens, a gradual ET opening occurred upon loading the soft palate muscle group, but complete opening was not achieved. Comparison revealed significant structural differences between sheep and human cadaver anatomy, including ET orientation, relative position to surrounding bone structures, and muscle group angles. CONCLUSION: The developed method allowed to accurately track the ET opening in sheep. There were significant differences between human and sheep, which questions the suitability of using sheep to study the ET. As a result, future use of sheep to study the human ET has considerable limitations.