Learning Objectives:
Introduction: The Eustachian tube (ET) consists of an osseous and of a cartilaginous part which measure one thirds to two thirds of the overall length, respectively. Savic et al. reported that the shapes of bony portion of ET are divided into three groups (triangular, rectangular and irregular).
Methods: Bony portion of ET was examined by computed tomography (CT) in patulous Eustachian tube, chronic inflammation middle ear diseases and control group. The aeration of mastoid was also examined.
Results: The group with poor aeration of mastoid is significantly higher rate of triangular shape than good aeration group. In addition, the bone between cochlea and carotid artery in poor mastoid aeration group is thicker than good aeration group.
Conclusions: The shapes of the tympanic orifice and bony portion of the ET are various. The shapes of bony portion of ET are related to aeration of the mastoid cell. It is important to evaluate bony portion of ET before transtympanic ET surgery.
