[Numerical simulation modeling of middle ear-eustachian tube ventilation based on Chinese digital visual human body]

Objective: To establish a three-dimensional model of middle ear-eustachian tube based on Chinese digital visual human dataset, and the deformation and pressure changes of the middle ear-eustachian tube system after eustachian tube opening are simulated by computer numerical simulation. Methods: The first female Chinese Digital Visual Human data was adopted. The images were imported by Amira image processing software, and the images were segmented by Geomagic software to form a three-dimensional model of middle ear-eustachian tube system, including eustachian tube, tympanum, tympanic membrane, auditory ossicles, and mastoid air cells system. The 3D model was imported into Hypermesh software for meshing and analysis. The structural mechanics calculation was carried out by Abaqus, and gas flow was simulated by Xflow. The tissue deformation and middle ear pressure changes during eustachian tube opening were numerically simulated by fluid-solid coupling algorithm. Several pressure monitoring points including tympanum, mastoid, tympanic isthmus, and external auditory canal were set up in the model, and the pressure changes of each monitoring point were recorded and compared. Results: In this study, a three-dimensional model of middle ear-eustachian tube and a numerical simulation model of middle ear ventilation were established, including eustachian tube, tympanum, mastoid air cells, tympanic membrane, and auditory ossicles. The dynamic changes of the model after ventilation could be divided into five stages according to the pressure. In addition, the pressure changes of tympanum and tympanic isthmus were basically synchronous, and the pressure changes of mastoid air cells system were later than that of tympanum and tympanic isthmus, which verified the pressure buffering effect of mastoid. The extracted pressure curve of the external auditory canal was basically consistent with that of tympanometry in terms of value and trend, which verified the effectiveness of the model. Conclusions: The numerical simulation model of middle ear-eustachian tube ventilation established in this paper can simulate the tissue deformation and middle ear pressure changes after eustachian tube opening, and its accuracy and effectiveness are also verified. This not only lays a foundation for further research, but also provides a new research method for the study of middle ear ventilation.