Mesh independence validation.

BackgroundEustachian tube (ET) dysfunction is associated with middle ear pathologies; however, the quantitative relationship between ET opening and pressure equalization remains insufficiently characterized. Computational fluid dynamics (CFD) offers a robust tool for analyzing middle ear pressure dynamics, particularly in elucidating pressure equilibrium mechanisms under partial ET opening conditions.ObjectiveThis study aimed to investigate pressure dynamics in the tympanic cavity, mastoid antrum, and air cells during ET opening using CFD, to compare pressure distributions between full and partial openings, and to determine whether partial opening can achieve equilibration equivalent to full opening.MethodsEight normal temporal bones were reconstructed from high-resolution computed tomography scans of four healthy adults. ET openings were simulated at 10%, 30%, 50%, and 100% patency using CFD, and results were validated against in vivo Tubomanometry data. Pressure variations in the tympanic cavity, mastoid antrum, and air cells were monitored throughout the process. Mesh independence was verified to ensure reliability, and statistical analyses were conducted using SPSS 27.0, with P ResultsCFD simulations revealed distinct pressure dynamics within the ET–middle ear system. Airflow velocity peaked at the narrow isthmus, generating a localized pressure drop. Effective middle ear pressure equilibration—across the tympanic cavity, antrum, and mastoid air cells—was achieved with partial ET opening in most cases: 30% opening sufficed for full equilibration in two ears, while 50% opening achieved complete equilibration in six. This equivalence to full patency was consistently observed during pressurization, stabilization, and depressurization phases.ConclusionEffective middle ear pressure equilibration can be achieved with partial ET opening (50%) in most cases (75% of ears). These findings provide valuable insight into middle ear physiology and its response under pathological conditions, offering a theoretical basis for optimizing the management of ET dysfunction.背景 咽鼓管（Eustachian tube, ET）功能障碍与中耳病理密切相关，但目前对于ET开放程度与压力平衡之间的定量关系仍未得到充分阐明。计算流体动力学（Computational Fluid Dynamics, CFD）是分析中耳压力动态变化的可靠工具，尤其有助于阐明ET部分开放状态下的压力平衡机制。 目的 本研究旨在通过CFD模拟，探究ET开放过程中鼓室、乳突窦及乳突气房内的压力动态变化，对比完全开放与部分开放状态下的压力分布差异，并明确部分开放的ET是否可达到与完全开放等同的压力平衡效果。 方法 本研究对4名健康成年人的高分辨率计算机断层扫描（Computed Tomography, CT）影像进行三维重建，获得8例正常颞骨标本。通过CFD模拟ET分别以10%、30%、50%及100%的开放度进行开放，并采用体内咽鼓管测压（Tubomanometry）数据对模拟结果进行验证。全程监测鼓室、乳突窦及乳突气房内的压力变化。验证了网格无关性以确保模拟可靠性，并使用SPSS 27.0软件进行统计学分析，以P<0.05为差异具有统计学意义。 结果 CFD模拟结果显示，ET-中耳系统内存在独特的压力动态变化特征。气流速度在狭窄的咽鼓管峡部达到峰值，引发局部压力下降。在大多数病例中，ET部分开放即可实现鼓室、乳突窦及乳突气房的有效中耳压力平衡：30%开放度即可使2例标本实现完全平衡，50%开放度则可使6例标本达到完全平衡。在加压、稳定及减压三个阶段中，均观察到部分开放与完全开放的压力平衡效果等效。 结论 大多数病例（75%）中，ET以50%的开放度即可实现有效的中耳压力平衡。本研究结果有助于深入理解中耳生理及其在病理状态下的反应，为优化ET功能障碍的临床管理提供了理论依据。