Padurariu Simona, de Greef Daniël, Jacobsen Henrik, Nlandu Kamavuako Ernest, Dirckx Joris J, Gaihede Michael
Department of Otolaryngology, Head and Neck Surgery, Aalborg University Hospital, Hobrovej 18, 9000 Aalborg, Denmark.
Laboratory of Biomedical Physics, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
Hear Res. 2016 Oct;340:113-120. doi: 10.1016/j.heares.2015.12.004. Epub 2015 Dec 15.
The tympanic membrane (TM) represents a pressure buffer, which contributes to the overall pressure regulation of the middle ear (ME). This buffer capacity is based on its viscoelastic properties combined with those of the attached ossicular chain, muscles and ligaments. The current work presents a set of in vivo recordings of the ME pressure variations normally occurring in common life: elevator motion. This is defined as a situation of smooth ambient pressure increase or decrease on a limited range and at a low rate of pressure change. Based on these recordings, the purpose was a quantitative analysis of the TM buffer capacity including the TM compliance.
The pressure changes in seven normal adult ME's with intact TM's were continuously recorded directly inside the ME cavity during four different elevator trips using a high precision instrument. The TM buffer capacity was determined by the ratio between the changes in ME and the ambient pressure. Further, the ME volumes were calculated by Boyle's Law from pressure recordings during inflation-deflation tests; subsequently the TM compliance could also be calculated. Finally, the correlation between the ME volume and buffer function was determined.
Twenty-one elevator trips could be used for the analysis. The overall mean TM pressure buffering capacity was 23.3% (SEM = 3.4), whereas the mean overall compliance was 28.9 × 10 μL/Pa (SEM = 4.8). A strong negative linear correlation was found between the TM buffer capacity and the ME volumes (R = 0.92).
These results were in fair agreement with the literature obtained in clinical as well as temporal bone experiments, and they provide an in vivo reference for the normal ME function as well as for ME modeling. The TM buffer capacity was found more efficient in smaller mastoids. Possible clinical implications are discussed.
鼓膜（TM）是一种压力缓冲器，有助于中耳（ME）的整体压力调节。这种缓冲能力基于其粘弹性特性以及与之相连的听骨链、肌肉和韧带的特性。当前研究展示了一组在日常生活中常见的中耳压力变化的体内记录：电梯运行。这被定义为在有限范围内以低压力变化率平稳地增加或降低环境压力的情况。基于这些记录，目的是对包括鼓膜顺应性在内的鼓膜缓冲能力进行定量分析。
使用高精度仪器，在四次不同的电梯行程中，直接在七个鼓膜完整的正常成年中耳腔内连续记录压力变化。鼓膜缓冲能力由中耳压力变化与环境压力变化的比值确定。此外，根据充气 - 放气测试期间的压力记录，通过玻意耳定律计算中耳容积；随后也可计算鼓膜顺应性。最后，确定中耳容积与缓冲功能之间的相关性。
二十一次电梯行程可用于分析。鼓膜的总体平均压力缓冲能力为23.3%（标准误 = 3.4），而总体平均顺应性为28.9×10 μL/Pa（标准误 = 4.8）。发现鼓膜缓冲能力与中耳容积之间存在强烈的负线性相关性（R = 0.92）。
这些结果与临床及颞骨实验中获得的文献结果相当一致，为正常中耳功能以及中耳建模提供了体内参考。发现鼓膜缓冲能力在较小的乳突中更有效。讨论了可能的临床意义。
