University Clinic Dresden, Department of Otolaryngology, Head and Neck Surgery, Technische Universität Dresden, Fetscherstraße 74, 01307 Dresden, Germany.
Hear Res. 2021 Jun;405:108233. doi: 10.1016/j.heares.2021.108233. Epub 2021 Apr 14.
Hearing a sound produces vibrations of the ossicles in the middle ear, which can be measured in the micrometer to nanometer range. Destruction of middle ear structures results most commonly from chronic inflammatory diseases. In these cases, passive and active middle ear implants are used for reconstruction of the ossicular chain. The positioning of the implants depends primarily on the surgeon's experience. So far, no objective assessment has been conducted to affirm if the chosen positioning is the best in each specific case. We have established a new method, allowing us to measure the middle ear transfer function (METF) intraoperatively. Using the new method, a magnet is placed on the umbo of the malleus handle and is stimulated by a coil positioned underneath the head. The resulting vibration is measured on the stapes footplate using Laser Doppler vibrometry (LDV). Acoustic and electromagnetic excitation show comparable METF in lower frequencies, which differ up to 10 dB in frequencies over 1 kHz. The position of the coil does not play a relevant part in the METF, whereas the location of the magnet on the tympanic membrane highly impacts the METF. This technique demonstrates reproducible results. Electromagnetic excitation is comparable to sound excitation and is suited for measuring the METF. A stable positioning of the magnet on the umbo is essential in order to acquire valid data.
听到声音会引起中耳听小骨的振动，这些振动的幅度可以在微米到纳米范围内进行测量。中耳结构的破坏最常见于慢性炎症性疾病。在这些情况下，通常使用被动和主动中耳植入物来重建听小骨链。植入物的定位主要取决于外科医生的经验。到目前为止，还没有进行客观评估来确定所选的定位是否是每个特定病例中最好的。我们已经建立了一种新的方法，可以在手术中测量中耳传递函数（METF）。使用新方法，将磁铁放置在锤骨柄的鼓脐上，并通过放置在头部下方的线圈对其进行刺激。使用激光多普勒测振仪（LDV）在镫骨足板上测量产生的振动。电磁激励和声学激励在低频下显示出可比的 METF，但在 1 kHz 以上的频率下，它们的差异可达 10 dB。线圈的位置在 METF 中没有起到相关作用，而鼓膜上磁铁的位置对 METF 有很大的影响。该技术显示出可重复的结果。电磁激励与声音激励相当，适用于测量 METF。为了获得有效数据，必须将磁铁稳定地放置在鼓脐上。
