Chen Tao, Ren Liu-Jie, Yin Dong-Ming, Li Jia, Yang Lin, Dai Pei-Dong, Zhang Tian-Yu
Eye & ENT Hospital of Fudan University, Fenyang Road 83, Shanghai 200031, China.
Eye & ENT Hospital of Fudan University, Fenyang Road 83, Shanghai 200031, China; Department of Aeronautics and Astronautics, Fudan University, Handan Road 220, Shanghai 200433, China.
Hear Res. 2017 Sep;353:97-103. doi: 10.1016/j.heares.2017.06.006. Epub 2017 Jun 23.
The Vibrant Soundbridge (VSB) active middle-ear implant provides an effective treatment for mild-to-severe sensorineural hearing loss in the case of normal middle ear anatomy and mixed hearing loss in middle ear malformation. The VSB floating mass transducer (FMT), with proper couplers, can be installed on various structures of the ossicular chain, e.g., the short and long process of the incus, the stapes head, and the stapes footplate. A long process (LP) coupler is most commonly used for FMT attachment to the long process of the incus with intact ossicular chain, while CliP and Bell couplers are two standardized and reliable methods for FMT attachment to the stapes head with missing incus and malleus. However, the difference and relationship of the vibration properties among these three FMT couplers remain unclear. In the present study, the stapes footplate velocity responses of the LP, CliP, and Bell couplers have been investigated in eight fresh temporal bones (TBs) to evaluate the vibration properties of these three couplers. Normal and reconstructed middle ear transfer functions (METFs) were determined from laser Doppler vibrometer (LDV) measurements. A mastoidectomy and a posterior tympanotomy were performed to expose the ossicular chain. The METFs of the normal middle ear and middle ear with LP-FMT-coupler were compared under acoustic stimulation, thus the mass effect of the FMT with LP coupler was evaluated. Additional comparisons were made between the stapes footplate vibrations of the LP-FMT-coupler (with the intact ossicular chain at the long process of the incus), CliP-FMT-coupler and Bell-FMT-coupler on the stapes head (after incus and malleus removed) under active electromechanical stimulation. After the installation of CliP-FMT-coupler and Bell-FMT-coupler to the middle ear, the average velocity amplitude of the stapes footplate, comparing to the LP-FMT-coupler, was about 15 dB higher between 1 and 6 kHz, and 10 dB lower at about 0.5 kHz. Quantitatively, there was no significant difference between the CliP-FMT-coupler and Bell-FMT-coupler. According to our study, installation of CliP-FMT-coupler or Bell-FMT-coupler on the stapes head provides considerable improvement of the middle ear mechanical and functional responses, comparing with the LP-FMT-coupler in the temporal bone experiments. Moreover, the installation of the Bell-FMT-coupler to the stapes head produces essentially the same footplate velocity responses in comparison to the CliP-FMT-coupler.
对于中耳解剖结构正常的轻至重度感音神经性听力损失以及中耳畸形的混合性听力损失，振动声桥（VSB）有源中耳植入物提供了一种有效的治疗方法。VSB浮动质量换能器（FMT）通过合适的耦合器，可以安装在听骨链的各种结构上，例如砧骨的短突和长突、镫骨头以及镫骨底板。长突（LP）耦合器最常用于在听骨链完整时将FMT连接到砧骨长突，而CliP和Bell耦合器是在砧骨和锤骨缺失时将FMT连接到镫骨头的两种标准化且可靠的方法。然而，这三种FMT耦合器的振动特性之间的差异和关系仍不清楚。在本研究中，对八块新鲜颞骨（TBs）中LP、CliP和Bell耦合器的镫骨底板速度响应进行了研究，以评估这三种耦合器的振动特性。通过激光多普勒振动计（LDV）测量确定正常和重建的中耳传递函数（METFs）。进行乳突切除术和后鼓室切开术以暴露听骨链。在声刺激下比较正常中耳和安装LP - FMT耦合器的中耳的METFs，从而评估LP耦合器的FMT的质量效应。在有源机电刺激下，进一步比较了LP - FMT耦合器（在砧骨长突处听骨链完整）、CliP - FMT耦合器和Bell - FMT耦合器在镫骨头上（砧骨和锤骨去除后）的镫骨底板振动。在中耳安装CliP - FMT耦合器和Bell - FMT耦合器后，与LP - FMT耦合器相比，镫骨底板的平均速度幅值在1至6kHz之间高约15dB，在约0.5kHz时低10dB。定量分析表明，CliP - FMT耦合器和Bell - FMT耦合器之间没有显著差异。根据我们的研究，在颞骨实验中，与LP - FMT耦合器相比，在镫骨头上安装CliP - FMT耦合器或Bell - FMT耦合器可显著改善中耳的机械和功能响应。此外，与CliP - FMT耦合器相比，在镫骨头上安装Bell - FMT耦合器产生的底板速度响应基本相同。
