Riemann Conrad, Sudhoff Holger, Todt Ingo
Department of Otolaryngology, Head and Neck Surgery, Bielefeld University, Campus Mitte, Klinikum Bielefeld, Bielefeld, Germany.
Front Surg. 2020 Nov 30;7:546779. doi: 10.3389/fsurg.2020.546779. eCollection 2020.
The importance of intracochlear pressure during cochlear electrode insertion for the preservation of residual hearing has been widely discussed. Various aspects of pre-insertional, intra-insertional, and post-insertional relevant conditions affect intracochlear pressure. The fluid situation at the round window during electrode insertion has been shown to be an influential factor. The aim of the study was to compare various insertion techniques in terms of the fluid situation at the round window. We performed insertion of cochlear implant electrodes in a curled artificial cochlear model. We placed and fixed the pressure sensor at the tip of the cochlea. In parallel to the insertions, we evaluated the maximum amplitude of intracochlear pressure under four different fluid conditions at the round window: (1) hyaluronic acid; (2) moisturized electrode, dry middle ear; (3) middle ear filled with fluid (underwater); and (4) moisturized electrode, wet middle ear, indirectly inserted. We observed that the insertional intracochlear pressure is dependent on the fluid situation in front of the round window. The lowest amplitude changes were observed for the moisturized electrode indirectly inserted in a wet middle ear (0.13 mmHg ± 0.07), and the highest values were observed for insertion through hyaluronic acid in front of the round window (0.64 mmHg ± 0.31). The fluid state in front of the round window influences the intracochlear pressure value during cochlear implant electrode insertion in our model. Indirect insertion of a moisturized electrode through a wet middle ear experimentally generated the lowest pressure values. Hyaluronic acid in front of the round window leads to high intracochlear pressure in our non-validated artificial model.
人工耳蜗电极插入过程中，蜗内压力对残余听力保护的重要性已得到广泛讨论。插入前、插入过程中和插入后相关情况的各个方面都会影响蜗内压力。电极插入过程中圆窗处的液体状况已被证明是一个影响因素。本研究的目的是比较不同插入技术在圆窗处液体状况方面的差异。我们在卷曲的人工耳蜗模型中进行了人工耳蜗电极的插入。我们将压力传感器放置并固定在耳蜗尖端。在插入过程中，我们评估了圆窗处四种不同液体状况下蜗内压力的最大幅度：(1)透明质酸；(2)湿润电极，中耳干燥；(3)中耳充满液体（水下）；(4)湿润电极，中耳湿润，间接插入。我们观察到，插入过程中的蜗内压力取决于圆窗前的液体状况。在中耳湿润情况下间接插入湿润电极时观察到的幅度变化最小(0.13 mmHg ± 0.07)，而通过圆窗前的透明质酸插入时观察到的值最高(0.64 mmHg ± 0.31)。在我们的模型中，圆窗前的液体状态会影响人工耳蜗电极插入过程中的蜗内压力值。通过中耳湿润间接插入湿润电极在实验中产生的压力值最低。在我们未经验证的人工模型中，圆窗前的透明质酸会导致较高的蜗内压力。
