Mechanisms of electrode fold-over in cochlear implant surgery when using a flexible and slim perimodiolar electrode array

Abstract

Objectives: This study evaluates the design of a thin perimodiolar cochlear implant electrode array (CI532) and assesses insertion-related rotation and fold-over. Methods: The study consisted on a cochlear model and temporal bone insertion studies. Twenty insertions were studied, under four different surgical insertion conditions in vitro, the intracochlear disposition of the electrode array and presence of tip fold over were recorded. Also, eight fresh human temporal bones were studied after insertion in two conditions: correct alignment of the electrode array during the insertion and misaligned. These surgical situations were investigated within this study using a video recording of the dynamics of insertion techniques and X-ray, including fluoroscopy, Cone Beam CT, and digital imaging analysis. Results: For electrodes inserted with a correct surgical technique, the placement was perfect, within the scala tympani. The wrapping factor was 0.53, and the perimodiolar distance was below 0.3 mm, with a mean insertion depth of 405 degrees. Conclusions: A perimodiolar position can be achieved with the new CI532 electrode array. The new electrode also seems to be reliable for atraumatic intracochlear placement in scala tympani (ST).

目的：本研究评价了一个细小的弯形人工耳蜗植入电极阵列（CI532）的设计, 并检测了与插入相关的旋转和折叠。

方法：本研究包括耳蜗模型和颞骨插入研究。研究了在4种体外不同的手术插入条件下的20次插入, 记录了电极阵列的耳内位置和尖端折叠的存在。在两个条件（插入期间电极阵列的正确对准和未对准）下进行插入之后, 还研究了8块新鲜人体颞骨。在本研究中, 使用插入技术和X射线动态的视频记录来研究这些手术情况, 包括荧光透视, 锥束CT和数字成像分析。

结果：对于使用正确的外科手术插入的电极, 其放置是完美的, 在下耳蜗管内。折叠因子为0.53, 弯形距离为0.3mm以下, 平均插入深度为405度。

结论：新的CI532电极阵列可以实现弯形状态。新电极似乎也可以用于在下耳蜗管中进行无创伤的耳蜗内置入。