Lower initial electrode impedances in minimally invasive cochlear implantation

Abstract

Background: The round window approach and the cochleostomy approach are two widely practiced methods to insert cochlear implant electrode arrays. Yet, there is no consensus on which is more minimally invasive. Objective: To compare the initial electrode impedance (EI) values and the incidence of abnormal electrodes of the round window approach and the cochleostomy approach, and to evaluate the effects of surgical techniques on the intracochlear microenvironment. Material and methods: One hundred and seventy-one patients received a unilateral Nucleus cochlear implant. Eighty-two patients were implanted using the round window approach, and 89 patients were implanted using the cochleostomy approach. EI was measured immediately after closure of the incision. Results: The round window group had lower average initial EI values than the cochleostomy group. For the EI values at each position, statistically significant differences were found in the basal-middle region (Electrode 1–14), but not in the middle-apical region (Electrode 15–22) of the electrode arrays. A lower incidence of high-impedance electrodes was found in the round window group. Conclusions: The round window approach leads to lower initial EI and less disturbance to the intracochlear microenvironment.

Chinese abstract

背景：圆窗入路和耳蜗造口入路是两种广泛应用的人工耳蜗电极阵列植入方法。然而, 对于哪一种更具微创性还没有达成共识。

目的：比较圆窗入路和耳蜗造口入路的初始电极阻抗（EI）值和异常电极发生率, 并评价手术技术对耳蜗内微环境的影响。

材料与方法：170例患者接受单侧核耳蜗植入术。82例患者采用圆窗入路, 89例患者采用耳蜗造口入路。切口闭合后立即测量EI。

结果：圆窗组的平均初始EI值低于耳蜗造口组。对于每个位置的EI值, 在电极阵列的基部-中部区域（电极1-14）中发现统计学显著差异, 但在电极阵列的中部-顶端区域（电极15-22）中没有发现统计上的显著差异。圆窗组高阻抗电极的发生率较低。

结论：圆窗入路导致低初始电极阻抗值, 并且对耳蜗内微环境的较少干扰。

Keywords:

• Cochlear implant
• electrode impedance
• surgical technique
• minimally invasive

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Ministry of Science and Technology of the People's Republic of China under Grant no. 2014CB541700; and Department of Science and Technology of Zhejiang Province under Grant no. 2015C03035.