Real-time intracochlear ECochG monitoring in minimally invasive cochlear implant surgery
WANG Yajing
LIU Jiahao
HUANG Qiqi
JIANG Yue
CHEN Suijun
ZHENG Yiqing
LIANG Maojin
Abstract：Objective To report results of real-time intracochlear electrocochleography(ECochG)monitoring during cochlear implantation.Methods A total of 63 patients(68 ears)undergoing cochlear implantation from March 2024 to April 2025 were enrolled(32 males and 31 females,age from 5 years and 10 months to 73 years).Based on preoperative low-frequency residual hearing,patients were divided into Group A(thresholds≤80 dB HL at 125 Hz,250 Hz,and 500 Hz;n=31,33 ears)and Group B(average threshold＞80 dB HL at 125 Hz,250 Hz,and 500 Hz;n=32,35 ears).During electrode insertion,ECochG potentials were measured in real time from the apical electrode to track changes in cochlear microphonic(CM)amplitude.Postoperatively,electrode positioning and low-frequency hearing preservation were evaluated.Results Real-time ECochG monitoring was successful in 65 of the 68 ears(95.6%).In Group A,CM waves were detected in 22 ears(68.8%),showing ascending Type A in 6 ears(18.8%),descending Type C in 5 ears(15.6%),fluctuating Type CC in 11 ears(34.4%),and no response(Type D)in 10 ears(31.2%).The CM amplitude ranged from 4 to 220 μV in this group.In Group B,CM was detectable only in 3 ears(9.1%),including ascending Type A in 1 ear(peak amplitude:240 μV)and fluctuating Type CC in 2 ears(peak amplitudes:6.5 μV and 8 μV).The rest 30 ears(90.9%)showed no response(Type D).In Group A,the average preoperative low-frequency hearing threshold was 75(59.5,78.5)dB HL for those showing Type A responses,with a average postoperative low-frequency threshold shift of 15(6.5,22.7)dB HL;78(76.5,80)dB HL for those showing Type C responses,with a postoperative shift of 22(15,26)dB HL;and 77(75,80)dB HL for those showing Type CC responses,with a postoperative shift of 17(10,25)dB HL,with no significant differences in preoperative or postoperative low-frequency thresholds among different CM waveform types.Electrode translocation into the scala vestibuli was observed in 2 ears(40%)with Type C responses,and not in Types A or CC responses.Conclusions Preoperative low-frequency residual hearing influences the intraoperative ECochG detection.Real-time intracochlear ECochG monitoring provides feedback to guide adjustments in electrode insertion(speed and angle),thereby reducing the incidence of electrode translocation and improving postoperative residual hearing preservation.
Keywords：cochlear implantationintracochlear ECochGminimally invasive cochlear implantation
Publication Date：2026-03-20
Online Publishing Date：2026-03-19(First online date of this platform, not the publication date of the document)
Pages：6( 262-267 )