[A clinical study of electrocochleography monitoring for residual hearing retention during minimally invasive cochlear implant].

Objective:To investigate the application value of intraoperative electrocochleography（ECochG） monitoring technique and insertion techniques in cochlear implant（CI） and analyze its relationship with postoperative residual hearing（RH） preservation. Methods:Thirty-one patients（35 ears） who received CI in our hospital from June 2022 to July 2024 were enrolled. The Advanced Bionics Active Insertion Monitoring（AIM） system was used for real-time ECochG monitoring during surgery. Intraoperative cochlear microphonics （CM） waveform changes were recorded and analyzed in relation to postoperative RH preservation. Results:①ECochG recordings were successfully obtained in 34 of 35 ears （97.1%）. ②According to Harris classification, there were 7 ears（20.6%） of Type A（rising）, 7 ears（20.6%） of Type C（declining）, 8 ears（23.5%） of Type CC（fluctuating）, and 12 ears（35.3%） of Type D（no response）. ③The total CM amplitude decrease was significantly moderately correlated with postoperative low-mid frequency hearing loss（r=0.67, P=0.017）. The total CM amplitude decrease was significantly moderately correlated with postoperative low frequency hearing loss（r=0.65, P=0.023）. ④For the mean amplitude variation, the Amax was 30.70 μV, the Amin was 8.64 μV, and the Aend was 18.27 μV. ⑤Sixteen cases completed postoperative follow-up, with an average low-mid frequency（125-1 000 Hz） residual hearing loss of 15.25 dB HL and a RH preservation rate of 87.5%. Conclusion:Intraoperative ECochG monitoring can effectively predict postoperative residual hearing changes, effectively guide surgical manipulation, and improve residual hearing preservation rate.