Preservation of Residual Hearing After Cochlear Implant Surgery With Deep Insertion Electrode Arrays

To evaluate the hearing preservation (HP) in cochlear implant (CI) recipients who did not fulfill the criteria for electric acoustic stimulation (EAS).

Prospective study SETTING:: Tertiary academic hospital.

Adults undergoing CI with deep insertion electrode arrays who had measurable residual hearing (RH) before surgery.

Demographic data, surgical technique, pure-tone average, and radiological findings were evaluated.

Pre- and postoperative pure-tone audiometry. A preservation study was therefore performed for the whole range of frequencies (THP), and for low frequencies (LFHP).

From the total 25 patients who underwent the surgical procedure, 6 of them (26.08%) did not retain any RH and 17 of them (73.91%) had some degree of HP. A clear association was observed between the use of the atraumatic technique (AT) and the percentage of some degree of HP. In patients who underwent the AT, LFHP was 72.79% and THP was 70.40%. In patients who did not undergo the technique, LFHP was 31.48% (p: 0.003) and THP was 23.50% (p: 0.002). LFHP was complete or partial (more than 25% of initial RH) in 92.3% of patients who underwent AT and in 50% of those who did not. Radiological findings showed that complete insertion is not associated with poorer HP.

If the appropriate technique is used, preservation of RH is feasible after cochlear implant surgery with deep insertion electrode arrays.