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Hearing Preservation in Cochlear Implant Surgery

A Meta-Analysis

Snels, Chantal*; IntHout, Joanna; Mylanus, Emmanuel*,‡; Huinck, Wendy; Dhooge, Ingeborg*

doi: 10.1097/MAO.0000000000002083

Objective(s): The aim of the present meta-analysis is to assess the effects of hearing preservation (HP) methods on residual hearing in patients undergoing cochlear implant (CI) surgery and to look at the effect of follow-up time on HP outcome.

Data Sources: A systematic search was conducted in PubMed, Embase, and Cochrane Library. Only articles in English were included.

Study Selection: Prospective studies published until January 2018 on hearing preservation methods were included.

Data Extraction: Studies were assessed on unaided pre- and postoperative hearing thresholds, follow up time, and methodological quality.

Data Synthesis: A random-effects meta-regression was performed for the HP outcome in relation to surgical technique, electrode array design, inserted electrode length, insertion speed, and corticosteroid use for different follow up times (1 month, 6 months, and 12 months or more postoperatively).

Conclusion: Hearing preservation in cochlear implant surgery is feasible. A statistically significant difference was found between the round window procedure and cochleostomy approach, in favor of the round window procedure at 6 months postoperatively (p = 0.001). A statistically significant difference was found between the straight and the perimodiolar electrode array at 1 month postoperatively in favor of the straight electrode array (p < 0.001). No statistically significant difference was found between the other HP methods. The round window approach with the straight electrode array might result in a better HP outcome at 1 month and 6 months postoperatively compared with the cochleostomy approach with the perimodiolar electrode array. A declining trend in HP outcome in both combinations was seen over time.

*Department of Otorhinolaryngology, Ghent University, Ghent, Belgium

Department for Health Evidence, Radboud Institute for Health Sciences

Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands

Address correspondence and reprint requests to Chantal Snels, M.Sc., Department of Otorhinolaryngology, University hospital Ghent, Corneel Heymanslaan 10, 9000 Ghent, Belgium; E-mail:

Conflict of interest and funding: This study is funded by Cochlear Benelux and E.M., I.D., W.H., and C.S. therefore report a conflict of interest. The remaining author Ji.H. reports no conflicts of interest.

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