Cochlear implantation using the underwater technique: long-term results

• Published in: European archives of oto-rhino-laryngology Vol. 275; no. 4; pp. 875 - 881
• Main Authors: Stuermer, Konrad Johannes, Schwarz, David, Anagiotos, Andreas, Lang-Roth, Ruth, Hüttenbrink, Karl-Bernd, Luers, Jan Christoffer
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.04.2018
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Audiometry, Pure-Tone; Auditory Threshold; Child; Child, Preschool; Cochlear Implantation - methods; Female; Follow-Up Studies; Head and Neck Surgery; Humans; Hydrostatic Pressure; Isotonic Solutions; Male; Medicine; Medicine & Public Health; Middle Aged; Neurosurgery; Otology; Otorhinolaryngology; Retrospective Studies; Round Window, Ear - surgery; Young Adult; Residual hearing; Electrodes; Cochlear implantation; Atraumatic surgery; Hearing preservation
• ISSN: 0937-4477; 1434-4726
• DOI: 10.1007/s00405-018-4886-7

Introduction The opening of the round window and the insertion of the electrode array into the scala tympani during cochlear implant surgery can lead to a pressure shock of the delicate inner ear structures. By filling the tympanic cavity with Ringer Solution during these surgical steps (underwater technique), the hydrostatic pressure of the fluid acts as a smooth pressure stabilizer, avoiding a pressure shock of the inner ear structures. The aim of this retrospective study was to present long-term results of this new method of cochlear implantation in underwater technique. Methods Altogether, 47 implantations in 43 patients with residual hearing at the frequencies 250, 500 and 1000 Hz in the unaided preoperative pure tone audiometry were included. A cochlear implantation via round window with a conventional full-length electrode was performed in underwater technique. Changes of residual hearing 7 weeks and 24 months after surgery were analyzed. Results Overall postimplant hearing preservation 7 weeks after implantation was achieved in 22 ears (47%). Subsequent follow-up was performed on average 24 months after surgery (range 12 months–4.2 years) in all patients. At this late postoperative evaluation, preservation of hearing was recorded in 18 ears (38%). Neither the follow-up time nor the type of electrode had a significant impact on the postoperative hearing loss. Conclusion The underwater technique is an atraumatic cochlear implantation technique with hearing preservation rates comparable to results in literature and a very small hearing preservation decline rate over time even when using full-length CI electrodes.