gms | German Medical Science

GMS Current Posters in Otorhinolaryngology - Head and Neck Surgery

Deutsche Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie e.V. (DGHNOKHC)

ISSN 1865-1038

Cochlear dimensions and cochlear implant electrode insertion resistance

Poster Otologie

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  • corresponding author Marius Polianskis - Vilnius University Santariskes Clinic, Vilnius, Lithuania
  • Eugenijus Lesinskas - Vilnius University, Vilnius, Lithuania

GMS Curr Posters Otorhinolaryngol Head Neck Surg 2017;13:Doc125

doi: 10.3205/cpo001679, urn:nbn:de:0183-cpo0016795

Veröffentlicht: 26. April 2017

© 2017 Polianskis et al.
Dieser Artikel ist ein Open-Access-Artikel und steht unter den Lizenzbedingungen der Creative Commons Attribution 4.0 License (Namensnennung). Lizenz-Angaben siehe



Introduction: Size variations of cochlea are common in patient populations. One of the goals of cochlear implantation could be full-length insertion, which may benefit patient hearing outcomes. Our objective is to measure cochlear size and evaluate its effect on full-length electrode insertion resistance.

Methods: Multiplanar reconstructions of high resolution CT defined by specific criteria were used to perform measurements: cochlear basal length and width, basal turn lumen diameter. All patients implanted with 31,5mm FlexSoft (MedEl) electrode array were included. Implantations were performed in a single tertiary referral center by single surgeon between 2011 and 2016. Electrode insertion resistance was measured using determined criteria.

Results: 111 cochlear implantations were performed (27 bilateral). Cochlear basal length average was 8,9 (7,9-10,2)mm, basal width - 6,2 (5,1-7,1) mm. Basal turn diameter - 1,6 (0,8-2,8) mm. Cochlear duct length was 37,5 (33,1-42,6) mm. Correlations between cochlear dimensions were determined. No resistance was encountered during insertion of electrode array in 52,7% implantations, in 19,1% - strong resistance was observed. Data analysis showed smaller than 8,99 mm cochlear basal length was associated with encountering resistance points during cochlear electrode insertion (p=0,02).

Conclusions: Though cochlea size might vary, cochlear structures retain similar ratio, which could leave small cochleae unnoticed during preoperative examination. In patients with smaller cochlear basal length, cochlear electrode insertion was associated with encountering resistance points. Measuring cochlear basal length before cochlear implantation might alert surgeon about possible difficulties inserting electrode array.

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