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Review
. 2019 Sep;14(3):94-100.
doi: 10.1016/j.joto.2019.01.002. Epub 2019 Jan 9.

Review on cochlear implant electrode array tip fold-over and scalar deviation

Anandhan Dhanasingh  1 , Claude Jolly  1
Affiliations
Review

Review on cochlear implant electrode array tip fold-over and scalar deviation

Anandhan Dhanasingh et al. J Otol. 2019 Sep.

Erratum in

Abstract

Objective: Determine the occurrence rate of cochlear implant (CI) electrode tip fold-over and electrode scalar deviation as reported in patient cases with different commercial electrode types.

Data-sources: PubMed search for identifying peer-reviewed articles published till 2018 on CI electrode tip fold-over and scalar deviation. Key-words for searching were "Cochlear electrode tip fold-over", "Cochlear electrode scalar position" and "Cochlear electrode scalar location".

Articles-selection: Only if electrode related issues were investigated in patient cases. 38 articles met the inclusion-criteria.

Results: 13 articles on electrode tip fold-over issue covering 3177 implanted ears, out of which 50 ears were identified with electrode tip fold-over with an occurrence rate of 1.57%. Out of 50 ears, 43 were implanted with pre-curved electrodes and the remaining 7 with lateral-wall electrodes. One article reported on both tip fold-over and scalar deviation. 26 articles reported on the electrode scalar deviation covering an overall number of 2046 ears out of which, 458 were identified with electrode scalar deviation at a rate of 22.38%. After removing the studies that did not report on the number of electrodes per electrode type, it was 1324 ears implanted with pre-curved electrode and 507 ears with lateral-wall electrode. Out of 1324 pre-curved electrode implanted ears, 424 were reported with scalar deviation making an occurrence rate of 32%. Out of 507 lateral-wall electrode implanted ears, 43 were associated with scalar deviation at an occurrence rate of 6.7%.

Conclusion: This literature review revealing the fact of higher rate of electrode insertion trauma associated with pre-curved electrode type irrespective of CI brand is one step closer to obsolete it from the clinical practice in the interest of patient's cochlear health.

Keywords: Electrode tip fold-over; Pre-curved electrode; Scalar deviation; Straight electrode.

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Figures

Fig. 1
Fig. 1
Literature review process.
Fig. 2
Fig. 2
Histogram chart showing the % of electrode related issues with two general types of CI electrodes.
Fig. 3
Fig. 3
Electrode tip geometry from all three major CI brands.
See this image and copyright information in PMC

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