Incomplete and false tract insertions in cochlear implantation: retrospective review of surgical and auditory outcomes
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To evaluate incidence, demographics, surgical, and radiological correlates of incomplete and false tract electrode array insertions during cochlear implantation (CI). To evaluate outcomes in patients with incomplete electrode insertion (IEI).
Otology and skull base center.
Patients and methods
Charts of 18 patients (19 ears) with incomplete or false tract insertions of the electrode array were evaluated who underwent CI, with at least 1 year follow-up (from 470 cases). Demographic findings, etiologies, pre-operative radiologic findings, operative records, post-operative plain radiographic assessment for extent of electrode insertion, and switch-on mapping were evaluated. Audiological outcomes were evaluated using maximum and last recorded vowel, word, sentence, and comprehension scores for patients with IEI.
Incidence of insertional abnormalities was 4.25% with 17 instances of incomplete and 2 cases of insertion into superior semicircular canal. Mean age and duration of deafness were 55.18 ± 4.62 and 22.12 ± 5.71 years. Etiologies in the IEI group were idiopathic, otosclerosis, meningitis, chronic otitis media (COM), temporal bone fractures, and Neurofibromatosis-2. 29.4% cases had cochlear luminal obstruction. Mean radiological and active electrophysiological length of insertion was 20.49 ± 0.66 and 19.49 ± 0.88 mm, respectively. No significant correlation was observed between audiological outcomes and insertional length except in time to achieve maximum word scores (p = 0.04). Age at implantation had significant correlations with last recorded word and comprehension scores at mean follow-up of 42.9 months, and with time to achieve maximum auditory scores.
IEI during cochlear implantation using straight electrodes can occur with or without cochlear luminal obstruction. Age plays an important role in the auditory rehabilitation in this patient subset.
KeywordsCochlear implantation Incomplete electrode insertion Extra-cochlear electrode insertion
We sincerely thank Mrs Tomasoni Viola and Natalie Lucio for the assistance in compliation of radiological data.
This study did not receive any funding.
Compliance with ethical standards
Conflict of interest
The authors declare no potential conflict of interest.
All procedures performed in the current study were in accordance with the institutional ethical standards and with the 1964 Helsinki declarartion with its amendments. No research involving animals was done in the current study.
Informed consent was obtained from all individual participants included in the study.
The authors declare that the manuscript is original.
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