Prevalence of cochlear implant electrode dislocation and speech perception after cochlear implant surgery and previous middle ear obliteration.

Introduction Patients who required an obliteration of the middle ear spaces are also eligible for cochlear implant surgery. Since the fixation of the electrode array, e.g. via a bone groove in the area of the posterior tympanotomy, is not possible in this case, the question arises whether this results in a higher rate of postoperative electrode dislocation. This retrospective study investigates the incidence of electrode dislocation and postoperative speech perception in patients after obliteration of the middle ear and following cochlear implant surgery.

Material and Methods Patients who underwent a middle ear obliteration and consecutive cochlear implant surgery between 2011 and 2021 were included in this study. Indicators for an electrode dislocation were defined as: stimulations of the facial nerve, increased impedances in telemetry, and loss of speech perception (Freiburg monosyllable test at 65dB). Measuring points were defined as pre surgery(T0) and 3 (T1), 6 (T2), and 12 months after surgery (T3), as well as the last available results (T4). Results: 38 patients (11f, 27m) were included in the analysis. There were no facial nerve stimulations or abnormalities in telemetry in any of the cases. Pre surgery (T0; n=38), the mean speech perception was 0% and showed approximately constant over T1(n=20) 55%, T2(n=25) 55.8%, T3(n=24) 54.58%, and T4(n=17) 54.41%.

Conclusion  After middle ear obliteration and consecutive cochlear implant surgery, a complication-free course is the rule and despite the lack of fixation of the electrode array, there is no increased rate of dislocations. Patients benefit clearly from the implantation in terms of speech perception.

Publication History

Article published online:
12 May 2023