Surgical Methods and Auditory Outcomes of Cochlear Implantation in Cochlear Ossification

Background: The aim of this study was to evaluate the surgical and auditory outcomes of cochlear implantation in patients with cochlear ossification. Methods: This study comprised 54 patients with cochlear ossification who underwent cochlear implantation in the cochlear implant center of a tertiary care hospital between January 1998 and May 2019. Clinical data were evaluated including surgical findings and audiological performances. The auditory outcomes of the implanted patients were assessed through the Categories of Auditory Performance-II test and Speech Intelligibility Rating test, respectively. The outcomes of patients with cochlear ossification were compared with those of 54 patients selected for the control group who underwent implantation with no cochlear ossification. Results: Auditory outcomes were comparable between the study group and the control group. The control group obtained significantly higher scores than those of the study group when compared using the Categories of Auditory Performance-II test and Speech Intelligibility Rating test batteries. Patients with meningitis produced poorer outcomes within the group comparisons of the study group. None of the patients experienced surgical complications. The extent of ossification was analyzed in terms of its effectiveness on audiological performance. Patients with complete ossification had significantly lower Categories of Auditory Performance-II and Speech Intelligibility Rating test scores. CONCLUSION: Cochlear implantation is a safe and beneficial procedure, even in patients with cochlear ossification. The ossified cochlea may require varied drill techniques beyond traditional implantation surgery for the insertion of the electrode array. It is, however, still difficult to predict audiological outcomes in patients with cochlear ossification.