[The 'major' complications of cochlear implantation]

The objective of the present study was to improve the selected surgical stages of cochlear implantation (CIP) taking into consideration the results of the analysis of the outcomes of re-operations.

A total of 53 patients (4 adults and 49 children) were referred to our clinic for re-operations deemed to be required for the management the major complications following CI during the period from 2014 to 2017. Primary cochlear implantation was performed in other clinics. Re-operations were carried out at different time intervals after the primary surgical intervention under the guidance of a single experienced surgeon.

The technical malfunction of the inner part of the implant prevailed among the causes behind the major complications of CI. It accounted for 47% of the total number of complications and required the replacement of the device. The next most frequent form of the complications (that accounted for 15% of all the cases) was the introduction of an active electrode into the cells of hypotympanum. The remaining complications occurred only in isolated cases. The detailed analysis of all the revealed complications was undertaken with the description of their causes and variants and the surgical strategy chosen for the management of each concrete patient. The decision about the necessity of either the removal or the substitution of the implant was taken on an individual basis. The successful outcome of the surgical treatment of all the operated patients with the major complications of cochlear implantation was achieved.

The frequency and severity of the major complications of cochlear implantation are directly dependent on the patient's anatomical features, surgeon's qualifications, the quality of the implants, and lifestyle factors (e.g. head trauma, etc.). Cochlear implantation continues to be the only method for hearing rehabilitation in the patients suffering from severe sensorineural impairment of hearing. In the cases of cochlear implantation with the prospects of delayed re-implantation, leaving the active electrode in the scala tympani of the cochlea is a necessary measure to prevent synechiae.