Complications after cochlear implantation in adult patients: a retrospective study.

OBJECTIVE: To examine the complication rate in adult patients during and after cochlear implantation. METHODS: A retrospective chart review was conducted of patients who had undergone cochlear implantation at a tertiary referral centre between 2009 and 2018. All complications and their treatments were categorised as either minor or major, as well as intra- or post-operative. RESULTS: The records of 392 patients with 395 implants were reviewed. The mean follow-up period was 89 ± 65.5 months (range, 6-408 months). The mean age of patients was 46 ± 15.2 years (range, 19-84 years). Sixty-two patients (16 per cent) had minor complications and 31 (8 per cent) had major complications. CONCLUSION: Although cochlear implantation has the potential for significant intra- and post-operative complications, the actual complication rate is relatively low, and it can therefore be considered a safe procedure.

Bilateral cochlear implantation in children: simultaneously or in consecutive sessions?

OBJECTIVE: This study aimed to evaluate and compare cases of simultaneous and consecutive bilateral cochlear implantation from the perspective of the duration of anaesthesia, surgical complications and hospitalisation. METHOD: Fifty patients with simultaneous bilateral cochlear implantation (group 1) and 47 patients with consecutive bilateral cochlear implantation (group 2) were included in this study. The two groups were compared in terms of the duration of anaesthesia, the duration of surgery, radiological findings, the complications and the post-operative hospitalisation time. RESULTS: Group 1 had a significantly shorter operation time than group 2 (p < 0.01). The mean total operation time was 189 minutes in group 1. In group 2, the mean operation times for the first and second surgery were 134 minutes and 136 minutes, respectively, and the total operation time for both surgical procedures in group 2 was 270 minutes. The duration of post-operative hospitalisation of the patients in group 1 was significantly shorter than the total post-operative hospitalisation after both operations for the patients in group 2 (p < 0.01). CONCLUSION: In conclusion, if there is no anatomical problem that may lead to a prolonged operation time or any risk regarding anaesthesia, simultaneous bilateral cochlear implantation can be performed safely.

The effect of local application of insulin-like growth factor for prevention of inner-ear damage caused by electrode trauma.

BACKGROUND: Electrode insertion during cochlear implantation causes cochlear damage and apoptosis. Insulin-like growth factor applied locally was investigated in 21 rats. METHODS: In the sham group, an intracochlear dummy electrode was inserted through the round window. In the control group, after the same insertion procedure, saline-soaked porcine skin gelatine was placed on the round window. In the study group, insulin-like growth factor 1 soaked gelatine was placed on the round window. Auditory brainstem response thresholds were measured and histopathological examination was performed. RESULTS: In the study group, at 2-4 kHz, one rat had deterioration, one showed improvement and the rest had stable thresholds 14 days after intervention. At 6 kHz, four rats showed improvement and the rest remained stable. At 8 kHz, four showed improvement, one had deterioration and two remained stable. In the other groups, hearing loss deteriorated in about half of the rats and remained stable in the rest. The mean post-operative 6 kHz threshold was significantly lower than that immediately after the intervention in the study group, contrary to the other groups. The study group had significantly better mean histopathological grading than the other groups. CONCLUSION: Local insulin-like growth factor 1 application may protect hearing after cochlear implantation.

Variations in Multiple Syndromic Deafness Genes Mimic Non-syndromic Hearing Loss.

The genetics of both syndromic (SHL) and non-syndromic hearing loss (NSHL) is characterized by a high degree of genetic heterogeneity. We analyzed whole exome sequencing data of 102 unrelated probands with apparently NSHL without a causative variant in known NSHL genes. We detected five causative variants in different SHL genes (SOX10, MITF, PTPN11, CHD7, and KMT2D) in five (4.9%) probands. Clinical re-evaluation of these probands shows that some of them have subtle syndromic findings, while none of them meets clinical criteria for the diagnosis of the associated syndrome (Waardenburg (SOX10 and MITF), Kallmann (CHD7 and SOX10), Noonan/LEOPARD (PTPN11), CHARGE (CHD7), or Kabuki (KMT2D). This study demonstrates that individuals who are evaluated for NSHL can have pathogenic variants in SHL genes that are not usually considered for etiologic studies.

Histopathological and audiological effects of mechanical trauma associated with the placement of an intracochlear electrode, and the benefit of corticosteroid infusion: prospective animal study.

OBJECTIVE: This study aimed to present the histopathological and audiological effects of mechanical trauma associated with the placement of a model electrode in the scala tympani in rats, and the effects of continuous topical corticosteroid application. METHOD: The study comprised three groups of rats. The round window membrane was perforated in all three groups and a model electrode was inserted in the round window. Group one received no further treatments. Groups two and three also had an intrathecal microcatheter compatible with a mini-osmotic pump inserted; in group two this was used to release normal saline and in group three the pump released 400 µg/ml dexamethasone. RESULTS: Dexamethasone infusion given after implantation of the intracochlear model electrode was more effective for preventing hearing loss than the administration of just one dose of dexamethasone. CONCLUSION: The findings suggest that continuous dexamethasone infusion is beneficial for preventing the loss of hair cells and neurons associated with early and late periods of intracochlear electrode trauma.