IMPORTANCEUnderstanding the reasons for cochlear implant (CI) revision surgery and device failure rates is important for clinicians when counseling patients who are considering CI.OBJECTIVES To analyze the revision surgery rate, reasons for revision surgery, and device failure and survival rates of different device models in recipients of CIs. DESIGN, SETTING, AND PARTICIPANTSIn this cohort study, cochlear implants at Samsung Medical Center, a tertiary referral center, were retrospectively reviewed. Patients who underwent CI surgery from October 2001 to March 2019 were included. In the device survival analysis, the first revision surgery was considered the primary event, and the end point of observation was June 1, 2019. INTERVENTIONS Therapeutic and rehabilitative CI surgery. MAIN OUTCOMES AND MEASURESThe revision surgery rate, reasons for revision surgery, and the failure and survival rates of different device models were analyzed. The Kaplan-Meier method and the log-rank test were used to present both the device survival and cumulative survival curves with rates. RESULTSIn this study, 43 of 925 patients with CIs (4.6%) underwent a revision surgery. Device failure was the most common reason (28 of 43 patients [65%]). Flap-associated problems and migration of the inner device were the next most important reasons (4 of 43 [9.3%] each). Overall, the 10-year cumulative survival rate of CI surgery was 94.4%, and the device survival rate was 96.0%. Thirteen different CI devices from 4 different manufacturers were implanted, and no meaningful differences in device failure were found among CI manufacturers or devices (hazard ratios for cumulative survival: Cochlear, 1.67 [95% CI, 0.72-3.88]; Advanced Bionics, 1.67 [95% CI, 0.61-4.53]; Med-El, reference; hazard ratios for device survival: Cochlear, 1.65 [95% CI, 0.55-4.99]; Advanced Bionics, 1.93 [95% CI, 0.56-6.74]; Med-El, reference). Several recalls were issued by manufacturers during the study period, and after excluding the recalled devices, the device survival rates for 5, 10, and 15 years were 98.2%, 97.7%, and 94.9%, respectively.CONCLUSIONS AND RELEVANCE Generally, implanted devices remain safe and stable for a long time, and no significant differences in survival rates were found between device types or manufacturers. Device failure was the main reason for CI revision, followed by flap-associated problems and migration of the inner device.

Intravenous gadolinium-enhanced inner-ear magnetic resonance imaging (IV-Gd inner-ear MRI) has been used to visualize endolymphatic hydrops (EH) in clinical diagnosis of Ménière’s disease (MD). However, lack of histological validation has led to several concerns regarding how best to interpret the resulting images. Here, we compared hydropic changes in temporal bone specimens with the results of IV-Gd inner-ear MRI in patients with MD. Histopathologic images of temporal bones from 37 patients with MD and 10 healthy controls were collected from the National Temporal Bone Bank of the Massachusetts Eye and Ear Infirmary in the United States. The EH ratios in the vestibule and cochlea were calculated from temporal bones using the methods used for IV-Gd inner-ear MRI, and the degree to which the saccular and utricular hydrops contributed to vestibular hydrops was measured. The presence of hydropic change in each semicircular canal was assessed using temporal bone images and compared with IV-Gd inner-ear MRI scans of 74 patients with MD. Based on human temporal bone imagery, the EH ratios in the cochlea and the vestibule on the affected side were 0.314 and 0.757, respectively. In the healthy control group, the ratio was 0.064 for the cochlea and 0.289 for the vestibule; these values were significantly different from those for the affected side of MD patients. The values for the affected ear were similar to the ratios from the IV-Gd inner-ear MRI scans in MD patients. In the vestibule, saccular hydrops were more common than utricular hydrops. The average EH ratios in the saccule and utricle were 0.513 and 0.242, respectively. No significant hydropic change from each of three semicircular canals was evident in temporal bone histopathology. However, herniation of otolithic organs (saccule or utricle) into the lateral semicircular canal was found in 44.4% of the patients, with saccular herniation (24.8%) more common than utricular herniation (16.7%). Although IV-Gd inner-ear MRI might not reflect fully the results of actual histopathology due to the limited resolution of MRI and image-processing techniques, the measured EH ratios from temporal bone specimens and IV-Gd inner-ear MRI scans were similar. Hydropic change in the three semicircular canals was not significant at either the ampullated or nonampullated end. Canal invasion of vestibular hydrops seen on MRI also appeared in temporal bone histopathology, and saccular invasion was dominant.

Background and Objectives: We sought to evaluate the diagnostic and prognostic value of measurable parameters of internal auditory canal (IAC) magnetic resonance imaging (MRI) in patients with idiopathic sudden sensorineural hearing loss (ISSNHL).Subjects and Methods: We retrospectively reviewed the patients with ISSNHL who underwent IAC MRI from January 2008 to March 2019. Measurable parameters of IAC MRI, such as the diameter of the IAC, bony cochlear nerve canal, and cross-sectional area of the cochlear nerve, were measured by a single examiner. These parameters were then compared between the affected and healthy sides. Inner-ear abnormalities such as intralabyrinthine hemorrhage or labyrinthitis were also evaluated. The relationship between the surveyed parameters and the diagnosis of ISSNHL was assessed.Results: A total of 208 patients with ISSNHL were included. The measured parameters of IAC MRI were not different between the affected and healthy sides and were also not associated with the diagnosis of ISSNHL. However, inner-ear abnormalities of IAC MRI in ISSNHL displayed a significant association with worse hearing before and after treatment. An age that was older than 40 years also correlated with poorer outcomes. Further, inner-ear abnormalities were more frequently detected when IAC MRI was performed early after ISSNHL onset.Conclusions: Patients with ISSNHL and inner ear abnormalities such as intralabyrinthine hemorrhage or labyrinthitis identified via IAC MRI may experience poorer hearing outcomes. To detect such abnormal findings, it is recommended to perform IAC MRI early after the onset of ISSNHL.