The objective of this study was to investigate the effect of intraoperative application of steroid suspension and coating of the electrode contacts with a thin film of iridium oxide on the short-term, time-dependent development of the intracochlear impedance in adults implanted with the Nucleus 24 Contour electrode. The time-dependent development of intracochlear impedances was investigated in four different groups of adult patients at daily and later weekly intervals until the first fitting. The four groups were as follows: 1) standard Nucleus 24 Contour (control, n = 7); 2) standard Nucleus 24 Contour with intraoperative application of steroids (Group S, n = 6); 3) iridium-coated Nucleus 24 Contour control (Group I, n = 8); and 4) iridium-coated Nucleus 24 Contour with intraoperative application of steroids (Group I + S, n = 5). All patients had postlinguistic onset of severe to profound sensorineural hearing loss and no or little benefit of conventional hearing aids. Absence of ossification or any other cochlear anomaly and also absence of signs of retrocochlear or central origin to the hearing impairment bilaterally had to be confirmed preoperatively. Steroid application reduced impedances significantly (Groups S and I + S), whereas iridium coating lowered variance of the impedance among patients but did not reduce the impedance significantly. The steroid-induced reduction is more pronounced at basal electrode contacts. Furthermore, there is some indication that the tissue growth could be faster in patients having the iridium-coated Contour electrode. Provided that the reduction of electrode impedances with application of steroids is persisting, intracochlear application of steroids can be considered on a regular basis. Iridium coating of the electrode contacts seems not to be justified to be included as standard procedure.

Objective: The objective of this study was to investigate the long-term effect of intraoperative application of steroid suspension and coating of the electrode contacts with a thin film of iridium oxide on the intracochlear impedance development after cochlear implantation and on the impedance difference before and after stimulation. Design: Time-dependent development of intracochlear impedances was investigated in 4 different groups of adult patients up to 4 years after implantation. Additionally, during rehabilitation period just after first fitting, impedances before and after stimulation were measured as to investigate the influence of electrical stimulation on the impedances. Results from standard Nucleus 24 Contour (control), standard Nucleus 24 Contour with intraoperative application of steroids, iridium-coated Nucleus 24 Contour, and iridium-coated Nucleus 24 Contour with intraoperative application of steroids were compared. Results: Steroid application reduced impedances significantly throughout the observation period of up to 4 years after implantation. Iridium oxide coating had no effect. Differences between the groups were mainly found on the basal and middle parts of the cochlea, but not close to the tip of the array, also indicating that postoperative fibrous tissue growth is stronger in the basal region of the cochlea. Group mean values of the stimulation effect were not influenced by the different treatments. Nevertheless, only in both steroid-treated groups a correlation between the impedance before stimulation and the stimulation effect was found. Conclusion: Although the differences between control and steroid-treated groups decrease with time, single intraoperative intracochlear steroid deposition was proven to lower postoperative impedances during first 3 to 4 years after implantation probably because of reduction of fibrous tissue growth.

Eustachian tube (ET) dysfunction is one of the causes for chronic otitis media. To develop new therapies such as stents to facilitate middle ear ventilation, a better knowledge on dimensions and positions of the ET in individual patients is necessary. Cone beam CT scans of 143 patients were retrospectively investigated. Parameters such as lengths of the ET and its cartilaginous and bony parts, diameters, angles as well as distance of the ostium from the nasal conchae were determined and evaluated for side, gender and age specific differences. The average length of the cartilaginous and bony tubes was smaller in women than men. The average deviation from the horizontal plane was 1.7° larger on the left side (35.4°) compared to the right side (33.7°). Tools to manipulate the ET or to insert stents into the ET should cover angles from at least 42° to 64°. The distance of the pharyngeal orifices from the conchae nasalis inferior increased with age, becoming most prominent above 70 years of age. This investigation provides necessary information to develop stents for human application and tools for safe positioning of the stents.