[Incomplete partition type III revisited-long-term results following cochlear implant. German version].

Area of Science:

• Otolaryngology
• Neurosurgery
• Audiology

Background:

• Incomplete Partition type III (IP III) is a malformation characterized by a missing lamina cribrosa between the cochlea and internal auditory canal (IAC).
• Cochlear implantation (CI) in IP III patients carries a risk of electrode array insertion into the IAC.
• This study investigates the surgical and audiological aspects of CI in IP III patients.

Purpose of the Study:

• To evaluate CI surgery protocols in IP III patients.
• To assess long-term audiological outcomes, including speech discrimination.
• To analyze mapping and electrophysiological data in IP III patients post-CI.

Main Methods:

• Eight IP III patients who received cochlear implants with perimodiolar electrode arrays were studied.
• Data analyzed included mapping, stapedius reflexes, electrode impedances, and ECAP thresholds.
• Speech discrimination was assessed using standardized tests and compared to a control group.

Main Results:

• IP III patients exhibited a significant increase in pulse width, electric load, and basal electrode impedances over 3 years post-CI.
• Intraoperative electrically-evoked stapedius reflexes were successfully measured in all patients.
• While speech recognition scores were lower than controls, the difference was not statistically significant.

Conclusions:

• The observed changes in electrode parameters in IP III patients may be due to cochlear nerve fibrosis and neurodegeneration.
• Long-term audiological results after CI in IP III patients are generally stable.
• Intraoperative imaging and stapedius reflexes are recommended for accurate electrode array placement control.