Use of the FLEX 28 Dexamethasone-Eluting Cochlear Implant Electrode in Electric-Acoustic Stimulation: A Case Report

Background/Objectives: During and after electric-acoustic stimulation (EAS) surgery (as well as regular cochlear implant surgery), the oral and/or intravenous administration of steroids is recommended to prevent acute inflammatory reactions and subsequent fibrosis. However, the effect does not last long. Therefore, with the hope of providing a sustained effect, a new dexamethasone (DEX)-eluting electrode (FLEX28 DEX) has recently been developed. Methods: A case study was performed at Shinshu University in February 2024 in which a DEX-eluting electrode array was utilized for a patient presenting with high-frequency hearing loss with a defined etiology (hearing loss due to a mitochondrial m.1555A > G variant). Results: Residual hearing was well preserved after EAS surgery, and post-operative impedance field telemetry was maintained at a very low level in contrast with a historical/retrospective control group (FLEX28 electrodes without DEX); therefore, it is expected that post-operative fibrosis will be minimized. Further, it was shown that the DEX-eluting electrode can also be applied to EAS. Conclusions: The DEX-eluting electrode was useful in maintaining post-operative impedance at a very low level, indicating that post-operative fibrosis could be minimized even after EAS surgery.