Surgical approach for EAS patients with loss of residual hearing

Patients with electroacoustic stimulation (EAS) and loss of residual hearing require a method to utilize the full spectral resolution of multichannel implants and complete cochlear coverage to ensure the best possible auditory stimulation without implant replacement. The aim of this study was to test the endaural access to a transmastoidal, partially inserted cochlear implant electrode for full insertion.

Two custom-made CI electrodes with 18 stimulation electrodes allow the use of 12 active channels available for electrical stimulation within the cochlea both after partial and complete insertion. 10 electrodes were implanted in 10 human temporal bones. After partial insertion via posterior tympanotomy, the electrode was inserted to its maximum length in a second step via an endaural access. Stenvers and hrCT were performed to measure the respective electrode positions and insertion angles.

X-ray and CT scans confirmed insertion angles between 236° and 307° for partial insertion. Access to the electrode via the auditory canal was possible to insert the electrode completely during the second step. This access allowed insertion angles between 360° and 540° to be achieved.

The investigations confirm the surgical principle of completing electrode insertion in EAS patients with previous partial insertion in the temporal bone model. With this two-stage procedure and the availability of appropriate implants, EAS patients could be offered a perspective in case of loss of residual hearing without replacing the entire CI.

Poster-PDF A-1412.PDF

Publication History

Article published online:
10 June 2020