Fully implantable hearing device with transducer on the round window as a treatment of mixed hearing loss.

Objective: To demonstrate the safety and efficacy of the Otologics Carina Middle Ear Transducer for treatment of mixed hearing loss through a case report.

Methods: A Carina fully implantable device with the MET transducer for conductive applications was implanted in a 48-year-old woman suffering from right mixed hearing loss (mean PTA loss: 80 dB). A facial recess approach was used to access the middle ear. Sclerotic tissue obliterated the stapes footplate so the approach selected was to place the transducer directly on the round window. The mounting bracket was placed on the mastoid and the prosthesis was advanced toward the round window until the Otologics surgical software indicated contact. Effective stimulation of the cochlea was confirmed intraoperatively by ABR monitoring.

Results: Postoperative unaided PTA thresholds were unchanged after surgery. When the implant was activated, the mean PTA functional gain was 39 dB.

Conclusions: The capability of the Carina MET Ossicular stimulator to provide appropriate gain relative to the degree of hearing loss indicates that the device offers a viable treatment option for mixed hearing loss. However, these promising initial results establish the need for future work on two fronts: (1) further studies are needed including a greater number of patients to confirm these preliminary results; (2) a long term follow-up must be carried out to detect any possible cochlear adverse effects on the cochlea, in particular on the basilar membrane.