Treatment of mixed hearing losses via implantation of a vibratory transducer on the round window

TLDR

Patients had previously undergone multiple ossiculoplasties or an unsuccessful VSB incus crimp, leaving severe mixed hearing loss. The VSB criteria were broadened to include ossicular chain defects, and the transducer was implanted onto the round window to bypass the conductive path and amplify cochlear input. Post‑operative aided thresholds averaged 30 dB HL and aided speech reception reached 100 % intelligibility at conversational levels, indicating that round‑window VSB implantation is a viable option for patients with failed ossiculoplasties.

Abstract

Early clinical findings are reported for subjects implanted with the Vibrant Med-El Soundbridge® (VSB) device. The present criteria for the VSB, limiting its application to patients with normal middle ear function, have been extended to include patients with ossicular chain defects. Seven patients with severe mixed hearing loss were implanted with the transducer placed onto the round window. All had undergone previous surgery: six had multiple ossiculoplasties, and one had the VSB crimped on the incus with unsuccessful results. Round window implantation bypasses the normal conductive path and provides amplified input to the cochlea. Post-operative aided thresholds of 30 dB HL were achieved for most subjects, as compared with unaided thresholds ranging from 60–80 dB HL. Aided speech reception thresholds at 50% intelligibility were 50 dB HL, with most subjects reaching 100% intelligibility at conversational levels, while unaided thresholds averaged 80 dB HL, with only one subject reaching 100% intelligibility. These results suggest that round window implantation may offer a viable treatment option for individuals with severe mixed hearing losses who have undergone unsuccessful ossiculoplasties.