Middle Ear Active Implant Indications, Comparative Audiometric Results from Different Approaches, and Coupling with the Vibrant Soundbridge®: A Single Center Experience over More Than 20 Years.

Abstract

Background: Middle ear active implants, such as the Vibrant Soundbridge (VSB), offer an alternative to reconstructive surgery and other implantable hearing aid systems for patients with conductive, mixed, or sensorineural hearing loss. The primary objective of this work is to describe the auditory results obtained with VSB in our patient cohort, measuring the auditory gain in terms of average tonal thresholds and spoken word discrimination at 65 dB. Secondly, auditory gain differences between different types of hearing loss, coupling to the ossicular chain compared to round and oval windows, and the impact of open versus more conservative surgical approaches, were analyzed.

Methods: A cross-sectional observational study, with retrospective data collection, was conducted at a tertiary care center. Clinical and audiometric data pre- and post-implantation were included, from patients who underwent VSB device placement surgery between 2001 and 2024.

Results: 55 patients with an average age of 62.58 ± 17.83 years and a slight preference in terms of the female gender (52.72%) were included in the study. The average gain in the PTA for all types of hearing loss was 41.56 ± 22.63 dB, while for sensorineural hearing loss (SNHL) the gain was 31.04 ± 8.80 dB. For mixed-conductive hearing loss (C-MHL) a gain of 42.96 ± 17.70 was achieved, notably, in terms of absolute values, at frequencies of 4000 and 6000 Hz, with gains reaching 49.25 ± 20.26 dB at 4 K and 51.16 ± 17.48 dB at 6 K. In terms of spoken word discrimination, for all types of hearing loss, an improvement of 75.20 ± 10.11% was achieved. However, patients with C-MHL exhibited an approximately 13% higher gain compared to those with SNHL (69.32 ± 24.58% vs. 57.79 ± 15.28%). No significant differences in auditory gain were found between open and closed surgical techniques, nor in the proportion of adverse effects, when comparing one technique with the other.

Conclusions: The VSB is effective in improving hearing in patients with mixed, conductive, and sensorineural hearing loss, with significant gains at high frequencies, especially through the round window membrane approach. The choice of surgical technique should consider the patient's anatomical characteristics and specific needs in order to optimize auditory outcomes and minimize postoperative complications.