A new implantable middle ear hearing device for mixed hearing loss : a feasibility study in human temporal bones

HYPOTHESIS: To assess the feasibility of a new, active middle ear device in temporal bones (TB). BACKGROUND: This device is designed for patients with mixed hearing loss subsequent to chronic middle ear infection, surgery, or trauma. This Bell-Vibroplasty is built from a VIBRANT MED-EL Vibrant Soundbridge and a Kurz Bell titanium partial ossicular replacement prosthesis. METHODS: In three fresh TBs, healthy and reconstructed middle ears were analyzed by means of laser Doppler interferometry. The sound transmission properties of a partial ossicular replacement prosthesis and a passive and an active Bell-Vibroplasty were compared with healthy middle ear function. RESULTS: The measurements provided reliable results with small standard deviations and good signal-to-noise ratios. The performance levels of the partial ossicular replacement prosthesis and of the passive Bell-Vibroplasty were comparable with that of healthy middle ear function. The activated Bell-Vibroplasty provided linear function and a flat frequency response within the measured frequency range (500 Hz-8 kHz), with peak deviations of less than 10 dB. The maximum output of the Bell-Vibroplasty was equivalent to 125-dB sound pressure level. CONCLUSION: Bell-Vibroplasty is feasible in TBs. Bell-Vibroplasty performance in TBs is sufficient to allow for a clinical trial as a next step.