Active middle ear implant application in case of stapes fixation: a temporal bone study

Area of Science:

• Otology and Hearing Restoration
• Biomedical Engineering
• Auditory Physiology

Background:

• Otosclerosis treatment often involves stapes prostheses, addressing conductive hearing loss but not sensorineural components.
• Active middle ear implants (AMEIs) are explored as an alternative for mixed hearing loss in otosclerosis.
• Current treatments may require supplementary hearing aids for residual sensorineural deficits.

Purpose of the Study:

• To evaluate the feasibility of directly driving the oval window with an AMEI in a simulated otosclerosis scenario.
• To compare the efficacy of AMEI oval window stimulation with traditional methods.
• To assess the impact of stapes fixation on AMEI performance.

Main Methods:

• Seven human temporal bones were prepared, exposing the stapes and round window (RW).
• Stapes and RW velocities were measured using an AMEI with a bell-shaped tip.
• Stapes footplate fixation was simulated, and oval window stimulation was performed with and without fascial interposition using a cylinder tip.

Main Results:

• Direct oval window drive with an AMEI produced high sound pressure levels (SPL) up to 138 dB.
• Simulated stapes fixation attenuated performance by approximately 25 dB.
• Oval window stimulation via stapedotomy yielded 110-114 dB SPL, with better performance when fascia was used.

Conclusions:

• Direct oval window stimulation using an AMEI is a viable approach, even with stapes fixation.
• This method shows performance comparable to conventional AMEI coupling.
• It presents a promising alternative for treating mixed hearing loss in patients with a fixed stapes footplate.