Intraoperative adjustments to optimize active middle ear implant performance.

Area of Science:

• Biomedical Engineering
• Otolaryngology
• Auditory Implants

Background:

• Active middle ear implants (AMEIs) offer a therapeutic option for hearing loss.
• Optimizing implant performance is crucial for patient outcomes.
• Understanding the mechanical interaction between implants and the ossicular chain is essential.

Purpose of the Study:

• To evaluate the impact of varying static loads on the performance of an AMEI.
• To determine the optimal loading parameters for incus stimulation.
• To assess the effect of loading on residual hearing.

Main Methods:

• Cadaveric temporal bones were used to assess incus drive efficacy.
• Laser Doppler velocimetry measured stapes velocities across a frequency range (0.25–8 kHz).
• Static loads were incrementally applied to the AMEI on the incus using an adjustment screw (62 μm increments).

Main Results:

• Initial AMEI contact resulted in significant sound pressure levels (L(Emax)) and minimal residual hearing loss.
• Increasing static load up to 125 μm (half turn) significantly improved AMEI performance.
• Loads exceeding 125 μm did not further enhance performance and increased residual hearing loss.

Conclusions:

• Intraoperative static loading of the incus with an AMEI can be optimized.
• Optimal performance gains are achieved with incremental loading up to 125 μm.
• This optimization can be performed without negatively impacting residual hearing.