A self-adjusting ossicular prosthesis containing polyurethane sponge.

Area of Science:

• Otolaryngology
• Biomedical Engineering
• Acoustics

Background:

• Optimal tension is crucial for incus-stapes replacement prosthesis acoustic performance.
• Prosthesis length determines postinsertion tension, which can change postoperatively, worsening hearing.
• Middle ear ossicular replacement prostheses (ORP) that adjust length in vivo may offer acoustic benefits.

Purpose of the Study:

• To evaluate the acoustic performance of a novel self-adjusting prosthesis (SAP) compared to conventional partial ossicular replacement prostheses (PORP).
• To assess the impact of varying prosthesis lengths and tensions on sound transmission in the middle ear.

Main Methods:

• A self-adjusting prosthesis (SAP) with a polyurethane sponge was tested in 5 fresh temporal bones.
• Stapes footplate displacement was measured using laser Doppler vibrometry before and after prosthesis insertion.
• The SAP and optimal length PORPs were tested with varying tensions simulated by glass shims.

Main Results:

• Optimal length PORPs showed decreased sound transmission below 1.0 kHz with increasing length.
• The SAP demonstrated equivalent sound transmission to PORPs below 4.0 kHz.
• The SAP provided superior sound transmission below 1.0 kHz across varied increased lengths.

Conclusions:

• A self-adjusting prosthesis (SAP) appears to mitigate the negative effects of length variations between the malleus and stapes.
• SAP technology holds promise for improving acoustic performance in middle ear ossicular replacement surgery.
• Further research into adjustable prostheses could lead to enhanced postoperative hearing outcomes.