New total ossicular replacement prostheses with a resilient joint: experimental data from human temporal bones.

Area of Science:

• Biomedical Engineering
• Otolaryngology
• Materials Science

Background:

• Prosthesis dislocations and extrusions are common complications following middle ear surgery.
• These issues often stem from altered distances between coupling points due to significant static eardrum displacements.

Purpose of the Study:

• To evaluate novel flexible total ossicular prostheses with integrated microjoints for middle ear reconstruction.
• To assess their ability to compensate for static displacements and mimic intact ossicular chain function.

Main Methods:

• Developed prostheses with titanium shafts in silicone bodies.
• Assessed sound transfer function and stapes footplate displacement in human temporal bones under static loads.
• Investigated stiffness and bending characteristics using quasi-static loading with varying silicone hardness.

Main Results:

• Prostheses demonstrated sound transfer comparable to intact ossicular chains under uncompressed conditions.
• Implants with softer silicone showed superior acoustic transfer in a compressed state.
• Minimum medial footplate displacement was observed with the soft silicone implant.

Conclusions:

• Titanium prostheses with resilient joints offer good sound transfer, even when compressed.
• The joint's bending capability compensates for ossicular chain length variations caused by middle ear pressure changes.
• Stable stapes footplate support is crucial for optimal prosthesis function.