Acoustomechanical properties of open TTP titanium middle ear prostheses

Area of Science:

• Biomaterials Science
• Otolaryngology
• Medical Device Engineering

Background:

• Middle ear prostheses are crucial for ossiculoplastic surgery to restore hearing.
• Existing prostheses face limitations in handling, visibility, and acoustomechanical properties.
• Biocompatible and biostable materials are essential for implantable medical devices.

Purpose of the Study:

• To identify acoustomechanical properties of materials for improved middle ear prostheses.
• To develop prostheses with enhanced handling, adjustable length, and superior acoustic characteristics.
• To create CE and FDA-approved prostheses for clinical ossiculoplastic applications.

Main Methods:

• Investigated various materials (Teflon, PEEK, PET, polysulfone, gold, Al2O3, carbon, titanium) using laser Doppler velocimetry (LDV) in mechanical middle ear models (MMM).
• Utilized a computer model (multibody systems approach, MBS) and computer-aided design (CAD) for prosthesis design and refinement.
• Tested handling in temporal bones and determined input impedance, mass, stiffness, and geometry.

Main Results:

• Developed FDA- and CE-approved filigreed titanium prostheses (Tübingen Titanium Prostheses, TTP) with an open head design.
• Prostheses available in fixed lengths (1.75–6.5 mm) and adjustable lengths (TTP-Vario).
• Achieved a combination of low mass and high stiffness, fulfilling all study requirements.

Conclusions:

• Titanium prostheses (TTP) demonstrate acoustomechanical advantages, including low mass and high stiffness.
• The open head design enhances intraoperative reliability by improving visibility of the prosthesis foot during stapes coupling.
• These findings support the clinical use of TTPs for improved ossiculoplastic outcomes.