[Experimental investigations on middle ear prostheses with an integrated micro joint]

Area of Science:

• Biomedical Engineering
• Otolaryngology
• Biomimetics

Background:

• Quasi-static pressure changes cause significant tympanic membrane displacement, risking prosthesis dislocation after total ossicular replacement prosthesis (TORP) reconstruction.
• Chronic middle ear ventilation issues can lead to prosthesis extrusion.
• Avian middle ear anatomy, specifically the flexible columella, offers insights into effective sound transmission and ear protection during pressure variations.

Purpose of the Study:

• To design and evaluate a novel micro-joint TORP inspired by avian middle ear structures.
• To assess the prosthesis's performance under simulated pressure changes relevant to altitude variations and Valsalva maneuvers.

Main Methods:

• A bionic approach was used to create a micro-joint TORP by incorporating a silicone ball joint into the prosthesis shaft.
• Frequency response measurements were conducted using laser Doppler vibrometry in a ventilated middle ear model.
• The prototype's response to increased external auditory canal pressure was investigated.

Main Results:

• Frequency response measurements indicated performance comparable to conventional TORPs.
• The micro-joint prosthesis demonstrated a significant reduction in stapes footplate excursion under increased external auditory canal pressure compared to standard TORPs.
• Limited prosthesis shaft deflection effectively absorbed pressure-induced forces.

Conclusions:

• The silicone-bordered micro-joint TORP effectively mitigates damaging stapes footplate excursions in complete ossicular reconstruction.
• This design reduces the risk of prosthesis dislocation and annular ligament damage while maintaining sound transmission.
• The bionic modification highlights potential for future advancements in prosthetic middle ear reconstruction.