Exploring Mechanisms Underlying Unexplained Air-Bone Gaps Post-Myringoplasty: Temporal Bone Model and Finite Element...

Area of Science:

• Otolaryngology
• Biomedical Engineering
• Acoustics

Background:

• Air-bone gap (ABG) is a key metric for middle ear function post-myringoplasty.
• Mechanisms behind persistent ABGs after tympanic membrane repair remain unclear.

Purpose of the Study:

• Investigate the causes of unexplained air-bone gaps following myringoplasty.
• Utilize cadaveric temporal bone measurements and finite element modeling to understand these mechanisms.

Main Methods:

• Modeled tympanic membrane (TM) perforations of 6%, 24%, and 50% area in temporal bone (TB) models.
• Simulated myringoplasty using paper patches and altered material properties in finite element (FE) models.
• Measured TM vibration at the umbo using laser Doppler vibrometry (LDV).

Main Results:

• Increased perforation size reduced TM vibration at the umbo in both TB and FE models.
• Post-repair, TM displacement at the umbo was not fully restored in either model.
• Flattening of the TM cone shape in FE models significantly decreased umbo displacement, similar to TB models with large perforations.

Conclusions:

• Repaired TM material properties and anatomical shape influence TM motion and wave propagation.
• Current clinical tools cannot assess these factors, leaving post-myringoplasty ABGs unexplained.
• Further research is needed to identify specific factors contributing to residual ABGs.