Prestrain in the rabbit eardrum measured by digital image correlation and micro-incisions

Area of Science:

• Biomechanics
• Auditory Science
• Materials Science

Background:

• Prestrain significantly impacts mechanical system vibrations, including the middle ear.
• Existing research on tympanic membrane (TM) prestrain is limited and inconclusive.

Purpose of the Study:

• To quantify prestrain in cadaveric rabbit tympanic membranes (TM).
• To investigate the effect of incision location and orientation on TM prestrain release.

Main Methods:

• Stereo digital image correlation was employed to measure TM prestrain.
• Controlled 0.33 mm incisions were made parallel to radial or circular fibers.
• Sample rehydration ensured accurate measurements by mitigating dehydration effects.

Main Results:

• Average TM prestrain values around incisions ranged from 3.52±2.34% to 13.62±7.92%.
• No significant differences in prestrain were observed between radial and circular incisions.
• Local variations in prestrain could not be definitively linked to specific TM locations.

Conclusions:

• The findings indicate the presence of substantial prestrain in rabbit TMs.
• TM prestrain should be considered in future middle ear function research, pending confirmation in human subjects.