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Extracting the Cochlea from a Human Temporal Bone: A Cadaveric Protocol
Published on: August 18, 2023
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Effect of conservation method on ear mechanics for the same specimen.
Lukas Graf1, Andreas Arnold2, Kourosh Roushan3
1Department of ENT, University Basel Hospital, Hebelstrasse 10, 4031 Basel, Switzerland; Department of ENT, Kantonsspital Aarau, Switzerland.
Hearing Research
|January 3, 2021
Summary
Thiel conserved temporal bones offer a viable alternative for ear mechanics research, though some changes in tympanic membrane, stapes, and round window motion occur after conservation.
Area of Science:
- Otorhinolaryngology
- Biomechanical Engineering
- Anatomical Pathology
Background:
- Fresh temporal bones are limited for ear mechanics studies.
- Thiel conserved specimens offer a non-decaying alternative for long-term experiments.
- Previous literature suggests similar air conduction motion in Thiel vs. fresh specimens.
Purpose of the Study:
- To directly compare ear mechanics in the same specimens before and after Thiel conservation.
- To quantify changes in tympanic membrane (TM), stapes (ST), and round window (RW) motion.
- To assess the suitability of Thiel conserved specimens for ear mechanics research.
Main Methods:
- 10 fresh frozen human heads were thawed and measured using laser Doppler vibrometry (LDV).
- Specimens were then embalmed using the Thiel method.
- Measurements were repeated at 3 and 12 months post-conservation.
Main Results:
- Magnitudes of TM, ST, and RW motion changed by a maximum of 10 dB.
- TM motion increased significantly at low frequencies after 12 months.
- ST and RW motion decreased significantly after 3 months, with ST motion decreasing by 5.7 dB and RW motion by 7.1 dB on average.
- Phase shifts between ST and RW motion remained minimal, indicating cochlear fluid integrity.
Conclusions:
- Thiel embalming alters TM motion after long-term conservation.
- ST and RW motion changes primarily occur after short-term conservation.
- Thiel conserved specimens are a suitable alternative to fresh specimens for studying normal human ear mechanics, with noted limitations for specific applications like implant design.
