How does prosthesis head size affect vibration transmission in ossiculoplasty?
OBJECTIVE
The transmission of vibrations from the tympanic membrane to the stapes footplate by an ossicular reconstruction prosthesis is affected by the size of the prosthesis head. We sought to determine if augmenting or reducing the head size of prosthesis had a systematic effect on transmission of vibrations to the stapes.


METHODS
We conducted a fresh cadaveric temporal bone middle ear study.


METHODS
The incus was replaced with a prosthesis using a tympanic membrane to stapes head (TASH)-type hydroxyapatite prosthesis in nine fresh cadaveric temporal bones. Three prosthesis head sizes were created: unaltered, reduced, and augmented. Stapes vibrations were measured with a laser Doppler vibrometer in response to acoustic frequency chirps at 90 dB SPL.


RESULTS
All three head size prostheses resulted in smaller stapes vibrations than the intact ear. There was no difference in the vibration transmission between the three different head sizes. All prostheses showed a vibration loss of 10 to 15 dB compared to the intact ear.


CONCLUSIONS
Within the range of sizes tested, prosthesis head size had little impact on vibration transmission to the stapes footplate.
Bance
Manohar
M
E.A.R. Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada. m.bance@dal.ca
Campos
Alfredo
A
Wong
Lillian
L
Morris
David P
DP
van Wijhe
Rene
R
D000161:Acoustic Stimulation; D001672:Biocompatible Materials; D002102:Cadaver; D004301:Doppler Effect; D017886:Durapatite; D006801:Humans; D007188:Incus / Q000601:surgery; D009998:Ossicular Prosthesis; D011474:Prosthesis Design; D013199:Stapes / Q000502:physiology*; D013499:Surface Properties; D014432:Tympanic Membrane / Q000502:physiology*; D014732:Vibration
D001672:Biocompatible Materials; D017886:Durapatite