Vibration characteristics and function of atelectatic segments in the tympanic membrane in fresh human cadaveric temporal bones.

Dimeric segments are commonly encountered in otological practice. They may be associated with a mild conductive hearing loss and often coexist with other tympanic membrane and middle ear abnormalities. Some otologists have advocated surgical management but the consequences of dimeric segment stiffening, shielding or excision and grafting on acoustic transfer to the stapes footplate has been poorly explored. In this study, laser Doppler vibrometry was used to measure vibrations at the tympanic membrane and the stapes footplate in the fresh cadaveric human temporal bone. The dimeric segment vibrates more than the adjacent, thicker normal tympanic membrane. Shielding or excision and grafting of the dimeric segment with thicker and stiffer materials has little effect on displacement at the stapes footplate.