Comparison of the Mechanical Performance of Ossiculoplasty Using a Prosthetic Malleus-to-Stapes Head with a Tympanic Membrane-to-Stapes Head Assembly in a Human Cadaveric Middle Ear Model

Abstract

Tension has a significant effect on prosthesis function. Malleus assembly to the stapes head type prostheses generally result in better transmission of vibrations to the stapes footplate than tympanic membrane assembly to the stapes head type prostheses.

Ossiculoplasty

“…It has been long known that there is an impedance mismatch involved with this transfer of energy from air to fluid, with only 0.1% of acoustic energy traveling through air actually transferring into a water medium [13]. The middle ear in classic descriptions functions as an impedance matching device through three major mechanisms: a hydraulic lever, ossicular lever, and catenary lever [14]. The hydraulic lever concentrates acoustic energy at the oval window and results from the 17-to 20-fold difference in vibratory surface of the tympanic membrane compared with the smaller area of the stapes footplate [15].…”

A Comparison Study of Partial Ossicular Reconstruction Prosthesis (PORP) Placement under the Malleus or Tympanic Membrane Graft in the Presence of the Malleus

“…The vertical placement of the prosthesis is a favorable position for a better hearing outcome [11] . Bance et al [9] reported the angulation of the prosthesis decreased the force transmission and better hearing outcomes of the MASH group on cadavers. Sacrificing the tensor timpani muscle to lateralize the malleus may help place the prosthesis in a proper vertical position, but it is vital to detect sufficient malleus stability.…”

“…PORPs are some of the most common tools available for otologists. Bance et al [9] first reported that the malleus to stapes assembly showed a better vibration transmission than the TM to stapes on cadaver temporal bone models and significantly related with tension. Since then, different studies have clinically shown that the preservation of the malleus maintains better hearing outcomes [6] .…”

“…The prosthesis head may interact with the narrow bony canal or annulus on the posterior quadrant. Interaction may cause fibrosis and decreased hearing outcomes in the long term [9] . Previous hearing results may be related to the early fibrotic process in the TASH group.…”

“…The same terminology from previously published studies was used [9] . Thirty-six (44.4%) patients (females: 19, males: 17) were included in the MASH group, and their ages ranged from 18 to 62 years (mean: 31.9, median: 29, std dev: 13.1).…”