title: Active middle ear implant application in case of stapes fixation: a temporal bone study.
abstract: OBJECTIVE
  Driving the oval window directly with an active middle ear implant (AMEI) can produce high levels of input to the inner ear.
  
  
  BACKGROUND
  Treatment of otosclerosis bypasses the stapes with a piston that penetrates the vestibule. Although this treats the conductive component of hearing loss, it does not treat the sensorineural part, which can be improved using an additional conventional hearing aid. Active middle ear implants have been proposed to be an alternative in treating otosclerosis in cases of mixed hearing losses.
  
  
  METHODS
  Seven temporal bones were prepared to expose the stapes and round window (RW). Stapes and RW velocities were measured while driving with an AMEI the stapes head with a bell-shaped tip. The stapes footplate was then fixed with acrylic cement; fixation was confirmed through attenuated RW velocities. A cylinder tip (0.5 mm) was then used to drive the inner ear through a stapedotomy with and without interposition of fascia.
  
  
  RESULTS
  Driving the stapes with an AMEI produced mean maximum equivalent ear canal sound pressure levels (SPL) of 138 dB (0.25-8 kHz at 1 V [RMS]). Stapes fixation caused a approximately 25-dB attenuation. Driving with a cylinder tip through the stapedotomy produced 114 dB SPL (24 dB less than normal) and 110 dB SPL (28 dB less than normal) performance with and without fascia, respectively. Performance with fascia was greater than without.
  
  
  CONCLUSIONS
  Driving the oval window with an AMEI in a scenario of stapes fixation was demonstrated to be feasible, with performance comparable to traditional AMEI coupling to the incus or stapes. These possibilities offer new perspectives to treat mixed hearing loss in case of fixed footplate.
authors.affiliation: Department of Physiology and Biophysics, School of Medicine, University of Colorado Denver, Aurora, Colorado 80045, U.S.A.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Devèze
authors.forename: Kanthaiah
authors.initials: K
authors.lastname: Koka
authors.forename: Stéphane
authors.initials: S
authors.lastname: Tringali
authors.forename: Herman A
authors.initials: HA
authors.lastname: Jenkins
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Tollin
mesh_terms: D000161:Acoustic Stimulation; D001843:Bone Cements; D002102:Cadaver; D002138:Calibration; D003054:Cochlear Implants; D004432:Ear, Middle / Q000502:physiology*; D006801:Humans; D010040:Otosclerosis / Q000601:surgery; D013199:Stapes / Q000502:physiology*; D013201:Stapes Surgery; D013701:Temporal Bone / Q000502:physiology*; D014159:Transducers; D014722:Vestibule, Labyrinth / Q000502:physiology; D014732:Vibration
chemical_list: D001843:Bone Cements