title: Standardized Active Middle-Ear Implant Coupling to the Short Incus Process.
abstract: BACKGROUND
  Active middle-ear implants with floating-mass transducer (FMT) technology are used to treat mild-to-severe sensorineural hearing losses. The standard surgical approach for incus vibroplasty is a mastoidectomy and a posterior tympanotomy, crimping the FMT to the long incus process. An alternative fixation side with less surgical trauma might be the short incus process and incus body.The aim of this study was to develop and test a short incus process coupling device for its functional properties in temporal bone preparations and clinical practice.
  
  
  METHODS
  An extended antrotomy and a posterior tympanotomy were performed in 10 fresh human temporal bones. As a control for normal middle-ear function, the tympanic membrane was stimulated acoustically, and the vibration of the stapes footplate was measured using laser Doppler vibrometry. FMT-induced vibration responses of the stapes were then measured for standard attachment at the long process and for 2 types of couplers designed for attachment at the short process of the incus (SP1 and SP2 coupler). Additionally, the functional outcome in 2 patients provided with an SP2 coupler was assessed postoperatively at 2 weeks, 3 months, and then 11 months, using pure-tone audiometry, auditory thresholds for frequency-modulated (warble) tones, vibroplasty thresholds, and speech audiometry in quiet and noise.
  
  
  RESULTS
  For the SP2 coupler, velocity-amplitude responses in temporal-bone preparations showed generally similar mean amplitudes as compared with the standard coupling of the FMT to the long process but with clearly increased mean amplitudes between 0.7 and 1.5 kHz and with reduced interindividual variation between 0.5 and 3 kHz. The clinical data of 2 patients with mild-to-severe sensory hearing loss showed good vibroplasty thresholds and convincing results for speech audiometry in quiet (Freiburger monosyllables at 65 dB SPL, 23 ± 31% unaided versus 83 ± 4% aided) and noise (Hochmair-Schulz-Moser-test at 65 dB SPL at 10 dB SNR, 32 ± 45% unaided and 42 ± 29% aided).
  
  
  CONCLUSIONS
  The attachment of the FMT to the short incus process with the SP2 coupler leads to good mechanical and functional coupling in an experimental setup and clinical practice.
authors.affiliation: *Department of Otorhinolaryngology, Head and Neck Surgery "Otto Koerner" University Medical Center Rostock, Rostock; †Department of Otolaryngology, Section of Physiological Acoustics and Communication, University of Tübingen, Tübingen; and ‡Department of Oto-Rhino-Laryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery, Comprehensive Hearing Center, University of Würzburg, Würzburg, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Mlynski
authors.forename: Ernst
authors.initials: E
authors.lastname: Dalhoff
authors.forename: Andreas
authors.initials: A
authors.lastname: Heyd
authors.forename: Daniela
authors.initials: D
authors.lastname: Wildenstein
authors.forename: Kristen
authors.initials: K
authors.lastname: Rak
authors.forename: Andreas
authors.initials: A
authors.lastname: Radeloff
authors.forename: Rudolf
authors.initials: R
authors.lastname: Hagen
authors.forename: Anthony W
authors.initials: AW
authors.lastname: Gummer
authors.forename: Sebastian P
authors.initials: SP
authors.lastname: Schraven
mesh_terms: D000293:Adolescent; D001301:Audiometry, Pure-Tone; D001302:Audiometry, Speech; D001309:Auditory Threshold; D002102:Cadaver; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000601:surgery*; D006801:Humans; D007188:Incus / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D008953:Models, Anatomic; D009622:Noise; D009998:Ossicular Prosthesis; D019919:Prosthesis Implantation / Q000379:methods*; D013199:Stapes; D013701:Temporal Bone / Q000601:surgery*; D014432:Tympanic Membrane; D014732:Vibration