title: Evolving acoustic characteristics of the canal wall down cavities due to neo-osteogenesis by periosteal flap.
abstract: OBJECTIVE
  To determine whether the acoustic properties of the canal wall down cavity would come closer to those of the normal ear canal as the cavity is lined with periosteal flap.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Tertiary referral center.
  
  
  METHODS
  Twenty one subjects who underwent canal wall down mastoidectomy and total ossicular replacement prosthesis tympanoplasty were selected.
  
  
  METHODS
  Canal wall down cavities were lined with postauricular periosteal flap. The acoustic properties of 21 canal wall down cavities (mastoidectomy ears) and 16 contralateral normal ears (control ears) were measured with a hearing aid fitting system.
  
  
  METHODS
  Frequency, amplitude, bandwidth, and Q factor of the resonance curve along with the loss in amplitude below 1 kHz were compared in a paired-wise manner between the first and third months and the third and sixth months postoperatively in mastoidectomy ears, and also between mastoidectomy and control ears.
  
  
  RESULTS
  In the mastoidectomy ears, the peak resonance frequency and bandwidth significantly increased at the end of the third and six months as the volume of the cavity decreased ( < 0.05). However, the amplitude and Q factor of the resonance curve remained stable. At the end of the first month, all parameters were different in both groups ( < 0.05). At the end of the sixth month, the frequency and bandwidth of the resonance curve in both groups were not different. The mastoidectomy ears had some decibel-amplitude loss below 1 kHz. Only its frequency changed as the cavity became smaller ( < 0.05).
  
  
  CONCLUSIONS
  New bone formation facilitated by a periosteal flap in the posterior part of the CWD cavity behind the facial ridge may provide acoustic properties similar to those of the normal ear canal.
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Gülhane Military Medical Academy, Ankara, Turkey. bsatar@ixir.com
authors.forename: Bülent
authors.initials: B
authors.lastname: Satar
authors.forename: Sertaç
authors.initials: S
authors.lastname: Yetişer
authors.forename: Yalçin
authors.initials: Y
authors.lastname: Ozkaptan
mesh_terms: D000158:Acoustic Impedance Tests; D000328:Adult; D001309:Auditory Threshold / Q000502:physiology; D018424:Cholesteatoma, Middle Ear / Q000601:surgery*; D004424:Ear Canal / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D008416:Mastoid / Q000503:physiopathology / Q000601:surgery*; D008875:Middle Aged; D009998:Ossicular Prosthesis; D010012:Osteogenesis / Q000502:physiology*; D010033:Otitis Media / Q000601:surgery*; D011183:Postoperative Complications / Q000175:diagnosis* / Q000503:physiopathology; D012815:Signal Processing, Computer-Assisted; D013524:Surgical Flaps; D014433:Tympanoplasty