title: Chronic otitis media with cholesteatoma with canal fistula and bone conduction threshold after tympanoplasty with mastoidectomy.
abstract: OBJECTIVE
  To understand the third mobile window effect of chronic otitis media with cholesteatoma with inner ear fistula on the bone conduction threshold, we examined changes in the bone conduction audiogram after tympanoplasty with mastoidectomy for chronic otitis media with cholesteatoma with canal fistula.
  
  
  METHODS
  Retrospective case review.
  
  
  METHODS
  Tertiary referral center.
  
  
  METHODS
  According to the intraoperative classification of Dornhoffer and Milewski, we focused especially on Type IIa (anatomic bony fistula with no perilymph leak). We checked the bone conduction threshold at least 3 times: just before, just after, and 6 months after surgery in 20 ears with Type IIa lateral semicircular canal fistula.
  
  
  METHODS
  Tympanoplasty with mastoidectomy.
  
  
  METHODS
  Bone conduction thresholds before and after tympanoplasty with mastoidectomy.
  
  
  RESULTS
  Compared with the preoperative bone conduction threshold, 6 cases were better, 12 cases were unchanged, and 2 cases were worse within the first postoperative week. Finally, 1 case was better, 15 cases were unchanged, and 4 cases were worse at the sixth postoperative month. Patients with a better bone conduction threshold in the low-tone frequencies immediately after surgery had a tendency to show no preoperative fistula symptoms. Postoperative spontaneous nystagmus had a tendency to be observed in patients with a worse bone conduction threshold in the high-tone frequencies.
  
  
  CONCLUSIONS
  The better bone conduction threshold at low-tone frequencies immediately after tympanoplasty with mastoidectomy and no preoperative fistula symptoms might imply the third mobile window theory. The worse bone conduction threshold in high-tone frequencies with spontaneous nystagmus after surgery might indicate inner ear damage.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Osaka University, Graduate School of Medicine, Osaka, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kitahara
authors.forename: Takefumi
authors.initials: T
authors.lastname: Kamakura
authors.forename: Yumi
authors.initials: Y
authors.lastname: Ohta
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Morihana
authors.forename: Arata
authors.initials: A
authors.lastname: Horii
authors.forename: Atsuhiko
authors.initials: A
authors.lastname: Uno
authors.forename: Takao
authors.initials: T
authors.lastname: Imai
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Mishiro
authors.forename: Hidenori
authors.initials: H
authors.lastname: Inohara
mesh_terms: D000328:Adult; D000368:Aged; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold; D001844:Bone Conduction; D002781:Cholesteatoma / Q000150:complications / Q000601:surgery*; D002908:Chronic Disease; D005260:Female; D005402:Fistula / Q000209:etiology / Q000601:surgery*; D006801:Humans; D008297:Male; D008416:Mastoid / Q000601:surgery*; D008875:Middle Aged; D010033:Otitis Media / Q000150:complications / Q000601:surgery*; D010897:Pitch Discrimination; D012189:Retrospective Studies; D016896:Treatment Outcome; D014433:Tympanoplasty / Q000009:adverse effects / Q000379:methods*; D055815:Young Adult