title: Analysis of mastoid findings at surgery to treat middle ear cholesteatoma.
abstract: OBJECTIVE
  To analyze mastoid findings, such as facial nerve dehiscence (FND), labyrinthine fistula, and dural exposure; to review its incidence at cholesteatoma surgery; to analyze its association with semicircular canal fistula; and to elucidate its relationship with dural exposure.
  
  
  METHODS
  One hundred fifty-two patients (65 males and 87 females; 155 ears) were enrolled in a retrospective study of tympanoplasty with or without mastoidectomy.
  
  
  METHODS
  Medical university center hospital.
  
  
  RESULTS
  The incidence of FND after exenteration of disease was 29.7% (46/155 ears) for total surgical procedures, 29.7% (43/145 ears) for initial procedures, and 30% (3/10 ears) for revision procedures. The prevalence of FND in the tympanic segment only was 87%, with 8.7% in the vertical segment only and 4.3% in both segments. Three patients (2.0%) developed facial palsy postoperatively, with 8 lateral semicircular canal fistulas (5.2% of total ears operated on), half of these with concomitant FND. The incidence of dural exposure of the mastoid tegmen in the entire surgical group was 16.8% (26 ears), 38.5% with concomitant FND.
  
  
  CONCLUSIONS
  The overall incidence of FND in our sample was high at 29.7%, with rates of lateral semicircular canal fistula and dural exposure of 5.2% and 16.8%, respectively. The relationship between FND incidence and presence of lateral semicircular canal fistula was positive in our study. The surgeon should bear in mind that the location of FND with cholesteatoma coincides with the most common area of iatrogenic facial nerve injury during otologic surgery.
authors.affiliation: Department of Otolaryngology, Chung-Ho Memorial Hospital, Kaohsiung, Taiwan.
authors.forename: Hsun-Mo
authors.initials: HM
authors.lastname: Wang
authors.forename: Jen-Chih
authors.initials: JC
authors.lastname: Lin
authors.forename: Ka-Wo
authors.initials: KW
authors.lastname: Lee
authors.forename: Chih-Feng
authors.initials: CF
authors.lastname: Tai
authors.forename: Ling-Feng
authors.initials: LF
authors.lastname: Wang
authors.forename: Hamm-Ming
authors.initials: HM
authors.lastname: Chang
authors.forename: Ying-Che
authors.initials: YC
authors.lastname: Hsu
authors.forename: Chee-Yin
authors.initials: CY
authors.lastname: Chai
authors.forename: Kuen-Yao
authors.initials: KY
authors.lastname: Ho
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D018424:Cholesteatoma, Middle Ear / Q000453:epidemiology* / Q000601:surgery; D005155:Facial Nerve Diseases / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008416:Mastoid / Q000601:surgery*; D008875:Middle Aged; D015995:Prevalence; D012189:Retrospective Studies; D017678:Sex Distribution; D013529:Surgical Wound Dehiscence / Q000150:complications / Q000453:epidemiology; D013624:Taiwan / Q000453:epidemiology; D014433:Tympanoplasty / Q000379:methods*