title: Patterns of failure in canal wall down mastoidectomy cavity instability.
abstract: OBJECTIVE
  To evaluate patterns of failure for canal wall down mastoid cavities requiring surgical revision.
  
  
  METHODS
  Retrospective review.
  
  
  METHODS
  Academic tertiary referral center
  
  
  METHODS
  Adults and children that underwent revision of an unstable open mastoid cavity from 1995 to 2010.
  
  
  METHODS
  Review of demographic data, tympanomastoid pathology, and plausible risk factors for an unstable cavity. Available computed tomography (CT) scans were reviewed for indicators of suboptimal cavity shape. Spearman's correlation analysis was undertaken. Findings were classified as Type 1 (primary tympanomastoid pathology), Type 2 (cavity shape/size), or Type 3 (negative host environment).
  
  
  METHODS
  Frequency of risk factors and correlation.
  
  
  RESULTS
  Approximately 130 cases were reviewed. Stapes erosion (49.2%), absent malleus (26.2%), cholesteatoma (44.6%), tympanic membrane perforation (34.6%), and fibrotic middle ear mucosa (20.8%) were common. CT scans often demonstrated an intact open mastoid tip (87.5%) and a high facial ridge (54.2%). Notable correlations were discovered between the facial ridge height proximally and the height distally (r = 0.46437, p = 0.0256) and tympanic membrane perforation and absent malleus (r = -0.17944, p = 0.0419). Approximately 68% of the subjects had at least 1 Class 1 risk factor present among cholesteatoma, tympanic membrane perforation/atelectasis, and extruded prosthesis. All CT scans reviewed demonstrated at least 1 class 2 factor.
  
  
  CONCLUSIONS
  Although primary tympanomastoid pathology is quite common, some aspect of suboptimal mastoid cavity size and shape is pervasive. Correlation analysis suggests that surgeons tend to either lower the facial ridge completely or not at all and that an absent malleus seems to be associated with a tympanic membrane perforation.
authors: Department of Otolaryngology-Head and Neck Surgery, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA. mbgluth@uams.edu
authors: Michael B
authors: MB
authors: Gluth
authors: Aaron M
authors: AM
authors: Metrailer
authors: John L
authors: JL
authors: Dornhoffer
authors: Page C
authors: PC
authors: Moore
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D002781:Cholesteatoma / Q000473:pathology; D004424:Ear Canal / Q000601:surgery*; D005260:Female; D005355:Fibrosis; D006801:Humans; D008297:Male; D008307:Malleus / Q000002:abnormalities / Q000473:pathology; D008416:Mastoid / Q000601:surgery*; D008875:Middle Aged; D013506:Otologic Surgical Procedures; D011183:Postoperative Complications / Q000453:epidemiology; D012307:Risk Factors; D013199:Stapes / Q000473:pathology; D013701:Temporal Bone / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed; D018058:Tympanic Membrane Perforation / Q000473:pathology; D055815:Young Adult