title: Radiographic evaluation of the tegmen in patients with superior semicircular canal dehiscence.
abstract: OBJECTIVE
  To determine a radiographic association between superior semicircular canal dehiscence (SSCD) and tegmen dehiscence (TD).
  
  
  METHODS
  Retrospective case-control series.
  
  
  METHODS
  Tertiary referral center.
  
  
  METHODS
  Patients seen between 2003 and 2010 with radiographic SSCD were compared with cochlear implant recipient controls.
  
  
  METHODS
  The tegmen and superior semicircular canal were evaluated on computed tomographic temporal bone scans.
  
  
  METHODS
  If detected, the widest point of the SSCD was measured. The tegmen was graded on a 5-point scale. After analysis, a radiographic TD was defined as any single area of absent tegmen greater than 5 mm, multiple areas of absent tegmen, or evidence of meningocele. Age, sex, and body mass index were also noted.
  
  
  RESULTS
  Thirty-eight patients with SSCD and 41 cochlear implant controls were identified. Seventy-six percent (29/38) of patients with unilateral or bilateral SSCD had a radiographic TD on at least 1 side compared with 22% (9/41) of the comparison group. Ninety-four percent (7/18) of patients with bilateral SSCD had a TD on at least 1 side. Patients with SSCD had a 10.2 times (p < 0.001) higher odds of having radiographic TD in either ear compared to the controls. Among patients with any SSCD, for every millimeter increase in the width of dehiscence, the relative risk for any TD increased more than 2-fold (odds ratio, 2.5; p = 0.019). Age, sex, and a body mass index greater than 30 did not confound the association between SSCD and TD.
  
  
  CONCLUSIONS
  There is a strong radiologic association between SSCD and TD, suggesting a similar etiologic process. The tegmen should be carefully evaluated in patients with SSCD. We have also proposed a new system for radiographically grading the integrity of the tegmen.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Stanford University, Stanford, California 94305-5739, USA.
authors.forename: Garani Shiranthana
authors.initials: GS
authors.lastname: Nadaraja
authors.forename: Richard K
authors.initials: RK
authors.lastname: Gurgel
authors.forename: Nancy J
authors.initials: NJ
authors.lastname: Fischbein
authors.forename: Andrew
authors.initials: A
authors.lastname: Anglemyer
authors.forename: Ashkan
authors.initials: A
authors.lastname: Monfared
authors.forename: Robert K
authors.initials: RK
authors.lastname: Jackler
authors.forename: Nikolas H
authors.initials: NH
authors.lastname: Blevins
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007759:Labyrinth Diseases / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D012665:Semicircular Canals / Q000000981:diagnostic imaging*; D013701:Temporal Bone / Q000000981:diagnostic imaging*