title: External aperture of the vestibular aqueduct in Meniere's disease.
abstract: OBJECTIVE
  To study the relationship of the length of the external aperture of the vestibular aqueduct and the ratio of the summating potential and action potential (SP:AP) in patients with Meniere's disease.
  
  
  METHODS
  Retrospective case study.
  
  
  METHODS
  Neurotology referral center.
  
  
  METHODS
  Fifty-four patients with Meniere's disease and nine control subjects without Meniere's disease.
  
  
  METHODS
  The external aperture of the vestibular aqueduct was measured from a three-dimensional surface reconstruction computed tomography scan. Transtympanic electrocochleography was performed on patients with Meniere's disease.
  
  
  METHODS
  The length of the external aperture of the vestibular aqueduct in the Meniere's disease ears was related to the SP:AP ratio in the Meniere's disease ears and compared with controls.
  
  
  RESULTS
  The average length of the external aperture was 3.79 +/- 2.92 mm in Meniere's disease ears and 5.35 +/- 1.73 mm in the control ears (p < 0.05). An enlarged SP:AP ratio was found in 95% of ears in the group with nonvisible external apertures of the vestibular aqueduct, 91% of ears in the <5 mm group, 58% of ears in the 5-7 mm group, and 29% of ears in the >7 mm group (chi-square = 24.814; p = 0.000).
  
  
  CONCLUSIONS
  The length of the external aperture of the vestibular aqueduct in patients with Meniere's disease is significantly shorter than in those without Meniere's disease. Endolymphatic hydrops, evidenced by an enlarged SP:AP ratio, was related to the length of the external aperture of the vestibular aqueduct. The shorter the external aperture, the more often the SP:AP ratio was enlarged. A short or nonvisible external aperture of the vestibular aqueduct is a predisposing factor to the development of Meniere's disease.
authors.affiliation: Shea Ear Clinic, Memphis, Tennessee 38119, USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: Shea
authors.forename: X
authors.initials: X
authors.lastname: Ge
authors.forename: R M
authors.initials: RM
authors.lastname: Warner
authors.forename: D J
authors.initials: DJ
authors.lastname: Orchik
mesh_terms: D001300:Audiometry, Evoked Response; D018159:Endolymphatic Hydrops / Q000150:complications / Q000175:diagnosis; D006311:Hearing Disorders / Q000150:complications / Q000175:diagnosis; D006801:Humans; D008279:Magnetic Resonance Imaging; D008575:Meniere Disease / Q000150:complications / Q000175:diagnosis*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed; D014723:Vestibular Aqueduct / Q000000981:diagnostic imaging* / Q000473:pathology*