title: Pulsatile tinnitus and the intrameatal vascular loop: why do we not hear our carotids?
abstract: OBJECTIVE
  Pulsatile tinnitus is characterized by hearing the heart beat or respiration in one or both ears. In 15% of patients with pulsatile tinnitus, no cause can be found. Other investigators have suggested that a vascular loop entering the internal auditory meatus can be another cause of arterial, pulse synchronous tinnitus. If so, we should constantly hear the arterial pulsations of the carotid arteries passing through the petrous bone.
  
  
  METHODS
  Using magnetic resonance imaging, 17 patients with unilateral pulsatile tinnitus and 46 with non-pulsatile tinnitus were analyzed for the presence of a vascular loop entering into the internal acoustic meatus. Four temporal bones were sectioned to find structural differences between the internal acoustic meatus and the pericarotid area. Four patients with intrameatal vascular loops and ipsilateral pulsatile tinnitus underwent surgery by Teflon interpositioning between the loop and the cochlea.
  
  
  RESULTS
  In unilateral pulsatile tinnitus, a statistically highly significant amount of intrameatal vascular loops was noted in comparison to non-pulsatile tinnitus. A well-developed pericarotid venous plexus was found histologically. Three of the four patients who underwent surgery were initially tinnitus free, but pulsations recurred after 3 months in one patient.
  
  
  CONCLUSIONS
  Vascular loops in the internal auditory canal may generate pulsatile tinnitus. It may be treated by placing Teflon between the cochlea and the intrameatal vascular loop. One then does not hear the pulsation of the carotids due to a dampening effect of a pericarotid venous plexus.
authors.affiliation: Department of Neurosurgery, University Hospital Antwerp, Antwerp, Belgium. dirk.de.ridder@uza.be
authors.forename: Dirk
authors.initials: D
authors.lastname: De Ridder
authors.forename: Leo
authors.initials: L
authors.lastname: De Ridder
authors.forename: Vicky
authors.initials: V
authors.lastname: Nowé
authors.forename: Hubert
authors.initials: H
authors.lastname: Thierens
authors.forename: Paul
authors.initials: P
authors.lastname: Van de Heyning
authors.forename: Aage
authors.initials: A
authors.lastname: Møller
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001158:Arteries / Q000503:physiopathology*; D002339:Carotid Arteries / Q000473:pathology / Q000503:physiopathology; D016022:Case-Control Studies; D007758:Ear, Inner / Q000098:blood supply* / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010579:Petrous Bone / Q000098:blood supply; D011138:Polytetrafluoroethylene; D019736:Prostheses and Implants; D012008:Recurrence; D013701:Temporal Bone / Q000473:pathology; D014012:Tinnitus / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery; D016896:Treatment Outcome; D014680:Veins / Q000473:pathology
chemical_list: D011138:Polytetrafluoroethylene