title: Transcochlear repair of persistent cerebrospinal fluid leaks.
abstract: OBJECTIVE
  The purpose of this study is to demonstrate the utility of a modified transcochlear obliteration of the petrous apex in repair of persistent cerebrospinal fluid (CSF) leaks. A review of temporal bone computed tomography (CT) scans and histological preparations for potential air cells leading to such leaks is also presented.
  
  
  METHODS
  Retrospective case review in an academic tertiary referral center.
  
  
  METHODS
  Patients for inclusion in this study had previously undergone either a suboccipital or translabyrinthine removal of an intracranial tumor with subsequent transmastoid and middle ear obliteration of air cell tracts to stop a CSF leak. Ninety CT scans and 178 temporal bones were reviewed and assessed for peritubal and petrous apex pneumatization.
  
  
  RESULTS
  Four patients had initial obliteration of the orifice of the eustachian tube and middle ear that failed to prevent leakage of CSF. The leak was ultimately controlled by a transcochlear petrous apicectomy. From The Ohio State University temporal bone collection, 178 specimens were available for examination. Peritubal pneumatization was found in 42% of the bones examined. The CT scans showed unilateral petrous apex pneumatization in 30% of the specimens and bilateral pneumatization in 11%.
  
  
  CONCLUSIONS
  Continuity of air cell tracts from the petrous apex surrounding the internal auditory canal to the medial eustachian tube can provide a path for CSF rhinorrhea that is difficult to stop by conventional means. A modified transcochlear approach successfully terminated persistent leaks in four such patients.
authors.affiliation: Department of Otolaryngology, Ohio State University, Columbus, USA.
authors.forename: I L
authors.initials: IL
authors.lastname: Grant
authors.forename: D B
authors.initials: DB
authors.lastname: Welling
authors.forename: M C
authors.initials: MC
authors.lastname: Oehler
authors.forename: M A
authors.initials: MA
authors.lastname: Baujan
mesh_terms: D000328:Adult; D002558:Cerebrospinal Fluid Otorrhea / Q000000981:diagnostic imaging / Q000601:surgery*; D004424:Ear Canal; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010579:Petrous Bone / Q000601:surgery; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed