title: Cerebrospinal fluid leak after acoustic neuroma surgery.
abstract: BACKGROUND
  CSF rhinorrhea is a common complication of acoustic neuroma surgery.
  
  
  METHODS
  Twenty cases of persistent cerebrospinal fluid rhinorrhea, 2 of transient leaks, and 2 of late meningitis occurring in a series of 156 posterior fossa acoustic neuroma removals were studied. Prophylaxis of leaks was usually attempted by filling opened air cells in the drilled internal auditory canal (IAC) with bone wax. Communications were repaired by rewaxing the IAC, or by fat packing of either the mastoid or the eustachian tube, middle ear, and mastoid.
  
  
  RESULTS
  Most leaks were diagnosed within 1 week of surgery, although 1 occurred 4 years postoperatively. Those seen later were usually recurrences of a previously repaired leak or cases of meningitis. Leaks were more common later in the series when a more lateral unroofing of the IAC was used. The communication usually occurred through air cells opened while unroofing the canal, but two were via the vestibule and oval window. Treatment failed in 38% of cases in which canal rewaxing was used. There were no failures when the communication was sealed by fat obliteration of the eustachian tube, middle ear, and mastoid.
  
  
  CONCLUSIONS
  Leaks are more common with a more lateral unroofing of the IAC. A leak may occur into the middle ear via the oval window. Optimal treatment is packing of the middle ear and mastoid with fat.
mesh_terms: D002559:Cerebrospinal Fluid Rhinorrhea / Q000209:etiology* / Q000628:therapy; D003388:Cranial Fossa, Posterior; D006801:Humans; D008581:Meningitis / Q000209:etiology; D009464:Neuroma, Acoustic / Q000601:surgery*; D011183:Postoperative Complications / Q000209:etiology* / Q000628:therapy