title: Endoscopically assisted prevention of cerebrospinal fluid leak in suboccipital acoustic neuroma surgery.
abstract: OBJECTIVE
  The purpose of this prospective study was to determine if direct inspection of air cells using endoscopy could reduce the occurrence of cerebrospinal fluid (CSF) leak in suboccipital acoustic neuroma surgery.
  
  
  BACKGROUND
  Cerebrospinal fluid leak remains one of the most common complications after acoustic neuroma surgery. The suboccipital approach for excision of acoustic neuromas has been used increasingly since gadolinium-enhanced magnetic resonance imaging has improved the ability to diagnose smaller tumors. Suboccipital approaches are reported to have CSF leak rates of as high as 27% with an average rate of 12%, most presenting as rhinorrhea. Ideally, this complication could be avoided by careful closure of all air cells exposed during the approach, especially those commonly found in the posterior wall of the internal auditory canal and in the retrosigmoid area. Packing these cells with a variety of materials has been done but often indirectly, as visualization of all cells by the conventional operating microscopes may not be possible. Failure to recognize patent cells because of limited visualization may be an important cause of postoperative CSF leak.
  
  
  METHODS
  This study compared CSF rhinorrhea rates of 38 consecutive suboccipital acoustic neuroma operations, in which conventional techniques were used to pack the temporal bone defect around the internal auditory canal, with the succeeding 24 consecutive operations, in which endoscopes were used to visualize all exposed air cells directly. After locating all patent air cells endoscopically, they were specifically sealed with bone wax, and then a small fat graft harvested from the wound margin was used to fill the remaining defect.
  
  
  RESULTS
  Postoperative CSF rhinorrhea occurred in 7 of 38 (18.4%) operations in which no endoscopic technique was used and in 0 of 24 operations in which endoscopes were used.
  
  
  CONCLUSIONS
  The use of endoscopes to visualize the temporal bone air cells that cannot be directly observed otherwise appears to reduce the incidence of postoperative CSF leak in suboccipital acoustic neuroma surgery.
authors.affiliation: Department of Otolaryngology, Jyväskylä Central Hospital, Finland.
authors.forename: H J
authors.initials: HJ
authors.lastname: Valtonen
authors.forename: D S
authors.initials: DS
authors.lastname: Poe
authors.forename: C B
authors.initials: CB
authors.lastname: Heilman
authors.forename: E C
authors.initials: EC
authors.lastname: Tarlov
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002559:Cerebrospinal Fluid Rhinorrhea / Q000517:prevention & control* / Q000601:surgery*; D004724:Endoscopy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000601:surgery*; D010579:Petrous Bone / Q000002:abnormalities / Q000000981:diagnostic imaging / Q000601:surgery; D011183:Postoperative Complications / Q000517:prevention & control*; D011446:Prospective Studies; D011859:Radiography