ENDOSCOPICALLY ASSISTED PREVENTION OF CEREBROSPINAL-FLUID LEAK IN SUBOCCIPITAL ACOUSTIC NEUROMA SURGERY

Hypothesis: The purpose of this prospective study was Eo determine if direct inspection of air cells using endoscopy could reduce the occurr ence of cerebrospinal fluid (CSF) leak in suboccipital acoustic neurom a surgery. Background: Cerebrospinal fluid leak remains one of the mos t common complications after acoustic neuroma surgery. The suboccipita l approach for excision of acoustic neuromas has been used increasingl y since gadolinium-enhanced magnetic resonance imaging has improved th e ability to diagnose smaller tumors. Suboccipital approaches are repo rted to have CSF leak rates of as high as 27% with an average rate of 12%, most presenting as rhinorrhea. Ideally, this complication could b e avoided by careful closure of all air cells exposed during the appro ach, especially those commonly found in the posterior wall of the inte rnal auditory canal and in the retrosigmoid area. Packing these cells with a variety of materials has been done but often indirectly, as vis ualization 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. Met hods: This study compared CSF rhinorrhea rates of 38 consecutive suboc cipital acoustic neuroma operations, in which conventional techniques were used to pack the temporal bone defect around the internal auditor y canal, with the succeeding 24 consecutive operations, in which endos copes were used to visualize all exposed air cells directly. After loc ating all patent air cells endoscopically, they were specifically seal ed with bone wax, and then a small fat graft harvested from the wound mar in was used to fill the remaining defect. Results: Postoperative C SF rhinorrhea occurred in 7 of 38 (18.4%) operations in which no endos copic technique was used and in 0 of 24 operations in which endoscopes were used. Conclusions: The use of endoscopes to visualize the tempor al bone air cells that cannot be directly observed otherwise appears t o reduce the incidence of postoperative CSF leak in suboccipital acous tic neuroma surgery.