title: Fluid-fluid level in cystic vestibular schwannoma: a predictor of peritumoral adhesion.
abstract: OBJECTIVE
  The aim of this study was to evaluate the clinical results and surgical outcomes of cystic vestibular schwannomas (VSs) with fluid-fluid levels.
  
  
  METHODS
  Forty-five patients with cystic VSs and 86 with solid VSs were enrolled in the study. The patients in the cystic VSs were further divided into those with and without fluid-fluid levels. The clinical and neuroimaging features, intraoperative findings, and surgical outcomes of the 3 groups were retrospectively compared.
  
  
  RESULTS
  Peritumoral adhesion was significantly greater in the fluid-level group (70.8%) than in the nonfluid-level group (28.6%) and the solid group (25.6%; p < 0.0001). Complete removal of the VS occurred significantly less in the fluid-level group (45.8%, 11/24) than in the nonfluid-level group (76.2%, 16/21) and the solid group (75.6%, 65/86; p = 0.015). Postoperative facial nerve function in the fluid-level group was less favorable than in the other 2 groups; good/satisfactory facial nerve function 1 year after surgery was noted in 50.0% cases in the fluid-level group compared with 83.3% cases in the nonfluid-level group (p = 0.038).
  
  
  CONCLUSIONS
  Cystic VSs with fluid-fluid levels more frequently adhered to surrounding neurovascular structures and had a less favorable surgical outcome. A possible mechanism of peritumoral adhesion is intratumoral hemorrhage and consequent inflammatory reactions that lead to destruction of the tumor-nerve barrier. These findings may be useful in predicting surgical outcome and planning surgical strategy preoperatively.
authors.affiliation: Departments of Neurosurgery.
authors.forename: Lei
authors.initials: L
authors.lastname: Xia
authors.forename: Hongwei
authors.initials: H
authors.lastname: Zhang
authors.forename: Chunjiang
authors.initials: C
authors.lastname: Yu
authors.forename: Mingshan
authors.initials: M
authors.lastname: Zhang
authors.forename: Ming
authors.initials: M
authors.lastname: Ren
authors.forename: Yanming
authors.initials: Y
authors.lastname: Qu
authors.forename: Haoran
authors.initials: H
authors.lastname: Wang
authors.forename: Mingwang
authors.initials: M
authors.lastname: Zhu
authors.forename: Dianjiang
authors.initials: D
authors.lastname: Zhao
authors.forename: Xueling
authors.initials: X
authors.lastname: Qi
authors.forename: Kun
authors.initials: K
authors.lastname: Yao
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D020863:Central Nervous System Cysts / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000473:pathology* / Q000601:surgery; D019635:Neurosurgical Procedures / Q000379:methods; D011183:Postoperative Complications; D011184:Postoperative Period; D012189:Retrospective Studies; D000267:Tissue Adhesions / Q000473:pathology; D016896:Treatment Outcome