title: Risk factors and tumor response associated with hydrocephalus after gamma knife radiosurgery for vestibular schwannoma.
abstract: BACKGROUND
  This study was designed to investigate the clinical characteristics and risk factors of hydrocephalus after gamma knife radiosurgery (GKRS) for vestibular schwannoma.
  
  
  METHODS
  The authors retrospectively reviewed clinical and neuroimaging findings of 221 patients who underwent GKRS for newly diagnosed vestibular schwannoma. Mean patient age was 54.1 years (range 7-83 years), mean tumor volume was 3,010.4 mm(3) (range 34.7 to 14,300 mm(3)), mean marginal dose was 12.5 Gy (range 11 to 15 Gy), and mean follow-up duration was 31.9 months (range 1 to 107.6 months).
  
  
  RESULTS
  Surgical intervention for cerebrospinal fluid (CSF) diversion after GKRS was necessary in 11 (5 %) of the patients. Median time between GKRS and ventriculoperitoneal (VP) shunt placement was 15.5 months (range 1.8-37.8 months). These 11 patients showed female predominance (11 females) and mean tumor volume was significantly larger than in the other without hydrocephalus (6,509 vs. 2,726 mm(3); p < 0.01). Decreases in tumor enhancement and swelling were observed in all 221 patients, and CSF protein was found to be elevated in five of nine patients with available data at the time of the shunt procedure. Hydrocephalic symptoms improved after VP shunt and tumor sizes further decreased at last follow-up in all patients.
  
  
  CONCLUSIONS
  Hydrocephalus after radiosurgery may co-occur with a temporary change of tumor volume after radiation treatment. Therefore, hydrocephalus should be kept in mind during the time of tumor volume transition. Furthermore, the authors suggest that frequent patient monitoring for hydrocephalus be maintained for up to 3-4 years after GKRS.
authors.affiliation: Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Gangnam-gu, Seoul, 135-710, Korea.
authors.forename: Seung Hoon
authors.initials: SH
authors.lastname: Lee
authors.forename: Ho Jun
authors.initials: HJ
authors.lastname: Seol
authors.forename: Doo Sik
authors.initials: DS
authors.lastname: Kong
authors.forename: Do-Hyun
authors.initials: DH
authors.lastname: Nam
authors.forename: Kwan
authors.initials: K
authors.lastname: Park
authors.forename: Jong Hyun
authors.initials: JH
authors.lastname: Kim
authors.forename: Jung-Il
authors.initials: JI
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002556:Cerebrospinal Fluid Proteins / Q000134:cerebrospinal fluid; D002648:Child; D005260:Female; D006801:Humans; D006849:Hydrocephalus / Q000209:etiology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000601:surgery*; D011183:Postoperative Complications / Q000209:etiology* / Q000601:surgery; D016634:Radiosurgery; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D047368:Tumor Burden / Q000502:physiology; D017287:Ventriculoperitoneal Shunt; D055815:Young Adult
chemical_list: D002556:Cerebrospinal Fluid Proteins