title: Posterior fossa craniotomy for trapped fourth ventricle in shunt-treated hydrocephalic children: long-term outcome.
abstract: OBJECTIVE
  Trapped fourth ventricle (TFV) is a rare late complication of postinfectious or posthemorrhagic hydrocephalus. This entity is distinct from a large fourth ventricle because TFV entails pressure in the fourth ventricle and posterior fossa due to abnormal inflow and outflow of CSF, causing significant symptoms and signs. As TFV is mostly found in children who were born prematurely and have cerebral palsy, diagnosis and treatment options are a true challenge.
  
  
  METHODS
  Between February 1998 and February 2007, 12 children were treated for TFV in Dana Children's Hospital by posterior fossa craniotomy/craniectomy and opening of the TFV into the spinal subarachnoid space. The authors performed a retrospective analysis of relevant data, including pre- and postoperative clinical characteristics, surgical management, and outcome.
  
  
  RESULTS
  Thirteen fenestrations of trapped fourth ventricles (FTFVs) were performed in 12 patients. In 6 patients with prominent arachnoid thickening, a stent was left from the opened fourth ventricle into the spinal subarachnoid space. One patient underwent a second FTFV 21 months after the initial procedure. No perioperative complications were encountered. All 12 patients (100%) showed clinical improvement after FTFV. Radiological improvement was seen in only 9 (75%) of the 12 cases. The follow-up period ranged from 2 to 9.5 years (mean 6.11 ± 2.3 years) after FTFV.
  
  
  CONCLUSIONS
  Fenestration of a TFV via craniotomy is a safe and effective option with a very good long-term outcome and low rate of morbidity.
authors.affiliation: Department of Pediatric Neurosurgery, Dana Children’s Hospital, Tel Aviv Sourasky Medical Center and Tel Aviv University, 6 Weizman Street, Tel Aviv, Israel.
authors.forename: Suhas
authors.initials: S
authors.lastname: Udayakumaran
authors.forename: Naresh
authors.initials: N
authors.lastname: Biyani
authors.forename: David P
authors.initials: DP
authors.lastname: Rosenbaum
authors.forename: Liat
authors.initials: L
authors.lastname: Ben-Sira
authors.forename: Shlomi
authors.initials: S
authors.lastname: Constantini
authors.forename: Liana
authors.initials: L
authors.lastname: Beni-Adani
mesh_terms: D002557:Cerebrospinal Fluid Shunts; D002675:Child, Preschool; D003388:Cranial Fossa, Posterior / Q000601:surgery*; D003399:Craniotomy; D005260:Female; D005500:Follow-Up Studies; D020546:Fourth Ventricle / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery*; D006801:Humans; D006849:Hydrocephalus / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D047928:Premature Birth; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome