title: Systematic review and meta-analysis of isolated posterior fossa malformations on prenatal imaging (part 2): neurodevelopmental outcome.
abstract: OBJECTIVE
  Diagnosis of isolated posterior fossa anomalies in children is biased by the fact that only those that are symptomatic are brought to the attention of the appropriate clinical personnel, and the reported rate is often affected by the adoption of different nomenclature, diagnostic criteria, outcome measures, duration of follow-up and neurodevelopmental tools. The aim of this systematic review was to explore the neurodevelopmental outcome of fetuses with a prenatal diagnosis of isolated posterior fossa anomalies.
  
  
  METHODS
  MEDLINE and EMBASE were searched electronically, utilizing combinations of the relevant medical subject heading terms for 'posterior fossa' and 'outcome'. Studies assessing the neurodevelopmental outcome in children with a prenatal diagnosis of isolated posterior fossa malformations were considered eligible. The posterior fossa anomalies analyzed included Dandy-Walker malformation (DWM), mega cisterna magna (MCM), Blake's pouch cyst (BPC) and vermian hypoplasia (VH). Two authors reviewed all abstracts independently. Quality assessment of the included studies was performed using the Newcastle-Ottawa Scale for cohort studies. Meta-analyses of proportions were used to combine data, and between-study heterogeneity was explored using the I(2) statistic.
  
  
  RESULTS
  A total of 1640 articles were identified; 95 were assessed for eligibility and a total of 16 studies were included in the systematic review. The overall rate of abnormal neurodevelopmental outcome in children with a prenatal diagnosis of DWM was 58.2% (95% CI, 21.8-90.0%) and varied from 0-100%. In those with a prenatal diagnosis of MCM, the rate of abnormal neurodevelopmental outcome was 13.8% (95% CI, 7.3-21.9%), with a range of 0-50%. There was no significant association between BPC and the occurrence of abnormal neurodevelopmental delay, with a rate of 4.7% (95% CI, 0.7-12.1%) and range of 0-5%. Although affected by the very small number of studies, there was a non-significant occurrence of abnormal neurodevelopmental delay in children with a prenatal diagnosis of VH, with a rate of 30.7% (95% CI, 0.6-79.1%) and range of 0-100%.
  
  
  CONCLUSIONS
  Fetuses diagnosed with isolated DWM are at high risk of abnormal neurodevelopmental outcome, while isolated MCM or BPC have a generally favorable outcome. The risk of abnormal developmental delay in cases with isolated VH needs to be further assessed. In view of the wide heterogeneity in study design, time of follow-up, neurodevelopmental tests used and the very small number of included cases, further future large prospective studies with standardized and objective protocols for diagnosis and follow-up are needed in order to ascertain the rate of abnormal neurodevelopmental outcome in children with isolated posterior fossa anomalies. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.
authors.affiliation: Fetal Medicine Unit, Division of Developmental Sciences, St George's University of London, London, UK.
authors.forename: F
authors.initials: F
authors.lastname: D'Antonio
authors.affiliation: Fetal Medicine Unit, Division of Developmental Sciences, St George's University of London, London, UK.
authors.forename: A
authors.initials: A
authors.lastname: Khalil
authors.affiliation: Hôpital d'Enfants Armand-Trousseau - Service de Radiologie, Cedex 12, Paris, France.
authors.forename: C
authors.initials: C
authors.lastname: Garel
authors.affiliation: Department of Obstetrics and Gynecology, Sant'Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Pilu
authors.affiliation: Department of Obstetrics and Gynecology, Università di Roma, Tor Vergata, Rome, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Rizzo
authors.affiliation: Fetal Neurology Clinic and Paediatric Neurology Unit, Wolfson Medical Center, Holon, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: T
authors.initials: T
authors.lastname: Lerman-Sagie
authors.affiliation: Fetal Medicine Unit, Division of Developmental Sciences, St George's University of London, London, UK.
authors.forename: A
authors.initials: A
authors.lastname: Bhide
authors.affiliation: Fetal Medicine Unit, Division of Developmental Sciences, St George's University of London, London, UK.
authors.forename: B
authors.initials: B
authors.lastname: Thilaganathan
authors.affiliation: Department of Medicine and Aging Sciences, University of Chieti-Pescara, and EMISAC, CeSI Biotech, Chieti, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Manzoli
authors.affiliation: Fetal Medicine Unit, Division of Developmental Sciences, St George's University of London, London, UK.
authors.forename: A T
authors.initials: AT
authors.lastname: Papageorghiou
mesh_terms: D003388:Cranial Fossa, Posterior / Q000002:abnormalities*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D009421:Nervous System Malformations / Q000000981:diagnostic imaging*; D011247:Pregnancy; D011256:Pregnancy Outcome; D016216:Ultrasonography, Prenatal
keywords: Blake's pouch cyst; Dandy-Walker malformation; mega cisterna magna; meta-analysis; neurodevelopmental outcome; posterior fossa anomaly; vermian hypoplasia