title: Effects of birth advancement in Chiari malformation in a surgical myelomeningocele model in rabbits.
abstract: OBJECTIVE
  In myelomeningocele (MMC), Chiari II malformation progresses during gestation because of the continuous loss of cerebrospinal fluid at the site of the defect. Our purpose was to assess the impact of birth advancement (BA) and prenatal corticosteroid treatment (PCT) on Chiari malformation in a surgical MMC model in rabbits.
  
  
  METHODS
  A surgical MMC-like defect was created in 75 fetal rabbits. Animals were distributed into 4 groups depending on the treatment received: not treated and those undergoing BA + PCT, BA, or PCT. The degree of Chiari malformation in newborn rabbits was defined as the percentage of downward protrusion of the hindbrain between the end of the occipital bone and the beginning of the first vertebral arch.
  
  
  RESULTS
  The degree of hindbrain herniation was 80% (8.15) in the not treated group, 36.8% (10.57) in BA + PCT, 41.8% (8.27) in BA, and 44.4% (8.32) in PCT. The BA + PCT, BA, and PCT groups showed less severe hindbrain herniation than not treated animals (mean decrease, 39.86%; SD, 10.57; P = .000). There were no significant differences between the BA + PCT, BA, and PCT groups (P = .311).
  
  
  CONCLUSIONS
  Birth advancement and prenatal administration of corticosteroids decrease the severity of the hindbrain herniation component of Chiari II malformation in surgical MMC in fetal rabbits.
authors.affiliation: Pediatric Orthopedic Unit, Hospital Universitari Vall d'Hebron, Barcelona, Spain. cgarcia@ir.vhebron.net
authors.forename: Cesar G
authors.initials: CG
authors.lastname: Fontecha
authors.forename: Marius
authors.initials: M
authors.lastname: Aguire
authors.forename: Francisco
authors.initials: F
authors.lastname: Soldado
authors.forename: Jose L
authors.initials: JL
authors.lastname: Peiro
authors.forename: Nuria
authors.initials: N
authors.lastname: Toran
authors.forename: Nuria
authors.initials: N
authors.lastname: Vidal
authors.forename: Vicente
authors.initials: V
authors.lastname: Martinez
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001139:Arnold-Chiari Malformation / Q000188:drug therapy* / Q000209:etiology* / Q000503:physiopathology; D001623:Betamethasone / Q000494:pharmacology*; D002531:Cerebellum / Q000473:pathology; D016001:Confidence Intervals; D004195:Disease Models, Animal; D005260:Female; D005315:Fetal Diseases / Q000401:mortality / Q000601:surgery*; D046689:Fetal Mortality; D005865:Gestational Age; D008591:Meningomyelocele / Q000150:complications / Q000401:mortality / Q000601:surgery*; D011247:Pregnancy; D011336:Probability; D011817:Rabbits; D016896:Treatment Outcome
chemical_list: D001623:Betamethasone