In utero repair of fetal posterior cephaloceles (meningocele and encephalocele) is being performed based on the premise that fetal surgery prevents progressive herniation of neural tissue and brain damage during pregnancy. However, the extent to which progressive herniation occurs during pregnancy, specifically from prenatal diagnosis to after delivery, is not well known. The objective of this study was to describe the natural history of patients with fetal cephaloceles focusing on the incidence of progressive herniation.
The authors conducted a retrospective cohort study of all patients referred to their center for posterior fetal cephalocele between 2006 and 2021. All patients underwent prenatal and postnatal MRI. Progressive herniation (primary outcome) was defined as an increase in the absolute volume of neural tissue within the cephalocele of > 5% or new herniation of a critical structure into the cephalocele. Total brain and cephalocele volumes were calculated to determine herniation progression from prenatal to postnatal MRI. Information on the presence of hydrocephalus, epilepsy, and developmental delay (secondary outcomes) was collected at 1 year of age.
Twenty patients met all study criteria. Ten patients (50%; 95% CI 0.27–0.73) demonstrated progressive herniation from prenatal to postnatal MRI. Three patients with progressive herniation were diagnosed with a meningocele prenatally and had an encephalocele postnatally. Two patients without progression had meningocele identified prenatally that regressed and became atretic by birth. Both prenatal hindbrain herniation (p = 0.03) and prenatal microcephaly (p = 0.05) were predictive of progressive herniation. The rates of hydrocephalus (44%), epilepsy (44%), and developmental delay (63%) were not associated with the occurrence of progressive herniation in this study.
In this study, progressive herniation was not a rare event (50%). Fetal hindbrain herniation and fetal microcephaly were associated with the occurrence of progressive herniation. These results support further investigations into why progressive herniation occurs in utero and if progressive cerebral herniation in utero plays a significant role in determining clinical outcome.
ParkerSE, MaiCT, CanfieldMA, Updated National Birth Prevalence estimates for selected birth defects in the United States, 2004-2006. Birth Defects Res A Clin Mol Teratol. 2010;88(12):1008–1016.2087890910.1002/bdra.20735)| false
EvansLL, HarrisonMR. Modern fetal surgery—a historical review of the happenings that shaped modern fetal surgery and its practices. Transl Pediatr. 2021;10(5):1401–1417.3418910110.21037/tp-20-114)| false
O’HayonBB, DrakeJM, OssipMG, TuliS, ClarkeM. Frontal and occipital horn ratio: a linear estimate of ventricular size for multiple imaging modalities in pediatric hydrocephalus. Pediatr Neurosurg. 1998;29(5):245–249.
O’HayonBB, DrakeJM, OssipMG, TuliS, ClarkeM. Frontal and occipital horn ratio: a linear estimate of ventricular size for multiple imaging modalities in pediatric hydrocephalus. Pediatr Neurosurg. 1998;29(5):245–249.991754110.1159/000028730)| false
HeffezDS, AryanpurJ, HutchinsGM, FreemanJM. The paralysis associated with myelomeningocele: clinical and experimental data implicating a preventable spinal cord injury. Neurosurgery. 1990;26(6):987–992.
HeffezDS, AryanpurJ, HutchinsGM, FreemanJM. The paralysis associated with myelomeningocele: clinical and experimental data implicating a preventable spinal cord injury. Neurosurgery. 1990;26(6):987–992.236267610.1227/00006123-199006000-00011)| false
Da SilvaSL, JeelaniY, DangH, KriegerMD, McCombJG. Risk factors for hydrocephalus and neurological deficit in children born with an encephalocele. J Neurosurg Pediatr. 2015;15(4):392–398.2565824810.3171/2014.10.PEDS14192)| false