Objective: The natural history of cephaloceles is not well understood. The goal of this study was to better understand the natural history of fetal cephaloceles from prenatal diagnosis to the postnatal period.
Methods: Between January 2013 and April 2023, all patients evaluated with a cephalocele at the Center for Fetal Diagnosis and Treatment were identified. All patients underwent prenatal and postnatal MRI. Demographic and imaging covariates were obtained from the electronic medical record. Volumetric analyses were performed to determine the percentage of neural tissue within the cephalocele. Progressive herniation was defined as an increase in cephalocele absolute neural tissue volume ≥ 5% or new herniation of an additional intracranial structure into the cephalocele.
Results: A total of 25 patients met the inclusion criteria. Of these patients, 6 (24%) exhibited progressive cephalocele herniation from the prenatal to postnatal MRI. The median sac volume was 2.2 mL (mean 6.2 mL, range 0.3-40.5 mL). The median change in brain volume in the patients with cephalocele progression was a decrease of 1.5% (mean -7.3%, range -36.4% to 3.1%). Cephalocele sac volume at the time of fetal imaging was predictive of progressive herniation, which persisted on multivariate analysis when controlling for gestational age, sex, and percentage of herniated neural tissue. While 44% of the patients had ventriculomegaly, 56% ultimately required permanent CSF diversion.
Conclusions: Progressive neural herniation from the fetal to postnatal period is not commonly seen in fetal cephaloceles. Sac volume is associated with an increased risk of progressive herniation into the cephalocele.
Keywords: cephalocele; congenital; encephalocele; fetal; neural herniation; progression.