Craniorachischisis: Pathophysiology, Clinical Associations, and Prenatal Diagnosis

Abstract

Craniorachischisis is the most severe form of neural tube defect, characterized by the association of anencephaly and rachischisis. It results from a nearly complete failure of neural tube closure during the third to fourth week of gestation, leading to the absence of the cerebral hemispheres, cranial vault, and meningeal covering, as well as direct exposure of the fetal spinal cord to amniotic fluid. Prolonged exposure to amniotic fluid and intrauterine mechanical trauma promotes progressive degeneration of the exposed neural tissue. Craniorachischisis rarely occurs in isolation and may be associated with cardiac, renal, craniofacial malformations, and genetic syndromes such as Meckel–Gruber syndrome. Prenatal diagnosis is primarily established by ultrasonography, with additional support from fetal magnetic resonance imaging and maternal alpha-fetoprotein measurement. The condition is generally lethal, with no possibility of surgical correction, and management is limited to palliative care, including emotional and spiritual support for the family. Adequate folic acid supplementation before conception and during early pregnancy remains the main preventive strategy. This study reviews the pathophysiology, clinical associations, and diagnostic aspects of craniorachischisis, contributing to a better understanding of this rare and severe neural tube defect.