Neural tube defects (NTDs) arises from an occurring defect within the neurulation process. Based on embryological considerations as well as the presence or the absence of exposed neural tissue, NTDs are classified into 2 types: Open Neural tube defects (ONTDs) or Closed Neural tube defects (CNTDs).
• ONTDs tend to impact the entire central nervous system (CNS) (e.g., Chiari II malformation, concomitant hydrocephalus). Besides, failure of the primary neurulation process could lead to ONTDs. There may be a possible leakage of cerebrospinal fluid (CSF) due to neural tissue exposure.
• CNTDs are commonly localized and confined to the spine (rarely impacting thebrain) arising from a defect within the 2ryneurulation. There is no exposure of neural tissue, and the lesion can be dysplastic.
Cranial presentations include the following:
• Anencephaly.
• Encephalocele.
• Congenital dermal sinus.
Spinal presentations include the following:
• Spina bifida aperta (cystica)
A-Meningocele.
B-Myelomeningocele.
• Spina bifida oculta
A- Congenital dermal sinus
B- Lipomatous malformations (lipomyelomeningoceles)
C- Split-cord malformation
• Diastematomyelia
• Diplomyelia
D- Caudal agenesis.