Open spina bifida (bone and skin defect ± sac)

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  Meningomyelocele: Sac + neural elements

  
  
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  Meningocele: Sac with fluid only

  
  
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  Myeloschisis: No sac (cord directly exposed)

Closed spina bifida: Skin-covered defect

Level: Lumbosacral > thoracic > cervical

Transverse view best for seeing dorsal element divergence

Longitudinal views and 3D best for evaluating level

Myelomeningocele: Complex cystic mass (most common)

Meningocele: Anechoic cystic mass

20% are myeloschisis (subtle): No sac, cord is part of defect

Chiari 2 brain findings with open spina bifida

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  Cerebellar compression, loss of cisterna magna

Tethered cord (cord seen at level of defect)

Associated anomalies: Club feet, scoliosis

Closed spina bifida: Chiari 2 absent or minimal

↑ maternal serum α-fetoprotein (msAFP)

Associated maternal folate deficiency

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  From maternal metabolic gene defect

  
  
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  Preconception high-dose folic acid for next pregnancy

4% aneuploidy rate when isolated (14% if other anomalies)

Prognosis depends on level and presence of hydrocephalus

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  80% require ventricular shunting or bypass of hindbrain compressive obstructive hydrocephalus (from Chiari 2)

  
  
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  Only 17% with normal continence

Look carefully at spine if cisterna magna is compressed (Chiari 2 is almost never isolated)

Use last rib to determine T12 and count inferiorly to determine level of spina bifida

If sac covering looks thick, follow it laterally to see if it is contiguous with skin (closed defect)