Myelomeningocele

  • Etiology:
    — Maternal folate deficiency or abnormal folate metabolism leads to failure of dorsal induction of central nervous system leading to failure of closure of posterior neural tube in third gestational week
  • Imaging MRI:
    — Neural placode protrudes through the osseous and cutaneous defect and is exposed
    — Meninges and spinal cord and nerve roots herniate into sac
    — Most are lumbosacral
    — Spinal cord is always tethered
    — Associated with Chiari II malformation (varies in severity)
  • DDX:
    — Myelocele (Myeloschisis) – Subarachnoid space is not expanded, neural placode remains within the confines of the dysraphic spinal canal
    — Myelomeningocele – Subarachnoid space is expanded, neural placode is elevated beyond the confines of the dysraphic spinal canal
  • Complications:
  • Treatment:
  • Clinical:
    — Overt not skin covered spinal dysraphism
    — Significant neurologic disability

Radiology Cases of Myelomeningocele

MRI of Chiari II malformation and myelomeningocele
Sagittal T1 MRI without contrast of the brain (left) shows a small posterior fossa with downward cerebellar tonsil herniation and a small fourth ventricle. There is kinking of the spinal cord at the cervico-medullary junction. Sagittal (above right) and axial (below right) T2 MRI without contrast of the spine shows a low-lying conus medullaris with the spinal cord nerve roots terminating in a posteriorly located cerebrospinal fluid filled sac which is not covered by skin at the level of the L5-S1 vertebral bodies.
3D CT of myelomeningocele
3D reconstruction of CT without contrast of the lumbar spine shows lack of fusion of the posterior elements of the L4-S5 vertebral bodies.

Clinical Cases of Myelomeningocele

Clinical image of occipital myelomeningocele
Clinical image shows an overt, non-skin covered spinal dysraphism.