C11.1 Fetal spinal pathology Flashcards
Describe the 3 ossification centres of the spine
What do the 2 neural processes form
The central part is formed by the centrum
The 2 lateral neural processes form:
Peduncles Transverse processes Laminae Spinous process Posterolateral part of the vertebral body
When does ossification of the laminae occur
18 wks
When in wks could you possibly miss a small spinal bifida
Before 18 wks
Risks of and NTD increases with which factors
Valproic acid (medication for seizures) Maternal diabetes (type 1) Folic acid deficiency History of spinal defects -previous preg -family history
What is spinal bifida
NTD in the boney structure of the spinal canal that can lead to the herniation of its contents including possibly meninges, CSF and neural tissue
What is encephalocele
Brain herniation
Describe spina bifida occulta
- involves only the deeper layers
- May only see a skin dimple or a path of hair on the back
- closed defect
- 15-20% of cases
Occult means hidden or concealed
Describe spina bifida aperta
- involves all layers from dura skin
- open defect
- 80-85% of cases
Aperta means open
What are the 2 types of spina bifida aperta
- meningocele- includes meninges and CSF
- completely cystic - Myelomeningocele- includes meninges, CSF and neural tissue/nerves
- not completely cystic
When is the quad screen done
16 wks
When would AFP be elevated w/ an NTD?
When the defect is not covered by skin
What are the other causes of elevated MSAFP
Abdo wall defects:
Omphalocele
Gastroschisis
Twins Fetal death Urinary obstruction Cystic hygroma Incorrect dates
NTD are associated w/ what syndromes
Meckel gruber syndrome which includes:
Encephalocele
Polycystic kindeys
Polydactyly
T21
Triploidy
What is spinal dysraphism
Abnormal closure of the spine/failure of fusion of vertebral arches
What is rachischisis
Another name for spinal dysraphism… failure of fusion of the vertebral arches
What are the radiological landmarks for the spine
T-12; most distal rib
L5: superior margin of the iliac wing/crest
S4: most caudal ossification center in the 2nd trim
Which limb or structures of the body are effected by NTD and how
Legs:
Club foot
Hip dislocation (not seen on US)
Caused by an imbalance of muscular activity due to nerve involvement of the neural tube defect
How does a spinal NTD appear on US
- splayed laminae
- protruding mass or cyst
- also look for Arnold chiari
Is it normal to have some widening in the thoracic and lumbar areas of the spinal
Yes, b/c there are a lot of nerves that come off this area going to the limbs
What is the prognosis of meningocele
Depends on the location and extent of the neural tissue involved … more superior in the spine the greater the disability
What is a hemivertebra and what does it lead to
Half a vertebra… leads to scoliosis
What is iniencephaly
A special case of dysraphism involving the back of the cranium and c-spine…
… there are segmentation errors of the upper spine which shortens the neck and head into a dorsiflexed position (called the star gazing position)
What would you expect to see in the brain w/ iniencephaly
Hydrocephalus
What is scoliosis
Lateral curvature of the spine
