Pediatrics: Spine Flashcards
Where is the central canal?
Central echogenic line (central echo complex)
Note: This is bright on ultrasound due to the interface of tissues (the amount of fluid inside it too small to produce a hypoechoic line).
Why is a tethered spinal cord problematic?
The vertebral canal grows faster than the spinal cord does, so a tethered cord will get stretched as the kid grows, leading to ischemia
What are the causes of a tethered spinal cord?
- Primary (isolated)
- Secondary (myelomeningocele, filum terminale lipoma, trauma, etc.)
What imaging features should make you suspect a tethered spinal cord?
- Low lying cord (conus below L2 inferior endplate)
- Thickened filum terminale (>2 mm)
Are lipomyelomeningoceles associated with chiari malformations?
No
Note: Meningomyeloceles ARE associated with chiari malformations.
Sacral dimple…
Think closed spinal dysraphism (spina bifida occulta)
Note: Dimples are a common cutaneous manifestation at the level of a spinal dysraphism.
Should pts with a cutaneous back dimple be screened for a tethered spinal cord?
High dimples (above the gluteal crease) should get screened
Low dimples (below the gluteal crease) should NOT be screened
What are some examples of pts that should be screened for tethered spinal cord with a spine ultrasound?
- Anal atresia (highly associated)
- High cutaneous dimples (above the gluteal crease)
Low-lying cord (terminating at L4) and fat-containing mass in teh spinal canal, consistent with tethered spinal cord secondary to a lipomyelocele
Terminal ventricle (ventriculus terminalis), a developmental variant
Note: These are usually small (<4 mm) and asymptomatic, but can cause neurological issue is they get large, as in this case.
Spondylolysis (pars interarticularis defect)
Note: There is a fracture of the scotty dog neck.
What is the classic clinical presentation of a pars interarticularis defect?
Back pain in an adolescent athlete
Note: Most are asymptomatic (75%).
Spondylolisthesis due to spondylolysis (pars interarticularis defect)
What is the most common location for a pars interarticularis defect (spondylysis)?
L5 (90%)
Note: L4 is the second most common location.
What is the eye of the scotty dog?
Pedicle
What is the neck of the scotty dog?
Pars interarticularis
Note: This is where you look for spondylolysis (pars interarticularis defect).
Complications of spondylolithesis
- Neural foraminal narrowing
- Spinal canal widening (when mild)
- Spinal canal stenosis (when severe)
What are the two major categories of spinal dysraphism?
- Open (AKA spina bifida aperta: neural tissue is exposed through a defect in bone and skin)
- Closed (AKA spina bifida occulta: when neural tissue is covered by skin)
What are the two major types of open spinal dysraphism?
- Myelomeningocele (98%)
- Myelocele (rare)
Myelocele
A rare form of open spinal dysraphism when the neural placode protrudes through the defect but is flush with the skin
Note: This is unlike the much more common myelomeningocele where the neural placode protrudes through and past the skin.
Myelomeningocele
The most common type of open spinal dysraphism (by far), where the neural placode protrudes through the skin.
Note: These are common with Chiari II malformations.
What are the closed spinal dysraphisms with a subcutaneous mass?
- Meningocele
- Lipomyelocele/lipomyelomeningocele
- Terminal myelocystocele
meningocele
A closed spinal dysraphism where there is herniation of a CSF filled sac through a defect in the posterior spinal elements
Note: There is NO neural tissue in the sac.
Lipomyelocele and lipomyelomeningocele
These are closed spinal dysraphisms where there is a lipoma with an associated dural defect. The neural placode-lipoma interface can be inside the spinal canal (lipomyelocele) or outside the spinal canal (lipomyelomeningocele). Both of these usually have a subcutaneous fatty mass above the gluteal crease on exam.
Which type of spinal dysraphism is most associated with a tethered spinal cord?
Lipomyelocele and lipomyelomeningocele
Note: These both are 100% associated with tethered spinal cords.
Terminal myelocystocele
A type of closed spinal dysraphism where there is herniation of a terminal syrinx into a posterior meningocele via a posterior spinal defect
What are the major types of closed spinal dysraphism without a subcutaneous mass?
- Intardural lipomas
- Fibrolipoma of the filum terminale
- Tight filum terminale
- Dermal sinus
What is the most common location for intradural lipomas?
Dorsal aspect of the thoracic spine
MRI demonstrated a linear T1 hyperintensity in the filum terminale, no filum terminale thickening, and a normal spinal cord position…
Fibrolipoma of the filum terminale (incidental finding)
When is the spinal cord considered low-lying?
If the conus medullaris terminates below the inferior endplate of L2
Tethered cord syndrome
This is when you have a tethered cord AND:
- Low back/leg pain
- Urinary bladder dysfunction
Tight filum terminale
Thickening of the filum terminale (>2 mm) with a low-lying cord (conus below L2) +/- as associated terminal lipoma
Note: This is a tethered spinal cord.
Dermal sinus
An epithelial lines tract that extends from the skin to deep soft tissues (e.g. spinal cord)
Note: These are T1 hypointense relative to surrounding subcutaneous fat.
Diastematomyelia
When there is a sagittal split in the spinal cord (almost always at the levels of T9-S1 with normal cord above and below the split)
Note: You can have two thecal sacs or just one. Each hemicord has its own central canal and dorsal/ventral horns.
Caudal regression syndrome with lumbosacral agenesis
Caudal regression syndrome is associated with…
- VACTERL
- Currarino triad
What is the Currarino triad?
- Anterior sacral meningocele
- Anorectal malformation
- Sacrococcygeal osseous defect (scimitar sacrum)
Blunted, truncated spinal cord that terminates at a high vertebral level…
Think caudal regression
Caudal regression
Note: The bilateral iliac bones are fused in the middle with no sacrum (shield sign).
Risk factors for caudal regression
Maternal diabetes
Newborn with anorectal malformation
Scimitar sacrum (sacrococcygeal osseous defect), think Currarino triad
Currarino triad:
- Anterior sacral meningocele
- Anorectal malformation
- Sacrococcygeal osseous defect (scimitar sacrum)
What is special about the meningocele in the Currarino triad?
It is an anterior (not posterior) sacral meningocele
