Pediatrics: Spine

Question 1

Where is the central canal?

Answer 1

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).

Question 2

Why is a tethered spinal cord problematic?

Answer 2

The vertebral canal grows faster than the spinal cord does, so a tethered cord will get stretched as the kid grows, leading to ischemia

Question 3

What are the causes of a tethered spinal cord?

Answer 3

• Primary (isolated)
• Secondary (myelomeningocele, filum terminale lipoma, trauma, etc.)

Question 4

What imaging features should make you suspect a tethered spinal cord?

Answer 4

• Low lying cord (conus below L2 inferior endplate)
• Thickened filum terminale (>2 mm)

Question 5

Are lipomyelomeningoceles associated with chiari malformations?

Answer 5

No

Note: Meningomyeloceles ARE associated with chiari malformations.

Question 6

Sacral dimple…

Answer 6

Think closed spinal dysraphism (spina bifida occulta)

Note: Dimples are a common cutaneous manifestation at the level of a spinal dysraphism.

Question 7

Should pts with a cutaneous back dimple be screened for a tethered spinal cord?

Answer 7

High dimples (above the gluteal crease) should get screened

Low dimples (below the gluteal crease) should NOT be screened

Question 8

What are some examples of pts that should be screened for tethered spinal cord with a spine ultrasound?

Answer 8

• Anal atresia (highly associated)
• High cutaneous dimples (above the gluteal crease)

Question 9

Answer 9

Low-lying cord (terminating at L4) and fat-containing mass in teh spinal canal, consistent with tethered spinal cord secondary to a lipomyelocele

Question 10

Answer 10

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.

Question 11

Answer 11

Spondylolysis (pars interarticularis defect)

Note: There is a fracture of the scotty dog neck.

Question 12

What is the classic clinical presentation of a pars interarticularis defect?

Answer 12

Back pain in an adolescent athlete

Note: Most are asymptomatic (75%).

Question 13

Answer 13

Spondylolisthesis due to spondylolysis (pars interarticularis defect)

Question 14

What is the most common location for a pars interarticularis defect (spondylysis)?

Answer 14

L5 (90%)

Note: L4 is the second most common location.

Question 15

What is the eye of the scotty dog?

Answer 15

Pedicle

Question 16

What is the neck of the scotty dog?

Answer 16

Pars interarticularis

Note: This is where you look for spondylolysis (pars interarticularis defect).

Question 17

Complications of spondylolithesis

Answer 17

• Neural foraminal narrowing
• Spinal canal widening (when mild)
• Spinal canal stenosis (when severe)

Question 18

What are the two major categories of spinal dysraphism?

Answer 18

• 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)

Question 19

What are the two major types of open spinal dysraphism?

Answer 19

• Myelomeningocele (98%)
• Myelocele (rare)

Question 20

Myelocele

Answer 20

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.

Question 21

Myelomeningocele

Answer 21

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.

Question 22

What are the closed spinal dysraphisms with a subcutaneous mass?

Answer 22

• Meningocele
• Lipomyelocele/lipomyelomeningocele
• Terminal myelocystocele

Question 23

meningocele

Answer 23

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.

Question 24

Lipomyelocele and lipomyelomeningocele

Answer 24

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.

Question 25

Which type of spinal dysraphism is most associated with a tethered spinal cord?

Answer 25

Lipomyelocele and lipomyelomeningocele

Note: These both are 100% associated with tethered spinal cords.

Question 26

Terminal myelocystocele

Answer 26

A type of closed spinal dysraphism where there is herniation of a terminal syrinx into a posterior meningocele via a posterior spinal defect

Question 27

What are the major types of closed spinal dysraphism without a subcutaneous mass?

Answer 27

• Intardural lipomas
• Fibrolipoma of the filum terminale
• Tight filum terminale
• Dermal sinus

Question 28

What is the most common location for intradural lipomas?

Answer 28

Dorsal aspect of the thoracic spine

Question 29

MRI demonstrated a linear T1 hyperintensity in the filum terminale, no filum terminale thickening, and a normal spinal cord position…

Answer 29

Fibrolipoma of the filum terminale (incidental finding)

Question 30

When is the spinal cord considered low-lying?

Answer 30

If the conus medullaris terminates below the inferior endplate of L2

Question 31

Tethered cord syndrome

Answer 31

This is when you have a tethered cord AND:

• Low back/leg pain
• Urinary bladder dysfunction

Question 32

Tight filum terminale

Answer 32

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.

Question 33

Dermal sinus

Answer 33

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.

Question 34

Diastematomyelia

Answer 34

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.

Question 35

Answer 35

Caudal regression syndrome with lumbosacral agenesis

Question 36

Caudal regression syndrome is associated with…

Answer 36

• VACTERL
• Currarino triad

Question 37

What is the Currarino triad?

Answer 37

• Anterior sacral meningocele
• Anorectal malformation
• Sacrococcygeal osseous defect (scimitar sacrum)

Question 38

Blunted, truncated spinal cord that terminates at a high vertebral level…

Answer 38

Think caudal regression

Question 39

Answer 39

Caudal regression

Note: The bilateral iliac bones are fused in the middle with no sacrum (shield sign).

Question 40

Risk factors for caudal regression

Answer 40

Maternal diabetes

Question 41

Newborn with anorectal malformation

Answer 41

Scimitar sacrum (sacrococcygeal osseous defect), think Currarino triad

Currarino triad:
- Anterior sacral meningocele
- Anorectal malformation
- Sacrococcygeal osseous defect (scimitar sacrum)

Question 42

What is special about the meningocele in the Currarino triad?

Answer 42

It is an anterior (not posterior) sacral meningocele