In this presentation we will discuss role of high resolution in characterizing normal variant and pathologies of spinal pathologies. This is a pictoral review.

1. Ultrasound of Spinal Cord in
Neonates
DR. Muhammad Bin Zulfiqar
PGR IV New Radiology Department SHL/SIMS
radiombz@gmail.com

2. Facts
• Sonography can characterize nearly all spinal anomalies sufficiently in
the first days of life.
• MRI is the study of choice when surgical therapy is required.
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007; 188:733–
738

3. Agenda
• Part I:
• Lumbar spine embryology,
• Sonography techniques
• Indications
• Normal anatomy
• Developmental variations and pitfalls
• Part 2
• abnormal entities.
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007;
188:733–738

4. Part 1

5. Embryology
• CNS starts to form during the third gestational week, beginning with
the process known as neurulation
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007; 188:733–738

6. Embryology
• Canalization occurs at the distal end of the neural tube in the caudal cell
mass, resulting in an ependyma-lined neural tube that unites with the rest
of the spinal cord to form the conus medullaris and ventriculus terminalis.
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007; 188:733–738

7. Embryology
• Finally, at 38 days of gestation,
retrogressive differentiation occurs
forming the filum terminale.
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007;
188:733–738

8. Technique of Ultrasound
• Images are obtained in the longitudinal and transverse planes using a linear
5–12-MHz transducer.
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007;
188:733–738

9. • A, Transverse lumbar sonogram shows normal anatomy as labeled. V = vertebra,
transverse process (arrowhead).
• B, Longitudinal lumbar sonogram shows normal anatomy as labeled. Note central
echoic complex (arrowheads), a normal finding that results from interface of
central end of anterior median fissure and not central spinal canal.
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007; 188:733–
738

10. Technique of Ultrasound
• The vertebral level
• Determined by counting down from the 12th rib
• Confirmed by counting up from the L5–S1 junction or the tip of
coccyx.
• If the vertebral level is unclear, correlation with radiographs (possibly
with a marker) may help.
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007; 188:733–738

11. Indications of Spinal Ultrasound
• Multiple congenital anomalies placing an infant at increased risk.
• Complicated sacral dimple (location above the gluteal crease, bottom
of pit not seen, possible drainage from dimple, and presence of skin
stigmata),
• Soft tissue mass suspected of being spina bifida occulta.
• Determination of reason for failed lumbar puncture
• Location of CSF that may be tapped.
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007; 188:733–738

12. Indications of Spinal Ultrasound
• Low-risk lesions
• Simple midline dimples (< 5 mm in diameter, within 2.5 cm of the
anus, no other cutaneous stigmata).
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007; 188:733–738

13. Indications of Spinal Ultrasound
• High-risk lesions
• Atypical dimples (> 5 mm in diameter, > 2.5 cm above the anus)
• Hemangiomas
• Cutis aplasia
• Hairy patches
• Skin tags
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007;
188:733–738

14. Normal Variants That May Simulate Disorders
• Ventriculus terminalis
• Filar cyst
• Prominent filum terminale
• Cauda equina pseudomass
• Pseudosinus tract
• Dysmorphic coccyx.
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007; 188:733–738

15. Ventriculus Terminalis
• The ventriculus terminalis, often seen on sonography and MRI in
children younger than 5 years, is due to incomplete fetal regression of
the embryonic terminal ventricle in the conus medullaris.
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007; 188:733–738

16. Ventriculus Terminalis
• A, Longitudinal sonogram of spine reveals distention of distal lumbar spinal
canal just above conus medullaris (arrowhead). Size smaller than 5 mm and
stability over time distinguish this normal variant from small syrinx. B,
Sagittal T2-weighted MR image at age 7 months shows stable distention of
distal spinal canal (arrowhead), excluding syrinx.
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007; 188:733–738

17. • Ventriculus terminalis in a healthy 7- week-old infant. Sagittal US scan
of the lumbar spinal canal shows a ventriculus terminalis
(arrowheads). 1 = conus medullaris with central echo complex.

18. Filar Cyst
• Origin:
• Normal arachnoid reflections form a pseudocyst like structure or that
it is a true ependyma-lined cystic embryonic remnant (possibly
indistinguishable from the ventriculus terminalis).
• Regardless of its origin, it is a normal variant
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007; 188:733–738

19. Filar Cyst
• Imaging criteria for filar cyst
• Location midline
• Within filum Just below conus
• Fusiform shape
• Well-defined
• Hypoechoic appearance of a simple cyst
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007; 188:733–738

20. Filar Cyst
• A, Transverse sonogram of proximal cauda equina shows well-defined,
midline, cystic collection (arrow). Note normal ventral and dorsal nerve
root bundles (arrowheads).
• B, Longitudinal sonogram reveals well-defined fusiform “cyst” in midline
(arrow) just below conus medullaris. Also note prominent echogenic
central spinal canal (arrowhead), a normal variant seen in some children.
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007; 188:733–738

21. • A, Longitudinal sonogram of filum and cauda equina (arrowhead)
shows unusually long filar cyst (calipers). Despite its length, it meets
criteria for filar cyst: location just below conus medullaris, fusiform
shape, well defined, thin walled, and hypoechoic.
• B, Longitudinal T2-weighted MR image shows ill-defined filar cyst
(arrows) that is better seen on sonography.
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007;
188:733–738

22. Prominent Filum Terminale
• A prominent filum terminale may cause concern when it stands out as
particularly echogenic in comparison with other nerve roots.
• It is distinguished as normal by its thickness and typical midline
course.
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007; 188:733–738

23. • Prominent filum terminale in 2-week-old boy with asymmetric gluteal
crease. Longitudinal sonogram shows hyperechoic filum of normal
size (< 1 mm) (arrow) at L5–S1.
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007; 188:733–738

24. “Pseudomass” due to Positional Nerve Root Clumping
• Positional clumping of the nerve roots occurs when an infant is
scanned in the decubitus position.
• Rescanning the child prone will cause the “mass” to disappear as the
nerve roots return to their normal position
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007; 188:733–738

25. • A, Transverse sonogram shows clumping of nerve roots (arrows) on
left due to left decubitus position.
• B, Longitudinal sonogram also reveals masslike appearance of nerve
roots (arrows). Prone images (not shown) were normal.
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007; 188:733–738

26. Pseudosinus Tract
• Pseudosinus tract seen on sonography as a residual cordlike region
composed of fibrous tissue extending from a skin dimple to the
coccyx.
• True dermal sinus tracts rarely occur at the tip of the coccyx
• Typically found in a more cranial location.
• If CSF is draining via a dimple, then a true sinus tract is likely, and MRI
is the imaging technique of choice.
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007; 188:733–738

27. • Pseudosinus tract in 12-day-old infant with dimple in gluteal crease.
Longitudinal sonogram shows cartilaginous, hypoechoic, dorsally
curving tip of coccyx (arrowhead), from which hypoechoic cordlike
structure (curved arrow) extends caudally and terminates at base of
skin dimple (straight arrow).
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007; 188:733–738

28. Dysmorphic Coccyx
• The tip of the coccyx can vary widely in shape, and in some cases may
mimic a mass when palpated on physical examination
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007; 188:733–738

29. • Misshapen coccyx in two neonatal girls, each with palpable “lump” beneath sacral dimple in
gluteal crease.
• A, Longitudinal sonogram of coccyx in 2-week-old girl shows hypoechoic cartilaginous tip
(arrowheads), which is acutely angulated dorsally as it extends toward skin surface. Palpated
“lump” was tip of coccyx.
• B, Longitudinal sonogram of coccyx in 2-week-old girl reveals it is straightened, with loss of its
normal ventral curve. Hypoechoic cartilaginous tip (arrowhead) extends dorsally toward skin
surface, causing clinically palpable “lump.”
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007; 188:733–738

30. Conclusion
• Neonatal spinal sonography is a useful screening technique for occult
spinal anomalies;
• it can characterize normal anatomy and normal variants that may
simulate disorders.
• Familiarity with these findings will prevent misinterpretation and
inappropriate referrals.
Lowe et al. Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders. AJR 2007; 188:733–738

31. Part 2
Congenital Anomalies

32. Pathomechanism
1. premature separation of the skin ectoderm from the neural tube
can lead to entrapment of mesodermal elements, such as fat.
2. Second, failed neurulation leads to dysraphisms, such as
myelomeningocele.
3. Anomalies of the filum terminale, such as fibrolipomas and caudal
regression syndrome, are caused by disembryogenesis of the caudal
cell mass.
Lowe et al. Sonography of the Neonatal Spine: Part 2, Spinal Disorders. AJR 2007; 188:739–744

33. Classification
• Classified on the basis of the presence or absence of a soft-tissue
mass and skin covering.
• Without a mass
• Tethered cord
• Diastematomyelia
• Anterior sacral meningocele
• Spinal lipoma.
Lowe et al. Sonography of the Neonatal Spine: Part 2, Spinal Disorders. AJR 2007; 188:739–744

34. Classification
• With a skin covered soft-tissue mass:
1. Lipomyelomeningocele
2. Myelocystocele.
• With a back mass but without skin covering
1. Myelomeningocele
2. Myelocele.
Lowe et al. Sonography of the Neonatal Spine: Part 2, Spinal Disorders. AJR 2007; 188:739–744

35. Tethered Cord
• Tethered cord, or low-lying conus medullaris, is caused by incomplete
regressive Differentiation and failed involution of the terminal cord.
• Symptoms occur because of traction on the abnormally anchored
filum terminale and adjacent nerve roots.
Lowe et al. Sonography of the Neonatal Spine: Part 2, Spinal Disorders. AJR 2007; 188:739–744

36. Tethered Cord
•Sonographic Diagnostic Criteria
1. low-lying conus (below the L2–L3 disk space)
2. Lack of normal nerve root motion during real-time Sonography
Lowe et al. Sonography of the Neonatal Spine: Part 2, Spinal Disorders. AJR 2007; 188:739–744

37. Tethered Cord
• Associated spinal findings
1. A thickened filum terminale,
2. Fibrolipoma
3. Spinal dysraphisms
4. Syringomyelia
5. Scoliosis,
6. Congenital spinal masses (lipomas, dermoids), cysts (myelocele)
7. Sinus tracts that contain fluid .
• Other nonneurologic anomalies are common as well, including
tracheoesophageal fistula, congenital heart disease, and renal anomalies
(VATER syndrome).
Lowe et al. Sonography of the Neonatal Spine: Part 2, Spinal Disorders. AJR 2007; 188:739–744

38. • Tethered cord in 2-day-old boy with multiple congenital
anomalies.
• A, Longitudinal sonogram shows low-lying conus
(arrowhead) at L5 vertebra and thickened, echogenic
fatty filum (arrow).
• B, Sagittal T1-weighted MR image confirms thick, fatty
filum (arrow) overlapping tethered cord from L4 to S1
level.
Lowe et al. Sonography of the Neonatal Spine: Part 2, Spinal Disorders. AJR 2007; 188:739–744

39. • Syrinx and tethered cord in 1-week-old girl with imperforate
anus and scoliosis.
• A, Longitudinal sonogram reveals low-lying conus at L4
vertebra with hypoechoic cystic space (arrow) expanding
lumbar spinal cord.
• B, Sagittal T2-weighted MR image confirms conus is
tethered at S1 level (arrowhead) and lumbar spinal cord
contains large, hyperintense, fusiform syrinx (arrow).
Lowe et al. Sonography of the Neonatal Spine: Part 2, Spinal Disorders. AJR 2007; 188:739–744

40. Spinal Lipoma
• Premature disjunction (embryologic separation of neural ectoderm
from cutaneous tissue elements) that allows mesenchyme to be
trapped between the neural folds and remain in contact with the
neural canal.
• They may be intradural, extradural, or a combination of both. In
addition to fat, 84% of lipomas also contain neural tissue or meninges
[2, 3].
Lowe et al. Sonography of the Neonatal Spine: Part 2, Spinal Disorders. AJR 2007; 188:739–744

41. Spinal Lipoma
• Associations:
• Tethered cord,
• Dysraphism (4%),
• Fatty filum or lipoma of filum (12%), and
• Vertebral anomalies
Lowe et al. Sonography of the Neonatal Spine: Part 2, Spinal Disorders. AJR 2007; 188:739–744

42. • Intradural lipoma and tethered cord in 2-week-old girl with hairy patch on lower
back.
• A, Longitudinal sonogram reveals typical features of hyperechoic lipoma (calipers)
attached to dorsal aspect of thoracolumbar spinal cord. Conus is tethered to mass
at L3–L4 disk space (arrow).
• B, Transverse sonogram at L3 vertebra shows conus (arrow) tethered to dorsal
lipoma (arrowhead).
Lowe et al. Sonography of the Neonatal Spine: Part 2, Spinal Disorders. AJR 2007; 188:739–744

43. Spina Bifida Occulta with Lipomyelomeningocele
• Spina bifida occulta is defined as any skin covered osseous defect of
posterior elements through which various combinations of neural
elements (neural placode), meninges, CSF, and adipose tissue
protrude.
• The cause is defective disjunction and neurulation with entrapped
mesenchyma in contact with the incompletely closed neural tube.
Lowe et al. Sonography of the Neonatal Spine: Part 2, Spinal Disorders. AJR 2007; 188:739–744

44. • Lipomyelomeningocele in 1-day-old girl with soft-tissue
swelling on lower back. A and B, Longitudinal (A) and
transverse (B) sonograms show lumbosacral dysraphism
through which spinal cord (straight arrow), hyperechoic
fatty tissue (curved arrow), and hypoechoic CSF
(arrowhead, B) pass. C, T1-weighted sagittal MR image
confirms lumbosacral dysraphism with intra- and
extradural adipose tissue (arrows), neural tissue
(arrowhead), and tethered cord.
Lowe et al. Sonography of the Neonatal Spine: Part 2, Spinal Disorders. AJR 2007; 188:739–744

45. Fatty Filum and Filar Fibrolipoma
• Fatty filum and filar lipomas are due to a minor anomaly of
canalization and retrogressive differentiation with persistent or
dedifferentiated fatty tissue.
• It is considered a normal variant when it is an isolated finding in a
normal size filum (< 1–2 mm). When the fatty tissue forms a mass, a
filar lipoma is diagnosed.
• Associated anomalies
1. Myelomeningocele
2. Tethered cord.
Lowe et al. Sonography of the Neonatal Spine: Part 2, Spinal Disorders. AJR 2007; 188:739–744

46. • Fatty filum in 23-week-old boy with sacral dimple who is otherwise
developmentally normal. A, Longitudinal sonogram shows focus of
segmental increased echogenicity within filum (arrowhead) posterior
to L4 vertebral body. B, Axial T1-weighted MR image confirms fat in
filum as localized area of increased signal intensity (arrowhead).
Lowe et al. Sonography of the Neonatal Spine: Part 2, Spinal Disorders. AJR 2007; 188:739–744

47. Caudal Regression Syndrome
• Caudal regression syndrome, which is thought to be due to abnormal
mesodermal formation of the caudal cell mass (possibly from hyperglycemia).
• It occurs most often in children of diabetic mothers
• Associations:
1. Genitourinary
2. Anal
3. Vertebral
4. Limb anomalies.
• The presentation and imaging appearance vary with the degree of deformity,
ranging from minimal to severe regression of the coccyx, sacrum, and lumbar
spine.
• Progressive absence of bone structures occurs in a caudal to cranial direction.
Lowe et al. Sonography of the Neonatal Spine: Part 2, Spinal Disorders. AJR 2007; 188:739–744

48. • Caudal regression syndrome in 3-day-old girl of
diabetic mother. A, Longitudinal sonogram shows
blunted distal cord (arrow), typical of caudal
regression syndrome. B, Sagittal T1-weighted MR
image confirms blunted conus medullaris and
associated fat in filum (arrow) as well as absence of
sacrum and coccyx (arrowhead).
Lowe et al. Sonography of the Neonatal Spine: Part 2, Spinal Disorders. AJR 2007; 188:739–744

49. Subdural Hematoma
• Subdural hematoma is uncommon in neonates;
• it may be iatrogenic after failed attempts at neonatal lumbar
puncture.
• Sonography is useful to determine whether the thecal sac is
compressed by a hematoma.
• Sonography can be used to determine the best timing and level for a
potential reattempt at lumbar puncture.
Lowe et al. Sonography of the Neonatal Spine: Part 2, Spinal Disorders. AJR 2007; 188:739–744

50. • Fig. 7—Subdural hematoma in febrile 2-month-old boy after multiple
attempts at lumbar puncture. A, Longitudinal sonogram identifies
hemorrhage as circumferential, echogenic material in subdural space
(straight arrow) that displaces dura (curved arrows) from posterior
elements (arrowhead) and collapses normal CSF-containing thecal sac. B,
Transverse sonogram also reveals circumferential echogenic subdural blood
(arrows) obliterating normal CSF, which contains thecal sac.
Lowe et al. Sonography of the Neonatal Spine: Part 2, Spinal Disorders. AJR 2007; 188:739–744

51. Conclusion
• Modern sonography technology allows
• Accurate screening
• Characterization of spinal abnormalities during the first few days of
life.
• It is useful for determining the type of lesion present in order to guide
the type and timing of intervention.
Lowe et al. Sonography of the Neonatal Spine: Part 2, Spinal Disorders. AJR 2007; 188:739–744

52. THANK YOU