1. Ultrasound Evaluation of the Neonate Spine Harry H. Holdorf1

2. Indications
Ultrasound of the neonate spine can be an accurate, fast, and cost-effective alternative to MRI imaging.
Evaluations include:
Congenital or acquired abnormalities of the neonate or young infant spinal canal.

3. The Neonatal Spine Embryology Anatomy Function Indications
Sonographic Technique
Sonographic Appearance
Pathology

4. Embryology
Neural plate - a thickened piece of ectoderm that becomes the neural tube
Spinal meninges - membranes that cover the nervous system; dura, arachnoid, pia mater
Paraxial mesoderm - tissue that forms on the lateral aspect of neural tube that eventually form the vertebral column 4

5. Embryology
Primary Neurulation – process by which the ectoderm becomes the neural tube; forms cervical through second sacral segment; occurs between day 18 to 28 of gestation
ectoderm...neural plate...neural folds...neural tube (Medscape)
Disjunction – process by which neuroectoderm separates from cutaneous ectoderm

6. Embryology – Primary Neurulation

7. Embryology – Primary Neurulation

8. Embryology
Secondary Neurulation – process that forms the conus medularis, cauda equina and filum terminale distal to S2 level
Canalization - Distal neural tube forms from the caudal cell mass; undifferentiated cells...caudal cell mass...neural tube. the ventriculus terminalis forms at the terminal end of the neural tube near the coccyx, marking the site of the future conus medularis.
Retrogressive differentiation - tissue caudal to ventriculus terminalis forms the filum terminalle, cauda equina and the ascention of the conus (Medscape) 8

9. Embryology – Secondary Neurulation
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10. Embryology – Secondary Neurulation

11. Anatomy -Vertebrae Vertebrae - Cervical, thoracic, lumbar
Sacrum – consists of 5 fused vertebrae
Coccyx – 3 or 4 fused vertebrae

12. Vertebrae C7 - T12 -L5 - S5

13. Sacrum

14. Anatomy – Spinal Cord
Spinal cord – extends from medulla oblongata and terminates at the filum terminale
Conus medularis – inferior end of cord that tapers into a V shape; the tip should be lie at the L2-L3 interspace or above
Filum terminale – cordlike extension of the conus medularis; should be less than 2 mm in diameter
Cauda Equina – group of nerve fibers that extend from the tip of the conus medularis

15. Anatomy

16. Function Spinal column protects the spinal cord and nerves
Provides support for body in upright position
Provides balance and weight distribution
Provide base to which ribs can attach
Nerves with cord carry impulses to/from brain

17. Why Sonography? Can be done on infants less than 6 months old
Posterior spinous processes have not ossified
Inexpensive
No radiation
Allows real-time visualization of cord movement
No sedation
Can be performed almost anywhere 17

18. Indications (JRC-DMS)
Sacral dimple (most common reason US ordered)
Hemangioma
Raised midline
Hairy patch
Tail-like projection of lower spine
Dx of myelomeningocele or myeloschisis
Lower extremity deformities

19. Sonographic Technique
Transducer - Highest frequency linear that enables visualization of anatomy
Cervical spine use curvilinear tx
Select appropriate system presets
Patient Positions
Prone
Decubitus
Upright (JCR-DMS)
Scan entire back in long and transverse

20. Sonographic Technique (AIUM)
Determine level of conus medullaris
Determine L5, then count cephalad
Determine S1, then count cephalad (1st coccygeal segment is more rounded, sacral more squared)
Last rib bearing vertebra is T12, then count caudal
Skin marker at location of conus can be correlated with radiograph

21. Sonographic Appearance (Rumack)
Spinal Cord is hypoechoic; size and shape vary with location
Cervical – oval
Thoracic – circular
Thoracolumbar - thicker
Central Echo complex – echogenic line within the cord; may see fluid within (see Rumack)
Filum Terminale – Center is relatively hypoechoic with bright outer margins (see Rumack); may not be distinguishable from nerve fibers

22. Sonographic Appearance
Nerve root interfaces are echogenic
Filar Cyst – Cystic structure at the tip of the conus medullaris at origin of filum terminale
Also referred to as terminal ventricle
Causes no clinical symptoms
Under normal conditions, the spinal cord should float freely within CSF
Will move with breathing and pulsations from vasculature

23. Normal Neonatal Spine

24. Normal Neonatal Spine

25. Conus medularis

26. Transverse lumbar sonogram shows normal anatomy as labeled
Transverse lumbar sonogram shows normal anatomy as labeled. V = vertebra, transverse process (arrowhead).

27. Pathology – Tethered Cord (Westbrook)
Fixation of the spinal cord in an abnormal location
Conus medullaris positioned below the level of L3
Can be due to a thickened filum terminale (greater than 2 mm) or a meningomyelocele
Can be associated with a lipoma, dermal sinus diastematomyelia
Limited cord motion

28. Pathology – Tethered Cord
Can be associated with other anomalies, i.e. spinal bifida, anorectal malformations, etc.
May not be discovered until later in life when growth may strain cord and cause symptoms
Weakness in muscles
Scoliosis
Changes in bladder function
Sensory loss

30. Pathology
Spinal Dysraphism – general term for congenital disorders that involve incomplete fusion of mesenchymal, bone and neural elements of the spine (Westbrook).
Overt – Open or uncovered lesions due to incomplete closure of posterior bony elements of spine
Occult – spinal anomalies that occur beneath intact skin

31. Pathology
In occult spinal dysraphism, ≥ 1 vertebrae do not form normally, and the spinal cord and meninges may also be affected. In spina bifida cystica, the protruding sac can contain meninges (meningocele), spinal cord (myelocele), or both (meningomyelocele).

32. Overt Lesions - Myelocele
Cyst-like spinal lesion that exposes the neural placode (spinal cord) to the environment
Spinal cord is flush with the plane of the dorsal skin. See Rumack.
Not covered with meninges or skin
Usually at lumbosacral level
Always associated with tethering of the spinal cord (Unsinn).
Chiari II syndrome occurs in 99% of patients with myelocele or myelomeningocele (Unsinn). 32

33. Overt Lesions - Myelomeningocele
Low termination of cord with herniation of neural elements (CSF and nerves) beyond bony defect and through the skin
Cord tethering is almost always involved (Westbrook).
Almost always associated with Chiari II malformation
Sonographic Findings - differentiate from meningocele; detect associated anomalies (hydromelia, lipoma, etc.)
See Rumack.

34. Pathology Occult Spinal Dysraphism
Spinal anomalies that occur beneath intact skin
Frequently there are visual indications that a problem exists
Some examples of occult lesions are
Spinal lipoma
Meningocele
Myelocystocele
Diastematomyelia
Hydromyelia
Dorsal Dermal Sinus

35. Spinal Lipoma
Fatty mass that extends into the spinal canal and can extend into subcutaneous tissue.
Usually located at the level of the conus or filum terminale
Can be associated with tethered cord
Can be difficult to differentiate from teratoma; use location of lesion to differentiate
Sonographical findings: echogenic mass
See Rumack.

36. Spinal Lipoma

37. Meningocele (Rumack) Cystic herniation of CSF and meninges
Neural elements not involved; cord usually develops normally
Uncommon 37

38. Meningocele

39. Myelocystocele
Malformation in which the dilated central canal of the spinal cord protrudes dorsally through a bony defect (Rumack)
Can occur in any region of spine
Not usually associated with Chiari II malformation 39

40. Diastamatomyelia
A sagittal division of the cord into hemicords, each containing a central canal and nerve roots
About ½ of patients will present with a surface stigmata of an underlying malformation
Diagnosis sometimes delayed until child develops orthopedic and/or neurologic symptoms
May occur alone or with other anomalies

41. Diastamatomyelia

42. Hydromyelia (JRC)
Dilatation of the central canal which may be diffuse or focal
Associated with myelomeningocele and diastamotomyelia
Sonographic findings: separation of echogenic linear structures of the central canal

43. Hydromyelia

44. Dorsal Dermal Sinus (Rumack)
Fluid tract extending from skin that may or may not penetrate the dura
Results from incomplete disjunction
Most often seen in the lumbosacral area
Skin opening usually is located cephalad to the sinus connection with the dura
Can be attached to cord and cause tethering
See Rumack.

45. Dorsal Dermal Sinus

46. Dorsal Dermal Sinus

47. References
ACR-AIUM Practice Guidelines for the Performance of an Ultrasound Examination of the Neontal Spine; October, 2007.
Images on slides were obtained from The pediatric spinal canal.ppt. Original author unknown.
Image Slide 5 from retrived on Sept 12, 2012
Image Slide 6 from retrieved on Sept. 12, 2012
Image Slide 8
Image Slide 9
Image Slide 14
Image Slide 30 – Meningelocele, myelocel,
Image Slide 40 –Diastamatomyelia
Image Slide 42 – Hydromyelia -
Image Slide 41 – Dorsal Dermal Sinus spine-24 Tethered Cord Syndrome: a review of the literature: embryology. Medscape News Today; retrieved on May 30, 2011 from
Image slide
Images Slide
Unsinn, K., Geley T., Freund, M & Gassner, I. US of the Spinal Cord in Newborns: Spectrum of normal findings, variants, congenital anomalies, and acquired diseases
Westbrook, C., Rouse, G. and DeLange, M. Sonographic evaluation of the Spine in infants and neonates. Journal of Diagnostic Medical Sonography 7: , 47