Neonatal Spine
Tanya Nolan
Embryology

Ectoderm


Neural tube arises from
ectodermal cells and
becomes the spinal
cord and brain.
Mesoderm

Forms bony spine,
meninges, and muscle
Embryology

Defects of the spine occur in the first 8.5 wks of
life as the fetal nervous system develops

Incomplete seperation of the neural tube from the
ectoderm


Premature Seperation


Lipomas
Failure of neural tube to fold and fuse in the midline


Cord tethering, Diastematomyelia, or a Dermal sinus
Myelomeningocele
Disorders of distal cord

Fibrolipomas of the filum terminale
Anatomy

Vertebral Column

Houses spinal cord,
spinal nerve roots,
and meninges

Total 33 Vertebrae





7 Cervical
12 Thoracic
5 Lumbar
5 Sacral
4 Coccygeal
Spinal Cord


Cylindrical, grayish
white structure
Meninges

Dura Mater


Outer strong, dense,
fibrous sheet
Arachnoid Mater

Middle layer
 Subarachnoid
Space: Filled with
cerebral spinal fluid.

Pia Mater

Inner vascular layer
Spinal Cord

Begins


Above the formamen
magnum and is
continuous with the
medulla oblongata
Terminates


Adult: Lower border of L1
Child: Upper border of L3
Spinal Cord

Conis Medularis


Filum Terminale


Inferiorly cord tapers to a
point
Prolongation of pia
matter that is attached to
the coccyx
Cauda Equina


“Horse tail”
Lower nerve roots
Nerve Roots


31 Pair
Carries impuses to and from the brain to the rest of the body.
Indications for Sonographic
Examination








Midline Cutaneous Abnormality
Sacral Dimple
 Deep
 Asymmetric
 Suspicious if more than 1 inch from anus
Hemangioma
Raised midline
Hairy Patch
Tail-like projection of lower spine
Diagnosis of myelomeningocele or myeloschisis
Lower extremity deformity
Sonographic Technique

Patient Position

Prone




Spine flexed (seperates
posterior elements)
Lateral Decubitus
Upright
Transducer


High frequency linear array
Possible stand off pad
Sonographic Technique

Where do you begin?



1) Sacral area & count stepwise ascent of sacral
vertebral elements
2) Count from lowest rib bearing vertebra (rib
over kidney & follow medially)
Determine level of Conus Medullaris!!!
Sonographic Appearance
Vertebral Bodies


Echogenic; anterior
Lamina


Slighly off midline; “Overlapping Roof Tiles”
Spinous Processes


Inverted “U”s
Coccyx


Hypoechoic, do not mistake for a fluid collection.
Spinal Cord


Hypoechoic with slightly echogenic borders and an echogenic line extending along
its middle.
Nerve Roots



Echogenic
Move and change configuration during respiratory variations.
Conus Medullaris


Normally above endplate of L3; Most cords end above L2. (Most tethered cords are
unquestionably low.)
Sonographic Appearance
Sagittal View

Anterior echogenic body surface; posterior dorsal spinal elements.


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1. Posterior elements or spinous processes
2. posterior arachnoid-dural layer bordering spinal canal
3. subarachnoid space filled with cerebrospinal fluid
4 posterior margin of the spinal cord
5. spinal cord with central echo complex
6. Anterior margin of the spinal cord
Sonographic Appearance
Level of the Conus – Sagittal View

Tapered conus medullaris shows the end of the spinal cord.



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1. Posterior elements or spinous processes
2. cauda medullaris
3. filum terminale
4. cauda equina and nerve roots.
Sonographic Appearance
Level of the Conus – Transverse View

Nerve roots are echogenic as they surround the spinal cord.

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1. Paravertebral muscles
2. Laminae of vertebral arches
3. subarachnoid space filled with cerebrospinal fluid
4. spinal cord with central echo complex
5. paired dorsal and ventral nerve roots
6. vertebral body.
Pathology
Tethered Cord


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Fixation of cord @
caudal location (below
L3)
Diminished cord
movement.
Cord mechanical
stretching, distortion,
and ischemia with
growth and activity.
TC
L
Tethered Cord

Sonographic
Findings



Visualization of
cord caudal to
normal
termination
Diminished cord
pulsation
Eccentric cord
location with the
canal
Intradural lipoma and tethered cord in 2-week-old girl with hairy patch
on lower back. 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.
Lipoma



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Mass of filum terminale
Continuous with
subcutaneous tissues &
presents as a fatty back
lump.
Frequently associated
with tethered cord.
Sonographic Finding

Echogenic Mass
Hydromelia

Dilation of central canal


Associated with
myelomeningocele and
diastemotomyelia


Diffuse or focal
May mimic or co-exist
with syringomyelia
Sonographic Findings

Separation of echogenic
linear structures of
central canal.
Hydromyelia in a 1-month-old infant in whom
lumbar myelomeningocele and thoracic
hydromyelia were noted on the 1st day of life.
Sagittal US scan shows a dilated central canal
(arrows).
Diastamatomyelia



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Cord is split at one or
more sites by a
septum
Assoiated with
meningocele or
myelomeningocele
Vertebral column
abnormal on plain
radiography
Sonographic
Findings

Split segments best
seen in transverse
views
Transverse scan of the lumbar spinal canal
shows left and right hemicords. Each
hemicord has an eccentric central canal
Cysts on Spinal Cord

May be seen in
cauda equine or
filum terminale


Small cysts in filum
terminale may be
remnants of a terminal
ventricle or an
arachnoid pseudocyst
Related to Tethered
Cord
Myelomeningocele
Spina Bifida



Low termination of
spinal cord
Protruding pouch
containing CSF and
nerves
Sonographic
Findings


Pre-op exams can
differentiate
between
myelomeningocele
and meningocele
Flat nontubulated
cord with nerve
roots extending
into the defect.
Dermal Sinus Tract





Small dimple-like opening in the
midline of the spine connecting
deep into the spinal cord.
The majority located at the level of
the sacrum or the lumbar region.
Communication with spinal canal
contents increases possibility of
meningitis
Attaches to the end of the spinal
cord, causing tethering.
Sonographic Findings


Easily followed if fluid filled or
disrupts normal soft tissue planes
Dural penetration is difficut to
ascertain or exclude on
sonography