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Ultrasound Ultrasound Evaluation of Evaluation of the Neonatethe Neonate

SpineSpineHarry H. Holdorf Harry H. Holdorf

IndicationsIndications

Ultrasound of the neonate spine can Ultrasound of the neonate spine can be an accurate, fast, and cost-be an accurate, fast, and cost-effective alternative to MRI imaging.effective alternative to MRI imaging.

Evaluations include:Evaluations include: Congenital or acquired abnormalities of Congenital or acquired abnormalities of

the neonate or young infant spinal the neonate or young infant spinal canal.canal.

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The Neonatal SpineThe Neonatal Spine

EmbryologyEmbryology AnatomyAnatomy FunctionFunction IndicationsIndications Sonographic TechniqueSonographic Technique Sonographic AppearanceSonographic Appearance PathologyPathology

EmbryologyEmbryology

Neural plate - a thickened piece of Neural plate - a thickened piece of ectoderm that becomes the neural ectoderm that becomes the neural tube tube

Spinal meninges - membranes that Spinal meninges - membranes that cover the nervous system; dura, cover the nervous system; dura, arachnoid, pia materarachnoid, pia mater

Paraxial mesoderm - tissue that Paraxial mesoderm - tissue that forms on the lateral aspect of neural forms on the lateral aspect of neural tube that eventually form the tube that eventually form the vertebral columnvertebral column 4

Embryology Embryology Primary Neurulation – process by Primary Neurulation – process by

which the ectoderm becomes the which the ectoderm becomes the neural tube; forms cervical through neural tube; forms cervical through second sacral segment; occurs second sacral segment; occurs between day 18 to 28 of gestationbetween day 18 to 28 of gestation ectoderm...neural plate...neural ectoderm...neural plate...neural

folds...neural tube (Medscape)folds...neural tube (Medscape) Disjunction – process by which Disjunction – process by which

neuroectoderm separates from neuroectoderm separates from cutaneous ectodermcutaneous ectoderm

Embryology – Primary Embryology – Primary NeurulationNeurulation

Embryology – Primary Embryology – Primary NeurulationNeurulation

EmbryologyEmbryology Secondary Neurulation – process that Secondary Neurulation – process that

forms the conus medularis, cauda forms the conus medularis, cauda equina and filum terminale distal to S2 equina and filum terminale distal to S2 levellevel Canalization - Distal neural tube forms from the Canalization - Distal neural tube forms from the

caudal cell mass; undifferentiated cells...caudal caudal cell mass; undifferentiated cells...caudal cell mass...neural tube. 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 Retrogressive differentiation - tissue caudal to ventriculus terminalis forms the filum terminalle, ventriculus terminalis forms the filum terminalle, cauda equina and the ascention of the conus cauda equina and the ascention of the conus (Medscape)(Medscape)

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Embryology – Secondary Embryology – Secondary NeurulationNeurulation

http://php.med.unsw.edu.au/http://php.med.unsw.edu.au/embryology/index.php?embryology/index.php?title=Development_Animation_-title=Development_Animation_-_Secondary_Neurulation_Secondary_Neurulation

Embryology – Secondary Embryology – Secondary NeurulationNeurulation

Anatomy -VertebraeAnatomy -Vertebrae

Vertebrae - Cervical, thoracic, lumbarVertebrae - Cervical, thoracic, lumbarSacrum – consists of 5 fused vertebraeSacrum – consists of 5 fused vertebraeCoccyx – 3 or 4 fused vertebraeCoccyx – 3 or 4 fused vertebrae

VertebraeVertebraeC7 - T12 -L5 - S5C7 - T12 -L5 - S5

SacrumSacrum

Anatomy – Spinal CordAnatomy – Spinal Cord

Spinal cord – extends from medulla Spinal cord – extends from medulla oblongata and terminates at the filum oblongata and terminates at the filum terminaleterminale Conus medularis – inferior end of cord Conus medularis – inferior end of cord

that tapers into a V shape; the tip should that tapers into a V shape; the tip should be lie at the L2-L3 interspace or abovebe lie at the L2-L3 interspace or above

Filum terminale – cordlike extension of Filum terminale – cordlike extension of the conus medularis; should be less than the conus medularis; should be less than 2 mm in diameter2 mm in diameter

Cauda Equina – group of nerve fibers that Cauda Equina – group of nerve fibers that extend from the tip of the conus extend from the tip of the conus medularismedularis

AnatomyAnatomy

FunctionFunction

Spinal column protects the spinal Spinal column protects the spinal cord and nervescord and nerves

Provides support for body in upright Provides support for body in upright positionposition

Provides balance and weight Provides balance and weight distributiondistribution

Provide base to which ribs can Provide base to which ribs can attachattach

Nerves with cord carry impulses Nerves with cord carry impulses to/from brainto/from brain

Why Sonography?Why Sonography?

Can be done on infants less than 6 Can be done on infants less than 6 months oldmonths old

Posterior spinous processes have not Posterior spinous processes have not ossified ossified

InexpensiveInexpensive No radiationNo radiation Allows real-time visualization of cord Allows real-time visualization of cord

movementmovement No sedationNo sedation Can be performed almost anywhereCan be performed almost anywhere17

Indications Indications (JRC-DMS)(JRC-DMS)

Sacral dimple (most common reason US Sacral dimple (most common reason US ordered)ordered)

HemangiomaHemangioma Raised midlineRaised midline Hairy patchHairy patch Tail-like projection of lower spineTail-like projection of lower spine Dx of myelomeningocele or myeloschisisDx of myelomeningocele or myeloschisis Lower extremity deformitiesLower extremity deformities

Sonographic TechniqueSonographic Technique

Transducer - Highest frequency Transducer - Highest frequency linear that enables visualization of linear that enables visualization of anatomyanatomy Cervical spine use curvilinear txCervical spine use curvilinear tx

Select appropriate system presetsSelect appropriate system presets Patient PositionsPatient Positions

ProneProne DecubitusDecubitus Upright Upright (JCR-DMS)(JCR-DMS)

Scan entire back in long and Scan entire back in long and transversetransverse

Sonographic Technique Sonographic Technique (AIUM)(AIUM)

Determine level of conus medullarisDetermine level of conus medullaris Determine L5, then count cephaladDetermine L5, then count cephalad Determine S1, then count cephalad (1Determine S1, then count cephalad (1stst

coccygeal segment is more rounded, coccygeal segment is more rounded, sacral more squared)sacral more squared)

Last rib bearing vertebra is T12, then Last rib bearing vertebra is T12, then count caudalcount caudal

Skin marker at location of conus can be Skin marker at location of conus can be correlated with radiographcorrelated with radiograph

Sonographic Appearance Sonographic Appearance (Rumack)(Rumack)

Spinal Cord is hypoechoic; size and shape vary Spinal Cord is hypoechoic; size and shape vary with locationwith location Cervical – ovalCervical – oval Thoracic – circularThoracic – circular Thoracolumbar - thickerThoracolumbar - thicker

Central Echo complex – echogenic line within the Central Echo complex – echogenic line within the cord; may see fluid within (see Rumack)cord; may see fluid within (see Rumack)

Filum Terminale – Center is relatively Filum Terminale – Center is relatively hypoechoic with bright outer margins (see hypoechoic with bright outer margins (see Rumack); may not be distinguishable from nerve Rumack); may not be distinguishable from nerve fibers fibers

Sonographic AppearanceSonographic Appearance

Nerve root interfaces are echogenicNerve root interfaces are echogenic Filar Cyst – Cystic structure at the tip Filar Cyst – Cystic structure at the tip

of the conus medullaris at origin of of the conus medullaris at origin of filum terminale filum terminale Also referred to as terminal ventricleAlso referred to as terminal ventricle Causes no clinical symptomsCauses no clinical symptoms

Under normal conditions, the spinal Under normal conditions, the spinal cord should float freely within CSFcord should float freely within CSF

Will move with breathing and Will move with breathing and pulsations from vasculaturepulsations from vasculature

Normal Neonatal SpineNormal Neonatal Spine

Normal Neonatal SpineNormal Neonatal Spine

Conus medularisConus medularis

Transverse lumbar sonogram shows Transverse lumbar sonogram shows normal anatomy as labeled. V = normal anatomy as labeled. V =

vertebra, transverse process vertebra, transverse process

((arrowheadarrowhead).).

Pathology – Tethered Pathology – Tethered Cord (Westbrook)Cord (Westbrook)

Fixation of the spinal cord in an Fixation of the spinal cord in an abnormal locationabnormal location

Conus medullaris positioned below Conus medullaris positioned below the level of L3the level of L3

Can be due to a thickened filum Can be due to a thickened filum terminale (greater than 2 mm) or a terminale (greater than 2 mm) or a meningomyelocelemeningomyelocele

Can be associated with a lipoma, Can be associated with a lipoma, dermal sinus diastematomyeliadermal sinus diastematomyelia

Limited cord motionLimited cord motion

Pathology – Tethered Pathology – Tethered CordCord

Can be associated with other Can be associated with other anomalies, i.e. spinal bifida, anomalies, i.e. spinal bifida, anorectal malformations, etc.anorectal malformations, etc.

May not be discovered until later in May not be discovered until later in life when growth may strain cord life when growth may strain cord and cause symptomsand cause symptoms Weakness in musclesWeakness in muscles ScoliosisScoliosis Changes in bladder functionChanges in bladder function Sensory lossSensory loss

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PathologyPathology Spinal Dysraphism – general term Spinal Dysraphism – general term

for congenital disorders that involve for congenital disorders that involve incomplete fusion of mesenchymal, incomplete fusion of mesenchymal, bone and neural elements of the bone and neural elements of the spine (Westbrook).spine (Westbrook). Overt – Open or uncovered lesions due Overt – Open or uncovered lesions due

to incomplete closure of posterior bony to incomplete closure of posterior bony elements of spineelements of spine

Occult – spinal anomalies that occur Occult – spinal anomalies that occur beneath intact skinbeneath intact skin

PathologyPathology In In occult spinal dysraphism,occult spinal dysraphism, ≥ 1 vertebrae do not form ≥ 1 vertebrae do not form

normally, and the spinal cord and meninges may also be normally, and the spinal cord and meninges may also be affected. In affected. In spina bifida cystica,spina bifida cystica, the protruding sac can the protruding sac can contain meninges (meningocele), spinal cord (myelocele), or contain meninges (meningocele), spinal cord (myelocele), or both (meningomyelocele). both (meningomyelocele).

Overt Lesions - Overt Lesions - MyeloceleMyelocele

Cyst-like spinal lesion that exposes the Cyst-like spinal lesion that exposes the neural placode (spinal cord) to the neural placode (spinal cord) to the environmentenvironment

Spinal cord is flush with the plane of the Spinal cord is flush with the plane of the dorsal skin. See Rumack.dorsal skin. See Rumack.

Not covered with meninges or skinNot covered with meninges or skin Usually at lumbosacral levelUsually at lumbosacral level Always associated with tethering of the Always associated with tethering of the

spinal cord (Unsinn). spinal cord (Unsinn). Chiari II syndrome occurs in 99% of Chiari II syndrome occurs in 99% of

patients with myelocele or patients with myelocele or myelomeningocele (Unsinn).myelomeningocele (Unsinn).

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Overt Lesions - Overt Lesions - MyelomeningoceleMyelomeningocele

Low termination of cord with Low termination of cord with herniation of neural elements (CSF and herniation of neural elements (CSF and nerves) beyond bony defect and nerves) beyond bony defect and through the skinthrough the skin

Cord tethering is almost always Cord tethering is almost always involved (Westbrook).involved (Westbrook).

Almost always associated with Chiari II Almost always associated with Chiari II malformation malformation

Sonographic Findings - differentiate Sonographic Findings - differentiate from meningocele; detect associated from meningocele; detect associated anomalies (hydromelia, lipoma, etc.)anomalies (hydromelia, lipoma, etc.)

See Rumack.See Rumack.

PathologyPathologyOccult Spinal Occult Spinal DysraphismDysraphism

Spinal anomalies that occur beneath Spinal anomalies that occur beneath intact skinintact skin

Frequently there are visual indications Frequently there are visual indications that a problem existsthat a problem exists

Some examples of occult lesions areSome examples of occult lesions are Spinal lipomaSpinal lipoma MeningoceleMeningocele MyelocystoceleMyelocystocele DiastematomyeliaDiastematomyelia HydromyeliaHydromyelia Dorsal Dermal Sinus Dorsal Dermal Sinus

Spinal LipomaSpinal Lipoma

Fatty mass that extends into the spinal Fatty mass that extends into the spinal canal and can extend into subcutaneous canal and can extend into subcutaneous tissue.tissue.

Usually located at the level of the conus Usually located at the level of the conus or filum terminaleor filum terminale

Can be associated with tethered cordCan be associated with tethered cord Can be difficult to differentiate from Can be difficult to differentiate from

teratoma; use location of lesion to teratoma; use location of lesion to differentiate differentiate

Sonographical findings: echogenic massSonographical findings: echogenic mass See Rumack.See Rumack.

Spinal LipomaSpinal Lipoma

Meningocele (Rumack)Meningocele (Rumack)

Cystic herniation of CSF and Cystic herniation of CSF and meningesmeninges

Neural elements not involved; cord Neural elements not involved; cord usually develops normallyusually develops normally

UncommonUncommon

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MeningoceleMeningocele

MyelocystoceleMyelocystocele

Malformation in which the dilated Malformation in which the dilated central canal of the spinal cord central canal of the spinal cord protrudes dorsally through a bony protrudes dorsally through a bony defect (Rumack)defect (Rumack)

Can occur in any region of spineCan occur in any region of spine Not usually associated with Chiari II Not usually associated with Chiari II

malformationmalformation

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DiastamatomyeliaDiastamatomyelia

A sagittal division of the cord into A sagittal division of the cord into hemicords, each containing a hemicords, each containing a central canal and nerve roots central canal and nerve roots

About ½ of patients will present About ½ of patients will present with a surface stigmata of an with a surface stigmata of an underlying malformationunderlying malformation

Diagnosis sometimes delayed until Diagnosis sometimes delayed until child develops orthopedic and/or child develops orthopedic and/or neurologic symptoms neurologic symptoms

May occur alone or with other May occur alone or with other anomaliesanomalies

DiastamatomyeliaDiastamatomyelia

Hydromyelia (JRC)Hydromyelia (JRC)

Dilatation of the central canal which Dilatation of the central canal which may be diffuse or focalmay be diffuse or focal

Associated with myelomeningocele Associated with myelomeningocele and diastamotomyelia and diastamotomyelia

Sonographic findings: separation of Sonographic findings: separation of echogenic linear structures of the echogenic linear structures of the central canal central canal

HydromyeliaHydromyelia

Dorsal Dermal Sinus Dorsal Dermal Sinus (Rumack)(Rumack)

Fluid tract extending from skin that may Fluid tract extending from skin that may or may not penetrate the duraor may not penetrate the dura

Results from incomplete disjunctionResults from incomplete disjunction Most often seen in the lumbosacral areaMost often seen in the lumbosacral area Skin opening usually is located cephalad Skin opening usually is located cephalad

to the sinus connection with the durato the sinus connection with the dura Can be attached to cord and cause Can be attached to cord and cause

tetheringtethering See Rumack.See Rumack.

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Dorsal Dermal SinusDorsal Dermal Sinus

Dorsal Dermal SinusDorsal Dermal Sinus

ReferencesReferencesACR-AIUM Practice Guidelines for the Performance of an Ultrasound Examination of the Neontal Spine; October, ACR-AIUM Practice Guidelines for the Performance of an Ultrasound Examination of the Neontal Spine; October, 2007.2007.

Images on slides 22-25 were obtained from The pediatric spinal canal.ppt. Original author unknown.Images on slides 22-25 were obtained from The pediatric spinal canal.ppt. Original author unknown.

Image Slide 5 from http://www.ncbi.nlm.nih.gov/books/NBK10080/figure/A2873/?report=objectonly retrived on Image Slide 5 from http://www.ncbi.nlm.nih.gov/books/NBK10080/figure/A2873/?report=objectonly retrived on Sept 12, 2012Sept 12, 2012

Image Slide 6 from http://www.ncbi.nlm.nih.gov/books/NBK10080/figure/A2879/?report=objectonly; retrieved on Image Slide 6 from http://www.ncbi.nlm.nih.gov/books/NBK10080/figure/A2879/?report=objectonly; retrieved on Sept. 12, 2012Sept. 12, 2012Image Slide 8 http://php.med.unsw.edu.au/embryology/index.php?title=Development_Animation_-Image Slide 8 http://php.med.unsw.edu.au/embryology/index.php?title=Development_Animation_-_Secondary_Neurulation_Secondary_NeurulationImage Slide 9 http://www.radsource.us/clinic/0807Image Slide 9 http://www.radsource.us/clinic/0807Image Slide 14 http://www.childrensmercy.org/content/view.aspx?id=6196Image Slide 14 http://www.childrensmercy.org/content/view.aspx?id=6196Image Slide 30 – Meningelocele, myelocel, Image Slide 30 – Meningelocele, myelocel, http://www.merckmanuals.com/professional/pediatrics/congenital_neurologic_anomalies/spina_bifida.htmlhttp://www.merckmanuals.com/professional/pediatrics/congenital_neurologic_anomalies/spina_bifida.htmlImage Slide 40 –Diastamatomyelia http://www.jultrasoundmed.org/content/29/9/1357/F2.expansion?ck=nckImage Slide 40 –Diastamatomyelia http://www.jultrasoundmed.org/content/29/9/1357/F2.expansion?ck=nckImage Slide 42 – Hydromyelia -http://www.ultrasoundcases.info/Slide-View.aspx?cat=507&case=2168Image Slide 42 – Hydromyelia -http://www.ultrasoundcases.info/Slide-View.aspx?cat=507&case=2168Image Slide 41 – Dorsal Dermal Sinus http://www.minnisjournals.com.au/ajum/article/Ultrasound-examination-of-Image Slide 41 – Dorsal Dermal Sinus http://www.minnisjournals.com.au/ajum/article/Ultrasound-examination-of-the-neonatal-spine-24 Tethered Cord Syndrome: a review of the literature: embryology. Medscape News Today; the-neonatal-spine-24 Tethered Cord Syndrome: a review of the literature: embryology. Medscape News Today; retrieved on May 30, 2011 from retrieved on May 30, 2011 from http://www.medscape.com/viewarticle/725080_2http://www.medscape.com/viewarticle/725080_2 Image slide 44 - http://www.ultrasoundcases.info/Slide-View.aspx?cat=507&case=4224Image slide 44 - http://www.ultrasoundcases.info/Slide-View.aspx?cat=507&case=4224Images Slide 45 - http://www.ultrasoundcases.info/Slide-View.aspx?cat=507&case=4224Images Slide 45 - http://www.ultrasoundcases.info/Slide-View.aspx?cat=507&case=4224

Unsinn, K., Geley T., Freund, M & Gassner, I. US of the Spinal Cord in Newborns: Spectrum of normal findings, Unsinn, K., Geley T., Freund, M & Gassner, I. US of the Spinal Cord in Newborns: Spectrum of normal findings, variants, congenital anomalies, and acquired diseasesvariants, congenital anomalies, and acquired diseases

Westbrook, C., Rouse, G. and DeLange, M. Sonographic evaluation of the Spine in infants and neonates. Westbrook, C., Rouse, G. and DeLange, M. Sonographic evaluation of the Spine in infants and neonates. Journal of Journal of Diagnostic Medical SonographyDiagnostic Medical Sonography 7:325-331, 325-331. 7:325-331, 325-331.

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