1. 1 The Neonatal Spine Holdorf PhD, MPA, RDMS, RVT, LRT(AS)

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

3. 3 Embryology Neural plate - a thickened piece of ectoderm that becomes the neural tube Neural plate - a thickened piece of ectoderm that becomes the neural tube Spinal meninges - membranes that cover the nervous system; dura, arachnoid, pia mater Spinal meninges - membranes that cover the nervous system; dura, arachnoid, pia mater Paraxial mesodern - tissue that forms on the lateral aspect of neural tube that eventually form the vertebral column Paraxial mesodern - tissue that forms on the lateral aspect of neural tube that eventually form the vertebral column 3

4. 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 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) ectoderm...neural plate...neural folds...neural tube (Medscape) Disjunction – process by which neuroectoderm separates from cutaneous ectoderm Disjunction – process by which neuroectoderm separates from cutaneous ectoderm

5. 5 Embryology Secondary Neurulation – process that forms the conus medularis, cauda equina and filum terminale distal to S2 level 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. 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) Retrogressive differentiation - tissue caudal to ventriculus terminalis forms the filum terminalle, cauda equina and the ascention of the conus (Medscape) 5

6. Anatomy Vertebrae - Cervical, thoracic, lumbar Vertebrae - Cervical, thoracic, lumbar Sacrum – consists of 5 fused vertebrae Sacrum – consists of 5 fused vertebrae Spinal cord – extends from medulla oblongata and terminates at the filum terminale 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 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 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 Cauda Equina – group of nerve fibers that extend from the tip of the conus medularis

7. Anatomy

8. 8 Vertebrae

9. 9 Sacrum

10. 10 Function Spinal column protects the spinal cord and nerves Spinal column protects the spinal cord and nerves Provides support for body in upright position Provides support for body in upright position Provide base to which ribs can attach Provide base to which ribs can attach Nerves with cord carry impulses to/from brain Nerves with cord carry impulses to/from brain

11. 11 Why Sonography? (Westbrook) Can be done on infants less than 6 months old Can be done on infants less than 6 months old Posterior spinous processes have not ossified Posterior spinous processes have not ossified Inexpensive Inexpensive No radiation No radiation Allows real-time visualization of cord movement Allows real-time visualization of cord movement No sedation No sedation Can be performed almost anywhere Can be performed almost anywhere 11

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

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

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

15. Sonographic Appearance (Rumack) Spinal Cord is hypoechoic; size and shape vary with location Spinal Cord is hypoechoic; size and shape vary with location Cerivcal – oval Cerivcal – oval Thoracic – circular Thoracic – circular Thoracolumbar - thicker Thoracolumbar - thicker Central Echo complex – echogenic line within the cord; may see fluid within (see Rumack p 1797 Figure 55-5). Central Echo complex – echogenic line within the cord; may see fluid within (see Rumack p 1797 Figure 55-5). Filum Terminale – Center is relatively hypoechoic with bright outer margins (see Rumack p 1797 Figure 55-6); may not be distinguishable from nerve fibers Filum Terminale – Center is relatively hypoechoic with bright outer margins (see Rumack p 1797 Figure 55-6); may not be distinguishable from nerve fibers

16. Sonographic Appearance Nerve root interfaces are echogenic Nerve root interfaces are echogenic Filar Cyst – Cystic structure at the tip of the conus medullaris at origin of filum terminale Filar Cyst – Cystic structure at the tip of the conus medullaris at origin of filum terminale Also referred to as terminal ventricle Also referred to as terminal ventricle Causes no clinical symptoms Causes no clinical symptoms See Rumack p 1798 fig. 55-7. See Rumack p 1798 fig. 55-7. Under normal conditions, the spinal cord should float freely within CSF Under normal conditions, the spinal cord should float freely within CSF Will move with breathing and pulsations from vasculature Will move with breathing and pulsations from vasculature

17. Normal Neonatal Spine

18. 18 Normal Neonatal Spine

19. Conus medularis

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

21. 21 Pathology – Tethered Cord (Westbrook) Fixation of the spinal cord in an abnormal location Fixation of the spinal cord in an abnormal location Conus medullaris positioned below the level of L3 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 due to a thickened filum terminale (greater than 2 mm) or a meningomyelocele Can be associated with a lipoma, dermal sinus diastematomyelia Can be associated with a lipoma, dermal sinus diastematomyelia Limited cord motion Limited cord motion

22. 22 Pathology – Tethered Cord Can be associated with other anomalies, ie spinal bifida, anorectal malformations, etc. Can be associated with other anomalies, ie spinal bifida, anorectal malformations, etc. May not be discovered until later in life when growth may strain cord and cause symptoms May not be discovered until later in life when growth may strain cord and cause symptoms Weakness in muscles Weakness in muscles Scoliosis Scoliosis Changes in bladder function Changes in bladder function Sensory loss Sensory loss

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

24. 24 Overt Lesions - Myelocele Cyst-like spinal lesion that exposes the neural placode (spinal cord) to the environment 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 p 1802, fig 55-14. Spinal cord is flush with the plane of the dorsal skin. See Rumack p 1802, fig 55-14. Not covered with meninges or skin Not covered with meninges or skin Usually at lumbosacral level Usually at lumbosacral level Always associated with tethering of the spinal cord (Unsinn). Always associated with tethering of the spinal cord (Unsinn). Chiari II syndrome occurs in 99% of patients with myelocele or myelomeningocele (Unsinn). Chiari II syndrome occurs in 99% of patients with myelocele or myelomeningocele (Unsinn). 24

25. Overt Lesions - Myelomeningocele Low termination of cord with herniation of neural elements (CSF and nerves) beyond bony defect and through the skin 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). Cord tethering is almost always involved (Westbrook). Almost always associated with Chiari II malformation Almost always associated with Chiari II malformation Sonographic Findings - differentiate from meningocele; detect associated anomalies (hydromelia, lipoma, etc.) Sonographic Findings - differentiate from meningocele; detect associated anomalies (hydromelia, lipoma, etc.) See Rumack, p 1804, fig 55-15. See Rumack, p 1804, fig 55-15.

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

27. Spinal Lipoma Fatty mass that extends into the spinal canal and can extend into subcutaneous tissue. 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 Usually located at the level of the conus or filum terminale Can be associated with tethered cord Can be associated with tethered cord Can be difficult to differentiate from teratoma; use location of lesion to differentiate Can be difficult to differentiate from teratoma; use location of lesion to differentiate Sonographical findings: echogenic mass Sonographical findings: echogenic mass See Rumack p 1805, fig. 55-16. See Rumack p 1805, fig. 55-16.

28. 28 Meningocele (Rumack) Simple - dorsal herniation of dura, arachnoid and CSF into subcutaneous tissue of the back; neural elements not involved Simple - dorsal herniation of dura, arachnoid and CSF into subcutaneous tissue of the back; neural elements not involved Complex - involves neural elements Complex - involves neural elements Lateral - extends laterally through an intervertebral foramen Lateral - extends laterally through an intervertebral foramen 28

29. 29 Myelocystocele Malformation in which the dilated central canal of the spinal cord protrudes dorsally through a bony defect (Rumack) 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 Can occur in any region of spine Not usually associated with Chiari II malformation Not usually associated with Chiari II malformation 29

30. Diastamatomyelia A sagittal division of the cord into hemicords, each containing a central canal and nerve roots (Rumack) See Figure 55-22 p1809 A sagittal division of the cord into hemicords, each containing a central canal and nerve roots (Rumack) See Figure 55-22 p1809 About ½ of patients will present with a surface stigmata of an underlying malformation 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 Diagnosis sometimes delayed until child develops orthopedic and/or neurologic symptoms May occur alone or with other anomalies May occur alone or with other anomalies

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

32. 32 Dorsal Dermal Sinus (Rumack) Fluid tract extending from skin that may or may not penetrate the dura Fluid tract extending from skin that may or may not penetrate the dura Results from incomplete disjunction Results from incomplete disjunction Most often seen in the lumbosacral area Most often seen in the lumbosacral area Skin opening usually is located cephalad to the sinus connection with the dura Skin opening usually is located cephalad to the sinus connection with the dura Can be attached to cord and cause tethering Can be attached to cord and cause tethering See Rumack p 1809, fig 55-20 See Rumack p 1809, fig 55-20

33. 33 References ACR-AIUM Practice Guidelines for the Performance of an Ultrasound Examination of the Neontal Spine; October, 2007. ACR-AIUM Practice Guidelines for the Performance of an Ultrasound Examination of the Neontal Spine; October, 2007. Images on slides 17-20 were obtained from The pediatric spinal canal.ppt. Original author unknown. Images on slides 17-20 were obtained from The pediatric spinal canal.ppt. Original author unknown. Tethered Cord Syndrome: a review of the literature: embryology. Medscape News Today; retrieved on May 30, 2011 from http://www.medscape.com/viewarticle/725080_2 Tethered Cord Syndrome: a review of the literature: embryology. Medscape News Today; retrieved on May 30, 2011 from http://www.medscape.com/viewarticle/725080_2 http://www.medscape.com/viewarticle/725080_2 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 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 7:325-331, 325-331. Westbrook, C., Rouse, G. and DeLange, M. Sonographic evaluation of the Spine in infants and neonates. Journal of Diagnostic Medical Sonography 7:325-331, 325-331. 33