26/01/2020 1 Spinal Trauma in Children

26/01/2020

Spinal trauma in children Lay-out

 normal variants and mimics

 epidemiology

 traumatic spine injuries in children - birth injuries - accidental Prof. Pia C Sundgren MD, PhD - vertebral body Department of Diagnostic Radiology - spinal cord - ligaments Co-Director Lund BioImaging Center (LBIC), Clinical Sciences, Lund University, Sweden

Lund University / Faculty of Medicine / Department of Clinical Sciences / Radiology / ECPNR/Rome/2020 Lund University / Faculty of Medicine / Department of Clinical Sciences / Radiology / ECPNR/Rome/2020 1 2

Normal spine in infants and children Pediatric spine - normal variants/findings

normal developmental anatomy that may mimic trauma: • ossification tip of dens (completes 3-6y)

wedge-shaped vertebral bodies C2-C7

incomplete ossification of tip of dens mimics increased distance between C2 and occiput

Pediatric spine - normal variants/findings Pediatric spine - normal variants/findings normal developmental anatomy that may mimic trauma: Synchondroses (symmetrical, expected location) • secondary ossification centers - unfused ring apophyses (normal physis are smooth with subchondral sclerotic lines)

Jones TM, et al. J Am Acad Orthop Surg 2011;19:600-611

Lustrin ES, et al. Radiographics 2003; 23: 539-560 Courtesy Prof T Huisman Lund University / Faculty of Medicine / Department of Clinical Sciences / Radiology / ECPNR/Rome/2020 Lund University / Faculty of Medicine / Department of Clinical Sciences / Radiology / ECPNR/Rome/2020 5 6

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Pediatric spine - normal variants/findings Injuries at birth wedged vertebral ossification congenital non-union bodies Brachial plexus birth palsy : 1 per 1000 live births

Risk factors: • macrosomia • prolonged labor • breech delivery The distance between non calcified atlas and dens: apophysis • previous deliveries with brachial plexus birth palsy child < 4.5 mm adult 3 mm

Plexus anatomy Classification of brachial plexus palsy

upper plexus C5 and pure upper trunk: C5 , C6 C6 upper plexus C5, C6, C7: Erb’s Palsy 80% lower plexus C7 and C8 ± T1 lower plexus C7, C8: Klumpke’s Palsy (very rare)

total plexus: 20% (from C5 to T1)

Erb´s palsy Klumpke´s palsy upper brachial plexus injury lower brachial plexus palsy infant is unable to: imbalance of the intrinsic and extrinsic muscles - abduct the arm from the shoulder - intrinsic muscles must be paralyzed - claw deformity - rotate the arm externally from the shoulder - long extensor muscles hyperextend the MCP joint - supinate the forearm - long flexor muscles flex the PIP and DIP joints

CAVE: injuries of the sympathetic branch to the stellate ganglion

= Horner’s syndrome

This results in the classic 'waiter's tip' appearance

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MRI of the spine and additional findings Treatment

- intramedullary edema in the acute phase in the absence of neurological improvement at - myelomalacia in the chronic phase 4 to 6 months - hypointense lesions on GRE T2-w* - hemorrhage microsurgical nerve reconstruction

postoperative improvement in muscular tone: - pure upper trunk 80% - Erb’s palsy 75% - complete palsy 45%

Accidental spine and spinal cord injury Causes for accidental injuries

 injury to the spinal column and spinal cord is the Cause < 3 years2 1-20 years1 overall major cause of disability, affecting predominately young healthy individuals Motor vehicle 66% 44% 47.7%

 spinal cord injuries are rare in infants Fall 15% 14% 20.8% and children (1-2% of all pediatric trauma victims) Pedestrian 11%

 the type of injuries is slightly different in the Bicycle 6% pediatric population compared to adults Violence 14.6% Sports 16% 14.2%

1Kokoska E et al. Characteristics of pediatric… J. Ped. Surg. 2001:36;100-105 (408 cases (+)) 2Polk-Williams A et al. Cervical spine injury…. J. Ped. Surg. 2008:43;1718-1721 (1523 cases (+)) Lund University / Faculty of Medicine / Department of Clinical Sciences / Radiology / ECPNR/Rome/2020 Lund University / Faculty of Medicine / Department of Clinical Sciences / Radiology / ECPNR/Rome/2020 15 16

Spinal trauma and spinal cord injury Misdiagnosis of acute cervical spine injuries < 8 years of age 50% in C1-C2 (-C3) region < 8 years of age 24% incidence of dislocations > 9 years of age 15%

most common site of diagnostic error is the occiput incidence of cord injuries to C2 region

> 8 years of age shift towards C5 and below predisposing factors for misdiagnosis: • unfamiliarity with pediatric cervical spine anatomy - C-spine fractures • not recognizing normal variants mortality rates 17% (overall), higher in small • suboptimal technique

children Avellino AM et al The misdiagnosis of acute cervical spine injuries.. Childs Nerv system 2005;21;122-127. (37 cases)

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Imaging of children with spine trauma CT - parameters

If low velocity trauma or minor fall: • technical specification of the scanner • anatomic region no pain at motion NO imaging no tenderness or plain films C1-C2 1-2 mm* no neurological deficits C-spine 2-3 mm* T+L-spine < 4 mm* If high velocity trauma or trauma with tenderness • required detail information CT reduced motion • 2D (3D) multiplanar reformatting pain at motion * Reconstructed slices, acquisition with sub-millimeter or suspected head injury (multitrauma) slices (0.6, 0.75…) Neurological symptoms MRI • Multi-trauma protocol NEXUS Low-Risk Criteria, CanadianC-spine rule, NICE guidelines 2016 Lund University / Faculty of Medicine / Department of Clinical Sciences / Radiology / ECPNR/Rome/2020 Lund University / Faculty of Medicine / Department of Clinical Sciences / Radiology / ECPNR/Rome/2020 19 20

Conventional MR parameters - protocol Causes for higher cervical injuries in children

increased flexibility of the cervical spine due to: • sagittal T2 STIR, T2-w, T1-w  incomplete ossifications of the vertebral bodies • axial T1SE, T2 fast SE,  ligament laxity • axial fat sat T2-w (soft tissue injury)  incomplete development of the spinous process • axial and sagittal T2* GRE (hemorrhage)  increased head-to-torso ratio • 3D – 3D TSE T2w SPACE (Siemens) 3D TSE T2w DRIVE (GE)  week cervical musculature 3D TSE T2w VISTA (Philips) cervical spine injuries at higher levels

Causes for higher cervical injuries in children Typical spine injuries in children

• uncinate processes small <10y • odontoid fracture, subluxation

• junction between vertebral body and end plates is • cranio-cervical dislocation or disassociation cartilaginous ~> risk for injury (Salter-Harris I) • Chance fracture (“seatbelt injury” especially in • more horizontal orientation of cervical facets the thoracic spine) greater range of physiologic flexion/extension • SWICORA • shallow occipital condyles always look for ligamentous injury

NOTE: always look for more VanderHave et al J Am Acad Orthop Surg 2011;19:319-327 (common with multiple injuries)

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Odontoid fracture Odontoid fracture

rapid deceleration with flexion (MVC

often through synchondrosis of C2 at the odontoid base

T1-w T2-w PD Axial T2-w

Complex of occipital-atlanto-axial dislocation Complex of atlanto-occpital dislocation occipital condyle is small, almost horizontal and lacks inherent stability Consider the complex when: severe hyperextension w/wo distraction - distance odontoid process and the basion > - rupture transverse lig. of the dens - 12 mm • anterior translation (hypereflextion) - occipital condyles and atlas > 5mm • posterior translation (hyperextension) • longitudinal - Wackenheim line does not touch the tip of the odontoid process incomplete – subluxation complete – dislocation/disassociation - joint widening on CT and joint fluid on MRI atlanto-occipital condyle distance > 5mm

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C0/1 dissociation

F/U

T2* T2 T2 T1 T2

Sub-endplate disruption with anterior CSF-cele and cord contusion

Courtesy Prof T Huisman Courtesy Prof T Huisman Lund University / Faculty of Medicine / Department of Clinical Sciences / Radiology / ECPNR/Rome/2020 Lund University / Faculty of Medicine / Department of Clinical Sciences / Radiology / ECPNR/Rome/2020 31 32

Asymmetrical dislocation Asymmetrical dislocation

CT underestimates the degree of soft tissue Vertebral bodies change shape on follow up !! injury Developing skeleton

Craniocervical distraction injury Craniocervical distraction injury

CT upon admission MRI upon admission CT sag CT sag CT cor

T1 sagT2 sag T2 cor

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Craniocervical distraction injury Craniocervical distraction injury

MRI 6 days later MRI 6 days later T1 sag T2 sag T2 cor T2 stir

Thoracic spine injuries Rotational shear fracture

• less frequent due to stabilizing rib cage

• axial forces may result in compression fractures with anterior wedging

• more frequently multiple levels involved, segments might be skipped

• most frequently T5 and T6 Oblique fracture with transverse • prognosis usually better than expected shear

Courtesy Prof T Huisman JHH 2906168 Lund University / Faculty of Medicine / Department of Clinical Sciences / Radiology / ECPNR/Rome/2020 Lund University / Faculty of Medicine / Department of Clinical Sciences / Radiology / ECPNR/Rome/2020 39 40

Chance fracture - failure of the interspinous ligaments at flexion - anterior axial loading - burst fracture of the vertebral body - widening of spinous processes in adolescent spine: - fracture line through the physeal plate (never through disc) in adult spine: - fracture line through the intervertebral disc/ vertebral body

DWI may be helpful to evaluate spinal cord integrity

Courtesy Prof T Huisman Lund University / Faculty of Medicine / Department of Clinical Sciences / Radiology / ECPNR/Rome/2020 Lund University / Faculty of Medicine / Department of Clinical Sciences / Radiology / ECPNR/Rome/2020 41 42

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Chance fracture Chance fracture

horizontal splitting of the neural arch and vertebral body • flexion-distraction of the spine • high energy MVA • often in thoracolumbar junction - transition from rigid to mobile area - change of intervertebral facet orientation (cor > sag) - going from kyphotic to lordotic

spine curve Courtesy T Huismann

T8 Chance fracture, stomach and splenic Spinal cord injury without radiographic abnormality laceration - SCIWORA -

specific to children and extremely rare in adults incidence: 19-34% of all spinal cord injuries in children more common in younger children < 8 years of age can have delayed onset of clinical symptoms and signs up to 4 days after initial injury recurrent SCIWORA several days to weeks after initial event (17%)

Spinal cord injury without radiographic abnormality Biomechanics in children - SCIWORA - The elasticity of neonatal bony spine is eight times that of the cord • immature and elastic pediatric spine • vulnerable to external forces • allows for significant inter-segmental movement • transient disc protrusion

5 6/7 cm mm compression and stretching of the spinal cord

cord injury Leventhal H. J. Pediatr 56:447 1969

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SCIWORA SCIWORA

4 month later

SCIWORA

3 year old in MVA

T1-w STIR T2-w

Ligamentous injury Tectorial membrane injury

hematoma

Meoded A, Poretti A, Singhi S, Huisman, AJNR 2010

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Ligamentous injury and retroclival hematoma

tectorial membrane

always use soft tissue algorithm (CT)

Meoded A, Poretti A, Singhi S, Huisman, AJNR 2010

Plexus injury Spectrum of injuries visualization of the nerve rootlets strongly suggests a preserved root

lack of visualization does not imply root avulsion pre-ganglionic: nerve root avulsion pseudomeningoceles are NOT pathognomonic of root avulsions post-ganglionic: conduction deficits intact roots have been shown in the presence of pseudomeningoceles

pseudomeningocele AND absent nerve rootlets best predictor of root avulsions

CT-myelography Pseudomeningoceles equal or better than standard myelography and MR imaging, especially at the C5 and C6 levels - evaluation of ventral and dorsal nerve roots - detection of intradural nerve defects

- usually filled with contrast media - appear as lateral outpouching of the thecal sac

- may lie within the spinal canal - or extend through the neural foramina

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Spondylolysis / spondylolisthesis Day 4 Plexus injury- nerve root avulsion

• decfects in pars interarticularis due to stress fracture stress reaction to isthmus (the weakest part )

• anterior or posterior displacement (slip) of a vertebra or vertebral column in relation to the vertebrae below methemoglobin • most common L5 in relation to S1 Day 14 • due to congenital defect (?), micro-trauma (sports), degenerative changes (elderly)

pseudomeningocele

Natural history and symptoms Change in contour due to -olisthes Widening of the spinal canal • majority (66%) of asymptomatic pars interarticularis defects occur before 12 years of age • only 13% become symptomatic (Fredrickson study - followed 500 kids for 20 years) • spondylolysis and -olisthesis are seen with equal frequency in asymptomatic as in symptomatic patients • the degree of forward slip is not correlated with the degree of pain or disability symptoms: low back pain worsened with activity, reduced range of motion, numbness, weakness of leg due to nerve compression

Fredrickson BE The natural history of spondylolysis.. J Bone Joint Surg 1984 Beck RW et al Radiographic anomalies … j Manipulative Physiol Ther. 2004 Libson E et al Symptomatic and asymptomatic … Int Orthop. 1982

Rt Lt Rt 15 year old boy with back pain, no known trauma, decreased football practice! Dr Annertz, Lund Lund University / Faculty of Medicine / Department of Clinical Sciences / Radiology / ECPNR/Rome/2020 Lund University / Faculty of Medicine / Department of Clinical Sciences / Radiology / ECPNR/Rome/2020 65 66

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Summary

• important to have good knowledge about • important to have good knowledge about - pediatric spine anatomy - pediatric spine anatomy - variants - variants • good quality images • good quality images • restrictive with CT in small children (radiation) •due restrictive three sets with of CTplain in X-rayssmall children (radiation) • liberal with MRI • liberal with MRI Rt Lt • high incidence of dislocations and cord injury (<10 yrs) Pseudoarthros • high incidence of dislocations and cord injury (<10 yrs) Lund University / Faculty of Medicine / Department of Clinical Sciences / Radiology / ECPNR/Rome/2020 Lund University / Faculty of Medicine / Department of Clinical Sciences / Radiology / ECPNR/Rome/2020 67 68

Summary Acknowledgement • important to have good knowledge about • Neurological recovery is more favorable in - pediatric spine anatomy children than in adults - variants Prof. Thierry Huismann for providing some images •• goodScoliosis quality following images SCI is common in children, especially if insult occurs at • restrictiveyoung age with CT in small children (radiation)

• liberal with MRI

• high incidence of dislocations and cord injury (<10 yrs) Lund University / Faculty of Medicine / Department of Clinical Sciences / Radiology / ECPNR/Rome/2020 Lund University / Faculty of Medicine / Department of Clinical Sciences / Radiology / ECPNR/Rome/2020 69 70

Thank you

Lund University / Faculty of Medicine / Department of Clinical Sciences / Radiology / ECPNR/Rome/2020 71