Thoraco-LumbarThoraco-Lumbar RadiographyRadiography

Moritz HaagerMoritz Haager

March 4, 2004March 4, 2004

AnatomyAnatomy

Thoracic SpineThoracic Spine

Lumbar SpineLumbar Spine

Determinants of StabilityDeterminants of Stability

T & L spines are more stable than C-spineT & L spines are more stable than C-spine Strong ligamentsStrong ligaments Stabilization by ribsStabilization by ribs Bigger intervertebral discsBigger intervertebral discs Larger facet jointsLarger facet joints Less mobilityLess mobility

Fractures & dislocations tend to occur where Fractures & dislocations tend to occur where curvature changescurvature changes T11-12 (thoracolumbar junction)T11-12 (thoracolumbar junction) L5-S1 (lumbosacral junction)L5-S1 (lumbosacral junction)

Mechanisms of InjuryMechanisms of Injury

Hyperflexion +/- rotationHyperflexion +/- rotation CommonestCommonest Usually see anterior wedge #’s or Chance #Usually see anterior wedge #’s or Chance #

ShearingShearing Ant or post translationAnt or post translation

HyperextensionHyperextension

Axial loadingAxial loading Compression or burst #’sCompression or burst #’s

3 Column Model3 Column ModelAnterior columnAnterior column

Ant longitudinal ligAnt longitudinal lig Ant annulus fibrosisAnt annulus fibrosis Ant vertebral bodyAnt vertebral body

Middle columnMiddle column Post longitudinal ligPost longitudinal lig Post annulus fibrosisPost annulus fibrosis Post vertebral bodyPost vertebral body

Posterior columnPosterior column Spinous processesSpinous processes Transverse processesTransverse processes LaminaLamina Facet jointsFacet joints PediclesPedicles Post ligamentous complexPost ligamentous complex

2 or more columns disrupted = 2 or more columns disrupted = unstableunstableMost disruption of middle columns are Most disruption of middle columns are unstableunstable

Stable or Unstable?Stable or Unstable?

Radiographic findings suggestive of instabilityRadiographic findings suggestive of instability Vertebral body collapse w/ widening of pediclesVertebral body collapse w/ widening of pedicles > 33% canal compromise on CT> 33% canal compromise on CT > 2.5 mm translation b/w vertebral bodies in any > 2.5 mm translation b/w vertebral bodies in any

planeplane Bilateral facet dislocationBilateral facet dislocation Abnormal widening b/w spinous processes or lamina Abnormal widening b/w spinous processes or lamina

and > 50% anterior collapse of vertebral bodyand > 50% anterior collapse of vertebral body

Stable or Unstable?Stable or Unstable?

Checklist for InstabilityChecklist for Instability Anterior elements disruptedAnterior elements disrupted 2 pts2 pts Posterior elements disruptedPosterior elements disrupted 2 pts2 pts Saggital plane translation > 2.5 mmSaggital plane translation > 2.5 mm 2 pts2 pts Saggital plane rotation > 5Saggital plane rotation > 5oo 2 pts2 pts Spinal cord or cauda equina damageSpinal cord or cauda equina damage 2 pts2 pts Disruption of costovertebral articulationsDisruption of costovertebral articulations 1 pt1 pt Dangerous loading anticipatedDangerous loading anticipated 2 pts2 pts

5 or more pts unstable until healed or surgically 5 or more pts unstable until healed or surgically stabilizedstabilized

Stable or Unstable?Stable or Unstable?

Risk of neurologic Risk of neurologic injury increases withinjury increases with > 35% canal narrowing > 35% canal narrowing

at T11-12at T11-12 > 45% canal narrowing > 45% canal narrowing

at L1at L1 > 55% canal narrowing > 55% canal narrowing

at L2 & belowat L2 & below

Approach to T & L SpinesApproach to T & L Spines

A – adequacy & alignmentA – adequacy & alignment All vertebrae need to be visibleAll vertebrae need to be visible Ant & post longitudinal linesAnt & post longitudinal lines Facet joints should lie on smooth curveFacet joints should lie on smooth curve Normal kyphosis & lordosisNormal kyphosis & lordosis All spinous processes should lie in straight lineAll spinous processes should lie in straight line

B – bonesB – bones Trace cortical margins of each vertebraeTrace cortical margins of each vertebrae Difference b/w ant & post body ht Difference b/w ant & post body ht << 2 mm 2 mm Progressive increase in vertebral body ht moving Progressive increase in vertebral body ht moving

down spinedown spine Wink sign & interpedicular distanceWink sign & interpedicular distance Don’t forget to look at transverse processesDon’t forget to look at transverse processes

Approach to T & L SpinesApproach to T & L Spines

C – cartilageC – cartilage Progressive increase in disc space moving Progressive increase in disc space moving

down spine (except L5-S1)down spine (except L5-S1) Facet joint alignmentFacet joint alignment

S –soft tissueS –soft tissue Look at paraspinal stripe and prevertebral Look at paraspinal stripe and prevertebral

spacespace

Case 1Case 1

38 yo female brought to ED after being 38 yo female brought to ED after being backed over by car driven by boyfriendbacked over by car driven by boyfriend

Intoxicated; c/o back pain & demonstrating Intoxicated; c/o back pain & demonstrating the remarkable versatility of the F-wordthe remarkable versatility of the F-word

Transverse process fracturesof L2-4

Significance of transverse processfractures is not the fractures in andof themselves but rather the high incidence of associated seriousintraabdominal injury (~20%)

Case 2Case 2

46 yo male presents to ED after falling 12 46 yo male presents to ED after falling 12 feet off ladder while putting up Christmas feet off ladder while putting up Christmas lights c/o back painlights c/o back pain

AnterolisthesisOf L4 on L5

CT demonstrates chronic anterolisthesis with no intrusion into spinal canal

Case 3Case 3

50 yo male again 10-12 foot fall off ladder 50 yo male again 10-12 foot fall off ladder while putting up Christmas lights while putting up Christmas lights (dangerous hobby)(dangerous hobby)

Mild ant wedging ofT3 & T4

Mild ant wedging ofT3 & T4

Case 4Case 4

21 yo belted passenger in rollover single 21 yo belted passenger in rollover single vehicle MVA at highway speedvehicle MVA at highway speed

Widened paraspinalline suggestinghematoma

Laterally displacedT5 pedicle

Anterior wedging of T4 & T5w/ loss of 30-40% of body ht

Case 5Case 5

29 yo driver offroading in pick-up truck – 29 yo driver offroading in pick-up truck – rolls it at speedrolls it at speed

Not belted, ejected from vehicle and Not belted, ejected from vehicle and trapped underneath for 3 hrstrapped underneath for 3 hrs

Paramediastinalsoft tissue density & widening

Suggestive ofcompression fractures

Case 6Case 6

22 yo male single vehicle rollover. Not 22 yo male single vehicle rollover. Not restrained – ejected through windshield at restrained – ejected through windshield at highway speedshighway speeds

Comminution & anterior wedgingof L2 w/ 50% loss of body Ht

Posterior displacement

Involvement of pedicles & laminar arch

CT demonstrates severe burst #w/ horizontal plane extending posteriorly through pediclesand transverse processes in keepingw/ a CHANCE fracture

Case 7Case 7

58 yo roofer presents to ED unconscious 58 yo roofer presents to ED unconscious after plunging 12 feet onto concrete after plunging 12 feet onto concrete through skylightthrough skylight

Schmorl’s node

Compression fracture of L3w/ no obvious post elementinvolvement