1. Thoraco-Lumbar Radiography
Moritz Haager
March 4, 2004

2. Anatomy

3. Thoracic Spine

4. Lumbar Spine

5. Determinants of Stability
T & L spines are more stable than C-spine
Strong ligaments
Stabilization by ribs
Bigger intervertebral discs
Larger facet joints
Less mobility
Fractures & dislocations tend to occur where curvature changes
T11-12 (thoracolumbar junction)
L5-S1 (lumbosacral junction)

6. Mechanisms of Injury Hyperflexion +/- rotation Shearing Hyperextension
Commonest
Usually see anterior wedge #’s or Chance #
Shearing
Ant or post translation
Hyperextension
Axial loading
Compression or burst #’s

7. 3 Column Model Anterior column Middle column Posterior column
Ant longitudinal lig
Ant annulus fibrosis
Ant vertebral body
Middle column
Post longitudinal lig
Post annulus fibrosis
Post vertebral body
Posterior column
Spinous processes
Transverse processes
Lamina
Facet joints
Pedicles
Post ligamentous complex
2 or more columns disrupted = unstable
Most disruption of middle columns are unstable

8. Stable or Unstable? Radiographic findings suggestive of instability
Vertebral body collapse w/ widening of pedicles
> 33% canal compromise on CT
> 2.5 mm translation b/w vertebral bodies in any plane
Bilateral facet dislocation
Abnormal widening b/w spinous processes or lamina and > 50% anterior collapse of vertebral body

9. Stable or Unstable? Checklist for Instability
Anterior elements disrupted 2 pts
Posterior elements disrupted 2 pts
Saggital plane translation > 2.5 mm 2 pts
Saggital plane rotation > 5o 2 pts
Spinal cord or cauda equina damage 2 pts
Disruption of costovertebral articulations 1 pt
Dangerous loading anticipated 2 pts
5 or more pts unstable until healed or surgically stabilized

10. Stable or Unstable? Risk of neurologic injury increases with
> 35% canal narrowing at T11-12
> 45% canal narrowing at L1
> 55% canal narrowing at L2 & below

11. Approach to T & L Spines A – adequacy & alignment B – bones
All vertebrae need to be visible
Ant & post longitudinal lines
Facet joints should lie on smooth curve
Normal kyphosis & lordosis
All spinous processes should lie in straight line
B – bones
Trace cortical margins of each vertebrae
Difference b/w ant & post body ht < 2 mm
Progressive increase in vertebral body ht moving down spine
Wink sign & interpedicular distance
Don’t forget to look at transverse processes
Exceptions: L5-S1 disc space is narrower than above ones
TP #’s are in and of themselves stable but markers for serious intraabdominal injury in ~20% of cases

12. Approach to T & L Spines C – cartilage S –soft tissue
Progressive increase in disc space moving down spine (except L5-S1)
Facet joint alignment
S –soft tissue
Look at paraspinal stripe and prevertebral space

13. Case 1
38 yo female brought to ED after being backed over by car driven by boyfriend
Intoxicated; c/o back pain & demonstrating the remarkable versatility of the F-word

14. Transverse process fractures
of L2-4
Significance of transverse process
fractures is not the fractures in and
of themselves but rather the high
incidence of associated serious
intraabdominal injury (~20%)

15. Case 2
46 yo male presents to ED after falling 12 feet off ladder while putting up Christmas lights c/o back pain

16. Anterolisthesis
Of L4 on L5

17. CT demonstrates chronic anterolisthesis with no intrusion into
spinal canal

18. Case 3
50 yo male again foot fall off ladder while putting up Christmas lights (dangerous hobby)

19. Mild ant wedging of
T3 & T4

20. Mild ant wedging of
T3 & T4

21. Case 4
21 yo belted passenger in rollover single vehicle MVA at highway speed

22. Anterior wedging of T4 & T5 w/ loss of 30-40% of body ht
Widened paraspinal
line suggesting
hematoma
Laterally displaced
T5 pedicle
Anterior wedging of T4 & T5
w/ loss of 30-40% of body ht
CT showed stable fractures

24. Case 5 29 yo driver offroading in pick-up truck – rolls it at speed
Not belted, ejected from vehicle and trapped underneath for 3 hrs

25. Paramediastinal
soft tissue density
& widening
Suggestive of
compression
fractures

27. Case 6
22 yo male single vehicle rollover. Not restrained – ejected through windshield at highway speeds

28. Posterior displacement
Involvement of pedicles &
laminar arch
Comminution &
anterior wedging
of L2 w/ 50% loss
of body Ht

29. CT demonstrates severe burst #
w/ horizontal plane extending
posteriorly through pedicles
and transverse processes in keeping
w/ a CHANCE fracture

30. Case 7
58 yo roofer presents to ED unconscious after plunging 12 feet onto concrete through skylight

31. Schmorl’s
node
Compression fracture of L3
w/ no obvious post element
involvement