1. Clearing the Pediatric C-Spine
Kelly R. Millar, MD, FRCPC
Emergency Physician, Alberta Children’s Hospital
Assistant Professor, University of Calgary

2. Overview Epidemiology Anatomic considerations
Clearing the pediatric c-spine
Who needs imaging?
What films should be ordered?
Who needs a CT/MRI?
Interpretation of Pediatric c-spine films
Cases

3. Epidemiology of Pediatric Cervical Spine Injury
5% of all spinal cord injuries occur in children
1000 pediatric spinal cord injuries in the US each year
80% of spinal injuries in children < 8 yrs are cervical (vs 30-40% in adults)

4. Epidemiology Many small case series
Often include up to age 20, so data very skewed to older “children”
2 recent large pediatric data sources have fair number of younger children:
The largest prospective series is the pediatric subset of the NEXUS trial
The largest retrospective series comes from the National Pediatric Trauma Registry

5. How common are pediatric C-spine injuries?

6. National Pediatric Trauma Registry
Prospective, multi-center database
Includes ages 0-20
Primary diagnosis traumatic injury
Patel et al (2001) J Ped Surg
10 yr review ( )
> 75,000 pediatric injuries in database
1.5% had cervical spine injury (N = 1098)

7. National Pediatric Trauma Registry Kokoska et al (2001) J Ped Surg
6 year review of same database
1994 – 99
Age distribution of
c-spine injuries →
Younger age groups well represented
Age (yrs)

8. Do children have the same injury patterns as adults?
NO!
Injuries differ in location and type
Why?
Developing spine has unique anatomy

9. Anatomic Considerations
Large head
Torque and acceleration stress occur higher in the c-spine
Fulcrum of motion C2-C3 in young children (vs C5-C6 in adults)
Younger children have an increased incidence of high C-spine injury

10. Location of Injury National Pediatric Trauma Registry
Patel et al
(2001)
J Ped Surg
Age
Age yrs
Age > 10 yrs
C1 – C4 injury
85%
57%
Kokoska et al
(2001)
J Ped Surg

11. anterior wedging of vertebral bodies
horizontal alignment of facet joints
Children prone to anterior dislocation
Young Child
Mature
University of Hawaii (

12. Underdeveloped neck musculature
Ligamentous laxity
Younger children have an increased incidence of ligamentous injury

13. Believed that the laxity of the peds spine acts to protect against spinal fracture in low energy trauma, however, may lead to SCIWORA in high-energy trauma
More on SCIWORA in a moment…

14. Type of injury Age 1- 10 yrs Age > 10 yrs Fractures 42% 65%
Dislocations
31%
20%
SCIWORA
27%
15%
National Pediatric Trauma Registry:
Kokoska et al (2001) J Ped Surg

15. How common are neuro deficits?
National Pediatric Trauma Registry: Patel et al (2001) J Ped Surg

16. What is SCIWORA?
Def: Spinal cord injury without radiographic abnormality on plain film or CT
Mechanism: transient vertebral displacement with subsequent realignment resulting in damaged spinal cord and normal appearing vertebral column
Young spinal column can stretch up to 5cm
Spinal cord ruptures after 5mm of traction

17. SCIWORA How common is it?
Literature extremely inconsistent with definition and incidence
Reported as 0-50% of peds spinal cord injuries
National Pediatric Trauma Registry: 17%
NEXUS: none!!

18. SCIWORA – case series Common themes:
Up to half may have delayed onset of symptoms (usually within 48 hrs)
SCI can be severe
Chance of recovery low if complete
May be related to spinal cord infarction

19. Epidemiology: Bottom Line
C-spine injuries in children are rare, but they do occur in about 1.5% of blunt trauma patients
In young children, be on look out for:
High c-spine injury
Ligamentous injury

20. How can we protect the pediatric C-spine?

21. Begins in Prehospital Setting: Immobilization
Aim for “neutral position”
Big head
When laying flat on backboard, neck is flexed
Must accommodate large occiput, using either an occipital depression or padding under the torso

22. Immobilization
Best immobilization achieved by modified spine board, rigid collar and taping
Too large a collar can distract the neck and worsen an injury – blocks are preferable to a poorly fitting collar

23. OK… Now the collar’s on… How do I get it off?
Challenges:
Preverbal or crying children:
Difficult to assess tenderness
Difficult to perform detailed neurologic exam
Questions:
Who needs imaging?
What type of imaging is needed?
When do I need a CT or MRI?

24. Clearing the Pediatric C-Spine PART 1: Who needs imaging?
Is there any pediatric evidence?
1 prospective study
Peds subset of NEXUS – Viccellio et al
1 retrospective study
Isolated head injuries – Laham et al

25. Imaging – Peds subset of NEXUS Viccellio et al (2001) Pediatrics
Prospective study of patients with blunt trauma + cervical spine radiography
Used 5 low-risk criteria:
No midline cervical tenderness
No evidence of intoxication
No altered level of consciousness
No focal neurological deficit
No painful distracting injury
If all 5 criteria met – considered low risk

26. NEXUS – peds subset 3065 patients < 18 years (9% of NEXUS)
Total # c-spine injuries: 30
603 / 3065 considered “low risk” (20%)
All low risk patients had negative radiographic evaluations (100% sensitive)

27. NEXUS – peds subset
Problem: Numbers are small, so 95% CI for sensitivity: 87.8% - 100%
Problem: Very few injuries in younger kids
Grouped as follows:
0-2 (lack of verbal skills) N = 88 (0)
3-8 (immature cervical spine) N = 817 (4)
9-17 (older children) N = 2150 (26)

28. NEXUS – peds subset Bottom line:
Authors “cautiously endorse” the use of the NEXUS criteria in children over age 8
Not enough power to ensure that the tool is safe to use in younger children
However, authors state that there is not a single case in the medical literature of a child with a c-spine injury who would have been classified as low risk using NEXUS

29. Laham et al (1994) Ped Neurosurg
Retrospective review of 268 children with apparent isolated HI
2 high risk criteria = incapable of verbal communication (due to age or HI) and neck pain
Did x-rays in all kids
No abnormal x-rays in low risk group
7.5% abnormal in high risk group
Authors concluded: In isolated HI with no neuro deficits, no x-rays needed if child can communicate and has no neck pain

30. What about the Canadian C-Spine Rules?
Have not been evaluated for use in patients < 16 years

31. Are there any consensus statements or guidelines?
American Association of Neurosurgeons (Guidelines committee of the section on disorders of the spine) [AANS]
Management of Pediatric Cervical Spine and Spinal Cord Injuries
Neurosurgery 2002;50(3) March supp
Guidelines based on available evidence and expert opinion

32. AANS Bottom Line: Children > 8 years
Evidence supports the use of NEXUS criteria:
Image if any one of:
Midline tenderness
Focal neurological deficit
Altered level of consciousness
Evidence of intoxication
Painful distracting injury

33. AANS Bottom Line: Children 8 years and under who are conversant
Although evidence is lacking, expert opinion supports the use of the NEXUS criteria
Given lack of evidence, and possible communication barriers in young children, it would be reasonable to consider imaging in high risk mechanisms:
high speed MVC
fall > 8 ft
axial load injury

34. What should we do with infants?
NEXUS – 88 patients < 2 yo – no injuries
NPTR – children < 2 yo : ~ 8 injuries per yr
No studies with large enough numbers to generate evidence-based practice recommendations
Have to go to expert opinion

35. AANS Bottom Line: Non-conversant Children
Advise obtaining images in all non-conversant children who have “experienced trauma”
Practically, this is not what’s done in most Canadian pediatric EDs

36. What should we do with infants?
See them quickly
Assess for altered LOC, neuro deficit, distracting injury
If no injury apparent, remove immobilization equipment in protected environment
Observe for spontaneous movement of neck
Most small children will “clinically clear” themselves

37. Clearing the Pediatric C-Spine
PART 2: What films do I need?

38. General agreement that a lateral and AP c-spine film are necessary
The sensitivity of the lateral film alone in peds is comparable to the adult literature ~85%

39. Odontoid views? Many authors have questioned the need
Swischuk surveyed 984 pediatric radiologists (432 responses)
Obtained reports of 46 pediatric fractures that were missed on lateral view and seen on odontoid view
Calculated a miss rate of per year per radiologist

40. Odontoid views?
Buhs et al (2000) J Ped Surg - Retrospective review of all c-spine injuries in children< 16 yrs over 10 year period at 4 Detroit trauma centres
AGE N
Occ/C1/2
Lat/AP
Missed occip – C2
0-8 15
6 (40%)
13 (87%)
2 – both odont # - plain odont unobtainable (seen on CT or MRI)
9-16 36
9 (25%)
23 (65%)
2 – both odont # - 1 seen on odont / 1 on CT
can’t r/o fracture with AP/lat alone

41. But odontoid views are hard to get in young children!!!
Consider:
0-3 years: 50% of injuries are at C1 / C2 level
4-12 years: 8% of injuries are at C1 / C2 level
Bottom line: If you are worried enough to image the c-spine, you need to get a good look at C1 / C2
~need odontoid view or CT

42. Oblique views? Ralston et al (2003) Ped Emerg Care:
Blinded retrospective review (8 year period)
Blunt trauma patients ≤16 yrs
AP/Lat + oblique views
N = 109

43. Oblique views? All with normal AP/Lat had normal obliques (N = 78)
If AP/Lat normal, obliques unlikely to add additional information
4 obliques resulted in revision of impression:
3 from equivocal to normal
1 from equivocal to abnormal (final dx = no injury)
May be of assistance in equivocal situation

44. Flexion-Extension views? Ralston et al (2001) Acad Emerg Med
Blinded retrospective review (6 year period)
Blunt trauma patients ≤16 yrs
AP/Lat (+ odont in 83%) + flex/ex views
N = 129
45 patients had initial AP/Lat read as normal – all had normal flex/ex views (no revision of impressions)
If primary series is normal…flex/ex views do not add info
84 patients had initial AP/Lat read as abnormal (including loss of lordosis -79 had revision of impression)

45. Revision of Impressions
Impression After Lat/AP
Impression After Lat/AP + Flex/ex
Final Diagnosis (considering CT, MRI, clinical)
Loss of lordosis
[N=50]
Normal
SCIWORA (2)
Ligament injury (2)
Disc injury (1)
Subluxation ? or
Segmental kyphosis
[N=22]
+ Subluxation (3)
Ligamentous injury (2)
Normal (19)
Fracture (1)
Soft Tissue Swelling [N=5]
Normal (5)

46. Flexion-Extension views?
Normal flex-ex views do not rule out an injury
If plain films worrisome, more sensitive modalities are warranted (CT +/- MRI)
May consider flex-ex after to look for major instability
If the concern is significant pain despite normal plain films, quality of flex-ex view likely limited due to pain and they cannot be used to “rule out” an injury

47. To CT or not to CT….
Routinely used in adults trauma patients to examine c-spine
There are significant concerns that exposing children to CT radiation may lead to an increased lifetime risk of cancer
Try to be much more selective with the use of CT in children
Limit scans to specific areas of interest

48. Indications for CT Valuable for:
Defining anatomy in regions where an abnormality is suspected on plain film
Viewing regions not visualized on plain film
ie – skullbase to C3 in intubated patient
Remember: a large proportion of young children with c-spine injury will have an isolated ligamentous injury, a normal CT cannot be used to exclude a c-spine injury
CT can miss odontoid #

49. Evidence for early CT? Keenan et al (2001) AJR
Retrospective study of 63 kids
Head injury + C-spine plain films
21/63 had early CT c-spine with initial head CT
42/63 had plain films alone - often repeat attempts
Analyzed multiple patient factors + total radiation dose received in process of imaging c-spine
Found kids in high speed MVC with GCS <8 had same radiation with repeated plain films as with early CT (new generation, helical CT with recons)

50. How about MRI ??? Keiper et al (1998) Neurorad
Retrospective case review
Children with hx of blunt c-spine trauma
Normal plain films + normal CT
One of:
Persistent or delayed neuro symptoms
Persistent significant neck pain
N = 52
MRI abnormal in 16/52 (31%)
4 went on to operative management

51. MRI ??? Flynn et al (2002) J Peds Ortho

52. What do these MRI studies mean for me? (…I can’t just order an MRI!)
In children with normal plain films and normal CT who have either:
Neurologic deficit
Significant persistent neck pain
~ they may still have a significant injury, so discuss case with referring neurosurgeon
Those with neuro deficits likely need urgent MRI
Those with ++ pain may benefit from one or more of Aspen collar, outpatient MRI, and neurosurg follow-up (at discretion of neurosx)

53. Clearing the Pediatric C-Spine
PART 3: Now I know what tests to do… How do I interpret pediatric C-spine films?

54. Follow same general approach as in adult c-spine films:
A – alignment
B – bones
C – cartilage
D – dens
S – soft tissues
Are some unique features in children that are important to recognize

55. Alignment – Subluxation of C2/C3?
University of Hawaii (

56. Alignment - Pseudosubluxation
24% C2 on C3
14% C3 on C4
(Age <7 years)
Swischuk’s line: posterior arch of C1 to C3 – should come within 1 mm of post arch of C2
University of Hawaii (

57. Bones Wedge shaped vertebral bodies Ossification centres
Can appear like tear-drop fractures of the vertebral bodies
University of Hawaii (

58. Dens Predental space – allow up to 5 mm in young children
Subdental synchondrosis - lucency at base of dens
Dens fuses with body of C2 between ages years
A thin lucency may be appreciable on the lateral view for many years (50% up to age 11)
May have ossification centre at tip of dens
University of Hawaii (

59. Prevertebral Soft Tissues
Allowable thickness changes with age
In general:
Above glottis:
½ vertebral body
Below glottis:
1 vertebral body
Often falsely thickened 2° to neck flexion (big occiput) or expiration
University of Hawaii (

60. Radiographically, most of the adult characteristics are present by age 8
Characteristics of peds c-spine injuries trend towards that of adults at about age 8-10 years
not equal to adults until about 15 years

61. Clearing the Pediatric C-Spine
PART 4: Specific injuries to watch for

62. Case 1 5 yo girl Hit by car while riding bike VSA at scene
Vitals recovered by EMS
Rose et al, Am J Surg 2003;185(4)

63. Atlanto-Occipital Dislocation
2.5 x more common in children than adults
Due to small occipital condyles and horizontal atlanto-occipital joints
Suspect if distance between occipital condyles and C1 is > 5mm at any point
Usually have ++ soft tissue swelling

64. Wackenheim Clivus Line
Line from clivus should
just touch posterior odontoid tip
The Encyclopaedia of Medical Imaging

65. Case 2 2 yo female High speed MVA Closed HI (GCS 11)
Proctor (2002) Crit Care Med

66. C1 – C2 Subluxation Predental space = 8mm
Prevertabral soft tissue swelling > ½ vertebral body

67. Case 3 3 yo male Fell out of barn loft Alert, crying but consolable
Says his head hurts
Makes no attempt to voluntarily move neck
University of Hawaii (

68. Dens Fracture Suspicious for dens fracture:
widening of the synchondrosis
anterior tilting of the odontoid
(may be posteriorly tilted in normal children)

69. Dens Fracture
Often lack neuro symptoms as spinal canal is wide at that level
Most common symptoms:
Occipital pain (injury to greater occipital nerve)
Refusal to extend neck
Believed to have high miss rate – can lead to chronic problems

70. What injuries should you be watching for in children < 8 years?
Occiput
█ ~ atlanto-occipital dislocation C1
█ ~ C1-C2 subluxation
C2 ~ odontoid fractures █
C3-C7 ~ ligamentous injury

71. References Patel et al: J Ped Surg 2001;36(2):373-376
Viccellio et al: Pediatrics 2001;108(2):e20
Kokoska et al: J Ped Surg 2001;36(1):
Radiology Cases in Pediatric Emergency Medicine, University of Hawaii (
Laham et al: Ped Neurosurg 1994;21:
Swischuk et al: Ped Radiol 2000;30:
Buhs et al: J Ped Surg 2000;35(6):
Ralston et al: Ped Emerg Care 2003;19(2):68-72
Ralston et al: Acad Emerg Med 2001;8(3):
Keenan et al: AJR 2001;177:
Keiper et al: Neurorad 1998;40(6):
Dare et al J: Neurosurg 2002;97(suppl 1):33-39
Rose et al, Am J Surg 2003;185(4)
The Encyclopaedia of Medical Imaging (
Proctor: Crit Care Med 2002;30(11)