Clearing the Pediatric C-Spine

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Clearing the
Pediatric C-Spine
Kelly R. Millar, MD, FRCPC
Emergency Physician, Alberta Children’s Hospital
Assistant Professor, University of Calgary
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

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)

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
How common are pediatric
C-spine injuries?
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 (1988-98)
> 75,000 pediatric injuries in database

1.5% had cervical spine injury (N = 1098)


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
45
40
35
30
25
20
15
10
5
0
1
3
5
7
9 11 13 15 17 19
Age (yrs)
Do children have the same injury
patterns as adults?
NO!

Injuries differ in location and type
Why?

Developing spine has unique anatomy
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
Location of Injury
National Pediatric Trauma Registry
50
45
40
35
30
25
20
15
10
5
0
Upper C1-C4
Lower C5-C7
Patel et al
(2001)
J Ped Surg
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Age
C1 – C4 injury
Age 1- 10 yrs
Age > 10 yrs
85%
57%
Kokoska et al
(2001)
J Ped Surg



Young Child
Mature
University of Hawaii
(www.hawaii.edu/medicine/pediatrics/pemxray)
anterior
wedging of
vertebral
bodies
horizontal
alignment of
facet joints
Children prone
to anterior
dislocation
Underdeveloped neck musculature
 Ligamentous laxity


Younger children have an increased
incidence of ligamentous injury

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…
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
How common are neuro deficits?
18%
17%
c-spine only
c-spine + cord
injury
65%
SCIWORA
National Pediatric Trauma Registry:
Patel et al (2001) J Ped Surg
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

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!!

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

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

How can we protect the
pediatric C-spine?
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

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
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?
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
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
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)

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)

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

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
What about the Canadian C-Spine
Rules?

Have not been evaluated for use in
patients < 16 years
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
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

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
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 evidencebased practice
recommendations
Have to go to expert opinion
AANS Bottom Line:
Non-conversant Children

Advise obtaining images in all nonconversant children who have
“experienced trauma”

Practically, this is not what’s done in most
Canadian pediatric EDs
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
Clearing the Pediatric CSpine
PART 2: What films do I need?
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%

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 0.007 per year
per radiologist

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
13
2 – both odont # - plain
(87%) odont unobtainable
(seen on CT or MRI)
9-16 36 9 (25%) 23
2 – both odont # - 1
(65%) seen on odont / 1 on CT
 can’t r/o fracture with AP/lat alone
0-8
15 6 (40%)
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
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

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
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)
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
[N=50]
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)
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
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

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 #
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)
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
MRI ???
Flynn et al (2002) J Peds Ortho
237
Blunt c-spine trauma
163
Cleared on
plain films/CT
+ clinical assess
64
Normal Film/CT
Neck pain
Neuro abn
Non-verbal/↓LOC
15
Abnormal MRI
Needing Tx
(5 stabilized)
49
Normal MRI
10
Equivocal film / CT
10
Normal MRI
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
2.
Significant persistent neck pain
~ they may still have a significant injury, so discuss case
with referring neurosurgeon
1.


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)
Clearing the Pediatric CSpine
PART 3: Now I know what tests to do…
How do I interpret pediatric C-spine
films?

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
Alignment – Subluxation of C2/C3?
University of Hawaii
(www.hawaii.edu/medicin
e/pediatrics/pemxray)
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 (www.hawaii.edu/medicine/pediatrics/pemxray)
Bones


Wedge shaped
vertebral bodies
Ossification centres

Can appear like teardrop fractures of the
vertebral bodies
University of Hawaii
(www.hawaii.edu/medicin
e/pediatrics/pemxray)
Dens





University of Hawaii
(www.hawaii.edu/medicin
e/pediatrics/pemxray)
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 4 - 6 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
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
(www.hawaii.edu/medicine/pedia
trics/pemxray)

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
Clearing the Pediatric CSpine
PART 4: Specific injuries to watch for
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)
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
Wackenheim Clivus Line
Line from clivus should
just touch posterior
odontoid tip
The Encyclopaedia of Medical Imaging
www.amershamhealth.com
Case 2



2 yo female
High speed MVA
Closed HI (GCS 11)
Proctor (2002) Crit Care Med
C1 – C2 Subluxation

Predental space
= 8mm

Prevertabral soft
tissue swelling > ½
vertebral body
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
(www.hawaii.edu/medicine/pe
diatrics/pemxray)
Dens Fracture

Suspicious for dens
fracture:



widening of the
synchondrosis
anterior tilting of the
odontoid
(may be posteriorly
tilted in normal
children)
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
What injuries should you be
watching for in children < 8 years?
Occiput
█
C1
█
C2
█
C3-C7
~ atlanto-occipital dislocation
~ C1-C2 subluxation
~ odontoid fractures
~ ligamentous injury
References
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
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):100-105
Radiology Cases in Pediatric Emergency Medicine, University of Hawaii
(www.hawaii.edu/medicine/pediatrics/pemxray)
Laham et al: Ped Neurosurg 1994;21:221-226
Swischuk et al: Ped Radiol 2000;30:186-189
Buhs et al: J Ped Surg 2000;35(6):994-997
Ralston et al: Ped Emerg Care 2003;19(2):68-72
Ralston et al: Acad Emerg Med 2001;8(3):237-245
Keenan et al: AJR 2001;177:1405-1409
Keiper et al: Neurorad 1998;40(6):359-363
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 (www.amershamhealth.com)
Proctor: Crit Care Med 2002;30(11)
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