Imagingthe Cervical Spine

7/27/2019 Imagingthe Cervical Spine

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The CERVICAL SPINE

Imaging the Traumatized Patient

MI Zucker, MD


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A dr Z Lecture

on imaging cervical

spine trauma.

With much gratitude to

Jack Harris, MD.


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Michael I. Zucker, MD

Professor, Dept. of

Radiology

Faculty, Dept. ofEmergency Medicine

UCLA Medical Center,

David Geffen School

of Medicine at UCLA


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10,000 spinal cord injuries per

year in USA Two-thirds are cervical cord.

The monetary, physical and emotional

losses are great.

Our goal: Early detection of injuries to

prevent or decrease neurological and

mechanical damage to the spinal column.


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STABILITY: A Word or Two

We talk about it, but what is it?

A useful definition: An injury is STABLE if

putting the spinal column through normal

range of motion does not increase

neurological or mechanical deficits.


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ANTERIOR COLUMN

The anterior

longitudinal ligament,

anterior 2/3 of thebody and disc.


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MIDDLE COLUMN

Posterior longitudinal

ligament and posterior

1/3 of body and disc.


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POSTERIOR COLUMN

The posterior osseous

arch and ligaments.


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DOES IT WORK?

If two or three columns injured, lesion is

unstable: Works well for C3 to T1.

Does not work so well for C1-2, so consider

most or all injuries here unstable.


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HOW DO YOU IMAGE THE

CERVICAL SPINE?Plain films?

CT?

MRI?

A combination of modalities?

Is there a consensus?


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NO

(But were headed toward one)


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My Opinion:

O*pin*ion: A belief held with confidence,

but not substantiated by proof.


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Imaging Minor Trauma

LATERAL view from skull base through at

least the top one-half of T1. May need to

supplement with Swimmers view.

Anterior-posterior (AP)

Open Mouth Odontoid (OMO)

If patient is not in cervical collar: Adding

Oblique views is an option.


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MINOR TRAUMA: Views


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Imaging Major Blunt Trauma

Cross-table

LATERAL plain film

in Trauma Suite. CT entire cervical

spine.

MRI also in selected

cases.

If you wish, AP,OMO, and Swimmersviews also -- IF theyDO NOT cause delay.

CT: Axial sectionsbase of skull throughT1- AND- Sagittal(like a lateral) andCoronal (like AP andOMO) reformatting.


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MAJOR TRAUMA: Imaging

Cross-table Lateral in

Trauma Suite

CT Base of skullthrough T1


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Swimmers View in Major

Trauma A SUPPLEMENTARY

view to see C7-T1 inlateral projection. NOT a

substitute for a bad lateral.One arm must be elevated,so THEORETICALLYcould worsen amechanical or

neurological injury. A state-of-the-art CT

sagittal reformat ispreferable: dont need tomove patient and imaging

easier and better.


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CT

Axial sections from

base of skull through

T1. ALWAYS do the

ENTIRE cervical

spine.

DONT do selective

imaging with modern

scanners.


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CT: Sagittal Reformatting

Reconstructed by

computer from axial

data: no additionalimaging needed.

Outstanding

lateral/swimmers

imaging.


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CT: Coronal Reformatting

Excellent OMO

Excellent AP


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MRI

Gold standard for

cord, thecal sac, nerve

root and disc injuries. Very good for

ligament injuries.

Fairly good for

fractures, but does

miss some. CT much

better.


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NEUROLOGIC DEFICIT

In my view, ANY neurologic deficit,extant or transient, is MAJOR

trauma, and will need CT followed by

MRI.


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Any abnormality on Plain Films

or worrisome examination:

do CT!

Remember: Fractures often come in

2s and 3s. The more serious injurymay be the one that is occult.


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ARE THERE RISKS?

Ionizing radiation can damage cells. Younger

people are more susceptible than older people.

Their cells are more sensitive and they have longerto manifest somatic or genetic damage.

The radiation dose is significantly higher in CT

than in plain films.

As in most decisions in medicine, one must weigh

the risks versus the benefits.


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My Approach to Success in

Image Interpretation Know what to order.

Know what an optimal imaging series is and

dont accept less.

Read by check list.

Know the common lesions.

Know the commonly MISSED lesions.


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Remember: The lesions are the

SAME regardless of the imagingmodality

Plain films are still the most common

modality.

If you learn on them, you can

translate your knowledge to CT andMRI.


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PLAIN FILM Series

LATERAL

ANTERIOR-POSTERIOR (AP)

OPEN MOUTH ODONTOID (OMO)

*REVERSE WATERS

*SWIMMERS

*OBLIQUES


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THE CHECK LIST

View by view


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LATERAL view

This is your MAIN viewwhere 90% of injuries aredetected.

You MUST see T1. If notseen, do Swimmers view,unless not safe to do so.

You did lateral andSwimmers and still no

luck? DONT QUIT: DOCT! Once you start anexam you must completeit.


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LATERAL View: First Survey

Look for gross

fracture or dislocation.

Count vertebrae. Look at skull, entire

airway and adjacent

soft tissues.


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LATERAL View: Prevertebral

Soft Tissues Contour is more

important thanmeasurements:

straight or concaveanteriorly, except atlarynx.

Top normal limits: C2

6mm; C6 22mm foradult, 14mm for youngchild.


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LATERAL View: Alignment

Anterior body line.

Posterior body line.

Spino-laminar line(called posterior

cervical line at C1-3).


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LATERAL View: Alignment

Turning the lateral view HORIZONTALLY can

help detect subtle malalignment.


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LATERAL View: Spaces

Disc spaces: too wide,

too narrow, not

uniform? Facet joints: too wide,

not uniform?

Interspinous distances:

too wide, too narrow,not uniform?


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LATERAL View: C1 and C2

Basion-dens distance:

average 8mm, top

normal 12mm. C1: Anterior and

posterior arch.

C2: Dens, Harris ring,

body especially ant/infcorner, pars and

posterior arch.


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LATERAL VIEW:

Predental Space In an adult, upper

normal is 2.5mm.

Space is parallel ornarrow V shape.

In a young child,

upper normal is4.5mm.


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LATERAL VIEW: Predental

Space


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LATERAL View: C3-T1

Body: loss of straight

or concave anterior

contour, loss ofheight?

Posterior arch: subtle

cortical irregularity,

overt fracture line?


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LATERAL VIEW: Child

Vertebral bodies are bullet

shaped.

Physiologic

pseudosubluxations are

common, especially C2-4.

Predental space is wider.

Lymphoid tissue makes

soft tissues more

prominent.


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SWIMMERS View

A supplemental view

to see C7-T1.

Must raise one arm.Probably not a good

idea if neurologic

deficit, altered level of

consciousness, upperarm injury. Could

worsen an injury.


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ANTERIOR-POSTERIOR View

Look at first few ribs,

sterno-clavicle junction,

lung apices.

Contour of lateral margins

of lateral masses.

Uncovertebral joints.

Alignment and contour of

spinous processes.

Position and contour of

trachea.


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The ODONTOID Views

Open Mouth Odontoid

(OMO) is main view.

Reverse Waters view

is supplementary, to

see top half of dens

ONLY.


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OMO

C1-2 lateral mass alignment

of lateral margins.

Dens: cortical margin

irregularities, fracture

lines, tilt.

Upper body of C2 for

fracture lines.

Mach lines can be confusing.


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The INJURIES

C1 and C2: by anatomic location

C3 to T1: by mechanism of injury

(Modified from the classification of John

Harris, et al.)


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The Atlas and the Axis

C1 and C2 injuries differ from the rest of

the cervical spine and are considered

separately. Although controversial, best to consider

ALL C1 and C2 injuries as UNSTABLE in

the acute trauma setting.


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C1: Isolated Arch Fractures

Anterior arch

Posterior arch

CAUTION: You maybe dealing with a

Jefferson fracture with

occult components:

Best to CT all C1fractures.


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JEFFERSON Fracture: C1

Axial load (burst) injury

Pure (4) or variant (2 or 3)

fractures, involving both

ant. & post. arches of C1

Cord injury in 15%

Lateral view: anterior and

posterior arch fractures

OMO view: lateral

displacement of C1 lateral

masses


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JEFFERSON Fracture: C1

The lateral masses of C1and C2 must be aligned onthe OMO view.

1-2mm of lateraldisplacement on one sideand an EQUAL medialdisplacement on the otheris head rotation.

ANY other pattern: lateraldisplacement on bothsides or lateral on oneside, and none on theother is abnormal.


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JEFFERSON Fracture

CT Classical Jefferson: 4

fractures, 2 ant./2 post.

Jefferson variants: 2or 3 fractures, but at

least 1 ant. & 1 post.


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DENS Fractures

Type I: alar ligament

avulsion of the tip; rare.

Type II: the dens

excluding the tip; 2/3.

Type III: high C2 body;

1/3.

Mechanism of Type II and

III is controversial.


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TYPE II Dens Fracture

Interrupted cortical

margin, lucent fracture

line, tilt especially

anterior

Cord injury in 15%

Delayed or non-union

50+%


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TYPE III Dens Fracture

Interrupted Harris

ring, fat C2, lucent

fracture line, tilt

especially ant.

Cord injury in 15%

Heals well.


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C2: PARS Fracture

Called Hangmans or

pedicle fracture, both

wrong.

Extension injury.

Cord injury in 15%.

Non-displaced,

displaced, subluxed.


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C2: Extension Teardrop Fracture

Avulsion by the

anterior longitudinal

ligament of the

anterior-inferior

corner of the body.

Extension mechanism.

Cord injury is low.


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C3 to T1

These levels are so similar they willbe considered as a unit.

The injuries are grouped by

mechanism into families.


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FAMILY FLEXION

Motto: Anterior impaction,

posterior distraction.

Family members:Wedge compression fracture

Hyperflexion sprain

Bilateral interfacetal dislocationHyperflexion teardrop fracture-dislocation

Spinous process fracture


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Wedge Compression Fracture

Anterior-superior marginof the body is fractured.

If loss of height less than

50%, one column injuryand so stable.

If height loss greater than50%, posterior ligaments

presumed torn and so 3

column unstable injury. If 3 bodies fractured,

unstable even if less than50% height loss each.


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Flexion-Extension Films

May be helpful inligament injuries

-but are-

Frequently useless dueto muscle spasm


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MRI

Gold Standard for

spinal canal, cord, disc

lesions.

Silver Standard for

ligament injuries, but

there is no Gold and

much better than plainfilms, CT, and

flexion/extension.


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Bilateral Interfacetal Dislocation

BID, also called locked

facets is anything but

locked. It is a severe 3

column injury that iscompletely unstable.

Cord is injured in 2/3.

Body is subluxed

anteriorly at least 50%. Marked posterior

distraction.


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Hyperflexion Teardrop Fracture-

dislocation Among the worst

survivable injuries,

with nearly 100%

severe cord lesion.

Completely unstable.

Little chance of

neurologicimprovement.


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Hyperflexion Teardrop Fracture-

dislocation CT Sagittal Reformat


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Spinous Process Fracture

CT Sagittal Reformat


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FLEXION-ROTATION

Injuries

Unilateral Interfacetal Dislocation

and Fracture-dislocation


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P t i A h F t


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Posterior Arch Fractures

Plain films are insensitive,CT is outstanding.

Isolated: pedicle, lateralmass, lamina or spinous

process.

Multiple fractures arecommon. Pedicle/laminafractures cause free-floating lateral mass.

May be additional elementof lateral bending.

Stability depends on whatis fractured.


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Extension Teardrop Fracture

Avulsion fracture caused

by anterior longitudinal

ligament.

Vertical narrow fracture ofanterior-inferior corner of

body.

Most common site is C2.

Unstable.


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AXIAL Loading

Burst fracturesexplode the body.

All are very unstable

and cause cord injuryin 2/3 (except C1).

There is usually anelement of flexion

also.


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BURST Fractures

On lateral, body is

compressed anteriorly,

inferior end plate often

fractured, posterior

body contour is

convex.

On AP, body fractureis vertical or oblique

and pedicles spread.


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BURST Fractures

CT more accurately

displays the fracture

pattern and the very

important degree of

narrowing of the

spinal canal.


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REMEMBER:

CT is much more sensitive for

fractures than plain films.MRI is the standard for soft tissue

injuries.

GOODBYE AND GOOD


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GOODBYE AND GOOD

IMAGING!

Copyright 2004 M. I. Zucker

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Imagingthe Cervical Spine