In acute trauma,
CT is the most useful technique for high risk patients; thus,
CT rather than cervical plain films should be the technique of choice.
CT can also be useful in follow-up.
With the appropriate protocol and post-processing,
MDCT improves the recognition,
characterisation,
and classification of traumatic cervical lesions for determining the appropriate treatment.
Contrast agents can be administered in the same study to rule out damage to cervical arteries.
MRI provides essential additional information in spinal cord and ligament injuries.
For follow-up,
plain films are still widely used.
CT,
and/or MRI can be used to complete the study.
Fig.
1
Fig. 1 |
1. ANATOMY
Craniocervical juntion is composed by:
-bones: occipital bone condyles,
atlas (anterior and posterior arch with no body) and axis (large body and superiorly projecting odontoid process)
-joints: atlantooccipital,
median and lateral atlanto-axial joints
-ligaments (anterior to posterior): anterior atlanto-occipital membrane,
odontoid ligaments apical and alar,
cruciate ligaments,
tectorial membrane and posterior atlanto-occipital membrane
Anatomic/funtional landmarks:
-Spine has and excellent continent/ content relation (1/3)
-Vertebral arteries are very resistant because of their elasticity
-Transverse ligament is the most important ligament in mantaining stability
Fig.
2-3
Fig. 2
Fig. 3
2.
CLINICAL SETTING
a) Low risk patient.
How to avoid the overuse of imaging?
Classifications like the Nexus or Canadian C-Spine Rule help determine whether plain films/CT are indicated.
They avoid excessive irradiation and reduce costs,
so they are progressively being included in clinical guidelines.
Fig.
4
Fig. 4
b) All multiple trauma patients in our center--> Body CT.
When are patients considered multiple trauma patients?
Fig.
5
Fig. 5
3- TECHNIQUE
Plain films :
-Odontoid projection: Anteroposterior,
mouth open as wide as possible.
Correct examination must show the atlas,
axis,
and atlantoaxial articulation.
-Lateral projection: Strict lateral.
Correct examination must show all the cervical vertebrae without rotation; the atlas and odontoid process must be clearly shown.
Variants: hyperflexion and hyperextension.
CT:
Sagittal and coronal reconstructions are necessary for correct assessment.
Traumatic cervical lesions suspected in a non polytraumatic patient can be ruled out by non-contrast CT.
All multiple trauma patients should be screened with contrast-enhanced body CT using cervical reconstruction with bone filter.
-Cervical CT: From the foramen magnum to T2.
Standard acquisition with bone filter (C or D) and high matrix.
Optionally,
arterial phase CT angiography images can be obtained .
-Body CT with cervical reconstruction: Two acquisitions: a) non-enhanced cranial CT,
b) contrast-enhanced CT from skull base to pelvis.
50-second delay.
For cervical reconstruction,
a higher matrix and bone filter is used.
MRI
Sagittal T1-weighted // Sagittal T2-weighted TSE / short-inversion-time inversion recovery (STIR)// axial spin-echo T1- and T2-weighted sequences.
Additional sequences in the neck to rule out arterial damage: Contrast-enhanced arterial study / Axial fat-suppression T1 and STIR.
4.
CLASSIFICATION OF LESIONS AND THEIR TREATMENT
Classification is essential to characterise the lesion and determine the best treatment for every patient.
Sometimes detection and classification are difficult due to multiple associated fractures.
Classification of traumatic occipitoatlantoaxial lesions by anatomical location
Atlantooccipital luxation
Traynelis,
1986
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Type I,
anterior displacement of atlas masses
Type II,
longitudinal occipitoatlantal displacement
Type III,
posterior displacement of atlas masses
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Occipital condyle fractures
Anderson & Montesano 1988
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Type I,
isolated fracture of occipital condyle
Type II,
condyle fracture with extension to clivus or occipital bone
Type III,
condyle avulsion
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Atlantoaxoid rotatory luxation
Fielding & Hawkins 1977
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Type I, anterior rotation of atlas mass
Type II,
rotation or anterior luxation of an atlas mass >3mm.
Type III,
anterior luxation of both atlas masses >5 mm.
Tipo IV,
posterior luxation of one or two atlas masses
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Isolated rupture of transverse ligament of atlas
Dickman,
1996
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Type I,
medial rupture of transverse ligament of atlas
Type II,
fracture or detachment of insertion tubercle from transverse ligament to atlas
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Atlas fractures.
Jefferson,
1920
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Type a,
unilateral or bilateral fracture of anterior arch
Type b,
unilateral or bilateral fracture of posterior arch
Type c,
simple fracture of an atlas lateral mass
Type d,
comminute fracture of an atlas lateral mass
Type e,
bilateral fracture of anterior and posterior arches (Jefferson fracture)
Type f,
linear or crossed fractures of anterior and posterior arches
Type g,
isolated rupture of transverse ligament of atlas
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Odontoid fractures.
Martín-Ferrer,
1997
D´Alonzo,
1974
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Apex fracture
Basis fracture
I,
Apex
II,
Basis
III,
Fracture extends through the body of the axis
|
Axial pedicles of axis.
Levine-Effendi & Edwards,
1985
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Type I,
< 3mm displacement with no angulation of C2-C3
Type II,
> 3 mm displacement and angulation
C2-C3 < 11º
Type IIa,
> 3mm of separation and angulation C2-C3 > 11º
Type III,
total luxation C2-C3 (hangman’s fracture)
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Axis body fractures.
Benzel,
1994
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Type I,
coronal fracture
Type II,
sagittal fracture
Type III, transverse fracture
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Chronic fractures (multiple possibilities)
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Associated fractures (multiple combinations)
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Others
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Marginal fractures of axis body,
laminas,
facets or spinous apophysis of axis,
transverse apophysis of atlas or axis
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Most frequent lesions.
In order of frequency
Fig.
6
Fig. 6
When surgery is indicated,
it aims to liberate neurological structures and maintain stability,
align vertebral segments,
stabilize vertebral elements,
prevent lesions from developing,
and permit maximal functional recovery.
In cases with associated fractures,
every treatment indication should be evaluated separately.
Most frequent pathologies and their treatment.
Fig.
7
Fig. 7
Most frequently used surgical techniques.
Fig.8
Fig. 8
5.
PRACTICAL CASES
1.
Quiz cases.
"Classification of traumatic occipitoatlantoaxial lesions by anatomical location" table above might help you.
2. See description and evolution of patient.
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