Download Craniocervical Junction Injury

Critical Imaging Findings of
Craniocervical Junction Injuries
for the In-Training Resident
Patrick Sanchez, Duy Bui
ASNR 2016 Annual Meeting
UC Davis Medical Center
Presentation ID 2250
Disclosures

I have no relevant financial disclosures to report.
Purpose

The purpose of this educational exhibit is to provide a focused review of the
anatomy, mechanisms of injury, and imaging findings of craniocervical
junction injuries. An emphasis will be placed on direct and indirect imaging
findings critical for the in-training resident to recognize.
Significance

The craniocervical junction (CCJ) is critical for maintaining cervical spine
stability

Nearly 1/3 of all cervical spine injuries involve the CCJ

Findings are often radiographically dramatic however may be subtle

Injuries often portend substantial morbidity but are potentially survivable

Primary imaging modalities include CT and MR
Basic Anatomy- Bones
Middle Atlantoaxial Joint
Atlanto-occipital Joint
Lateral Atlantoaxial Joint
Middle
Atlantoaxial
joint
Lateral
Atlantoaxial
joints
Atlanto-Occipital
joint
Anterior
arch
ofofC1C1
odontoid
process
Lateral
masses
C2 surface
Occipital
condyles
totoand
superior
of C1
FunctionRotation
Lateral flexion
lateral masses
Most
mobile
portion of cervical spine
FunctionFlexion/Extension
Middle Atlantoaxial Joint
Atlanto-occipital Joint
Lateral Atlantoaxial Joint
Anatomy- Ligaments

Ligamentous structures provide a bulk of CCJ stabilization

The transverse/alar ligaments and tectorial membrane are the most important stabilizers

Ligamentous structures can be divided into those intrinsic to the CCJ and additional extrinsic supporting
structures


Intrinsic
 Odontoid ligaments (apical, alar)
 Cruciate ligaments (transverse, superior/inferior crura)
 Anterior/Posterior longitudinal ligaments
 Tectorial membrane
Extrinsic
 Nuchal ligament
 Ligamentum flavum
 Anterior and posterior atlanto-occipital membranes
Apical Ligament- Joins the apex
of the dens to the anterior
margin of the foramen
magnum. Along with alar
ligaments limits axial rotation of
the CCJ.
Tectorial Membrane- Superior extension of
posterior longitudinal ligament. Attaches
from posterior C2 body to anterior foramen
magnum. Limits excessive extension.
Basic Anatomy- Ligaments
Apical Ligament
Anterior
Longitudinal
Ligament
Tectorial Membrane
Posterior Atlantooccipital Membrane
Atlanto-occipital Joint Capsule
Lateral
Atlantoaxial Joint
Capsule
Posterior Longitudinal
Ligament
Ligamentum Flavum
Anterior Longitudinal LigamentTraverses the anterior vertebral bodies
extending from the C1 anterior tubercle
downward.
Alar Ligaments
Alar- paired ligaments
which attach the
posterolateral dens to the
medial occipital condyles.
Limits excessive rotation
and lateral flexion.
Occipital Condyles
C1 Lateral Masses
Transverse Ligament
Transverse Ligamentattaches to lateral masses
of C1 and posterior aspect
of odontoid process.
Divides C1 arch into
anterior and posterior
compartments. Allows
axial rotation.
Odontoid Process
Transverse Ligament
Lateral Mass C2
Diagnostic Evaluation

CT – Initial imaging modality of choice. Evaluation of bony injury and limited
evaluation of soft tissues.


Indicated in the setting of trauma with focal neurologic deficit, c-spine tenderness,
altered consciousness, intoxication, or distracting injury
MR – Evaluation of soft tissue and ligamentous injury, spinal cord compression





Guidelines for utilization are less clear
Often at discretion of treating physician
Common indications include high energy trauma, unreliable neurologic exam, +/- CCJ
anomaly on CT
Patients whose neurologic status cannot be evaluated within 48hrs of injury
Treatment planning for unstable cervical spine
Injury Patterns

Bone fractures


Ligament disruption




Potential to heal with conservative treatment
Potentially unstable, may require surgery
Often the result of rotational and shearing forces
Can be disrupted by fracture near attachment sites, avulsion injuries, or intrasubstance
tears
Combination

Most injuries at the CCJ are a combination of both
Following will be a series of examples of bone and ligamentous injuries of the CCJ.
Grade 2 Occipital Condylar Fracture
Anderson and Montesano described 3 types of occipital condyle fracture based on
morphology and injury mechanism.
Grade 1- Compression fracture with impaction
Grade
3 Occipital
Condylar
Avulsion
Fractures
Grade 2- Linear condyle
fracture.
Associated
with
direct blow.
Grade 3- Avulsion injury. Secondary to rotational injury.
Implies injury of alar ligament
Often requires surgical intervention
Atlas C1 Arch Fracture
AKA Jefferson Fracture
Classically from an axial loading
along the axis of the cervical
spine although it can also occur
secondary to hyperextension or
flexion injuries.
Anterior/Posterior arch are
weakest links.
Sometimes associated with
transverse ligament injury.
Type 1 Odontoid Fractures
3 subtypes have been described based on the
fracture site.
The mechanism of injury is variable.
Type 1- Avulsion fracture from tip of the dens at
insertion of alar ligaments
Type 2- Fracture at base of dens or above
junction with body
Often requires surgery
Type 3- Fracture extends into body of atlas
Type 2 Dens Fracture
Type 3 Dens Fracture
Cases
We will now exam 3 separate cases demonstrating a combination of bone and
ligament injuries at the CCJ.
1.
Complex CCJ Ligamentous Injury
2.
Pediatric CCJ Dissociation Injury
3.
Atlanto-occipital Subluxation Injury
1. Complex CCJ Ligamentous Injury
Coronal CT scan demonstrates Type 3
occipital condyle avulsion fractures.
There are associated paired apical
ligament tears on this coronal proton
density MR image.
The Sagittal T2 MR image demonstrates several additional midline ligament disruptions.
Partial tectorial membrane tear
Anterior longitudinal
ligament complex tear
Ligament disruptions contribute
to an acute spinal cord
compression.
2. Pediatric CCJ Dissociation Injury
Sagittal CT images demonstrate
vertical widening of the atlantooccipital and lateral atlantoaxial
joints without fracture.
The apical ligament is torn and there is
stripping of the tectorial membrane
from the clivus.
Sagittal T2 weighted MR images confirm
atlanto-occipital and atlantoaxial joint
space widening with fluid in the joint
spaces.
Disruption of the anterior
Coronal proton density images
longitudinal ligament complex.
demonstrate a right alar ligament tear.
3. Atlanto-occipital Subluxation
Sagittal CT images demonstrate
widening of the atlanto-occipital
joints with anterior displacement
of the occipital condyles to C1
lateral masses. There is an
associated occipital condyle
fracture and fracture through the
C1 anterior arch.
Sagittal T2 and Axial proton density MR images
demonstrate additional ligamentous injuries which
could not be seen on the CT.
Thinning and partial disruption of the tectorial membrane.
Disruption of the anterior longitudinal ligament complex.
Bilateral alar ligament tears
associated with occipital
condylar displacement and
fractures.
The patient survived and was subsequently treated with an occipital to C2 fusion as
seen on this Sagittal CT image.
Take Away Points

CCJ injuries are now more commonly imaged as injury management in the
field has improved.

Understanding normal anatomy of the CCJ is critical to describe injury
patterns.

CT exams may demonstrate only some of the injuries and MRI is crucial to
fully evaluating the soft tissue and ligamentous structures.

Understanding common injury patterns aids in the recognition and diagnosis
of additional injuries.
References

Riascos R, Bonfante E, Cotes C, et al. Imaging of Atlanto-Occipital and Atlantoaxial Traumatic Injuries: What
the Radiologist Needs to Know. Radiographics 2015;35:2121-2134

Joaquim AF, Patel AA. Craniocervical Traumatic Injuries: Evaluation and Surgical Decision Making. Global
Spine J 2011;1:37-42

Junewick JJ. Pediatric Craniocervical Junction Injuries. AJR 2011;196:1003-1010

Smoker W. Craniovertebral Junction: Normal Anatomy, Craniometry, and Congenital Anomalies.
Radiographics 1994;14:255-277

Deliganis AV,Baxter AB, Hansen JA, et al. Radiologic Spectrum of Craniocervical Distraction Injuries.
Radiographics 2000; 20:S237-S250

Rojas CA, Bertozzi JC, Martinez CR, Whitlow J. Reassessment of the Craniocervical Junction: Normal Values on
CT. AJNR 2007; 28:1819-23