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Case 27 - Jefferson Fracture on MRI

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In addition to the evaluation of the stability of the ligaments

0:05

with atlanto-occipital and atlanto-axial dissociation,

0:11

we obviously want to look at the vertebral bodies themselves.

0:15

This is an example of a Jefferson fracture.

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It's a comminuted fracture,

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actually a burst fracture of the C1 vertebra.

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Sometimes it will just affect the anterior

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arches of the C1 vertebra.

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Sometimes it also affects the posterior arch

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of the C1 vertebra.

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As you can see here,

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we have the right sided posterior arch,

0:38

which is somewhat comminuted,

0:40

as well as the anterior arch of C1.

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Now, this in and of itself, does not necessarily mean it's

0:46

an unstable fracture. If the ligaments are intact,

0:49

it actually may represent a stable fracture.

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These fractures are also nicely demonstrated

0:54

on the coronal reconstruction,

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where we can see the fracture fragment on the left

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side, as well as the comminuted

1:02

fracture fragment on the right side.

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And as we proceed a little bit more posteriorly,

1:07

you can see the additional line of fracture.

1:10

Let's look at this on the sagittal scan.

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And we want to look and make sure that

1:15

the lentilodontoid distance is preserved.

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And this looks perfectly fine, nicely at pose

1:22

there. You can see a fracture fragment on the

1:25

superior arch of the anterior arch of C1.

1:28

Here is the fracture going through both anteriorly

1:32

as well as in the posterior arch,

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representing this somewhat comminuted burst fracture.

1:38

Looks like it's a little bit worse on

1:40

the right side than the left side.

1:43

The orientation of the fracture fragments

1:46

on the coronal image is very important.

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What you see is that there is offset of the lateral mass of

1:53

C1 from the lateral mass of C2 on both sides.

1:59

So this should normally be aligned.

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This is all part of that same mechanism of

2:04

burst where it kind of explodes outward.

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And so these lateral masses are laterally displaced

2:11

in this type of fracture, the Jefferson fracture.

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On the CT scan of the Jefferson fracture,

2:19

we saw that the lateral mass of C1 was displaced laterally

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on both sides compared to the lateral

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mass of the odontoid process.

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That suggests that there probably is ligamentous injury.

2:32

Let's look at the MRI scan on the same patient.

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So this is the T2-weighted scan.

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Here's the STIR images.

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We've talked about how the STIR image is the best

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sequence for looking at ligamentous injury.

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So we will follow the anterior longitudinal ligament upward

2:49

and we see that there does appear to be an intact anterior

2:55

longitudinal ligament as we go up to the clivus.

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There is some prevertebral edema as this bright signal intensity.

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As we follow the posterior longitudinal ligament, we notice

3:09

that we have this disruption of the posterior longitudinal

3:12

ligament as it converts to the tectorial membrane.

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And there we have a discontinuity here.

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So there is ligamentous disruption

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of the tectorial membrane.

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As we go off midline, we see the atlanto-occipital region, on this

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side shows normal distance and just

3:36

very slight high signal intensity.

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The atlantoaxial space is also normal with

3:44

just a little bit of bright signal intensity.

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As we go off posteriorly towards where the fracture has occurred,

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we do see bright signal intensity edema

3:53

in the adjacent soft tissues.

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But note that when we go to the contralateral side, we see

4:00

something different. Here we have brighter signal intensity.

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It's narrower anterior than posteriorly.

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So this kind of triangular look implies that there is

4:11

ligamentous injury extending along the posterior

4:14

margin of the atlantoaxial space,

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and that is asymmetric from the right side to the left side,

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where you see that there's the same distance between the two.

4:28

So there is this little offset.

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And there is likely this ligamentous injury as well as

4:34

the injury that we described to the tectorial membrane.

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We want to look at the spinal laminar line

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and the spinal laminar ligaments,

4:41

which effectively are the ligamentum flavum.

4:44

They look just fine. And there isn't really offset here.

4:48

The atlanto-odontoid space is preserved.

4:53

If we look at the axial scans,

4:55

we will see that bright signal intensity here

5:00

which is largely in the retropharyngeal space,

5:04

more so than the prevertebral space.

5:06

There is a little bit of bright signal intensity

5:08

in the prevertebral space,

5:09

but this is anterior to the longus musculature.

5:15

So here's our longus musculature.

5:17

This is actually in the retropharyngeal space

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rather than the prevertebral space.

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On this MRI scan,

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I want you to pay attention to the flow

5:29

voids of the vertebral arteries.

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Notice that the left vertebral artery shows a normal flow void,

5:37

but the right vertebral artery has

5:40

high signal intensity within it.

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This implies that there may be dissection or thrombosis of the

5:47

right vertebral artery that is associated with the fracture,

5:51

which, as you recall,

5:52

was more on the right side than the left side on the CT scan.

5:57

So there has been compromise of the

6:00

right vertebral artery versus the left vertebral artery.

Report

Faculty

David M Yousem, MD, MBA

Professor of Radiology, Vice Chairman and Associate Dean

Johns Hopkins University

Tags

Neuroradiology

Head and Neck

Emergency

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