0:01

This is an example of unilateral facet dislocation.

0:05

And we are looking at the right side and the left side.

0:08

So you notice that on the right side,

0:12

the superior facet is dislocated posterior to the inferior facet.

0:17

But on the left side,

0:19

the superior facet is anterior to the inferior facet

0:22

in the normal position. It's a little bit angular,

0:24

quite normal, but it's a unilateral facet dislocation.

0:29

With unilateral facet dislocation,

0:31

the degree of offset of the superior vertebral body to the

0:35

inferior vertebral body is usually less than half or

0:38

less than one-fourth. This is grade 1 offset.

0:42

You notice that there is widening here between the

0:45

spinous processes and the posterior elements.

0:49

This patient had associated injury to the spinal

0:53

cord despite only grade 1 offset.

0:57

The cord here is bright in signal intensity

1:00

and has been damaged.

1:02

You see that the patient has disruption here of the

1:05

ligamentum flavum and the interspinous ligament.

1:08

This is the posterior column, the third column.

1:11

Here we have the posterior longitudinal ligament coming up,

1:14

and then it's flapping in the breeze here.

1:17

So this is the second column injury.

1:19

The anterior column likely infected as well with bright

1:23

signal intensity in the intervertebral disc.

1:25

So injury to the spinal cord, not only that,

1:28

but this patient also showed carotid dissection secondary

1:33

to the trauma. It's usually not secondary to the fracture,

1:36

which would usually affect the vertebral artery,

1:38

but secondary to the trauma, there was a carotid dissection.

1:43

So this is how,

1:44

with the CT scans that show these type of offsets,

1:49

you're going to recommend MRI scan to

1:52

confirm the injuries to the ligaments.

1:55

There are some patients that we just recommend MRI scan because

2:00

the patient continues to have cervical spine

2:03

pain and we're trying to explain it.

2:05

And so you will see cervical spine MRI scan even

2:09

in the face of normal cervical spine CT scans.

2:14

Here's a patient where the alignment is normal.

2:18

The anterior alignment line is normal.

2:22

The posterior alignment line is normal.

2:24

The spinolaminar line shows a normal configuration.

2:28

A little bit of distance here is normal.

2:31

But as we get off midline,

2:33

we see that the patient has a fracture, which is

2:36

going from the pedicle into the facet joint.

2:39

In this case, without dislocation and without malalignment.

2:45

So a unilateral facet fracture.

2:48

Here on axial CT scan,

2:50

you see the fractures going through

2:53

both of the facet joints,

2:55

in this case extending to the pedicle central vertebral body

3:00

fracture, as well as the junction between the lamina with the

3:05

transverse process and then extending

3:07

into the medial aspect of the pedicle.

3:09

I want to emphasize that after looking at the fractures,

3:12

make sure you do spend the time to look at the soft tissue

3:15

windows because this is important to demonstrate that

3:18

this patient has an epidural hematoma associated with the

3:21

fractures, displacing the spinal cord

3:24

anteriorly and to the right side.

3:27

This would either need to be evacuated if the patient is

3:30

symptomatic or the cord is being compromised or serial scans,

3:36

usually MRI scan,

3:37

to see whether that this is expanding

3:40

over the course of time.

Unilateral Facet Dislocation with Carotid Dissection

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