0:01

What makes this epidural abscess different from others.

0:05

On the T1-weighted scan,

0:07

we actually don't see very much down here in the lumbar spine,

0:10

despite the fact that the patient was complaining of

0:13

severe back pain radiating into the lower extremities.

0:17

On the T2 weighted scan,

0:20

we see that the thecal sac and the nerve roots are being

0:23

displaced anteriorly by a collection that is here at the

0:28

L4-L5, and extending to the top of the S1 level.

0:31

This is probably better demonstrated on the STIR image

0:35

where we see the nerve roots being displaced anteriorly.

0:38

We see that the thecal sac is narrowed at the border with

0:41

the lesion, identifying this as an epidural process,

0:44

and we see it extending to the S1 level.

0:48

So we can understand how the patient would be having symptoms

0:51

of lower extremity problems given the irritation

0:54

and displacement of the nerve roots.

0:56

As we look at the spinal canal,

0:58

where we would be looking for bright signal intensity in a disc,

1:01

not really there.

1:03

We'd be looking for bright signal intensity in endplates,

1:05

not really there. This is merely a Schmorl's node,

1:08

which is kind of a normal variant.

1:10

So this is a bit peculiar.

1:12

What's the source of the etiology of this collection?

1:16

Well, as we scroll from side to side,

1:19

we are able to identify that there is bright signal intensity

1:24

associated with the facet joints at the L3-L4 and L4-L5 level,

1:30

extending into the paraspinal posterior musculature here.

1:35

So here's one facet joint with bright

1:37

signal intensity synovium.

1:39

Here's another facet joint with bright signal intensity synovium,

1:42

and appears as if there is an infectious process going on in

1:46

these paraspinal muscles on this side compared to the

1:49

normal paraspinal muscle on the contralateral side.

1:53

Now, even on this side,

1:54

we are seeing bright signal intensity in the facet joints.

1:57

Let's take a look at the axial scans.

2:00

Unfortunately,

2:00

this patient had kidney issues and

2:03

could not receive contrast dye,

2:06

and so we don't have the advantage of going

2:09

with post-gadolinium enhanced imaging.

2:12

Here we are in the lower spinal canal at the L4 level and we

2:17

are seeing that this collection is predominantly

2:19

on the right side in the epidural space,

2:21

displacing the thecal sac anteriorly to the left.

2:25

Here we have the facet joints showing bright signal intensity

2:30

and there is, in the paraspinal musculature,

2:33

high signal intensity, suggesting myositis.

2:37

So this is indeed a patient who has an abscess which is

2:40

multilocular. Here, actually down lower down in the sacral region,

2:45

we see that there's more of this collection on the left side than

2:49

the right side, that might account for this bright

2:52

signal intensity in the musculature.

2:55

This patient had an infectious septic synovitis of

2:59

the facet joints leading to an epidural abscess,

3:03

which was posteriorly located and caused compression of

3:07

the nerve roots, leading to a cauda equina syndrome.