0:00

Well, in this case,

0:01

the striking abnormality is the large

0:05

amount of bone tissue which is extending

0:07

from the C2 vertebra down to

0:09

the upper thoracic level,

0:10

anterior to the spinal canal.

0:13

It is associated with relative absence

0:16

of degenerative disc narrowing.

0:18

And this flowing osteophyte from

0:23

multiple levels is a manifestation

0:25

of diffuse idiopathic skeletal hyperostosis.

0:29

And that generally shows flowing

0:31

osteophytes across three to four levels

0:34

or more, with preservation of discs.

0:39

However, this would not be an issue in a

0:42

patient who has a myelopathy,

0:45

because we're anterior to the spinal

0:47

canal and not doing anything

0:48

to the thecal sac.

0:50

So as we start to look through

0:52

the images on the axial scan,

0:55

we notice that we do have an area where

0:58

there is bone formation posteriorly

1:01

in the midline,

1:03

and this represents ossification of the

1:06

posterior longitudinal ligament.

1:08

You can see it on these multiple levels here,

1:13

concluding at approximately the C4 level.

1:16

So if we show that axial scans,

1:20

you can see it coming down to the C4 level.

1:24

So, although the DISH is quite dramatic,

1:28

it's the ossification of the posterior

1:31

longitudinal ligament, which is the

1:33

potential cause of spinal stenosis,

1:37

most notably in this level,

1:38

at the C2-C3 level,

1:42

with this bone material along the

1:45

posterior edge of the vertebra.

1:47

Why is this not an osteophyte?

1:50

This extends from mid level C2 across

1:54

the entire vertebral body of C3

1:57

down to the upper half of C4.

2:00

That would not be what we would expect

2:01

for an osteophyte, which basically

2:03

goes from endplate to endplate.

2:06

If we look on the axial scan,

2:08

we may be able to tell the degree to

2:10

which it's indenting the thecal sac.

2:15

I want to just look down here below at

2:18

this upper thoracic level

2:22

here on the right side,

2:23

and you can see that this patient also

2:25

has some deformity on the right side

2:28

associated with the ligamentum flavum,

2:31

which is causing some indentation on

2:33

the thecal sac posterior laterally.

2:36

This is yet another manifestation of

2:38

DISH that may occur in association with

2:42

the ossification of the posterior

2:44

longitudinal ligament.