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Describing Disc Protrusion Location and Important Features

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We've just heard the terminology that I use for

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the description of disc disease and I want to use

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this example for employing that terminology.

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Here at the L5-S1 level,

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we see a disc herniation that is associated with

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compression of the thecal sac.

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And see it on the T1-weighted scan as well.

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So as we look at this,

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we're going to first make a distinction as far as

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whether or not we believe this represents a disc

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protrusion or an extrusion. On the sagittal scan,

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if we use our

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little measuring device,

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it appears as if the portion that is at the base

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in communication with the parent disc is

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wider than any location more distally.

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And therefore, I would use the term protrusion

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based on the sagittal and then move to the axial

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scan, and kind of confirm the same in that this is

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a wide based disc herniation that has a width that

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is wider at the communication with the parent

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disc here than anywhere more distally.

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So at the beginning, we'll be talking about this

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is a disc herniation, it is a protrusion.

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As we look at the axial scan,

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it's pretty clear that this is a disc herniation

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which is compressing the thecal sac,

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as well as the intrathecal nerve roots.

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So, at this axial level of the lateral recess at L5-S1,

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we see the L5 nerve roots getting out.

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However, as we go down a little bit more inferiorly,

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we're going to see that there is compression of

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the thecal sac and the intrathecal

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S1 nerve roots. Looks like, in this case, bilaterally.

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So the term that I'll be using

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is compressing or displacing.

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So disc herniation, protrusion,

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compressing or displacing.

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The next thing we want to talk about is its location.

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The location of the disc herniation is

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centrally, however, as we scroll,

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we see that it does extend into

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the neural foramen as well.

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So a central, as well as right foraminal disc

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herniation, the location of the disc herniation.

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The next thing we're going to talk about is,

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where is the nerve root compressed?

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Well, the nerve root is compressed within the thecal sac,

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as you see here,

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as well as involvement of the foraminal

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disc herniation of the level above.

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So this would be L5 in the foramen

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but S1 in the thecal sac.

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And then, we would talk about the size of it.

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So this looks to, you know, we could measure it,

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but it's greater than two-thirds

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of the spinal canal width.

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And therefore, we would say that there's marked

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spinal stenosis by a large disc herniation.

Report

Description

Faculty

David M Yousem, MD, MBA

Professor of Radiology, Vice Chairman and Associate Dean

Johns Hopkins University

Tags

Spine

Non-infectious Inflammatory

Neuroradiology

Musculoskeletal (MSK)

MRI

Acquired/Developmental

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