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<v ->This brings us back to Ankylosing Spondylitis,

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and the syndesmophytes.

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So let's think about those for a moment.

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The definition of a syndesmophyte is simple.

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It's ossification involving the anulus fibrosis

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of the intervertebral disc.

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When Ankylosing Spondylitis begins in a younger person,

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without bulging of the disc,

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the syndesmophytes first they extend from the corner

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of one vertebral body to the corner of another,

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and they are vertically oriented.

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When the disease begins in an older person,

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as in this person, who has some protrusion of the discs,

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there are curvilinear syndesmophytes that develop.

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But once again, they extend

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from the corner of one vertebral body, to the neighbor.

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That's the definition, or the appearance,

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of a syndesmophyte.

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Is Ank-Spond the only condition

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that produces a syndesmophyte?

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The answer is no.

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Alkaptonuria, perhaps, you know, it as Ochronosis,

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produces ossification involving the disc

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and produces sydesmophytes as well.

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Now we were asked, what is the difference

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between all these patterns of bone formation?

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So let's use this slide to work it out.

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A syndesmophyte, thin vertical linear,

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or curvilinear extending from the corner

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of one vertebral body to its neighbor.

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An osteophyte begins where sharpies fibers attach to bone.

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So not at the edge or corner of the vertebral body

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but several millimeters away, first growing horizontally

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and then turning vertically.

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And in psoriasis and in reactive arthritis

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what occurs is a process known as

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paravertebral ossification.

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This is ossification in the soft tissues

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about the intervertebral disc.

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I'll show you what it looks like in a minute.

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That's the definition, excuse me,

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of paravertebral ossification

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and it's different than an osteophyte and a syndesmophyte.

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So here on your left, syndesmophyte,

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curvilinear running from one verterbral corner to another

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looking like stalagtites in a cave.

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On your right, the osteophyte, the fancy disease

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degenerative disease that produces this, is known

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as Spondylosis Deformans.

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It's a degenerative disease of the anulus fibrosis.

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But these are broader outgrows.

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They look more like coral than they do stalagtites.

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They grow horizontally and vertically

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and they tend not to begin at the very edge

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of the vertebral body.

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On your left syndesmophytes, vertical

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or curvilinear ossifications.

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On your right, paravertebral ossification in psoriasis.

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So this is ossification in the connective tissue

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around the disc. All right?

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So here's what it looks like.

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It initially is immature, but it becomes mature.

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It extends from a mid vertebral body level

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to a mid vertebral body level.

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And interestingly it skips from one side

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to the other side of the spine and perhaps back again.

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So there are differences in the appearance.

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Now, Dish is its own phenomenon.

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We don't know why Dish occurs.

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It was described this by Forestier.

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It's called Forestier's disease as well.

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It's a terrific disease for radiologists

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cuz it ties together alot of the odds it ends

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we see not just in the spine, but in extra spinal sites.

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But let's talk about the spine.

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Dish dominates in the mid and lower thoracic spine.

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We see it better on a lateral radiograph

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than on a frontal radiograph.

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One of the criteria arbitrary is flowing ossification

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connecting four continuous vertebral bodies.

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It produces a bumpy spinal contour

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where the bumps opposite the intervertebral disc faces.

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And there's a radiolucency often between the ossified.

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This is the ossified anterior longitudinal ligament

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and the anterior surface of the vertebral body.

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This is what it might look like in a specimen.

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So this is Dish.

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This is Ankylosing Spondylitis.

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Now it's of interest that in both of those diseases

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if they're severe, your pens,

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your spine becomes very rigid.

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I always think of it as a pencil.

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And therefore, if you stumble and fall

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what can occur is a broken pencil. All right?

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And the location of the break varies.

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In Dish, classically it's at a mid vertebral body level

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whereas in Ankylosing Spondylitis,

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it's generally at the level of the syndesmophytes.

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So what happens when the pencil breaks?

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Well, if the upper part of the pencil breaks

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and that's the cervical spine, that's pretty bad.

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Those patients present immediately to the hospital

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or not at all because it can be fatal.

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But if the lower part of the pencil breaks,

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such as I'm showing you here,

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although there is back pain those patients

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may not immediately come to the hospital.

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And to be totally honest, I know it sounds funny,

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they get up from the floor, all right,

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with Ankylosing Spondylitis, they've been tiphodic

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for the last 20 years of their life.

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They're now lordotic, as you can see here

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and they can see further ahead.

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I've heard that comment from some of them,

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that all of a sudden, they're not facing the floor.

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They're looking straight ahead.

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So they don't present occasionally despite the back pain.

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And because of that,

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a peculiar finding occurs at the site of fracture.

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Let me just show you a couple of examples of fractures

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at the syndesmophytes here in the thoracal lumbar region

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and in the cervical region showing you this can occur

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at different levels.

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But if it occurs lower down

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and they don't present immediately,

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they end up with something that's best called

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improper fracture healing.

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You're gonna hear the term pseudoarthrosis.

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it's not really a pseudoarthrosis,

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but it's resorption about the fracture site.

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Now there are fractures through the posterior elements

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and if you get a CT, that's gonna help you,

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but otherwise you're gonna look at this and say

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I got an infection on my hands,

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look elsewhere and you can see in fact

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the findings of Ankylosing Spondylitis. All right?

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So this is something that you will come across

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improper fracture healing.

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Now the question arose,

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what about doing wider field of view or whole body imaging?

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I indicated we have very little experience with it

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but the wider the field of view,

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perhaps you'll see not only involvement

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of the sacroiliac joints,

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you'll pick up the enthesitis at the issual tuberocity

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synovitis of the at the hip.

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So yeah, there is an advantage to that.

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And this is whole body imaging.

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Marcello sent me this image just to show you,

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yeah, if you do this and you are able to do it

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with the equipment you have,

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you'll pick up abnormal throughout the skeleton,

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which can be very, very useful.

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We have no experience using it.