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<v ->We're gonna finish up in the last few minutes,

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just a few brief words about calcification of discs.

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This is a common phenomenon that we see,

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particularly in middle-aged and elderly persons.

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A number of years ago we did a study,

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we had removed, in fact, the spines at the time of autopsy

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in hundreds and hundreds of cadavers,

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and we decided to evaluate

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two-hundred-twenty-three of those cadavers

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by radiographing the spine.

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We found, in fact, in that population,

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where the average age of death was sixty-seven years,

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there was an eighty percent frequency of calcification,

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often in more than one level within the discs.

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The classic location was in the inner aspect

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of the annulus fibrosis and in the nucleus pulposus,

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but in other cases, as shown here for example,

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in the bottom, this image,

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that more diffuse annular calcification was present.

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This was believed to be dystrophic,

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and a calcium phosphate disposition was what was apparent

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when you studied the cause of the calcification.

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There's always been a question of,

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is there an increased risk of disc herniation

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when you have a heavily calcified disc?

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There are a number of articles that have said

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the answer to that question is yes.

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We certainly have seen examples of calcified discs

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that have herniated into the spinal canal.

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Here's one example, studied by CT and MR imaging.

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If you think of the dachshund dog,

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one of the characteristic problems that that dog,

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breed, has is these herniated, calcified discs

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in portions of the dog's spine.

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So I believe there is an increased risk for widespread--

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for disc herniation when there's

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diffuse calcification of that disc.

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Disc calcification in children may have a different meaning,

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and although, indeed, patients are usually symptomatic,

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these calcifications occurring in the cervical spine,

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there is a significant frequency of herniation

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of the disc material, as shown here,

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reported in twenty to sixty percent of persons

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who have such calcification.

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But generally, over a period of months,

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the calcification and the clinical manifestations go away.

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Rarely there is recurrence of this particular problem.

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And also, I would remind you that

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there are other causes of disc calcification,

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ochronosis or alkaptonuria,

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where the calcifications begin in the inner-aspect

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of the annulus fibrosis, but then can become diffuse

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or wafer-like associated with ossification across the disc.

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These are syndesmophytes by definition.

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So this is ochronosis,

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and in pyrophosphate crystal deposition,

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the classic occurs in outer fibers of the annulus fibrosis.

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This can look like syndesmophytes.