Disc herniation size changes over 8 years

PainSci » bibliography » Kjaer et al 2016
updated Jun 3, 2024

Tags: etiology, back pain, traction, spine, correlation with signs, pro, pain problems, treatment, imaging, diagnosis

Two pages on PainSci cite Kjaer 2016: 1. The Complete Guide to Low Back Pain 2. How do disc herniations change over time?

PainSci commentary on Kjaer 2016: ?This page is one of thousands in the PainScience.com bibliography. It is not a general article: it is focused on a single scientific paper, and it may provide only just enough context for the summary to make sense. Links to other papers and more general information are provided wherever possible.

Impressively, this is “the first study to investigate changes in the size of lumbar disc herniations” over a long period, using reliable objective measurements taken with MRI. They took three scans of 140 herniated intervertebral discs in 106 people at ages 41, 45, and 49. Subjects were excluded if they didn’t have herniations at both the first and second scans. The researchers looked at changes and correlations between protrusion size, disc height, and cross-sectional area.

The results showed that disc herniations are mostly quite stable: about 65% of them got no worse or better. However, 17.5% of intervertebral disc herniations do spontaneously resolve on their own, and only 12.5% got worse. The small remainder of 5% fluctuated. Larger herniations were predictive of reductions in area and height. Five scans would have been a nice improvement to the design, but even from three we can see that, clearly, “lumbar disk herniation has an uncertain natural history” (Hong). Indeed.

Those numbers are not awesome numbers — clearly herniations do not all just magically go away — but I do think they are different and much less discouraging numbers than most people have in their heads.

(No one knows how this works, by the way. Why would a disc herniation spontaneously resolve? Or pop in and out of its proper place like a gopher? It’s a mystery.)

~ Paul Ingraham

original abstract †Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

BACKGROUND: A lumbar disc herniation (LDH) is a localised displacement of disc material, which may initiate changes in the disc and adjacent structures such as the nerve root and the spinal canal. Knowledge about how morphological changes in the disc relate to changes in other spinal structures might give the clinician a better understanding of the natural history and consequences of lumbar disc herniations. However, few longitudinal studies have investigated this process using reliable measures from magnetic resonance imaging (MRI). The objectives of this study were to examine changes in and associations between the size of lumbar disc herniations, dural sac area and disc height over an eight-year period using MRI at three time-points.

METHODS: Individuals from a population-based cohort, the 'Backs on Funen Cohort', had MRIs taken at age 41 years and again at 45 and 49 years. Only disc levels with MRI-confirmed disc herniations at 41 or 45 years were included. Cross-sectional areas (mm(2)) of the LDH, dural sac and disc height were calculated from measurements performed on sagittal T2-weighted images using a previously validated method. Changes over time for the three MRI findings were defined as "unchanged", "increased ", "decreased", or "fluctuating". Only changes beyond 95% limits of agreement of the same measurements were regarded as valid. Associations between the three types of measures were examined cross-sectionally and longitudinally.

RESULTS: One hundred and forty disc levels, from 106 people (48 women and 58 men), were included. Over eight years, 65% of the herniations remained unchanged, 17.5% decreased, 12.5% increased, and 5% had a fluctuating pattern. Increased herniation size was associated with decreased dural sac area (β-0.25[-0.52;0.01]) and increased disc height (β 0.35[0.14;0.56]). Moreover, larger herniation size predicted a statistically significant reduction in both dural sac area (β-0.35[-0.58;-0.13]) and disc height (β-0.50[-0.81;-0.20]).

CONCLUSIONS: On average, most LDHs do not change over a four- to eight-year period. However, larger herniation size predicts a reduction in both dural sac area and disc height. Further research should be done to determine the correlations between the progression of LDH and resolution of patient symptoms.

original abstract †Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

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