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Long-term longitudinal study links increased vertebra height with decreased adjacent disc height
The researchers noted in the conclusion of their study that the degeneration and remodeling of discs and vertebrae occurs in concert.
In a longitudinal study with 15-year follow-up, researchers found the height of adjacent vertebrae increased when disc height decreased.
The research, which was published in the Spine Journal, involved studying MRI scans for a group of 232 Finnish men whose spines were previously scanned between 1992 and 1993. In the time from 1997 to 1998 and 2007 to 2008, 105 men were re-examined and they had a mean age of 63 years at the 15-year follow-up, based on the study results.
“Increases in vertebra height were noted, along with the occasional appearance of a double line or layered endplate,”
Michele
Crites-Battié
The researchers used SpEx software to measure the subjects’ mid-sagittal and mid-axial spine. They segmented lumbar structures on proton density images.
After segmenting the discs and the vertebra, disc height was measured from the area of the disc divided by the width either including or not including osteophytes, and vertebrae were measured similarly, according to Battié.
Tapio Videman
Disc height decreased in the upper lumbar region by 8.7% and by 12% in the lower region. Yet, the investigators found no statistically significant changes in standing height during the 15-year follow-up, with mean standing height decreasing from 174.7 cm to 174.4 cm. The lumbar spine block length from T12 to L1 and L5 to S1 decreased 1.3%.
Based on the study, there was a 0.13 mm per year mean annual shortening of the L1-S1 lumbar spine block. This, the researchers noted, was in line with the subjects’ mean standing height.
Vertebral height increases, which were associated with disc narrowing, were 4.1% mean in the lower lumbar region and 2.7% in the upper lumbar region, according to the study abstract. The researchers saw increased height in 88% of upper lumbar vertebrae and 93% of lower lumbar vertebrae and they found that 83% of all discs decreased in height. – by Renee Blisard Buddle and Susan M. Rapp
References:
Videman T. Spine J. 2013;doi:10.1016/j.spinee.2013.11.018. [Epub ahead of print]
For more information:
Tapio Videman, MD, PhD, can be reached at 3-48 Corbett Hall, University of Alberta, Edmonton, AB, Canada T6G 2G4; email: tapio.videman@ualberta.ca.
Disclosure: Battié has no relevant financial disclosures.
Perspective
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The authors are to be congratulated on carrying out a long-term, population–based, longitudinal MRI study on a group of 116 men with a mean of 15 years follow-up. The major finding of this study is that concomitant with the reduction in disc height, there is an increase in the vertebral body height suggesting that there is a relationship between intervertebral disc degeneration (IVDD) and vertebral body bone changes. These findings add to those of Kuisma and colleagues, Mok and colleagues and Benneker and colleagues that implicate the vertebral marrow and endplate in IVDD.
Indeed, it should be born in mind that the changes described in the study are in the region of millimeters, and that the vertebral endplate is somewhat irregular, making measurements difficult. Moreover the scanner and scanning parameters are understandably not the same 15 years apart. Thus the study is subject to systematic errors, and it would be important to have these findings replicated by others.
Nevertheless, the study does help focus attention of the disc research community on the importance of not only looking at the disc, but the whole spinal unit of bone-disc-bone in order to understand the causes of, and risk factors in, IVDD.
References:
Kuisma M. Spine. 2007; doi:10.1097/01.brs.0000261561.12944.ff.
Mok FP. Spine. 2010; doi:10.1097/BRS.0b013e3181d534f3.