Reconsideration of Pfirmann classification for Disc degeneration : possible subtypes in collapse disc — The International Society for the Study of the Lumbar Spine
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Reconsideration of Pfirmann classification for Disc degeneration : possible subtypes in collapse disc (#1020)

Yuji Yamada 1 , Koichi Sairyo 2 , Toru Maeda 1 , Masatoshi Morimoto 2
  1. Anan Medical Center, Anansi Takarada, TOKUSHIMA PREFECTURE, Japan
  2. Orthopaedics, Tokushima University, Tokushima, Japan

[Purpose] In MRI findings, the Pfirrmanns’s classification is widely applied to evaluate the degeneration of intervertebral discs. In this classification, the disc brightness decreases as grade progress. In grade 4, disc brightness becomes more low, in grade 5, the intervertebral discs proceed to collapse with low signal intensity. On the other hand, we sometimes observe the high signal intensity in collapsed disc. In this study, we investigate the prevalence of the collapsed disc with high signal intensity in MRI findings and considered about the mechanism of high signal intensity.

 

[Method] Among 2470 intervertebral discs of 494 patients who underwent lumbar spine MRI from July 2019 to June 2020 were evaluated. We defined intervertebral disc height of 5 mm or less as having collapse in MRI. The evaluation item was STIR of the intervertebral disc brightness (high (H group) or low (L group)), Modic degeneration of the upper and lower vertebral discs to be evaluated (None, type I, II, III).

 

[Results] Collapse was found in 138 of 494 patients (28%), and in 213 of 2470 discs (9%) . Mean age was 73.4 years (37-93 years), 60 males, 78 females. Group H which were suggested inflammation by STIR were found in 45 discs (21%). That is, we could find inflammation in the collapsed disc. Group L had the remaining 168 discs (79%). Modic change were 30 discs (14%) without MC, 20 discs (9%) for type I, 109 discs (51%) for type II, and 54 discs for type III (25%). There were no significant differences in MC types when classified into H and L groups. However only one intervertebral disc collapse was found in 89 (14 in H group, 75 in L group), and two or more intervertebral discs were found in 49 (16 in H group, 33 in L group). The number of patients which have many intervertebral collapse discs were significantly higher in the H group (p = 0.02).

 

[Discussion] In this study, we evaluated the inflammation of grade 5 by STIR, in which the intervertebral disc collapses at T2. A high signal was observed inside the intervertebral disc in 21%. Conventionally, it is said that the collapse discs becomes hypomobile and stabilizes and reduces low back pain, but it has become clear that, in a certain rate, inflammation is seen in the intervertebral disc and the end plate. Pfirmann classification Grade V is divided into subtypes depending on the disc inflammation.

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