Morphology of endplate in lumbar degenerative disc disease, a MRI study

English Keywords:Lumbar disc degeneration  Endplate shape  MRI  Modic changes

English Abstract:

  【Abstract】　Objectives: To investigate the morphology of endplate shape in lumbar degenerative disc disease by means of magnetic resonance imaging(MRI) and the correlation between endplate shape and lumbar disc degeneration. Methods: A retrospective review was carried out in this study. The preoperative lumbar MRIs of 110 patients with single lumbar intervertebral disc herniation(group A) and 35 patients suffering from discogenic low back pain(group B) were reviewed and analyzed respectively. The morphology of endplate was classified into three groups: concave, flat and irregular based on the midsagittal T1-weighed MRI; the degree of disc degeneration was graded on T2-weighed MRI according to the Pfirrmann′s method, with one to five points behaving grade Ⅰ to Ⅴ; all endplates were determined by Modic grading system. The associations between morphology of endplate in lower lumbar spine and disc degenerative degree as well as Modic changes were evaluated retrospectively.　Results: ①Among the 435 lower lumbar spine endplates, concave represented the maximum proportion(215/435), with 50.6% in group A(167/330) and 45.7% in group B(48/105), and they almost sited in L3/4(108/215) and L4/5(83/215). Flat accounted for 29.0%(126/435), mostly sited in L5/S1(76/126). Irregular represented the least proportion(94/435), with 23.0% in group A(76/330) and 17.1% in group B(18/105), almost sited in L5/S1(45/94). ②In group A, the average degenerative degree for concave, flat and trregular endplate was 3.31±0.81 point, 3.66±0.64 point and 4.16±0.67 point respectively, which showed significant difference(P<0.05). Flat(37/110) and irregular(43/110) endplates were more common than concave ones in herniated discs, however which(137/220) were more common in no-herniated discs, which showed significant difference(P<0.05). For patients with lumbar disc herniation, irregular endplates were associated with Modic changes more often than the other two shapes(P<0.05), but the latter two shapes showed no difference(P＞0.05). ③In group B, the average degeneration degree for concave, flat and irregular endplate was 3.23±0.86 point, 3.54±0.85 point and 3.94±0.54 point respectively, with significant difference existing only in concave and irregular shape(P<0.05). Conclusions: Endplate morphology is associated with degree of disc degeneration and Modic changes. Disc degeneration presents from concave to flat and finally to irregular shape on MRI. Endplate shape on MRI can reflect the degree of disc degeneration to a certain degree.