Correlation between paravertebral muscle degeneration, lumbar disc degeneration and serum vitamin D level in elderly patients

English Keywords:Lumbar disc degeneration  Paravertebral Muscle  Fat Infiltration  Serum vitamin D

English Abstract:

  【Abstract】 Objectives: To study the relationship between the degeneration of paraspinal muscles, the degree of lumbar disc degeneration with serum vitamin D levels. Methods: 150 elderly patients [105 females, 45 males, aged 41 to 93 (67.0±10.1) years old] with lumbar disc degenerative diseases underwent lumbar MRI and serum vitamin D levels test. According to the Pfirrmann standard, the degree of lumbar disc degeneration was graded by evaluating the structure of the nucleus pulposus, the signal strength of the nucleus pulposus, the boundary of the nucleus pulposus and the annulus fibrosus, and the height of the intervertebral disc. There were no patients with grade Ⅰ, and the number of cases with grades Ⅱ to Ⅴ were as follows: L4/5, n=17, 59, 60 and 14; L5/S1, n=22, 46, 55 and 27. The standard cross-sectional area of the paravertebral muscles (psoas, erector spinae, and multifidus) were measured on the T2 phase of the L4/5 and L5/S1 segments. The degree of muscle fat infiltration was graded according to the Goutallier classification by evaluating the amount of fat infiltration. According to the Endocrine Society clinical practice guideline, serum vitamin D levels were classified as normal(≥30ng/ml), insufficiency(20-30ng/ml) and deficiency(＜20ng/ml). Classification data was analyzed using rank sum test, quantitative data was analyzed using one-way ANOVA or Kruskal-Wallis test, and correlation analysis between variables was performed using Spearman correlation coefficient. Results: In the L4/5 segment, the cross-sectional areas of psoas, erector spinae and multifidus were negatively correlated with the degree of lumbar disc degeneration(r=-0.294, -0.250, -0.182). In the L5/S1 segment, the cross-sectional areas of the psoas and multifidus were negatively correlated with the degree of lumbar disc degeneration(r=-0.344, -0.346). The stage of fat infiltration of the erector spinae and multifidus were correlated with the degree of lumbar disc degeneration(L4/5: r=0.174, 0.188; L5/S1: r=0.193, 0.283). The proportion of patients with lumbar disc degeneration accompanied by vitamin D deficiency were higher in Pfirrmann Ⅲ-Ⅴ than those in Pfirrmann Ⅱ (Grade Ⅱ-Ⅴ: L4/5, 47.06%, 59.32%, 60.00% and 57.14%; L5/S1, 45.45%, 58.70%, 56.36% and 70.37%). Compared with those with normal vitamin D levels, patients with vitamin D insufficiency or deficiency presented higher proportions of erector spinae and multifidus Goutallier grade 2-4. There was no or only slight fat infiltration in more than 98% psoas, and the psoas was hardly affected by the degree of lumbar disc degeneration and vitamin D level. Conclusions: The cross-sectional area of the paravertebral muscles decreased with the degree of lumbar disc degeneration. The severity of fat infiltration of the erector spinae and multifidus were related to the degree of lumbar disc degeneration. Patients with more severe lumbar disc degeneration were more likely to have vitamin D deficiency. Patients with vitamin D deficiency may have more severe fat infiltration in the erector spinae and multifidus.