Correlation between lower lumbar multifidus muscles fatty atrophy and corresponding level degenerative diseases in patients with low back pain using MRI

摘要

Purpose To investigate the potential correlation between multifidus muscles (MM) fatty atrophy and MR signs of lumbar spine degeneration in patients with low back pain (LBP). Methods Following IRB approval, lumbar spine MRI of 518 patients (278 females and 240 males; age, 10-92 years) with LBP were retrospectively reviewed by two experienced musculoskeletal radiologists. MM fatty atrophy was graded at L4-5 and L5-S1 levels per modified Goutallier classification. Disc degeneration, herniation was graded according to Pfirrmann classification, and facet joint osteoarthritis was graded according to Fujiwara classification. Gender, age and body mass index (BMI) were recorded as well. Mann-Whitney U test was used to determine whether there was a difference in fatty atrophy between woman and man. Kendall’s tau-b coefficient and ordinal multiple logistic regression were used to evaluate relationship between MM fatty atrophy and signs of lumbar spine degeneration. Intra-observer agreement was tested using weighted Kappa. Results There was significant difference among the grades of fatty atrophy between woman and man. Both at L4-L5 and L5-S1 levels, correlation between MM fatty atrophy with age, disc degeneration, facet joint osteoarthritis was significant (p < 0.001). No correlation was found between MM fatty atrophy with BMI, disc herniation at L4-5 (p = 0.187,0.307) and L5-S1 (p = 0.307,0.927). Among the independent variables included in the logistic regression model, gender, age and facet joint osteoarthritis at L4-5 level were statistically significant. Older people (OR = 1.11 at L4-5 level; OR = 1.08 at L5-S1 level), women (OR = 5.88 at L4-5 level; OR = 7.46 at L5-S1 level) with higher-grade facet joint osteoarthritis at L4-5 level (OR = 0.14, 0.26, 0.34; Grade 4 as reference) are more prone to MM fat degeneration than younger people, man and lower-grade facet joint osteoarthritis (p < 0.001). Intra-observer agreement was good with Kappa value range from 0.79 to 0.98. Conclusion In patients with low back pain, MM fatty atrophy in the lower lumbar spine was related to age, gender, facet joint osteoarthritis at L4-5 levels.