• Journal of Korean Physical Therapy Science
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• v.28 no.3
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• pp.42-52
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• 2021

Background: The purpose of this study was to investigate the effects of the severity and direction of lumbar disc herniation (LDH) on the facet joints and paraspinal muscles. Design: Cross-sectional design. Methods: The subjects were divided according to the diagnosis for severity of unilateral herniation of L4-L5 disc. The groups consisted of disc protrusion group (n=15), disc extrusion group (n=15), and no disc herniation group (n=15). The asymmetry and angle of facet joints and the cross-sectional area of paraspinal muscles were analyzed and compared using magnetic resonance imaging (MRI). Results: The results showed that the angle of facet tropism was larger in disc extrusion group than the disc protrusion group and the difference was found to be significant difference (p<0.01). In addition, when both left and right angles of patients with unilateral disc herniation were measured, the results showed larger facet joint angle in the herniated area of the disc extrusion group than in the disc protrusion group. When paraspinal muscles were measured according to the severity of disc herniation and the degree of facet joint asymmetry, there was no difference in paraspinal muscles between the disc protrusion and disc extrusion groups. Meanwhile, the multifidus muscle was smaller in the group with facet tropism than the group without facet tropism (p<0.03), while there were no significant differences in the erector spinae and psoas muscles. Conclusion: Progression of disc herniation resulted in increased facet joint tropism, increased angle of the facet joints in the direction of disc herniation, and decreased size of the multifidus muscle.