Spontaneous Resorption of Lumbar Disc Herniation is Less Likely When Modic Changes are Present

Abstract

Study Design. A retrospective survey on 85 consecutive patients with primary single-levellumbar disc herniation (LDH).Objective. To investigate associations between Modic changes (MCs) and the likelihood of resorption of herniated lumbar intervertebral discs.Summary of Background. Spontaneous resorption of LDH has been demonstrated, while the mechanisms are unclear. MCs are closely associated with disc degeneration, but research focusing on their association with spontaneous resorption of LDH have not been specifically investigated.Methods. Eighty-five consecutive LDH patients (52 men, 33 women, aged 20-66yrs) were included. Patient diagnosis was based on clinical presentation, MRI and CT. Patients were divided into surgical and conservative groups, and further divided into MC and non-MC subgroups. Spontaneous resorption and clinical success in the conservative group were assessed by reduction in the herniated volume AND Oswestry disability index (ODI).Disc tissues collected from the surgical group were examined histologically, and immunohistochemistry was used to identify endothelial cells and macrophages.Results. In total, 35/85 patients showed MC, mostly Type II. Herniated tissue in MC group contained relatively more hyaline cartilage endplate than non-MC group (on average, 50% vs 8%, P<0.05) but less nucleus pulposus (18% vs 55%, P<0.05). Conservative treatment reduced ODI scores in non-MC group from 29.4 to 23.5 on average (P <0.05), but reductions in MC group (30.1 to 29.0) were non-significant. Herniated volumes reduced following conservative treatment in non-MC group (0.44 to 0.21 cm, P<0.05) but not in MC group (0.52 to 0.45 cm, P>0.05). More neovascularization and macrophage infiltration was observed in herniated tissue from non-MC group than MC group (P <0.001).Conclusions. Modic changes in LDH patients are associated with cartilaginous herniations which resorb poorly, so that patients respond less well to conservative treatments. Loss of cartilaginous endplate may explain the origins of MCs, and their association with disc infection.

PMID:

 

24503683

 

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