Cartilaginous Endplate Damage May be a Root Pathology Underlying Modic Changes on Lumbar Spine MR Images.

Abstract

Study DesignRabbit model study.ObjectiveTo examine whether cartilaginous endplate (CEP) destruction leads to endplate and vertebral marrow signal changes (Modic changes, MCs) on MR images.MethodsSixteen adult rabbits were used in the study and underwent an anterolateral procedure to expose the L2-6 intervertebral discs. The L4/5, L3/4 and L2/3 discs underwent annulotomy, annulotomy and CEP curettage, or annulotomy and chemonucleolysis, respectively, while the L5/6 disc served as a shame control. MR imaging was performed preoperatively and at 1, 3, and 6 months postoperatively to evaluate the presence or absence of MCs. After the last imaging, animals were sacrificed for histological study, focusing on endplate pathologies and their associations with MCs.ResultsAmong the 64 endplates that underwent CEP curettage or were exposed to chemonucleolysis, there were 6 (9.4%), 19 (29.7%), and 32 (50%) endplates with MCs at 1, 3 and 6 months, respectively. No MCs developed in the sham controls. Both surgical curettage and chymopapain injection successfully induced CEP destruction. Endplates with full layer CEP defects were most likely to develop MCs (59.6% vs 11.4%, <i>P</i> < 0.001). Moreover, endplates with MCs had a greater histological degeneration score than those without (8.97 ± 1.92 vs 5.35 ± 2.28, <i>P</i> < 0.001) and higher expression levels of inflammatory factors (IL-1β, TNF-α, and IL-6, <i>P</i> < 0.05 for all) in the subchondral vertebral marrow.ConclusionsCEP destruction, induced either by physical curettage or chemical lysis, can lead to long-lasting inflammation in the vertebral marrow and Modic-like signal changes on MR images. CEP destruction may be a root pathology underlying MCs.