title: Spontaneous resorption of lumbar disc herniation is less likely when modic changes are present.
abstract: METHODS
  A retrospective survey on 85 consecutive patients with primary single-level lumbar disc herniation (LDH).
  
  
  OBJECTIVE
  To investigate associations between Modic changes (MCs) and the likelihood of resorption of herniated lumbar intervertebral discs.
  
  
  BACKGROUND
  Spontaneous resorption of LDH has been demonstrated, whereas the mechanisms are unclear. MCs are closely associated with disc degeneration, but research focusing on their association with spontaneous resorption of LDH has not been specifically investigated.
  
  
  METHODS
  Eighty-five consecutive patients with LDH (52 males, 33 females, aged 20-66 yr) were included. Patients' diagnosis was based on clinical presentation, magnetic resonance imaging, and computed tomography. 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. Disc tissues collected from the surgical group were examined histologically, and immunohistochemistry was used to identify endothelial cells and macrophages.
  
  
  RESULTS
  In total, 35 of 85 patients showed MC, mostly type II. Herniated tissue in MC group contained relatively more hyaline cartilage endplate than that in non-MC group (on average, 50% vs. 8%, P < 0.05) but less nucleus pulposus (18% vs. 55%, P < 0.05). Conservative treatment reduced Oswestry Disability Index scores in non-MC group from 29.4 to 23.5 on average (P < 0.05), but reductions in MC group (30.1-29.0) were nonsignificant. Herniated volumes reduced after conservative treatment in non-MC group (0.44-0.21 cm3, P < 0.05) but not in MC group (0.52-0.45 cm3, P > 0.05). More neovascularization and macrophage infiltration was observed in herniated tissue from non-MC group than from MC group (P < 0.001).
  
  
  CONCLUSIONS
  MCs in patients with LDH are associated with cartilaginous herniations that 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.
  
  
  METHODS
  3.
authors: *Department of Orthopaedics, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, P. R. China; and †The first people's Hospital of Linhai, Linhai city, Zhejiang province, P.R.China.
authors: Zhi
authors: Z
authors: Shan
authors: Shunwu
authors: S
authors: Fan
authors: Qingbo
authors: Q
authors: Xie
authors: Letu
authors: L
authors: Suyou
authors: Junhui
authors: J
authors: Liu
authors: Chongyan
authors: C
authors: Wang
authors: Fengdong
authors: F
authors: Zhao
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007403:Intervertebral Disc / Q000473:pathology*; D007405:Intervertebral Disc Displacement / Q000473:pathology*; D008159:Lumbar Vertebrae / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D055815:Young Adult