title: Modic (endplate) changes in the lumbar spine: bone micro-architecture and remodelling.
abstract: OBJECTIVE
  In the literature, inter-vertebral MRI signal intensity changes (Modic changes) were associated with corresponding histological observations on endplate biopsies. However, tissue-level studies were limited. No quantitative histomorphometric study on bone biopsies has yet been conducted for Modic changes. The aim of this study was to characterise the bone micro-architectural parameters and bone remodelling indices associated with Modic changes.
  
  
  METHODS
  Forty patients suffering from disabling low back pain, undergoing elective spinal surgery, and exhibiting Modic changes on MRI (Modic 1, n = 9; Modic 2, n = 25; Modic 3, n = 6), had a transpedicular vertebral body biopsy taken of subchondral bone. Biopsies were first examined by micro-CT, for 3D morphometric analysis of bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular separation, trabecular number, and structure model index. Then, samples underwent histological analysis, for determination of bone remodelling indices: osteoid surface to bone surface ratio (OS/BS), eroded surface to bone surface (ES/BS) and osteoid surface to eroded surface ratio (OS/ES).
  
  
  RESULTS
  Micro-CT analysis revealed significantly higher BV/TV (up to 70% increase, p < 0.01) and Tb.Th (up to +57%, p < 0.01) in Modic 3 biopsies, compared to Modic 1 and 2. Histological analysis showed significantly lower OS/BS in Modic 2 biopsies (more than 28% decrease, p < 0.05) compared to 1 and 3. ES/BS progressively decreased from Modic 1 to 2 to 3, whereas OS/ES progressively increased with significantly higher values in Modic 3 (up to 159% increase, p < 0.05) than in Modic 1 and 2.
  
  
  CONCLUSIONS
  Significant differences were found in bone micro-architectural parameters and remodelling indices among Modic types. Modic 1 biopsies had evidence of highest bone turnover, possibly due to an inflammatory process; Modic 2 biopsies were consistent with a reduced bone formation/remodelling stage; Modic 3 biopsies suggested a more stable sclerotic phase, with significantly increased BV/TV and Tb.Th compared to Modic 1 and 2, linked to increased bone formation and reduced resorption.
authors: Medical Device Research Institute, School of Computer Science, Engineering and Mathematics, Flinders University, Sturt Rd., Bedford Park, South Australia, 5042, Australia, egon.perilli@flinders.edu.au.
authors: Egon
authors: E
authors: Perilli
authors: Ian H
authors: IH
authors: Parkinson
authors: Le-Hoa
authors: LH
authors: Truong
authors: Kuan C
authors: KC
authors: Chong
authors: Nicola L
authors: NL
authors: Fazzalari
authors: Orso L
authors: OL
authors: Osti
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D015519:Bone Density; D016723:Bone Remodeling / Q000502:physiology*; D001842:Bone and Bones; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000000981:diagnostic imaging / Q000473:pathology*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000648:ultrastructure*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D055114:X-Ray Microtomography