title: Influence of degenerative changes of intervertebral disc on its material properties and pathology.
abstract: OBJECTIVE
  To investigate the material properties of normal and degenerated intervertebral discs (IVDs) and examine the effect of degenerative changes on IVD pathology.
  
  
  METHODS
  A computer-based online search was undertaken to identify English articles about material properties of IVDs published from January 1950 to 2011 in PubMed database. The retrieved keywords included material properties, intervertebral disc and degeneration. Based on the principles of reliability, advancement and efficiency, the obtained data were primarily examined, and the original source was retrieved to read the full-text. Repetitive articles were excluded. The data of material properties of normal and degenerated IVDs were summarized and analyzed by meta-analysis.
  
  
  RESULTS
  The data of Young's modulus, Poisson's ratio, shear modulus, hydraulic permeability and intradiscal pressure of normal and degenerated IVDs were obtained. Compared with normal IVDs, the Young's modulus and shear modulus of annulus fibrosus and nucleus pulposus were higher in degenerated IVDs, the Poisson's ratio was lower while the hydraulic permeability and intradiscal pressure were higher. Besides, the degeneration-related alterations in IVDs had an influence both on itself and other spinal structures, leading to diseases such as bulging disc, discogenic pain and spinal stenosis. Meanwhile, the heavy mechanical loading and injury indicated important pathways to IVD degeneration.
  
  
  CONCLUSIONS
  To a certain extent, the degenerative changes of IVD influence its material properties. And the degeneration-related alterations of composition can cause structural failure of IVDs, leading to injuries and diseases.
authors.affiliation: State Key Laboratory of Trauma, Burns, and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing 400042, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.forename: Hai-Bin
authors.initials: HB
authors.lastname: Chen
authors.forename: Ling
authors.initials: L
authors.lastname: Zhang
authors.forename: Li-Ying
authors.initials: LY
authors.lastname: Zhang
authors.forename: Jing-Cheng
authors.initials: JC
authors.lastname: Liu
authors.forename: Zheng-Guo
authors.initials: ZG
authors.lastname: Wang
mesh_terms: D004195:Disease Models, Animal; D006801:Humans; D007403:Intervertebral Disc; D055959:Intervertebral Disc Degeneration; D015203:Reproducibility of Results