title: Biomechanical analysis of cervical spondylotic myelopathy: the influence of dynamic factors and morphometry of the spinal cord.
abstract: OBJECTIVE
  Patients with cervical spondylotic myelopathy (CSM) have the same clinical symptoms that vary according to the degree of spinal cord compression and the cross-sectional cord shape. We used a three-dimensional finite element method (3D-FEM) to analyze the stress  distributions of the spinal cord with neck extension under three cross-sectional cord shapes.
  
  
  METHODS
  Experimental condition for the 3D-FEM spinal cord, ligamentum flavum, and anterior compression shape (central, lateral, and diffuse types) was established. To simulate  neck extension, the spinal cord was extended by 20° and the ligamentum flavum was shifted distally according to movement of the cephalad lamina.
  
  
  RESULTS
  The stress distribution in the spinal cord increased due to invagination of the ligamentum flavum into the neck extension.  The range of stress distribution observed for the diffuse type was wider than for the central and lateral types. In addition, the stress distribution in the spinal cord was increased by the pincer movement of the ligamentum flavum and by the anterior compression of the spinal cord. The range  of stress distribution observed for the diffuse type under antero-posterior compression was also wider than for the central and lateral types.
  
  
  CONCLUSIONS
  This simulation model showed that the clinical symptoms of CSM due to compression of the diffuse type may be stronger  than for the central and lateral types. Therefore, careful follow-up is recommended for anterior compression of the spinal cord of diffuse type.
authors.affiliation: Yamaguchi University Graduate School of Medicine, Yamaguchi University, Japan. n005uk@yamaguchi-u.ac.jp
authors.forename: Norihiro
authors.initials: N
authors.lastname: Nishida
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Kato
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Imajo
authors.forename: Syunichi
authors.initials: S
authors.lastname: Kawano
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Taguchi
mesh_terms: D001696:Biomechanical Phenomena; D002574:Cervical Vertebrae; D020342:Finite Element Analysis; D006801:Humans; D013117:Spinal Cord Compression; D013118:Spinal Cord Diseases; D055009:Spondylosis