title: Radiological pathogenesis of cervical myelopathy in 60 consecutive patients with cervical ossification of the posterior longitudinal ligament.
abstract: METHODS
  The radiological pathogenetic factors for cervical myelopathy in 60 consecutive patients with cervical ossification of the posterior longitudinal ligament (OPLL) were investigated retrospectively.
  
  
  OBJECTIVE
  To clarify which patients with OPLL will develop cervical myelopathy.
  
  
  METHODS
  Sixty consecutive patients with OPLL were radiologically assessed comparing the myelopathic patient group (M group, n=41) and the mild or non-myelopathic patient group (non-M group, n=19).
  
  
  RESULTS
  The narrowing ratio of the spinal canal in the M group (47.1%) was significantly greater (P=0.026) than that in the non-M group (38.3%). The two groups showed a significant difference (P=0.0016) with regard to the Pavlov ratio (M group, 0.73; non-M group, 0.84). The total range of motion of the cervical spine did not differ between the two groups but the per cent range of motion was significantly greater (P=0.037) in the M group than in the non-M group.
  
  
  CONCLUSIONS
  This study suggests that factors important in the onset or aggravation of myelopathy are factors related to pathological compression by OPLL, cervical soft disc herniation, developmentally narrow spinal canal, and local or non-proportional hypermobility.
authors.affiliation: Department of Orthopaedic Surgery, Tottori University, Faculty of Medicine, Yonago, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Morio
authors.forename: H
authors.initials: H
authors.lastname: Nagashima
authors.forename: R
authors.initials: R
authors.lastname: Teshima
authors.forename: K
authors.initials: K
authors.lastname: Nawata
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D017846:Longitudinal Ligaments / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009333:Neck; D009999:Ossification, Heterotopic; D011859:Radiography; D012189:Retrospective Studies; D013118:Spinal Cord Diseases / Q000000981:diagnostic imaging* / Q000209:etiology