title: Dynamic changes in the spinal cord cross-sectional area in patients with myelopathy due to cervical ossification of posterior longitudinal ligament.
abstract: BACKGROUND
  Dynamic changes in the spinal cord cross-sectional area due to cervical ossification of the posterior longitudinal ligament (C-OPLL) are unknown, but dynamic multidetector-row computed tomography (MDCT) may be a useful tool.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the influence of dynamic factors on the spinal cord in patients with C-OPLL using MDCT during flexion and extension after myelography.
  
  
  METHODS
  This was a prospective cohort study.
  
  
  METHODS
  Participants included 107 prospectively enrolled consecutive patients with C-OPLL and myelopathy.
  
  
  METHODS
  The outcome measure was the extension/flexion ratio at the spinal cord cross-sectional area at the most stenotic cervical level (SCASL).
  
  
  METHODS
  Dynamic MDCT was performed, and the SCASL was measured. Patients were divided into the kyphosis group or lordosis group according to C2-C7 alignment. They were divided further into the K-line (-) group or K-line (+) group. The Japanese Orthopedic Association (JOA) score was used to determine myelopathy severity.
  
  
  RESULTS
  All patients with C-OPLL had myelopathy, with a mean JOA score of 10.7 and mean disease duration of 16.7 months. The average extension/flexion ratio at all disc levels was less than 100%, suggesting that the spinal cord was compressed more during extension. In the kyphosis group, the spinal cord was compressed slightly more during flexion than during extension. In the K-line (-) group, the spinal cord was compressed more during flexion, although C2-C7 alignment was slightly lordotic on average. Large changes in the spinal cord cross-sectional area during extension-flexion and disease duration significantly influenced the severity of myelopathy.
  
  
  CONCLUSIONS
  Dynamic MDCT was useful for evaluating dynamic changes in the spinal cord. At the most stenotic level, the spinal cord became narrower during extension at all disc levels. In the kyphosis group and K-line (-) group, it became narrower during flexion. Cervical flexion may induce greater spinal cord compression in patients with kyphosis and K-line (-).
authors.affiliation: Department of Orthopaedic Surgery, Chubu Rosai Hospital, 1-10-6 Koumei Minato-ward, Nagoya-city, Aichi 444-8530, Japan; Department of Orthopaedic Surgery, Nagoya University Hospital, Graduate School of Medicine, 65 Tsurumai Showa-ward, Nagoya-city, Aichi 466-8550, Japan. Electronic address: kenyubankara@yahoo.co.jp.
authors.forename: Kenyu
authors.initials: K
authors.lastname: Ito
authors.affiliation: Department of Orthopaedic Surgery, Chubu Rosai Hospital, 1-10-6 Koumei Minato-ward, Nagoya-city, Aichi 444-8530, Japan.
authors.forename: Yasutsugu
authors.initials: Y
authors.lastname: Yukawa
authors.affiliation: Department of Orthopaedic Surgery, Chubu Rosai Hospital, 1-10-6 Koumei Minato-ward, Nagoya-city, Aichi 444-8530, Japan.
authors.forename: Keigo
authors.initials: K
authors.lastname: Ito
authors.affiliation: Department of Orthopaedic Surgery, Chubu Rosai Hospital, 1-10-6 Koumei Minato-ward, Nagoya-city, Aichi 444-8530, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Machino
authors.affiliation: Department of Orthopaedic Surgery, Chubu Rosai Hospital, 1-10-6 Koumei Minato-ward, Nagoya-city, Aichi 444-8530, Japan.
authors.forename: Shunske
authors.initials: S
authors.lastname: Kanbara
authors.affiliation: Department of Orthopaedic Surgery, Nagoya University Hospital, Graduate School of Medicine, 65 Tsurumai Showa-ward, Nagoya-city, Aichi 466-8550, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Nakashima
authors.affiliation: Department of Orthopaedic Surgery, Nagoya University Hospital, Graduate School of Medicine, 65 Tsurumai Showa-ward, Nagoya-city, Aichi 466-8550, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Hida
authors.affiliation: Department of Orthopaedic Surgery, Nagoya University Hospital, Graduate School of Medicine, 65 Tsurumai Showa-ward, Nagoya-city, Aichi 466-8550, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Ishiguro
authors.affiliation: Department of Orthopaedic Surgery, Nagoya University Hospital, Graduate School of Medicine, 65 Tsurumai Showa-ward, Nagoya-city, Aichi 466-8550, Japan.
authors.forename: Shiro
authors.initials: S
authors.lastname: Imagama
authors.affiliation: Department of Orthopaedic Surgery, Chubu Rosai Hospital, 1-10-6 Koumei Minato-ward, Nagoya-city, Aichi 444-8530, Japan.
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Kato
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019412:Anatomy, Cross-Sectional; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D009192:Myelography; D017887:Ossification of Posterior Longitudinal Ligament / Q000150:complications / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D016059:Range of Motion, Articular; D013116:Spinal Cord / Q000000981:diagnostic imaging*; D013117:Spinal Cord Compression / Q000000981:diagnostic imaging; D013118:Spinal Cord Diseases / Q000000981:diagnostic imaging* / Q000209:etiology
keywords: Cervical spine; Dynamic; K-line; Multidetector-row computed tomography; Ossification of posterior longitudinal ligament; Spinal cord cross-sectional area