title: Measurement of volume-occupying rate of cervical spinal canal and its role in cervical spondylotic myelopathy.
abstract: OBJECTIVE
  To compare volume-occupying rate of cervical spinal canal between patients with cervical spondylotic myelopathy (CSM) and normal subjects, and to investigate its significance in cervical spine disease.
  
  
  METHODS
  Spiral computed tomography (CT) scan (C4-C6 cervical spine unit) was performed in 20 normal subjects and 36 cases of CSM at a neutral position, and data were transferred to the Advantage Workstation Version 4.2 for assessment. Bony canal area and fibrous canal area in each cross section, and sagittal diameters of cervical spinal canal and cervical spinal body were measured. Volume-occupying rate of cervical spinal canal was calculated using MATLAB. Cervical spinal canal ratio and effective cervical spinal canal ratio were calculated, and Japanese Orthopaedic Association score was used to assess cervical spinal cord function.
  
  
  RESULTS
  Volume-occupying rate of cervical spinal canal at a neutral position was significantly higher in CSM patients as compared to normal subjects (P < 0.01). There was no correlation between cervical spinal canal ratio and JOA score in CSM patients, with a Pearson's correlation coefficient of 0.171 (P > 0.05). However, sagittal diameter of secondary cervical spinal canal, effective cervical spinal canal ratio and volume-occupying rate of cervical spinal canal were significantly associated to JOA score, with Pearson's coefficient correlations of 0.439 (P < 0.05), 0.491 (P < 0.05) and -0.613 (P < 0.01), respectively.
  
  
  CONCLUSIONS
  Volume-occupying rate of cervical spinal canal is an objective reflection of compression on cervical spine and spinal cord, and it is associated with cervical spinal cord function. These suggest that it may play a significant role in predicting the development of CSM.
authors.affiliation: Orthopedics Department, The First Affiliated Hospital of Anhui Medical University, Hefei, 230022, China. dongfulong@sina.com
authors.forename: Fulong
authors.initials: F
authors.lastname: Dong
authors.forename: Cailiang
authors.initials: C
authors.lastname: Shen
authors.forename: Shu
authors.initials: S
authors.lastname: Jiang
authors.forename: Renjie
authors.initials: R
authors.lastname: Zhang
authors.forename: Peiwen
authors.initials: P
authors.lastname: Song
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Yu
authors.forename: Shiyu
authors.initials: S
authors.lastname: Wang
authors.forename: Xiaohu
authors.initials: X
authors.lastname: Li
authors.forename: Gang
authors.initials: G
authors.lastname: Zhao
authors.forename: Changhai
authors.initials: C
authors.lastname: Ding
mesh_terms: D000328:Adult; D002574:Cervical Vertebrae / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D013115:Spinal Canal / Q000473:pathology*; D013117:Spinal Cord Compression / Q000473:pathology*; D055009:Spondylosis / Q000473:pathology*