title: Reevaluation of the Pavlov ratio in patients with cervical myelopathy.
abstract: BACKGROUND
  This study was designed to reevaluate the effectiveness of the Pavlov ratio in patients with cervical myelopathy.
  
  
  METHODS
  We studied 107 patients who underwent open door laminoplasty for the treatment of cervical myelopathy between the C3 to C7 levels. We determined the Pavlov ratio on preoperative and postoperative cervical spine lateral radiographs, the vertebral body-to-canal ratio on sagittal reconstruction CT scans, and the vertebral body-to-cerebrospinal fluid (CSF) column ratio on T2-weighted sagittal MR images from C3 to C6. The severity of myelopathy was determined using the JOA score on both preoperative and postoperative images. The recovery rate was also calculated. The Pavlov ratio in plain radiographs from patients with myelopathy was compared with the ratio of the vertebral body to the spinal canal on CT and MRI.
  
  
  RESULTS
  The average Pavlov ratio between C3 and C6 ranged from 0.71 to 0.76. On CT scan, the average vertebral body-to-canal ratio between C3 and C6 ranged from 0.62 to 0.66. On MRI, the vertebral body-to-CSF column ratio between C3 and C6 ranged between 0.53 and 0.57. A positive correlation was noted between the Pavlov ratio and the vertebral body-to-canal ratio on sagittal-reconstruction CT (correlation coefficient = 0.497-0.627, p = 0.000) and between the Pavlov ratio and the vertebral body-to-CSF column ratio on MRI (correlation coefficient = 0.511-0.649, p = 0.000).
  
  
  CONCLUSIONS
  We demonstrated a good correlation between the Pavlov ratio and both the vertebral body-to-canal ratio on CT and the vertebral body-to-CSF column ratio on MRI. Therefore, the Pavlov ratio can be relied upon to predict narrowing of the cervical spinal canal in the sagittal plane.
authors.affiliation: Department of Orthopedic Surgery, Kyung Hee University College of Medicine, Korea. sks@khmc.or.kr
authors.forename: Kyung-Soo
authors.initials: KS
authors.lastname: Suk
authors.forename: Ki-Tack
authors.initials: KT
authors.lastname: Kim
authors.forename: Jung-Hee
authors.initials: JH
authors.lastname: Lee
authors.forename: Sang-Hun
authors.initials: SH
authors.lastname: Lee
authors.forename: Jin-Soo
authors.initials: JS
authors.lastname: Kim
authors.forename: Jin-Young
authors.initials: JY
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002555:Cerebrospinal Fluid; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D012016:Reference Values; D012189:Retrospective Studies; D013115:Spinal Canal / Q000000981:diagnostic imaging; D013118:Spinal Cord Diseases / Q000000981:diagnostic imaging* / Q000473:pathology*; D014057:Tomography, X-Ray Computed