Reevaluation of the Pavlov ratio in patients with cervical myelopathy.
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.
Suk
Kyung-Soo
KS
Department of Orthopedic Surgery, Kyung Hee University College of Medicine, Korea. sks@khmc.or.kr
Kim
Ki-Tack
KT
Lee
Jung-Hee
JH
Lee
Sang-Hun
SH
Kim
Jin-Soo
JS
Kim
Jin-Young
JY
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