Pavlov's Ratio of the Cervical Spine in a Korean Population: A Comparative Study by Age in Patients with Minor Trauma without Neurologic Symptoms

BACKGROUD: There are many studies on the vertebral body-to-canal ratio, the so-called Pavlov's ratio of the cervical spine. However, there are no studies on its relation with age to clarify each bony component's contribution to the spinal canal formation and its size. The aim of this study was to investigate differences and changes in the vertebral body-to-canal ratio according to age in an asymptomatic population. METHODS: This is a cross-sectional study of 280 asymptomatic individuals. A total of 140 men and 140 women representing each decade of life from the first to the seventh were included in this study. The anteroposterior length of the vertebral body and canal from C3 to C6 was measured on sagittal radiographs to calculate the vertebral body-to-canal ratio. RESULTS: The average Pavlov's ratio was significantly larger (p < 0.001) in the first decade of life. The average Pavlov's ratio of the individuals in the first decade of life was 1.09 between C3 and C6 (1.08 at C3, 1.07 at C4, 1.11 at C5, and 1.13 at C6; range, 0.78–1.51). There was no significant difference among the other decades of life. CONCLUSIONS: We assessed the Pavlov's ratio of the cervical spine in an asymptomatic population. It is our belief that the spinal canal size is the largest in the first decade of life, and the Pavlov's ratio becomes almost fixed throughout life after maturity.