Changes in Sagittal Spinopelvic Parameters according to Pelvic Incidence in Asymptomatic Old Korean Men

ABSTRACT

STUDY DESIGN: A radiographic study of normal subjects. OBJECTIVES: To analyze sagittal spinal parameters according to the size of pelvic incidence (PI). SUMMARY OF LITERATURE REVIEW There has been no previous study about the classification of spinopelvic parameters that has used a large cohort of asymptomatic older men with the same ethnic background as those in the current study. MATERIALS AND METHODS: We examined 160 males aged over 50 without disease, trauma, or history of operation on spine or lower extremities. Sagittal standing radiographs of the whole spine on 36-inch film were taken. Group 1 (n=30) had a PI of less than 40degrees. Group 2 (n=71) had PI between 40degrees and 50degrees, and group 3 (n=59) had a PI greater than 50degrees. Thoracic kyphosis, thoracolumbar kyphosis, lumbar lordosis, the vertebral slope of T12, sacral slope, and pelvic incidence were measured. The distances from the plumb line of C7, T12, and the lumbar apex to the posterosuperior corner of the sacrum were also measured. RESULTS: Subjects' average age was 64.1(53~83).Lumbar lordosis, sacral slope and pelvic tilt were all significantly increased in group 3. Thoracic kyphosis and the vertebral slope of T12 were not different between groups. The distances from the plumb line of C7, T12, and the lumbar apex to the posterosuperior corner of the sacrum were significantly translated anteriorly in group 3. CONCLUSIONS: Group 3, who had the largest PI, demonstrated the largest lumbar lordosis and the most forward transition of trunk. However there were no differences in thoracic kyphosis and the vertebral slope of T12 among the three groups.