RECIPROCAL ANGULATION OF VERTEBRAL BODIES IN THE SAGITTAL PLANE IN ANASYMPTOMATIC GREEK POPULATION

Study Design. A prospective study conducted on several roentgenographi c parameters of the standing sagittal profile of the spine in an asymp tomatic Greek population. Objectives. To preterm segmental analysis of the sagittal plane alignment of the normal thoracic, lumbar and lumbo sacral spines and to compare the findings with those derived from simi lar populations. Summary of Background Data. Until recently, little at tention has been paid to the sagittal segmental alignment of the spine , and there are only a few studies (in French and American populations ) in which radiographic analysis of sagittal spinal alignment is inves tigated. Methods. Ninety-nine consecutive asymptomatic Greek volunteer s (38 men, 61 women), an average age of 52.7 +/- 15 years old (range, 20-79 years), were included in this prospective study, on the basis of several inclusion criteria. These volunteers were divided into six di stinct age groups. The radiologic parameters, which were measured (by Cobb's method) on the lateral standing roentgenograms of the whole spi ne were: thoracic kyphosis (T4-T12), lumbar lordosis (L1-L5), total lu mbar lordosis (T12-S1), distal lumbar lordosis (L4-S1), sacral inclina tion (measured from the line drawn parallel along the back of the prox imal sacrum and the vertical line), pelvic tilting, vertebral body inc lination, and relative segmental inclination between pairs of adjacent vertebrae. Results. Thoracic kyphosis and lumbar lordosis (T12-S1, L1 -L5) were not gender related. Thoracic kyphosis increased with age (P < 0.001), the lumbar spine (L1-L5) gradually became less lordotic as t he thoracic kyphosis increased (P < 0.003), and total lumbar lordosis was not age related. Sacral inclination correlated strongly with both thoracic kyphosis (P < 0.002) and L1-L5 lordosis (P < 0.001). Pelvic t ilting correlated strongly with L1-L5 lordosis (P < 0.0075) but dit no t correlate with thoracic kyphosis and age. Vertebral body inclination showed a narrow variability in T6-T12 and in L4 and a wide variabilit y in T4, T5, L1-L3, and S1. Distal lumbar lordosis represents the 68.6 % of the total lumbar lordosis. Conclusions. In the results of this st udy, a reliable table of reference for roentgenographic parameters in the sagittal plane of the spine was established in an asymptomatic Gre ek population. The parameters are similar to those used in previous st udies. Thus, these data should be considered in preoperative planning and postoperative evaluation of achieved correction during restoration procedures of the spine in the sagittal plane.