Shape of the lumbo-sacral spine in the sagittal plane in L5-S1 spondylolisthesis.

Background. Analyses of the relations between sagittal radiographic parameters in spondylolisthesis are rare, although the anterior slippage in spondylolisthesis can affect the natural relationship between the inclination of the sacrum and lumbar lordosis. The aim of our study was to determine the inclination of the sacrum, lumbar lordosis, anterior slippage and their mutual correlations of each other in patients with L5/S1 spondylolisthesis. Material and methods. Sagittal radiographic parameters according to the Winter and Wiltse method were investigated in 75 patients with spondylolisthesis and in 40 patients without spondylolistesis and in a control group (K). Patients with spondylolisthesis were graded in two groups according to the extent of subluxation as rated by the Taillard method: 40 patients with spondylolisthesis not exceeding 30% (group I) and 35 patients with spondylolisthesis exceeding 30% (group II). We searched for correlations between progression of the subluxation, lumbar lordosis and sacral inclination in each group. Results. Measurements of the inclination of the sacral and lumbar lordosis varied within the group. This suggests that the sagittal plane configuration of the lumbo-sacral spine is influenced by the grade of subluxation in patients with spondylolisthesis. Conclusion. Sagittal plane configuration of the lumbo-sacral spine is a significant factor in the assessment of patients with L5/S1 spondylolisthesis because of its relation to the grade of subluxation.