Relationship between the spino-pelvic parameters and the slip grade in isthmic spondylolisthesis

Purpose of the study Analysis of changes in the spino-pelvic alignment, depending on the slip grade in patients with low and high-grade isthmic slip. Materials and methods A group of 60 patients who had lumbar spine radiograms adequate to measure the spino-pelvic parameters selected from a series of 195 cases of isthmic spondylolisthesis. We analyzed the following spino-pelvic parameters: pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), lumbosacral angle by Dubousset (LSA) and lumbar lordosis (LL). The ANOVA statistical test was used to examine whether there is a significant correlation between (1) the slip grade and the value of PI, PT, and LL, and the Pearson correlation was used to examine a correlation between (2) the size of PI and the value of other spino-pelvic parameters, (3) the value of LL and SS, (4) value of the LSA and LL, PI and PT. Results The greater the slip grade, the greater the value of PI, PT, and LL and lower LSA. Positive correlations have been found between PI and SS, PT and LL. There was also a positive correlation between LL and SS. Negative correlations were noted between LSA and LL, PI and PT. Conclusion The spino-pelvic alignment changes with the grade of isthmic spondylolisthesis, and the individual spino-pelvic parameters correlate together to form a causal chain in the development of isthmic spondylolisthesis