Correlation of Pelvic Parameters with Isthmic Spondylolisthesis

Study Design A retrospective radiological evaluation. Purpose To verify that PI is related with progression of IS as well as development of IS and to assess the differences of pelvic parameters between the L4 & L5 IS, as well as between single & two level IS. Overview of Literature High pelvic incidence (PI) has been known to be related with development of IS. However, the previous studies were limited to just L5 spondylolisthesis or there was no differentiation between L4 & L5 spondylolisthesis Methods Sixty five IS patients and 30 persons as a control group participated the study. Among the 65 patients, 30 had L4 IS, 30 had L5 IS and 5 had bi-level IS. We used the whole spine lateral radiographs to measure the slip percentage, the pelvic tilt (PT) and the pelvic incidence (PI), and we compared them between the normal control group and the IS patients, as well as between single-level and bi-level spondylolisthesis, and we investigated the correlation between the degree of slip of spondylolisthesis and the pelvic parameters. Results The averages of the PT, PI and lumbar lordosis (LL) in the control group and the IS group were 11.0° vs 21.4° (p0.05). On comparison between the single-level IS group and the bilevel IS group, there was a significant difference of the PT and PI (p