Degenerative retrolisthesis: is it a compensatory mechanism for sagittal imbalance

Abstract

Study Design: Retrospective analysis of a prospectively collected patient database.

Objective: to investigate the spinopelvic morphology and global sagittal balance of

degenerative retrolisthesis, and to determine whether retrolisthesis is a result of spinopelvic morphology or a compensatory mechanism of global sagittal balance.

Summary of Background Data: We investigated the spinopelvic morphology and global sagittal balance of patients with a degenerative retrolisthesis or anterolisthesis. A total of 269 consecutive patients with a degenerative spondylolisthesis were included in this study.

There were 95 men and 174 women with a mean age of 64.3 years (SD 10.5; 40 to 88). A total of 106 patients had a pure retrolisthesis(R group), 130 had a pure anterolisthesis (A group), and 33 had both (R+A group).

Results: A backward slip was found in the upper lumbar levels (mostly L2 or L3) with an almost equal gender distribution in both the R and R+A groups. The pelvic incidence and sacral slope of the R group were significantly lower than those of the A (both p < 0.001) and R+A groups (both p < 0.001). The lumbar lordosis of the R+A group was significantly

greater than that of the R (p = 0.025) and A groups (p = 0.014). The C7 plumb line of the R group was located more posteriorly than that of the A group (p = 0.023), but was no different from than that of the R+A group (p = 0.422). The location of C7 plumb line did not differ between the three groups (p = 0.068). The spinosacral angle of the R group was significantly

smaller than that of the A group (p < 0.001) and R+A group (p < 0.001).

Conclusions: Our findings imply that there are two types of degenerative retrolisthesis: one occurs primarily as a result of degeneration in patients with low pelvic incidence, and the other occurs secondarily as a compensatory mechanism in patients with an anterolisthesis and high pelvic incidence.