Effect of Percutaneous Kyphoplasty on the progression of intervertebral disc degeneration: a retrospective cohort study

BACKGROUND: The effect of percutaneous kyphoplasty (PKP) or rather polymethylmethacrylate (PMMA) on adjacent intervertebral discs is still controversial. The evidence from experimental study to clinical study presents bipolar conclusions. In this study, we investigated the effect of PKP on adjacent intervertebral disc degeneration (IDD). METHODS: The experimental group included adjacent intervertebral discs of vertebrae treated with the PKP procedure, and the control group included adjacent intervertebral discs of non-traumatized vertebrae. All measurements were taken by magnetic resonance imaging or X-ray. The intervertebral disc height, the modified Pfirrmann grading system (MPGS), and its differences with Klezl Z and Patel S (ZK and SP) classifications were compared. RESULTS: A total of 264 intervertebral discs from 66 individuals were selected for the study. The comparison of intervertebral disc height between the two groups pre and post-operatively resulted in a p-value of > 0.05. No significant change was observed in the adjacent discs in the control groups post-operatively. Post-operatively, the mean Ridit increased significantly from 0.413 to 0.587 in the upper disc and from 0.404 to 0.595 in the lower disc in the experimental group. The comparison of MPGS differences showed that the predominant value was 0 in the Low-grade leaks group and 1 in the Medium and high-grade leaks group. CONCLUSIONS: The PKP procedure can accelerate adjacent IDD, but it does not cause disc height changes in the early stage. The quantity of cement leaking into the disc space positively correlated with the rate of disc degeneration progression.