Factors Affecting Delayed Union of Vertebral Fractures Following Percutaneous Kyphoplasty

Background: Although percutaneous kyphoplasty (PKP) could achieve rapid pain relief for the elderly with osteoporotic vertebral compression fracture (OVCF), some patients still had risks of suffering vertebrae delayed union which led to persisting pain and vertebral collapse. Preventing the delayed vertebral union could reduce the further morbidities and medical costs for patients with OVCF after PKP. Objectives: To explore the factors involved in delayed vertebral union after PKP in patients with OVCF. Study Design: Retrospective analysis. Setting: All data were from Hong-Hui hospital in Xi'an. Methods: There were 580 patients treated using single-segment PKP between January 2011 and January 2012. Demographics, clinical data, types of vertebral fracture, and surgical data were collected to analyze the factors associated with delayed vertebral union after PKP. Results: Twenty-nine patients (5%) experienced delayed vertebral union. Univariate analyses showed that preoperative bone mineral density (BMD), cement consumption, intravertebral cleft, restoration rate of vertebral height, and improvement in kyphotic angle were associated with delayed union of vertebrae after PKP (P < 0.05). Multivariate analysis revealed that preoperative BMD (odds ratio (OR) = 0.452, 95% confidence interval (CI): 0.207 - 0.987, P = 0.046), intravertebral cleft (OR = 9.156, 95% CI: 3.712 - 22.585, P < 0.001), and restoration rate of vertebral height (OR = 2.731, 95% CI: 1.622 - 4.599, P < 0.001) were independently associated with delayed union of vertebrae. Limitation: A multi-center study is recommended to confirm our findings and explore the factors related to vertebrae delayed union. Conclusions: Preoperative BMD, intravertebral cleft, and restoration rate of vertebral height could be factors independently associated with delayed union of vertebrae after PKP in patients with OVCF.