Risk Factors for Adjacent Vertebral Fractures Following Cement Vertebroplasty: The Clinical Significance of Multiple Preexisting Vertebral Compression Fractures.

Study design: A retrospective cohort study.

Objective: The study retrospectively analyzed the factors associated with the development of adjacent vertebral fractures.

Summary of background data: Adjacent vertebral fractures (AVF) may occur following cement vertebroplasty, and several risk factors have been reported with controversies.

Methods: A total of 123 patients, with a mean age of 79.2 years, who underwent single-level vertebroplasty were included in the investigation. We systematically collected data encompassing baseline demographics, osteoporosis parameters, surgical details, radiologic measurements, and Hounsfield unit (HU) values in the lumbar spine. Subsequently, univariable, followed by multivariable logistic regression analyses, were employed to identify the risk factors of AVFs.

Results: Thirty of 123 patients had AVFs within 6 months following vertebroplasty. The AVF group exhibited a higher percentage of multiple preexisting vertebral compression fractures (P=0.006), a greater volume of injected cement (P=0.032), and a more pronounced reduction in local kyphosis (P=0.007). Multivariable logistic regression analysis revealed multiple preexisting vertebral compression fractures and a reduction in local kyphosis exceeding 8 degrees were independent risk factors for AVFs (P=0.008 and 0.003, respectively), with odds ratios of 3.78 (95% confidence interval: 1.41-10.12) and 4.16 (95% CI: 1.65-10.50), respectively. Subgroup analysis showed that patients with multiple preexisting vertebral compression fractures (VCFs) had significantly lower bone mineral density Z-score, T-score, and HU values compared with those without preexisting VCFs (P<0.05). Conversely, there were no significant differences in T-score or HU values between patients with no VCFs and those with a single VCF.

Conclusion: This study demonstrated that both bone strength and local alignment are key factors associated with adjacent vertebral fractures. Specifically, having multiple preexisting vertebral compression fractures and a reduction in local kyphosis exceeding 8 degrees are independent risk factors. The presence of more than one previous vertebral compression fracture serves as a significant clinical indicator of advanced bone density reduction in patients with osteoporosis, offering a quick and straightforward method for identifying high-risk patients. Patients exhibiting these risk factors should be monitored more closely for favorable clinical outcomes.

Level of evidence: Level III-retrospective nonexperimental study.