Factors affecting recompression of augmented vertebrae after successful percutaneous balloon kyphoplasty: a retrospective analysis

Background: The instantaneously recovered stability and strength following vertebral augmentation prevent continuous micro-motion and further collapse of fractured vertebrae. Despite this, during follow-up of our patients, we observed recompression of augmented vertebrae with significant vertebral height loss and aggravation of local kyphotic deformity. Purpose: To identify the risk factors related to recompression and to evaluate the clinical significance of recompression. Material and Methods: One hundred and twenty-one patients who underwent single-level kyphoplasty for osteoporotic vertebral fractures were retrospectively analyzed and classified into the following two groups: group 1 with recompression and group 2 without recompression. Characteristics of patients and fractured vertebrae were compared between the two groups. Univariate and multivariate regression analyses were performed to identify risk factors for recompression. We evaluated the visual analogue scale (VAS) and the Oswestry disability index (ODI) scores in both groups to elucidate the clinical impact. Results: During an average of 20.754.43 months of follow-up, 17 augmented vertebrae developed recompression. In the recompression group, vertebral height loss was accompanied by significantly aggravated local kyphotic deformity. The local kyphotic angle differed significantly between the two groups at final follow-up (P=0.011). However, the VAS and ODI scores were maintained at final follow-up in both groups although the values were slightly higher in group 1. Solid lump distribution pattern (OR=8.718; P=0.003) and the degree of vertebral height restoration (OR=1.260; P<0.001) were identified as the most important risk factors for recompression. Conclusion: Fractured vertebrae containing solid lump cement and those with more vertebral height restoration are at higher risk of recompression. More attention should be given to these patients considering the aggravated local kyphotic deformity.