Correlation of Sagittal Imbalance and Recollapse after Percutaneous Vertebroplasty for Thoracolumbar Osteoporotic Vertebral Compression Fracture: A Multivariate Study of Risk Factors

STUDY DESIGN: A retrospective case control study. PURPOSE: This study aimed to assess the clinical significance of sagittal balance for predicting and managing the recollapse of cemented vertebra following percutaneous vertebroplasty (PVP) in patients with thoracolumbar osteoporotic vertebral fracture (OVF). OVERVIEW OF LITERATURE: Recently, the recollapse of cemented vertebra following PVP for OVF has been reported. Although the risk factors for recollapse have been determined, the association between sagittal spinopelvic parameters and sagittal imbalance with recollapse has not been established. METHODS: Ambulatory patients who underwent single-level PVP for thoracolumbar OVF with a follow-up of at least 24 months were retrospectively reviewed. The patients were divided into two groups depending on the presence of symptomatic recollapse at the cemented vertebra: (1) recollapsed (RC) group and (2) noncollapsed (NC) group. The patient characteristics and radiographic measurements associated with sagittal imbalance were analyzed at each follow-up visit. RESULTS: Overall, 134 patients (RC group, n=28; NC group, n=106) were enrolled. The mean fracture-free interval was 3.2 months (range, 1.2–25.1 months). The multivariate binary logistic regression analysis identified low bone mineral density (p=0.047), degree of dynamic mobility within the vertebra (p=0.025), and sagittal imbalance as significant risk factors for recollapse (p=0.013; odds ratio, 5.405). The progression of sagittal imbalance and thoracolumbar kyphosis (T10–L2) was more significant in the RC and sagittal imbalance groups than in the NC group (both p=0.000). CONCLUSIONS: Sagittal imbalance, lower bone mineral density, and dynamic mobility within the vertebra are associated with the recollapse of cemented vertebrae following PVP. Sagittal imbalance, rather than local kyphosis or thoracolumbar kyphosis, is particularly significant in that it results in more progressive collapse and sagittal deformity and is accompanied by substantial back pain and neurological deficits. Therefore, a stricter and more active management, including anti-osteoporosis medication, is required for the treatment of OVF with sagittal imbalance of the spine.