Intravertebral Vacuum Cleft and Its Varied Locations within Osteoporotic Vertebral Compression Fractures: Effect on Therapeutic Efficacy.

BACKGROUND Previous studies have reported a high incidence of re-collapse of the augmented vertebrae after percutaneous vertebral augmentation (PVA) for osteoporotic vertebral compression fractures (OVCFs) with intravertebral vacuum cleft (IVC) during long-term follow-up. Previous IVC might be considered an important predisposing factor for re-collapse, but the prior studies could not find a significant correlation. OBJECTIVE To determine the incidence and distribution characteristics of IVCs and to further assess IVCs in their varied locations. To assess the long-term therapeutic efficacy of PVA for OVCFs with IVC. STUDY DESIGN A retrospective cohort study. SETTING Department of spinal surgery, an affiliated hospital of a medical university. METHODS A retrospective review was performed on 594 patients who underwent PVA to treat OVCFs from January 2010 to December 2013. Eighty-two patients with the IVC sign were enrolled in the study. The follow-up period was a minimum of 2 years. The difference between IVC and non-IVC patients was compared. Comparisons of the radiological and clinical findings at varied IVC locations were made pre-operatively and post-operatively (immediate, at one year, and at 2 years). RESULTS IVC incidence correlated with older patient age and severe demineralization. Other baseline parameters showed no significant differences. The rate of cement leakage and vertebral fracture was significantly lower in the IVC groups than in the non-IVC groups intraoperatively. There was no significant difference in the incidence of cement leakage or adjacent vertebral fractures between the 3 IVC groups. In the immediate postoperative period, all patients benefited from significant improvement in vertebral body height and kyphotic angle correction. However, significant re-collapse was observed at the 2-year post-operative follow-up for the IVC patients when compared to the non-IVC patients. Among the 3 IVC groups, the most severe re-collapse was observed with inferior endplate IVCs. Superior endplate IVCs and IVCs extending to both endplates demonstrated only mild re-collapse at the 2-year follow-up. LIMITATION Due to the infrequency of this process, the number of patients with IVCs was small. CONCLUSION PVA treatment was initially effective in all patients with OVCFs. However, significant re-collapse of the augmented vertebrae with IVCs, especially those with inferior endplate IVCs, was found with long-term follow-up. Key words: Intravertebral vacuum cleft, percutaneous vertebral augmentation, osteoporotic vertebral compression fractures, affected vertebrae, augmented vertebrae.