Influence of Compression Ratio Differences between Magnetic Resonance Images and Simple Radiographs on Osteoporotic Vertebral Compression Fracture Prognosis after Vertebroplasty

OBJECTIVE: The extent of collapse progression after vertebroplasty in osteoporotic vertebral compression fractures (OVCF) has known to be various. In this study, we investigated that how much difference of compression ratio between standing simple radiograph and supine magnetic resonance imaging (MRI) affects the collapse progression after vertebroplasty. METHODS: This retrospective cohort study was carried out based on 27 patients with 31 OVCFs undergone vertebrplastyin the thoracolumbar junction (T12-L2), from January to December 2009. The OVCFs were divided to two groups, the smaller group A and larger group B, by mean compression ratio difference (8.1%) between standing simple radiograph and supine MRI. RESULTS: There were no significant differences in the baseline characteristics of the two groups except age. There were also no significant differences between the periodic compression ratio, back pain, Cobb's angle during follow-up period. However, Group B seemed to show improvements from the initial state to the point just after the operation, but eventually took a much worse course than group A. In the end, judging from the compression ratios of the two groups at the last follow up, group A showed less progression. CONCLUSION: Although the clinical outcome was not different significantly, a greater compression ratio difference in the initial study resulted in a greater collapse progression at last follow-up. Therefore, we suggest that it is important to check the initial standing simple radiograph, as well as supine MRI, for predicting collapse progression after vertebroplasty.