Experimental and clinical study on barium used to increase radiopacity of bone cement for vertebroplasty

Objective To investigate preferable mixing ratio of barium used to increase radiopacity of bone cement for vertebroplasty. Methods Bone cement was classified into four groups according to the ratio of powder/liquid (g/ml) as 3∶2, and the percentage of BaSO_4 in powder as 0, 10%, 20%, 30%, respectively. CT value, strength and stiffness of bone cement were measured respectively in each group. Five vertebral bodies (VBs) from each of two spines harvested from female cadavers were disarticulated and compressed in a materials testing machine to determine initial strength and stiffness.The fractures were repaired by using bone cement whose ratio of powder/iquid (g/ml)was 3∶2 and the percentage of BaSO_4 in powder was 20%. After augmentation,the VBs were recrushed. Thirty-one cases with 36 vertebraes underwent PVP, which were performed with bone cement whose ratio of powder/iquid (g/ml) was 3∶2 and the percentage of BaSO_4 in powder was 20%. Visual analogue scale point (VAS) (10-point scale) before vertebroplasty,24 hours after, one week and one month after vertebroplasty were recorded respectively. Results The CT value, the strength and the stiffness of bone cement with different percentage of BaSO_4 in powder were significantly different(P0.05). VBs augmented with bone cement whose ratio of powder/iquid (g/ml) was 3∶2 and the percentage of BaSO_4 in powder was 20% have a different biomechanical properties compared with preaugmentated. There are significant differences among the scores of VAS with different time points. No further or new vertebral compression occurred in all patients during the follow-up of 193-611 days. No major compications occurred in this series, except asymptoamic cement leak around vertebrae. Conclusion Bone cement whose ratio of powder/iquid (g/ml) 3∶2 and the percentage of 20% BaSO_4 in powder has satisfactory radiopacity. It can increase the biomechanical properties of VBs effectively. Stable therapeutic effects can be attained by using this kind of bone cement on percutaneous vertebroplasty. It's feasible to apply this kind of bone cement on the percutaneous vertebroplasty.