Cement leakage and filling pattern study of low viscous vertebroplastic versus high viscous confidence cement

BACKGROUND Vertebral augmentation has recently evolved as a medical procedure for the treatment of vertebral compression fractures, the most common type of skeletal fractures related to osteoporosis. METHODS This study compared the cement leakage and filling behavior of 2 existing delivery systems (Confidence and Vertebroplastic; DePuy Spine, Raynham, MA). The Confidence system with the high viscosity cement has been recently introduced in an attempt to curtail cement leakage. RESULTS The comparison was performed using an established benchmark model wherein the cement leakage, filling behavior can be assessed. A double-conduit introducer needle was used to deliver the cement and to measure the intravertebral pressure while delivering the cement. There were 5 experimental groups in this study: 3 low-viscosity groups, whose cement was injected at 3.5, 6.5, and 9.5 minutes after admixing the powder and monomer, and 2 high-viscosity groups injected at 3.5 and 6.5 minutes. The mass of leaked cement generally decreased with delaying the start of the injection. Specifically, for the low-viscosity, the average smallest leakage mass obtained was 2.6 ± 1.2g when the cement was delivered at 9.5 minutes. If delivered after 3.5 minutes, the mass of cement leak was 4.0 ± 1.2g. The high-viscosity system has showed improved results in curtailing cement leakage, as compared to low-viscosity. Specifically, if injected after 3.5 and 6.5 minutes, the cement leakage amounts were 1.5 ± 1.2g and 0.92 ± 0.6g, respectively. Similarly, the uniformity of cement filling increased when the delivery was delayed and when the high-viscosity system was applied. Furthermore, there were no significance changes in the intravertebral pressures between the low- and high-viscous groups. No correlation between the leakage mass and the IV pressures was noted. CONCLUSION The cement thickness and timing of delivery are key in controlling the intravertebral cement filling and physician may want to explore the use of low- or high-viscous cement for different fractures. The thickness of the cement has no significant impact on the intravertebral pressures.