Background: Vertebral compression fractures are common among the elderly, which is conditioned by osteoporosis. They cause back pain and limit the patient's activities. The Kiva® VCF Treatment System is a new device to treat vertebral compression fractures. Compared to other methods, the utilization of the Kiva System reduces the risk for complications and delivers improvements in back pain reduction and functionality.
Objectives: Evaluation of safety and effectiveness of the Kiva System in comparison to balloon kyphoplasty on the basis of matched pairs.
Methods: 52 patients (47 - 89 years, 68 fractures) were treated with balloon kyphoplasty or with the new Kiva System. Back pain and impairment of motility were assessed preoperatively and 6 months postoperatively, with the Visual Analog Scale (VAS) and Oswestry Disability Index (ODI). The operation time and cement extravasation were recorded. Control radiographs were evaluated for new fractures and vertebral heights.
Results: Mean VAS values in both groups improved from preoperatively 87.6 ± 12.8 and 83.1 ± 14.9 to 10.8 ± 20.8 and 24.6 ± 11.0 6 months after the treatment. The improvement after 6 months in the Kiva group was significantly better than in the balloon kyphoplasty group (P < 0.0001). Mean ODI scores in both groups also improved from 68.7% ± 15.8% in the Kiva group and 80.6% ± 8.6% in the balloon kyphoplasty group preoperatively to 24.8 ± 18.6% and 33.2 ± 6.3% 6 months after treatment. The mean operation time for the Kiva group was 12.7 ± 3.7 minutes per vertebra and cement leakage occurred in 6 patients. The mean operation time for the balloon kyphoplasty group was 34.1 ± 7.0 minutes per vertebra and cement leakage occurred in 8 patients. Anterior and mid vertebral height in the Kiva group increased from preoperatively 21.06 ± 7.44 mm and 18.36 ± 5.64 mm to postoperatively 22.41 ± 7.14 mm and 20.41 ± 6.00 mm. Anterior and mid vertebral height in the balloon kyphoplasty group increased from preoperatively 21.68 ± 2.06 mm and 21.97 ± 1.78 mm to postoperatively 25.09 ± 2.54 mm and 25.29 ± 2.10 mm. Vertebral height restoration could be therefore maintained with both procedures for 6 months. In the Kiva group 2 cases of nonadjacent fractures and one case of adjacent fractures were observed. In the balloon kyphoplasty group 9 cases of adjacent, as well as 5 cases of nonadjacent, fractures were observed. In the Kiva group significant fewer fractures occurred.
Limitations: The study includes only 26 patients for each procedure, which were compared on the basis of matched pairs.
Conclusion: The Kiva System appears to be a safe and effective procedure for the treatment of vertebral compression fractures. Six months after treatment with the Kiva System, better VAS values than the values after the treatment with balloon kyphoplasty were recorded. Reduction in functional impairment was as successful as it was after balloon kyphoplasty. Vertebral height restoration was observed in both groups, which was sustained for 6 months. The risk of cement extravasation during the Kiva Treatment is nearly the same as in balloon kyphoplasty; however, it requires a shorter operation time and produces less new fractures.