Elastoplasty: A Silicon Polymer as a New Filling Material for Kyphoplasty in Comparison to PMMA

Background: Painful vertebral compression fractures (VCF) caused by osteoporosis are a common health problem in the elderly population. If conservative treatments are unsuccessful, surgical treatments like vertebroplasty or kyphoplasty are recommended. But the use of Polymethylmethacrylat (PMMA) bone cement for augmentation surgery is associated with risks. Objectives: Evaluation of the effectiveness and safety of a newly developed silicon polymer (VK100) that can be used instead of PMMA bone cement for kyphoplasty treatments. Study Design: A retrospective study of 30 patients comparing the outcomes of kyphoplasty treatments conducted with PMMA and VK100. Setting: Clinic for Orthopedics and Trauma Surgery Bonn, Germany. Methods: Thirty patients with one to 3 VCF were treated either with balloon kyphoplasty using VK100 or balloon kyphoplasty using PMMA bone cement. Data from both groups was compared by a matched pair analysis. The medial vertebral height was measured at each examination radiologically. The patients stated their pain intensity using the Visual Analogue Scale (VAS) and the patient’s functional impairment was evaluated with the Oswestry-Disability-Index (ODI). All data were assessed before surgery, and 3 days, 3 months, 6 months, and 12 months after surgery. Intraoperative and postoperative adverse events were documented. Results: The patients’ functional impairment and pain improved significantly after surgery. The course of ODI and VAS was comparable in both treatment groups, but the improvement in the VK group was significantly ongoing until the 12 month follow-up. Vertebral height improvement was significant in both groups, but the PMMA group achieved a better absolute restoration. The vertebral height stayed constant during the follow-up in the VK group and worsened significantly in the PMMA group. There was no significant difference between groups concerning the occurrence of additional fractures; and no other types of complications or surgery-related adverse events were observed in either the PMMA group or in the VK group. Limitations: The study is only a matched pair analysis of 15 patients for each procedure and the amount of injected filling material was not recorded. Conclusion(s): The study results demonstrate that the clinical outcome of VAS and ODI of using the silicon polymer VK100 is comparable or slightly better than using PMMA. VK 100 shows a trend to minor additional fractures during the follow-up. However, height restoration is not satisfactory in comparison to PMMA, although vertebral height stayed more or less constant in the VK group. To address the augmentation success further, it would be necessary to study a larger patient group over a longer study period and to assess additional parameters such as bone density and injected amount of filling material. Key words: Vertebral compression fracture, kyphoplasty, augmentation, osteoporosis, back pain, VK 100, elastoplasty