Purpose

Implant leakage is the most common complication of vertebral augmentation. Alternative injectable materials must demonstrate intravascular safety comparable to or better than polymethyl methacrylate (PMMA). This study assessed the systemic effects of a triphasic calcium-based implant or PMMA injected directly into the femoral vein in a large animal model designed to mimic severe intravascular implant leakage.

Methods

Six skeletally mature female sheep were randomly assigned (n = 3) to either the PMMA or the triphasic implant (AGN1, composition: calcium sulfate, β-tricalcium phosphate, brushite) treatment group. Femoral veins of each sheep were directly injected with 0.5 mL of implant material to mimic leakage volumes reported during PMMA vertebroplasty. To compare acute systemic effects of the materials, cardiovascular parameters, laboratory coagulation markers, and calcium and sulfate serum levels were monitored for 60 min after implant injection. Thrombotic and embolic events were evaluated by radiologic imaging, necropsy, and histopathology.

Results

Heart rate, systemic arterial blood pressure, arterial oxygenation, arterial carbon dioxide content, and coagulation markers remained within physiological range after either AGN1 or PMMA injection. No blood flow interruption in the larger pulmonary vessels was observed in either group. Lung histopathology revealed that the severity of thrombotic changes after AGN1 injection was minimal to slight, while changes after PMMA injection were minimal to massive.

Conclusion

Acute systemic effects of intravascular AGN1 appeared to be comparable to or less than that of intravascular PMMA. Furthermore, in this preliminary study, the severity and incidence of pulmonary histological changes were lower for AGN1 compared to PMMA.

中文翻译：

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在肺栓塞绵羊模型中静脉注射三相钙基植入物显示出最小的急性全身效应

目的

植入物渗漏是椎体强化最常见的并发症。替代注射材料必须证明血管内安全性与聚甲基丙烯酸甲酯 (PMMA) 相当或更好。本研究评估了在大型动物模型中直接注入股静脉的三相钙基植入物或 PMMA 的全身效应，该模型旨在模拟严重的血管内植入物渗漏。

方法

六只骨骼成熟的雌性绵羊被随机分配 ( n  = 3) 到 PMMA 或三相植入物（AGN1，成分：硫酸钙、β-磷酸三钙、透钙磷石）治疗组。每只羊的股静脉直接注射 0.5 mL 植入材料，以模拟 PMMA 椎体成形术期间报告的渗漏量。为了比较材料的急性全身效应，在植入物注射后监测了 60 分钟的心血管参数、实验室凝血标记物以及钙和硫酸盐血清水平。通过放射成像、尸检和组织病理学评估血栓形成和栓塞事件。

结果

注射 AGN1 或 PMMA 后，心率、全身动脉血压、动脉氧合作用、动脉二氧化碳含量和凝血指标均保持在生理范围内。两组均未观察到较大肺血管的血流中断。肺组织病理学显示，AGN1 注射后血栓形成变化的严重程度从最小到轻微，而 PMMA 注射后的变化从最小到大量。

结论

血管内 AGN1 的急性全身效应似乎与血管内 PMMA 相当或更小。此外，在这项初步研究中，与 PMMA 相比，AGN1 的肺组织学变化的严重程度和发生率较低。