Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada.
Spine (Phila Pa 1976). 2009 Dec 1;34(25):2745-53. doi: 10.1097/BRS.0b013e3181b4abf5.
An original investigation that characterizes polyvinyl alcohol cryogel (PVA-C) in the context of the human lumbar intervertebral disc (IVD).
To evaluate the mechanical properties of PVA-C under physiological conditions; to assess PVA-C's suitability as a key component in a tissue-mimicking artificial lumbar intervertebral disc; and to identify suitable formulations that mimic the nucleus pulposus and anulus fibrosus.
Current lumbar intervertebral disc prostheses provide suboptimal symptom relief and do not restore natural load-cushioning. PVA-C is a promising material due to its high water content, excellent biocompatibility, and versatile mechanical properties.
PVA-C samples were prepared with different PVA concentrations and number of freeze-thaw cycles (FTC). Unconfined compression was conducted to characterize various PVA-C formulations. Compressive stress relaxation and creep were performed to assess the stability of PVA-C under loading. The results were compared to the mechanical properties of human lumbar intervertebral discs obtained from literature.
PVA-C compressive elastic modulus increased with increasing PVA concentration and number of FTC's. The 3% 3FTC is the optimal formulation for mimicking the nucleus pulposus in compression. In general, compressive stress relaxation and creep decreased with increasing PVA concentration and number of FTC's. Compressive stress relaxation and creep were lower for PVA-C than human lumbar intervertebral discs, suggesting that PVA-C will likely exhibit stable and predictable mechanical response in vivo. All formulations provided good mimicry of the human IVD in stress relaxation and creep. PVA-C also provided good match to the anulus fibrosus matrix.
Good unconfined compression, stress relaxation and creep behavior, combined with excellent biocompatibility, makes PVA-C a suitable choice as a major component of a tissue-mimicking artificial IVD. A potential artificial IVD design combining two or more different PVA-C formulations could provide excellent overall mimicry of the human IVD. Results of this investigation provide a solid foundation for future work in this area.
一项原创性研究，以人类腰椎间盘为背景，对聚乙烯醇水凝胶（PVA-C）进行了描述。
在生理条件下评估 PVA-C 的机械性能；评估 PVA-C 作为组织模拟人工腰椎间盘关键部件的适宜性；并确定模拟髓核和纤维环的合适配方。
目前的腰椎间盘假体提供的症状缓解效果并不理想，也不能恢复自然的负荷缓冲功能。PVA-C 是一种很有前途的材料，因为它具有高含水量、良好的生物相容性和多种机械性能。
使用不同的 PVA 浓度和冻融循环（FTC）次数制备 PVA-C 样品。通过无约束压缩对各种 PVA-C 配方进行了特性描述。进行压缩应力松弛和蠕变实验，以评估 PVA-C 在加载下的稳定性。结果与文献中获得的人类腰椎间盘的机械性能进行了比较。
随着 PVA 浓度和 FTC 次数的增加，PVA-C 的压缩弹性模量增加。在压缩模拟髓核方面，3%3FTC 是最佳配方。一般来说，随着 PVA 浓度和 FTC 次数的增加，压缩应力松弛和蠕变减小。与人类腰椎间盘相比，PVA-C 的压缩应力松弛和蠕变较低，这表明 PVA-C 在体内可能表现出稳定和可预测的机械响应。所有配方在应力松弛和蠕变方面都很好地模拟了人类 IVD。PVA-C 也很好地模拟了纤维环基质。
良好的无约束压缩、应力松弛和蠕变行为，加上出色的生物相容性，使 PVA-C 成为组织模拟人工 IVD 的主要成分的合适选择。结合两种或更多不同 PVA-C 配方的潜在人工 IVD 设计，可以提供对人类 IVD 的极好整体模拟。本研究结果为该领域的未来工作提供了坚实的基础。
