Musculoskeletal Research Center, Department of Orthopaedic Surgery, MedStar Union Memorial Hospital, Baltimore, MD, USA.
Product Development, Globus Medical Inc., Audubon, PA, USA.
J Tissue Eng Regen Med. 2019 Sep;13(9):1664-1671. doi: 10.1002/term.2920. Epub 2019 Jul 18.
The inherent properties of the human amniotic membrane (HAM) suggest its potential for use as a physical barrier during surgery to protect neural elements and vessels from the surrounding environment. The objective of this study was to evaluate the effect of a dual-layer, chorion-free amnion patch (DLAM; ViaShield®, Globus Medical Inc., Audubon, PA, USA) processed from HAM as a protective barrier following lumbar laminectomy in a sheep model. A multiplex immunoassay was performed to quantify the inherent cytokines present in the amnion after processing. Twelve skeletally mature female crossbred Suffolk sheep were randomly divided into two equal post-operative periods (4 and 10 weeks). Each sheep underwent a laminectomy at L3 and L5, and one of the surgical sites randomly received the DLAM treatment. At each postsurgical time point, the extent of epidural fibrosis and neurohistopathological responses at the laminectomy sites was assessed based on epidural fibrosis-dura tenacity scores and decalcified histology, respectively. Immunoassay results showed that inflammatory mediators and immunomodulatory cytokines were present in the amnion after processing, but no proangiogenic cytokines were detected. At 10 weeks, tissue tenacity was significantly less in the DLAM treatment group when compared with the operative control (1.2 ± 0.4 vs. 2.8 ± 0.4, p < 0.05), demonstrating the ability of DLAM to act as a barrier and cover the dura. Gross observations showed fewer fibroblasts in the DLAM group in comparison with the control at both post-operative time points. Fibroblast infiltration analysis indicated that at both 4 and 10 weeks, there were significantly more infiltrated fibroblasts in the operative control sites than in the DLAM-treated sites, expressed as a percentage of the total number of fibroblasts present (4 weeks: 72.3 ± 10.2% vs. 10.8 ± 10.1%, p < .05; 10 weeks: 84.9 ± 15.8% vs. 43.1 ± 11.6%, p < .05). Additionally, fibroblasts travelled further into the dura in the operative control group compared with the DLAM-treated group at both time points. In conclusion, this study found that DLAM reduced fibroblast infiltration and tissue tenacity following lumbar laminectomy in a sheep animal model. These findings support the potential use of DLAM in clinical practice as a protective barrier for neural elements and anterior vessels.
人羊膜（HAM）的固有特性表明其具有用作手术中物理屏障的潜力，以保护神经组织和血管免受周围环境的影响。本研究的目的是评估双层、无绒毛膜羊膜贴片（DLAM；ViaShield ® ，Globus Medical Inc.，Audubon，PA，USA）作为保护屏障在绵羊模型腰椎板切除术后的效果。使用多重免疫测定法来定量分析处理后的羊膜中存在的固有细胞因子。将 12 只骨骼成熟的雌性杂交短毛绵羊随机分为两个相等的术后期（4 周和 10 周）。每只绵羊在 L3 和 L5 进行椎板切除术，其中一个手术部位随机接受 DLAM 治疗。在每个术后时间点，根据硬膜外纤维化-硬膜坚韧度评分和脱钙组织学分别评估椎板切除部位的硬膜外纤维化和神经组织病理学反应的程度。免疫测定结果表明，处理后的羊膜中存在炎症介质和免疫调节细胞因子，但未检测到促血管生成细胞因子。在 10 周时，与手术对照组相比，DLAM 治疗组的组织坚韧度显著降低（1.2 ± 0.4 vs. 2.8 ± 0.4，p < 0.05），表明 DLAM 具有作为屏障和覆盖硬膜的能力。大体观察结果显示，在两个术后时间点，DLAM 组的成纤维细胞数量均少于对照组。成纤维细胞浸润分析表明，在 4 周和 10 周时，手术对照组的浸润成纤维细胞数量明显多于 DLAM 治疗组，以存在的总成纤维细胞数的百分比表示（4 周：72.3 ± 10.2% vs. 10.8 ± 10.1%，p < 0.05；10 周：84.9 ± 15.8% vs. 43.1 ± 11.6%，p < 0.05）。此外，与 DLAM 治疗组相比，在两个时间点，成纤维细胞在手术对照组中向硬膜内迁移的距离更远。总之，本研究发现，在绵羊动物模型中，DLAM 可减少腰椎板切除术后的成纤维细胞浸润和组织坚韧度。这些发现支持在临床实践中使用 DLAM 作为神经组织和前血管的保护屏障。
