Rezaei Asghar, Giambini Hugo, Miller Alan L, Liu Xifeng, Elder Benjamin D, Yaszemski Michael J, Lu Lichun
Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA.
Department of Orthopaedic Surgery, Mayo Clinic, Rochester, MN 55905, USA.
Appl Sci (Basel). 2020 Oct;10(19). doi: 10.3390/app10196912. Epub 2020 Oct 2.
The spinal column is the most common site for bone metastasis. Vertebral metastases with instability have historically been treated with corpectomy of the affected vertebral body and adjacent intervertebral discs, and are more recently treated with separation surgery. With demographics shifting towards an elderly population, a less invasive surgical approach is necessary for the repair of vertebral defects. We have modified a previously reported expandable hollow cage composed of an oligo[poly(ethylene glycol) fumarate] (OPF) containment system that could be delivered via a posterior-only approach. Then, the polymer of interest, poly(methyl methacrylate) (PMMA) bone cement, was injected into the lumen of the cage after expansion to form an OPF/PMMA cage. We compared six different cage formulations to account for vertebral body and defect size, and performed a cage characterization via expansion kinetics and mechanical testing evaluations. Additionally, we investigated the feasibility of the OPF/PMMA cage in providing spine stability via kinematic analyses. The in-vitro placement of the implant using our OPF/PMMA cage system showed improvement and mechanical stability in a flexion motion. The results demonstrated that the formulation and technique presented in the current study have the potential to improve surgical outcomes in minimally invasive procedures on the spine.
脊柱是骨转移最常见的部位。历史上，对于伴有不稳定的椎体转移瘤，采用受累椎体及相邻椎间盘的椎体切除术进行治疗，最近则采用分离手术。随着人口结构向老年化转变，对于椎体缺损的修复，需要一种侵入性较小的手术方法。我们对先前报道的一种由聚（富马酸乙二醇酯）（OPF）容纳系统组成的可扩张中空椎间融合器进行了改进，该融合器可通过仅后路的方式植入。然后，在扩张后将感兴趣的聚合物聚甲基丙烯酸甲酯（PMMA）骨水泥注入融合器腔内，形成OPF/PMMA融合器。我们比较了六种不同的融合器配方，以适应椎体和缺损大小，并通过扩张动力学和力学测试评估对融合器进行了表征。此外，我们通过运动学分析研究了OPF/PMMA融合器在提供脊柱稳定性方面的可行性。使用我们的OPF/PMMA融合器系统进行植入物的体外放置，在屈曲运动中显示出改善和力学稳定性。结果表明，本研究中提出的配方和技术有可能改善脊柱微创手术的手术效果。
