Farrokhi Majid Reza, Torabinezhad Simin, Ghajar Korush Azodi
Shiraz Neurosciences Research Center, Department of Neurosurgery, Shiraz University of Medical Sciences, Shiraz, Iran.
J Spinal Disord Tech. 2010 Jun;23(4):272-7. doi: 10.1097/BSD.0b013e3181b63da6.
An experimental pilot study using an acrylic interbody cage in a dog cervical spine fusion model.
To compare bony fusion in autologous bone grafting with a novel acrylic cage in terms of preservation of disc height, biomechanical properties, and histologic characteristics.
Degenerative diseases of cervical intervertebral discs are commonly treated by anterior decompression and interbody fusion. To restore physiologic disc height and achieve fusion, the disc is replaced with bone graft, bone cement, interbody fusion cages, or other materials. The advantages of bone cement in contrast to bone graft and interbody fusion cages are immediate stability and less subsidence, although real bony fusion cannot be achieved. To overcome this problem, we designed a new, inexpensive acrylic cage.
Ten adult hybrid dogs underwent C3/C4 (5 dogs) and C4/C5 (5 dogs) discectomy and fusion with an acrylic interbody fusion cage made of polymethylmethacrylate filled with bone graft (n=5, group1) or an autologous iliac bone graft (n=5, group 2). Dynamic functional x-ray was obtained 1 and 12 weeks after the operation. After 12 weeks, the animals were killed and fusion sites were evaluated with quantitative computed tomographic scanning to evaluate bone mineral density. Subsistence was quantified with biomechanical testing. Histopathologic analysis was used to evaluate fusion and possible foreign body reactions associated with the acrylic cage.
The acrylic cage led to significantly higher disc space height and less subsidence than bone grafting (P<0.021). Bone mineral density after 12 weeks was greater with the acrylic cage, but the difference was not statistically significant. Histologically, new bony tissue and hyaline cartilage were seen inside the acrylic cage, accompanied by mild chronic inflammation.
The acrylic cage showed significantly higher mechanical stiffness and less subsidence than bone grafting. Additional studies with more subjects and longer follow-up periods are needed to compare the cost effectiveness of acrylic cages and polyetheretherketone devices.
一项在犬颈椎融合模型中使用丙烯酸椎间融合器的实验性初步研究。
比较自体骨移植与新型丙烯酸融合器在椎间盘高度保留、生物力学性能和组织学特征方面的骨融合情况。
颈椎间盘退变疾病通常采用前路减压和椎间融合术治疗。为恢复生理椎间盘高度并实现融合，椎间盘需用骨移植、骨水泥、椎间融合器或其他材料替代。与骨移植和椎间融合器相比，骨水泥的优点是即刻稳定性和较少下沉，尽管无法实现真正的骨融合。为克服这一问题，我们设计了一种新型、廉价的丙烯酸融合器。
十只成年杂种犬接受了C3/C4（5只犬）和C4/C5（5只犬）椎间盘切除术，并分别用填充有骨移植材料的聚甲基丙烯酸甲酯制成的丙烯酸椎间融合器（n = 5，第1组）或自体髂骨移植（n = 5，第2组）进行融合。术后1周和12周进行动态功能X线检查。12周后，处死动物，通过定量计算机断层扫描评估融合部位的骨密度。通过生物力学测试对下沉情况进行量化。组织病理学分析用于评估融合情况以及与丙烯酸融合器相关的可能异物反应。
与骨移植相比，丙烯酸融合器导致椎间盘间隙高度显著更高且下沉更少（P < 0.021）。12周后丙烯酸融合器组的骨密度更高，但差异无统计学意义。组织学上，在丙烯酸融合器内可见新的骨组织和透明软骨，伴有轻度慢性炎症。
与骨移植相比，丙烯酸融合器显示出显著更高的机械刚度和更少的下沉。需要更多受试者和更长随访期的进一步研究来比较丙烯酸融合器和聚醚醚酮装置的成本效益。
