椎体间纤维性融合重建兔脊柱稳定性的初步探索

Primary research of intervertebral fibrous fusion for rabbit spine segmental instability: an experimental study

中文关键词:  纤维性融合  聚乳酸聚酯  脊柱节段失稳  新西兰兔

英文关键词:Fibrous Fusion  Poly L-lactic-co-glycolic acid(PLGA)  New Zea-land white rabbits  Spine segmental instability

中文摘要:

  【摘要】　目的：研究椎体间纤维性融合后脊柱节段的稳定性，探讨椎体间纤维性融合在治疗脊柱节段失稳中的可行性。方法：将18只6月龄新西兰白兔随机分为两组，均摘除L4/5椎间盘髓核，A组在椎间植入环状聚乳酸-聚羟基乙酸（poly L-lactic-co-glycolic-acid，PLGA）可吸收支架；B组单纯髓核摘除。于术前、术后4周、12周行X线检查，运用Image J软件测量椎间盘高度指数（DHI）并计算其百分数（％DHI），分别于术后4周、8周、12周处死3只动物，行组织病理及免疫组化观察。结果：1只动物死亡，17只实验动物术后存活至预期时间，未补充实验动物。12周时，侧位X线片示两组椎间高度较术前均有下降，两组椎间高度的差异有统计学意义（P＜0.05），A、B两组屈伸活动度与术前相比差异均无统计学意义（P＞0.05）。X线片显示A组手术节段椎体无明显移位及反向成角，B组1只兔子出现前屈位腰椎后凸曲度增加，手术节段椎间隙变窄并邻近软骨终板钙化。细胞组织学观察：术后4周时A组见新生血管及纤维组织生成，有少量类软骨细胞出现，未观察到PLGA支架结构；B组见较多纤维细胞生成。术后8周时，A组出现软骨细胞，纤维组织排列不规则，并见少量的胶原纤维及成纤维细胞；B组纤维组织进一步增生，形成瘢痕样组织。术后12周时，A组大量的胶原纤维、软骨组织交互长入，排列杂乱无序，此时的胶原纤维较8周时增多；B组仍为纤维细胞和瘢痕组织，且Ⅰ型胶原表达高于Ⅱ型胶原。结论：椎体间植入PLGA并利用其与椎体骨髓血的诱导成骨作用短期内可以形成椎间纤维融合；短期内观察椎间纤维融合能够维持一定的脊柱节段稳定性并保留部分生理活动功能，但中远期效果有待进一步观察。

英文摘要:

  【Abstract】 Objectives: To investigate the spinal stability and the feasibility of fibrous fusion for spine segmental instability. Methods: 18 New Zealand white rabbits（6 months old） were randomly divided into 2 groups: nucleotomy and PLGA implantation after drilling holes on the vertebral endplate(group A) and nucleotomy alone(group B). In group A, after L4/5 nucleotomy, a ring-like PLGA scaffold was implanted. X-ray weas performed before and 12 weeks after the operation. The DHI was measured by using Image J software while evaluating the disc height, segmental stability, segmental range of motion(ROM), and immunohistochemical analysis was performed at 4, 8, and 12 weeks and their results were recorded． Results: 17 animals were survived after operation(no additional animal). 12 weeks later, disc height decreased in both groups, showing significant difference between group A and group B(P＜0.05), no significant difference of ROM between two groups with preoperation(P＞0.05). The flexion-tension lateral X-ray of group A did not show vertebral surge or reverse angle. But in group B, 1 animal′s flexion lateral X-ray showed recurvation deformity and adjacent segment endplate calcification, and the operation intervertebral space became narrower than the preoperative. No PLGA scaffold structure was found at 4 weeks postoperatively, fibrillar tissue formation was evidenced in both groups, but few of chondrocyte-like cells and neocapillaries proliferated in group A. At 8 weeks postoperatively, chondrcyte cells and a large number of disordered fiber tissues occurred, a few of collagenous fiber and fibrocyte cells were found in group A, while fiber cells and scar tissues in group B. Amount of collagenous fiber and cartilage interactively compacted into the intervertebral space, and the collagenous fiber increased than before in group A while still fiber cells and scar tissues in group B, that more type Ⅰ collgen than type Ⅱ collagen was evidenced. Conclusions: Bone marrow blood of vertebrae can form relatively effective fiber fusion as well as reconstructive segmental stability, which can preserve segmental motion, but its long term effects need further research.