椎体成形术对兔手术椎体相邻椎间盘的影响

Effect of vertebroplasty on the adjacent intervertebral disc in rabbits

[目的]探讨椎体成形术(vertebroplasty,VP)是否会引起兔手术椎体相邻椎间盘的退变,以及椎间盘的退变程度与聚甲基丙烯酸甲酯(polymethyl methacrylate,PMMA)用量的相关性。[方法]80只5个月龄雌性新西兰大白兔,随机选16只为正常对照组(A组),剩余的64只采用去势法建立兔骨质疏松模型后随机分为4组,设L5为手术椎体。B组(实验对照组)L5不注入任何药物;C组L5注入PMMA 0.1 ml;D组L5注入PMMA 0.3 ml;E组L5注入PMMA 0.5 ml。每组分别于术前及术后1、3、6个月各处死4只动物,进行X线、MRI检查,通过计算椎间盘高度指数百分数(disc height Index percentage,DHIP)和MRI指数,来定量分析椎间盘退变程度。并取相邻椎间盘送病理,采用Masuda评分评估椎间盘退变程度。[结果]A、B组椎间盘的DHIP、MRI指数和Masuda评分在各个时间点均无明显变化。C、D、E组在术前及术后1个月时的DHIP、MRI指数和Masuda评分较A、B组无明显改变。第3个月时,E组椎间盘的DHIP、MRI指数较其他各组均有降低,且MRI指数和Masuda评分较A、B组有统计学差异(P<0.05)。第6个月时,D、E组椎间盘的DHIP、MRI指数和Masuda评分跟术前及术后1、3个月比较均有显著统计学差异(P<0.05),E组的DHIP和MRI指数均明显低于A、B、C、D组。组织学退变也较A、B、C、D明显,Ma-suda评分明显高于A、B、C、D组。[结论]VP可以引起手术椎体相邻椎间盘的退变,并且椎间盘退变程度与PM-MA用量相关。

[ Objective] To investigate whether vertebroplasty can lead to the degeneration of adajecent disc in rabbits, and the correlation of degeneration degree to the doses of polymethyl methacrylate （PMMA） . [ Methods] Eighty female New Zeal- and white rabbits of 5 months old were used for the study, and sixteen of them were randomly selected for the normal control group （Group A） . The other sixty four rabbits were established an osteoporosis rabbit model by bilateral ovariectomy, and then divided into four groups of 16 rabbits each. The fifth lumbar vertebrate （ L5 ） was injected into nothing as experimental control group （Group B）, and 15 was injected with 0. 1 ml, 0. 3 ml and 0. 5 ml PMMA as Group C, D and E, respectively. Four rab- bits were selected randomly, then X - ray, MRI and histological observation were performed preoperatively and at the first, third, sixth month postoperatively. The DHIP （ disc height index percent） and MRI index （ the product of nucleus pulposus are- a and average signal intensity） of each disc were calculated to analyze degrees of disc degeneration. And disc degeneration was graded by Masuda~ standard of histological grading scale. The data were statistically analyzed by SPSS19.0. [ Results] There were no obvious changes at every time point on DHIP, MRI index and Masuda grade in Group A and B. There were also no obvi- ous changes on DHIP, MRI index and Masuda grade preoperatively and at the first month postoperatively in Group C, D and E compared to Group A and B. However, at the third month, the DHIP and MRI index decreased in Group E compared with the A, B, C and D groups. And there were significant differences of MRI index and Masuda grade between Group E and Group A, B （P 〈 0. 05 ） . At the sixth month, there were significant differences of DHIP, MRI index and Masuda grade in Group D and E between the preoperative and 1 postoperative surgery （ P 〈 0. 05） - month as well as 3 - month ~ And the DHIP and MRI index in Group E were statistically significantly lower than those of in Group A, B, C and D. The Masuda grade in Group E was also sta- tistically significantly higher than those of in Group A, B, C and D. [ Conclusion] Vertebroplasty can lead to the degeneration of adjacent disc in rabbits, and intervertebral disc degeneration degree is correlative to the closes of PMMA.