新西兰大白兔腰椎间盘退变、固定融合术后相邻椎间盘退变模型的建立

Establishment of adjacent disc degeneration model after fixed fusion surgery in New Zealand white rabbits with lumbar disc degeneration

目的建立新西兰大白兔腰椎间盘退变、固定融合术后相邻椎间盘退变的动物模型。 方法取10个月龄健康新西兰大白兔15只，雌雄不限，用18G穿刺针在透视下经皮穿刺定位L3～L4椎间盘，定期观察磁共振成像（MRI），当L3～L4椎间盘出现退变后，切除L3～L4椎间盘取横突椎体间植骨融合、钛板内固定，术后连续观察相邻椎间盘MRI的变化，术后12周处死兔，做相邻椎间盘的组织病理学观察。 结果穿刺椎间盘术前、后各时间点兔反应评分比较，差异均无统计学意义（F＝1.563，P＝0.061）；椎间盘切除固定融合术后各时间点兔反应评分与术前比较，差异均有统计学意义（F＝6.178，P＝0.000）。而穿刺和融合、固定术后两组比较各时间点兔反应评分均明显降低，差异均有统计学意义（t＝7.952和5.791和3.944，P＝0.000和0.000和0.000），存活率100%。动态查MRI，发现穿刺椎间盘后第4周开始在T2像上整体表现为信号下降，融合固定术后相邻椎间盘有不同程度退变表现，第4周后经皮穿刺椎间盘术后和椎间盘切除固定融合术后的相邻椎间盘退变差异无统计学意义（P＝0.084），第8、12周后相邻椎间盘退变差异有统计学意义（P＝0.002）；固定融合术后12周处死实验动物，见固定节段完全融合，周围被骨痂包饶，相邻节段椎间盘在大体表现为髓核色灰暗，呈脂肪样改变，量少；苏木素-伊红（HE）染色：髓核界限不清，髓核组织被软骨组织所替代，中央呈变性样改变。 结论为椎间盘切除固定融合术后相邻椎间盘退变的研究提供了一种可靠的动物模型。

Objective To establish New Zealand white rabbit model of adjacent disc degeneration after fixed fusion surgery. Methods Take 15 male or female New Zealand white rabbits of 10 - month - old, with a 18G needle positioning L3 - L4 disc under fluoroscopic, and regular observe their magnetic res- onance imaging （MRI）. We removal of the I3 -IA disc, and take transverse interbody fusion, fix with ti- tanium plate, when L3 - IA intervertebral disc degenerate. Continuously observe they changes of the adja- cent disc on MRI after the surgery. We will execute them 12 weeks after surgery, and make histopathologic observation adjacent disc. Results There is no difference between before and after disc puncturing surgery about the reaction rates of animals（ F = 1. 563, P = 0. 061 ）. After discectomy and fusion surgery, the reac- tion rates of animals on different time is different, and the difference is statistically significant （ F = 6. 178, P = 0. 000）. And after discectomy and fusion surgery, all the reaction rates of animals on different time are ireduced compared to pre - operation, and the difference is statistically significant （ t= 7.952 and 5. 791 and 3. 944, P = 0. 000 and 0. 000 and 0. 000 ）. The survival rate of New Zealand white rabbit is 100%. Continuously observe MRI, we find that the signal of T2 falls in the fourth week after the disc puncturing surgery, and there are different levels degeneration performance of adjacent disc after fusion fixation surgery. The reaction rates of animals on two surgeries is different, and the difference is not statistically significant after 4 weeks （P = 0. 084）. But after 8 or 12 weeks, the difference is statistically significant （P = 0. 002）. When we executed the animals 12 weeks after surgery, we found that the fixed segment is fully in- tegrated and is wrapped around by the poroma. The nucleus of adjacent segment disc is dark colored, and it showed a fat - like changes and the amount is little. HE staining ： ill - defined nucleus, nucleus pulposus is replaced by cartilage, central nucleus degenerate. Conclusion This research study provides an ideal, reliable animal model for the research of adjacent disc degeneration after discectomy and fusion surgery.