人工髓核柔性稳定系统对犬邻近颈椎间盘影响的实验研究

Empirical study of the effect on dog′s intervertebral disc adjacent to operative segments by using prosthetic disc nucleus with flexible stabilization device

目的:比较人工髓核柔性稳定一体化系统与钢板内固定系统置入对犬施术节段邻近颈椎间盘退变的影响。方法:选择健康杂种犬23只,雌雄不限,犬龄1.5～2.5岁,体重20.0～30.0kg。预实验组5只,测量犬颈椎间盘压力正常参考值。18只实验用犬随机分为人工髓核柔性稳定组(A组,9只)及钢板内固定组(B组,9只),均经前路行C3/4椎间盘摘除、内置物置入手术。术中测量邻近颈椎间盘(C4/5)压力,并计算施术前后C4/5椎间盘压力差作为撑开压力,t检验比较A、B组间压力差有无显著性差异。术后6个月处死动物,行影像学(Pearce标准)及组织学观察,评价邻近上位颈椎间盘(C2/3)退变程度。结果:A、B组间施术前后邻近颈椎间盘(C4/5)压力差无显著性差异(P>0.05)。术后6个月,B组动力位X线片发现C2/3有失稳表现者4例(44.4%)。MRIT2加权像C2/3椎间盘Pearce分级A组(平均1.78级)低于B组(平均3.22级);A组C2/3椎间盘退变组织学分级(平均1.56级)亦低于B组(平均2.78级),且差异均有显著性(P<0.05)。各组内撑开压力与椎间盘退变分级呈正相关(P<0.05)。结论:过高的撑开压力易导致犬施术节段邻近颈椎间盘退变,应用人工髓核柔性稳定系统较钢板固定可以有效防止邻近节段的退变。

Objective：To study the effect on intervertebral disc adjacent to operative segments by using prosthetic disc nucleus with flexible stabilization device or by using plate systems comparatively.Method：23 dogs of medical fitness were included, 1.5-2.5 years old,weight 20.0-30.0kg.Reference value of cervical intervertebral disc was measured by 5 dogs of force-empirical group.18 empirical dogs were divided into 2 groups,group A （prosthetic disc nucleus with flexible stabilization devices）,9 dogs,and group B （plate systems）,9 dogs.All cases underwent anterior discectomy on C3/4,and were implanted with internal fixators.The pressure of intervertebral disc adjacent to operative segment （C4/5） was measured in the operation.The pressure change from preoperative to postoperative in group A and group B was evaluated by t-test.All animals were killed after 6 months.The degeneration degrees of intervertebral disc adjacent upon operative segments （C2/3） were evaluated by imaging （by Pearce standard） and histological study.Result：There was no significant difference between group A and group B in pressure change of intervertebral disc adjacent to operative segments （P〉0.05 ）.The instability of intervertebral disc adjacent to operative segment（C4/5） was observed by dynamic X-ray at 6 months post operation,and 4 cases of instability were found in group B （44.4%）.There was significant difference on Pearce classification by MRI T2 weighting between group A （mean 1.78） and group B （mean 3.22）（P〈0.05）,and on degeneration degrees of histological anatomy between group A（mean 1.56） and group B （mean 2.78）（P〈0.05）.The significant positive correlations were discovered between the pressure change and degeneration degrees in each group （P〈0.05）.Conclusion：Exorbitant brace pressure can induce the degeneration on dog＇s intervertebral disc adjacent to operative segments,and the degeneration can be decreased by using prosthetic disc nucleus with flexible stabilization devices compared with plate systems.