人工硬膜修补硬脊膜及预防椎管内粘连的实验观察

An experimental observation of the histopathological response of the artificial dura as an onlay dural graft and the prevention of peridural fibrosis and adhesion

目的:观察人工硬膜(胶原海绵)敷贴修补硬脊膜破损的组织病理学反应和预防术后硬脊膜周围纤维化粘连的效果。方法:实验A,30只家兔随机分成3组,每组10只,造成硬脊膜纵形破损,随机分别应用人工硬膜、明胶海绵敷贴裂口处和旷置。术后8d和30d处死动物,行肉眼和组织学观察,同时进行缺损区瘢痕组织的成纤维细胞密度评级。实验B,12只家兔随机分成2组,每组6只,进行T10和T12椎板切除,使硬膜裸露,T10缺损旷置,作为空白对照,T12缺损用人工硬膜或明胶海绵进行覆盖,术后30d,处死动物取材。肉眼和组织学观察硬膜缺损处并按有关的组织学评级标准半定量分析。结果:实验A中人工硬膜在体内未引起不良反应。组织学观察发现植入物内有大量的成纤维细胞长入、毛细血管形成和胶原沉积,植入物有降解趋势。实验B中与空白对照组比较,人工硬膜组硬脊膜周围粘连较轻(P<0.05)。结论:人工硬膜(胶原海绵)作为一种硬脊膜移植材料具有较好的组织相容性,有促进组织修复作用;早期能防止硬脊膜外瘢痕组织向椎管内侵入,起到空间屏障作用,在一定程度上减轻了纤维瘢痕组织侵入椎管所造成的硬脊膜周围纤维性粘连。

Objective：To evaluate the histopathological response of the artificial dura as an onlay dural graft and its efficacy as an interpositional material in the prevention of postlaminectomy peridural fibrosis and adhesion in an in vivo study （rabbit model ）.Method ： Protocol A,durotomy and repair with onlay dural grafts（grafts were not sutured） was performed.30 New Zealand white rabbits were utilized.Laminectomy of a 1.0×0.5cm defect at T12 was performed and then a 0.3cm linear dural incision was made.30 animals were randomly allocated into 3 subgroups,10 animals in each.In GS group,absorbable gelatin sponge was implanted as a dural graft without suture.In CS group,artificial dura（collagen sponge） was implanted as an onlay dural graft.In control group,the dural laceration was left untreated.Groups of rabbits were sacrifced at 8 and 30 days postoperatively.Macroscopic and histological evaluations of each specimen were performed,including a descriptive e- valuation and quantitative scoring of the graft-sided cellular （fibroblasts） density.Protocol B,laminectomy and implantation of the interposition materials was performed.12 New Zealand white rabbits were randomly allocated into 2 subgroups.All of the rabbits underwent laminectomy at T10 and T12.Half of the rabbits（6） had collagen sponge implantation and the other 6 had gelatin sponge implants at a randomly assigned level,with the remaining level served as an internal control （left uncovered ）.The animals were sacrificed at 30d postoperatively.Qualitative and semi-quantitative gross pathological and histological evaluations were performed for both the control and the experimental sites to assess the sponges＇ efficacy in preventing peridural fibrosis.Result： The use of artificial dura casused no severe adverse effect in vivo.Histological evaluation showed graft infiltration by fibroblasts,deposition of collagen and neovascularity.According to the scores of cell density,there was no difference among CS group,GS group and control group （P〉0.05） at 8 days of postoperation.However,significant differences were observed at the different time intervals （8 and 30d） within each group.Compared to the control site,collagen sponge could prevent the invasion of fibrosis into the spinal canal and the area in contact with the exposed dura postlaminectomy after the period of 30 days （P〈0.05）.However,no difference in efficacy was detected between the GS and control group.Conclusion：The artificial dura （collagen sponge） is safe to be used as an onlay dural graft.As an interposition material,collagen sponge promotes the healing process and is effective in preventing peridural fibrosis at the early stage.However its effect at the later stage of scar formation is still unknown.Further research on the use of collagen sponge as a dural graft is necessary to clarify its ＂watertight＂ features and barrier membrane effect.