放射状视神经切开手术机制的初步研究

Experiment study of laminal cribrosa after radial optic neurotomy in cats'eye

目的观察猫眼行放射状视神经切开术(RON)后视盘结构的改变,探讨RON的临床机制。方法健康成年猫18只分为术后1、15、30、90d四组,右眼行RON。术后1d组为6只。分别于术后1、15、30、90d取材,行组织病理学观察。结果术后1d巩膜切口呈"一"型裂开,手术间隙与蛛网膜下腔相通,伴少量出血及炎性细胞浸润;15～30d切口呈"枣核"型,神经胶质细胞增生,胶原纤维沿切口缘环形增生,以Ⅰ型和Ⅲ型为主,筛孔呈长裂隙状;90d瘢痕组织将筛板和巩膜切口完全填充,Ⅲ型胶原排列不规则,边缘的筛孔形态恢复。结论手术将视盘周围的巩膜环及视神经眼内段软膜锐性切开,切口在巩膜环处呈逐渐扩宽趋势并与蛛网膜下腔相通;这可能是RON减轻临床症状的机制之一。

Objective Central retinal vein occlusion （CRVO） can result in loss of vision from intraretinal hemorrhage, edema,or retinal isehemia. Recently, Opremeak has advocated the use of a radial optic neurotomy as a possible treatment of CRVO. This experiment tried to explore the anatomical changes of the optic nerve head after radial optic neurotomy in cats. Methods A total of 18 healthy cats were used in the experiment and divided into four groups. The cats from each operative group was sacrificed at the 1 st （6 cats） , 15th （4 cats） , 30th （ 4 cats） , 90th day （ 4 cats ） after radial optic neurotomy unilaterally. The sections of enucleated cat eyes were prepared routinely and embedded in paraffin,and the cross sections were stained by special staining. Results At the 1st day after the operation, the fissure at incision site was seen and local hemorrhage and inflammatory cells infiltrated into the circumambience and backside. No damage of major vessel wall was found, and the cerebral pialmater of orbital optic nerve kept integrate. Histological examination of the optic nerve demonstrated foci of hemorrhage, reactive gliosis and inflammatory cells. At the 15th day, incision was core-like shape and hyperplastic neuroglia cells and fibroblasts aggregated at the incision. At the 30th day, there was obvious proliferation of fibril type Ⅲ at the neurotomy. The aligned texture of collagen site fibril of the laminal cribrosa near the incision moved closely to each other. At the 90th day,a discrete scar was noted at the site that reached the cribriform and sclera. Conclusion Radial optic neurotomy can cut scleral ring and pia mater of optic nerve sharply. The incision of radial optic neurotomy connected with cerebral pia mater of obital optic nerve and became broaden gradually at the site of scleral ring. The potential role of incision is relevant to the subject.