Insertion Of Esophageal Stents In Rabbits And The Comparison Of "Partially-covered" Self-expanding Metal Esophageal Stent With "Full-covered" Stents

Objective1. To analyze the ways of insertion of the esophageal stentsin rabbits, in order to improving the achievement ratio of the procedure and cutting down the mortality.2. To evaluate the difference of the "partially—covered" and "full-covered" self-expanding esophageal metal stent, data collectionfocused on the anti-migration, complication and the mucosal hyperplasiahyper. The aim is to provide the experimental basement for the improvement of the esophageal stents.Methods1. Sixteen male New-Zealand rabbits were randomly divided into insertion of the "partially—covered" self-expanding esophageal metal stents group and the conventional stents group. After anaesthesia, all rabbits were implanted different esophageal stents with endoscopy and fluoroscopy in the esophagus. Then they were raised in cage by oneself.2. The rabbits took the fluoroscopy examination respectively on 1,2 weeks after stent implantation. If the stent had migrated into the stomach, the rabbit was killed immediately. All rabbits were killed at 4 weeks. Esophageal mucosal hyperplasiahyper and the stents were observed. Tissue around the stent was investigated with microscopy.Result1. After stents implantation, the rabbits took few food than before, and the weight decreased expressly. 2. Stents migration: Stents migration were observed in 12. 5% of the experimental group and 75% of the control group.3. Complications: Food bolus impaction occurred in 2 experimental group and 1 control group rabbits. In addition, 1 rabbit in "partially—covered" stent died because of esophago-mediastinum fistula.4. After 4 weeks, much food stayed between the stent and esophageal wall in both two groups, and the stent was certified unobstructed by visualization. Tissue at the regions of two ends of the stent was investigated with naked eye and there was not apparent hyperpiasia in both two groups. The pathological changes were not obvious, either.ConclusionUse the rabbits as an animal model for esophageal stents implanation is feasible. To control the incidence of the complication must by accumulating the experiences and improving the experimental ways. The result demonstrate that the " partially—covered " stent on the anti-migration was superior to the conventional covered stents. With respect to mucosal hyperpiasia, there was no apparent difference between these two groups. But this conclusion need more samples to certificate in further studies.