| Object To design a novel stent with modified ends and to investigate the effect of this airway stent in ruducing benign hyperplasia through animal experiments.Methods This novel ends-modified covered self-expandable metallic stent (SEMS) was designed by authors and custom-made with the help of the Micro-Tech Corp. A total of 12 experimental beagles were randomly divided into two groups (each n=6) in this experiment: the experimental group, placed with ends-modified covered SEMSs, and the control group placed with cylindrical covered SEMSs. At the 2nd,4th,8th and 16th week after placement, all beagles were examined with CT scans to calculate stenosis indexes and to measure degrees of displacement. All beagles were sacrificed and the tracheal specimens surrounding the airway stents were collected for macroscopic examination, HE staining and proliferating cell nuclear antigen (PCNA) staining at the 16th week. The positive expression of proliferative cells was analyzed quantificationally.Results All stents were successfully placed. The experimental group had significantly larger stenosis indexes compared with the control group as a whole (P<0.01). The difference of stenosis indexes between the two groups was statistically significant at the 4th and 8th week (P<0.05), while there was no statistical difference at the 2nd or 16th week (P>0.05). Pathologic tracheal wall injuries were basically same in both groups. There was also no statistical difference of complications or degrees of displacement between two groups (P>0.05).Conclusion Improvement of the design at the end of covered stents is an effective way to ruduce benign hyperplasia. This new modle of airway stent used in the experimental group can prevent benign stent-related restenosis. |
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