Novel detachable stents for the treatment of benign esophageal strictures

The radial force of esophageal stents may not completely change during extraction and therefore, the procedure of stent removal may cause tissue damage. The present study reports the manufacture of 2 novel detachable stents, which were designed to reduce tissue damage through their capacity to be taken or fall apart prior to removal and evaluated the supporting properties of these stents and the extent of local mucosal injury during their removal. The stents were manufactured by braiding, heat-setting, coating and connecting. The properties of the stents were evaluated by determining the following parameters: Expansion point, softening point, stent flexibility, radial compression ratio and radial force. A total of 18 rabbits with induced esophageal stricture were randomly assigned to 3 groups as follows: Detachable stent (DS) group, biodegradable stent (BS) group and control group. The stricture rate, complications, survival, degradation and stent removal were observed over 8 weeks. The stents of the DS and BS groups provided a similar supporting effect. The stricture rate, incidence of complications and survival were also similar between the 2 groups, while significant differences were noted between the DS and control groups and between the BS and control groups. In the BS group, the stents were degraded and moved to the stomach within 7 weeks (2 in 6 weeks and 3 in 7 weeks). The debris was extracted using biopsy forceps. In the DS group, all stents were easy to remove and 2 cases exhibited minor hemorrhage. In conclusion, the 2 types of novel detachable stent provided an equally efficient supporting effect in vitro and in vivo and may reduce the incidence of secondary injury during stent removal.