Comparison of three kinds of self-expandable metallic stents induced granulation tissue hyperplasia in the rabbit trachea

To compare stent-induced granulation tissue hyperplasia of bare (SEMS), polyurethane-covered (PU-SEMS) and electrospun nanofibre-covered (EN-SEMS) self-expandable metallic stents in the rabbit trachea. Twenty-seven rabbits were randomly assigned to 3 groups that received SEMS, PU-SEMS or EN-SEMS. Computed tomography and sacrifice were performed as scheduled. Haematoxylin–eosin and Masson’s trichrome staining protocols were performed for pathological analysis. The data for tracheal ventilation area ratio, qualitative histological scoring, number of epithelial layers, and thicknesses of papillary projection and submucosa were documented and statistically analysed. All stents were successfully placed under the guidance of fluoroscopy without complications. Post-stenting 3 and 7 days, computed tomography revealed that the fully expandable EN-SEMS was similar to the SEMS and PU-SEMS. The mean stented tissue score in the SEMS group was higher than those of both the PU-SEMS and EN-SEMS groups at 3 days post-stenting. The pathological findings suggested that there was no papillary projection formation 3 days after stent placement. The thickness of papillary projection in the SEMS group was significantly higher than those of the PU-SEMS and EN-SEMS groups at 7 days post-stenting. After stenting 4 weeks, the tracheal ventilation area ratio of SEMS, PU-SEMS and EN-SEMS was 0.214 ± 0.021, 0.453 ± 0.028 and 0.619 ± 0.033, respectively. There were significant between-group differences. In conclusion, the stent-induced granulation tissue formation in EN-SEMS is less severe than that of PU-SEMS and SEMS. EN-SEMS has smaller radial force, and the tracheal ventilation ratio after stent placement better than that of PU-SEMS.

Comparison of Emergency Resection, Self-Expanding Metallic Stents and Decompressing Stoma for Left-Sided Obstructive Colon Cancer: A Protocol for Systematic Review and Network Meta-Analysis

Background: The optimal management strategy for patients with left-sided obstructive colon cancer remains unclear. The aim of this study is to compare the efficacy and safety of emergency resection (ER), self-expanding metallic stents (SEMS) and decompressing stoma (DS) for left-sided obstructive colon cancer.Methods: Electronic searches by titles/abstracts of ER, SEMS and DS for left-sided obstructive colon cancer will be performed using the following electronic bibliographic databases: PubMed, Cochrane Library, Embase and clinical trials. The protocol of this network meta-analysis has been registered on PROSPERO (CRD42021243097). The primary outcomes are the oncological outcomes such as local recurrence rate and overall and disease-free survival. Secondary outcomes of this study include peri- and postoperative outcomes, successful primary anastomosis, temporal and permanent stoma. Included randomized controlled trials will be evaluated on their risk of bias with the Cochrane Collaboration’s risk of bias tool. The quality of observation studies will be assessed using Risk Of Bias In Non-Randomized Studies of Interventions (ROBINS-I) tool. The overall quality of the evidence will be judged based on Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) criteria in the network meta-analysis. Heterogeneity, publication bias, subgroup analysis and sensitivity analysis will be explored.Discussion: Considering the importance of acute intestinal obstruction in left-sided colon cancer, we hope that this network meta-analysis can aid and accelerate the consolidation of evidence, such that health-care professionals and patients are provided with high-quality evidence to facilitate decisions on how to manage patients with left-sided obstructive colon cancer. We will conduct subgroup and sensitive analysis to determine the potentially appropriate population for either ER or a bridge to surgery (SEMS or DS) and provide a foundation for future studies from our network meta-analysis.