A Comparison of a Fully Covered and an Uncovered Segmented Biodegradable Esophageal Stent in a Porcine Model: Preclinical Evaluation of Degradation, Complications, and Tissue Reactions

Table 1

Grading system for degree of esophageal tissue reaction: TRS.

Grade	Criteria and definitions
0	Normal tissue without inflammation
1	Confined inflammation; hyperplastic tissues at proximal, distal part or meshes with nodes not exceeding stent interior plane
2	Hyperplastic tissue ingrowth protruding from the stent interior plane with a single nodule not larger than 5 mm in diameter
3	Hyperplastic tissue ingrowth protruding from the stent interior plane with a nodule not larger than 10 mm in diameter
4	Diffuse inflammation; hyperplastic tissue ingrowth protruding from the stent interior plane with a node larger than 10 mm in diameter
5	Esophageal lumen blockage caused by tissue ingrowth or overgrowth