Stents for colorectal obstruction: Past, present, and future

Table 1 Comparison of efficacy and complication of stent by type (covered stent vs uncovered stent)

Study	No. of patients	Stent	Indication	Mean age	Covering material	Patency duration between stent types	Complication
Kang et al[6]	26	Not reported	Palliation/BTS	58.0	Fully/Partially (polyurethane)	No difference	More migration in fully covered stent group
Choi et al[7]	74	Choo stent™	Palliation	60.0	Fully/Partially (polyurethane)	No difference	More migration in covered stent group
Lee et al[2]	80	Niti-S™	Palliation/BTS	63.3	Partially (polyurethane)	No difference	More migration in covered stent group
Park et al[3]	151	WallFlex™	Palliation/BTS	61.4	Partially (polytetrafluoroethylene)	No difference	More tumor ingrowth in uncovered stent group/more migration in covered stent group
		Comvi™
Moon et al[4]	68	Niti-S™ D-type	Palliation/BTS	65.8	Partially (polytetrafluoroethylene)	No difference	More migration in covered stent group
		Comvi™
Park et al[8]	103	Wallstent™	Palliation	67.3	Partially (polytetrafluoroethylene or silicon)	No difference	No difference between stent types/variable migration rates between manufacturers
		Niti-S™
		Bonastent™
		Hanarostent™
Choi et al[9]	152	Niti-S™	Palliation/BTS	70.0	Not reported	No difference	More migration and perforation in covered stent group
		Hanarostent™
		Choo stent™
		Bonastent™

BTS: Bridge to surgery; No: Number; PS: Prospective study; RS: Retrospective study.

Table 2 Commercially available colorectal stents

Name	Material	Diameter (mm)	Flare	Flare diameter (mm)	Length (mm)	Covered/uncovered	Feature	Manufacturer
Colonic Z-stent™	Stainless steel	25	A	35	40, 60, 80, 100, 120	Uncovered	No foreshortening	Cook
Evolution™	Nitinol	25	A	30	60, 80, 100	Uncovered	Controlled-release delivery system	Cook
		20	A	22	80, 100, 125, 150	Partially covered
		18, 20	A	23, 25	80, 100, 120	Fully covered
Wallstent™ Endoprosthesis	Stainless steel	20, 22	NA	NA	60, 90, 120	Uncovered	Reconstrainable	Boston Scientific
Wallstent™ Enteral	Elgiloy	20, 22	NA	NA	60, 90	Uncovered	Reconstrainable	Boston Scientific
Wallflex™ Colonic	Nitinol	22, 25	A	27, 30	60, 90, 120	Uncovered	Reconstrainable	Boston Scientific
Ultraflex™ colonic	Nitinol	25	A	30	57, 87, 117	Uncovered	Non-Reconstrainable	Boston Scientific
Hanarostent™ colorectal	Nitinol	22	A	28	60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170	Covered	Reconstrainable	MI tech
		24	A	30	60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170	Uncovered
Bonastent™	Nitinol	22, 24, 26	NA	NA	60, 80, 100, 120, 140, 160	Covered	Non-foreshortening	EndoChoice
						Uncovered
Niti-S™ D-Enteral colonic stent	Nitinol	18, 20, 22, 24	NA	NA	60, 80, 100, 120, 140, 150	Uncovered	Reconstrainable	Taewoong medical
Comvi™ Colonic stent	Nitinol	18, 20, 22	NA	NA	60, 80, 100, 120	Triple layered	Reconstrainable	Taewoong medical
Niti-S™ S-enteral colonic stent	Nitinol	18, 20	A	24	60, 80, 100, 120, 140, 150	Covered	Reconstrainable	Taewoong medical

A: Available; NA: Not available.

Table 3 Comparison of clinical guidelines

	BTS	Proximal colonic lesions	Palliative	Extra colonic obstruction	Benign lesions	Covered vs uncovered
ESGE	Δ	Δ	○	Δ	X	=
ASGE	○	Δ	○	Δ	Δ	<
KSGE	Δ	Δ	○	Δ	Δ	=

ESGE: European Society of Gastrointestinal Endoscopy; ASGE: American Society of Gastrointestinal Endoscopy; KSGE: Korean Society of Gastrointestinal Endoscopy; BTS: Bridge to surgery; SEMS: self-expanding metal stents; ○: Recommended; Δ: Consider stent based on clinical situation; X: Not recommended; >: Covered type is preferred; <: Uncovered type is preferred; =: Same effectiveness.