Types of esophageal stents

Currently, there are three esophageal stents used in the United States. They are as follows (Table 1).

Gianturco Z-stents are made from 0.018-in stainless steel wire bent in a zig-zag fashion to form segments 2-cm long, which are connected using nonabsorbable suture to form lengths from 6 to 14 cm. The stent is 18 mm in its internal diameter, with the proximal and distal ends flared to 25 mm. The Z-stents are available in fully covered and

Table 1

Gianturco-Z stent1

Ultraflex2

Wallstent II

Material

Stainless steel

Nickel titanium

Elgiloy

(Nitinol)

Covering

Yes

Yes

Yes

Design

Zig-zag configuration

Mesh

Mesh

Self-expanding

+

+

+

Diameter before

Implantation

28F

16F

18F

Shaft diameter

Post implantation

18 mm

18,23 mm

20 mm

Flange diameter

21,25 mm

23,28 mm

28 mm

Degree of

Shortening

0%-10%

30%-40%

30%

Radial force

++

+

+++

Fistula Closure

Yes

Yes

Yes

1Gianturco Z-Stent (Wilson-Cook Medical, Winston-Salem, NC) 2Ultraflex stent (Microvasive, Inc., Natick, MA) 3Wallstent II (Microvasive)

1Gianturco Z-Stent (Wilson-Cook Medical, Winston-Salem, NC) 2Ultraflex stent (Microvasive, Inc., Natick, MA) 3Wallstent II (Microvasive)

Esophageal
Fig. 2. Esophageal stents. (A) Covered Gianturco Z-Stent (Wilson-Cook Medical, Winston-Salem, NC). (B) Uncovered Gianturco Z-Stent (Wilson-Cook Medical, Winston-Salem, NC). (C) Ultraflex stent (Microvasive, Inc., Natick, MA). (D) Wallstent II (Microvasive) Covered Z stent.

partially covered versions (Fig. 2A,B), and some have a Dua antireflux valve for gastroesophageal junction tumors to prevent reflux of gastric contents.

The Ultraflex stent (Fig. 2C) is a self-expanding stent made of 0.15-in nitinol wire with a luminal diameter of 18 mm and a proximal flange diameter of 23 or 28 mm upon deployment. Nitinol is a nickel titanium alloy that is unique for its shape memory properties. The stents vary in length from 7 to 15 cm. Ultraflex stents have less radial force that Wallstents (12). They are available coated and uncoated. The uncoated stent is more susceptible to tumor ingrowth and overgrowth (36%) (13).

The Wallstent (Fig. 2D) consists of eight stainless steel wires arranged in a spiral shape, forming a wire mesh. They are available in lengths of 10 cm and 15 cm. The stent is partially covered with a polyurethane coating. The conical configuration of the stent is designed to limit distal stent migration. It is available in two sizes: 1) small (proximal diameter of 24 mm, distal diameter 16 mm, total length 12 cm) for tumors without prestenotic dilatation; and 2) large (30-mm proximal diameter, 20-mm distal diameter, and a total length of 14 cm).

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