A newly-designed shape-memory coil stent for esophageal stricture: a preliminary report.

A newly designed coil esophageal endoprosthesis was developed using a thermal shape-memory titanium-nickel alloy. The major advantages of this stent lie in (a) its small diameter while in its compressed state in ice water and (b) the large lumen which is achieved once it has been warmed to body temperature. The technical feasibility and tissue compatibility of this stent were tested on four beagle dogs: two with an anastomotic stricture and two with a stenosis induced by the injection of monoethanolamine oleate. The teflon-coated stent was inserted under fluoroscopy and removed 4 weeks after implantation. No signs of esophageal reobstruction were observed in any of the animals after implantation or extraction of the stent, although the dog which had received the first stent without teflon coating developed obstruction caused by granulation tissue. Our preliminary experience strongly suggests that the shape-memory alloy stent with teflon coating may be used in the endoscopic treatment of anastomotic stenosis after esophagectomy, as well as of esophageal obstruction caused by carcinoma.