A new self-expandable and removable metal stent for biliary obstruction--a preliminary report

We report our experience with a new self expandable metallic stent, a coil spring made from a nickel-titanium alloy. The super elastic characteristic of this metal offers a very strong radial force and previous dilatation of biliary strictures is not necessary. The stent is endoscopically inserted constricted over an introducing catheter, expanding spontaneously after release to its original 8 mm diameter. During the last six months, eleven stents were inserted in nine patients with pancreatic carcinoma to relieve jaundice. Another stent was percutaneously implanted treating a benign stricture in a patient with a choledochojejunostomy after a Whipple operation. Clinical improvement was achieved in all the patients except in one who died from liver metastases 5 weeks later. In two patients, although stents were obstructed after 2 and 4 months from insertion, they were easily removed by pulling their distal end through the endoscopic working channel. After a mean follow up of 4.5 months, patients had no evidence of biliary reobstruction. Although follow-up is short, these results are encouraging, and this new metallic stent seems to have several advantages over the current commercially available ones.