RESULTS OF THE NEW NITINOL SELF-EXPANDABLE STENTS FOR DISTAL BILIARY STRICTURES

Background and Study Aims: The nitinol stent is a self-expandable spir al stent made of nickel-titanium alloy. We performed a pilot study to evaluate the method of stent insertion and stent efficacy. Patients an d Methods: Twenty-eight patients with irresectable malignancy had niti nol stents inserted for obstructive jaundice due to distal biliary str ictures. They were followed prospectively for a median of ten weeks (r ange 1-48) until stent occlusion or death. All patients underwent sphi ncterotomy prior to stent insertion. Stent deployment was assisted by subsequent balloon dilation of the stent in two patients. Plastic sten t insertion was used to temporarily brace the nitinol stent in another three patients. Results: Short-term relief of jaundice was achieved i n 20 of the 28 patients (71%). The remaining eight patients had persis tent jaundice due to failure of stent insertion (three patients) or ea rly stent dysfunction (five patients). Long-term success was achieved in 12 of 28 patients (43%). Ten of the 12 patients died without compli cations after a median of 13.5 weeks (range 3-48). One of the 12 patie nts is still alive with the stent in place for 40 weeks, and one patie nt underwent elective bypass surgery, and the stent was removed surgic ally Eight of the 28 patients had recurrent symptoms due to late stent dysfunction after a median of 19 weeks (range 6-32). Conclusions: Nit inol stents are technically difficult to insert. The problem of stent dysfunction (13 of 28, 46%) is not improved by the use of nitinol sten ts. Whether improvement of the insertion technique and enhancement of the expanding force of the stent may improve stent efficacy merits fur ther evaluation.