Results of the new nitinol self-expandable stents for distal biliary structures

The nitinol stent is a self-expandable spiral stent made of nickel-titanium alloy. We performed a pilot study to evaluate the method of stent insertion and stent efficacy.

Twenty-eight patients with irresectable malignancy had nitinol stents inserted for obstructive jaundice due to distal biliary strictures. They were followed prospectively for a median of ten weeks (range 1-48) until stent occlusion or death. All patients underwent sphincterotomy prior to stent insertion. Stent deployment was assisted by subsequent balloon dilation of the stent in two patients. Plastic stent insertion was used to temporarily brace the nitinol stent in another three patients.

Short-term relief of jaundice was achieved in 20 of the 28 patients (71%). The remaining eight patients had persistent jaundice due to failure of stent insertion (three patients) or early stent dysfunction (five patients). Long-term success was achieved in 12 of 28 patients (43%). Ten of the 12 patients died without complications after a median of 13.5 weeks (range 3-48). One of the 12 patients is still alive with the stent in place for 40 weeks, and one patient underwent elective bypass surgery, and the stent was removed surgically. Eight of the 28 patients had recurrent symptoms due to late stent dysfunction after a median of 19 weeks (range 6-32).

Nitinol stents are technically difficult to insert. The problem of stent dysfunction (13 of 28, 46%) is not improved by the use of nitinol stents. Whether improvement of the insertion technique and enhancement of the expanding force of the stent may improve stent efficacy merits further evaluation.