New self-expandable spiral metallic stent: preliminary clinical evaluation in malignant biliary obstruction

To describe a new self-expandable spiral-shaped metallic stent and to evaluate its clinical efficacy in malignant biliary obstructions.

The stent was made of a 0.01-inch (0.25-mm) stainless steel wire bent in a zigzag pattern and was formed into a spiral configuration by differing the length of legs on each bend. One revolution was composed of 10 bends, and the stent was longitudinally connected by hanging each bending point of abutting bends, without use of suture or silver solder. Twenty-six stents were placed to relieve malignant biliary obstruction in 18 patients. Follow-up of 5-11 months (mean, 7 months) was obtained.

All stents were placed in the desired location, and no procedural complications were encountered. Within 1 week after placement, all stents regained 90% or more of their original diameters. Five patients died (range, 5-36 weeks), and 13 patients are still alive (range, 20-45 weeks). Two patients experienced recurrent jaundice and underwent further treatment. The stent was easily inserted, expanded well, was flexible, could be repositioned, and did not shorten.

Favorable clinical results were obtained with this spiral stent in malignant biliary obstruction, and further clinical testing is warranted.