Expanded metal

Abstract: BACKGROUND AND STUDY AIMS The biliary stents in current use have a tendency to be blocked, so we designed a self-expandable metal stent covered with polyurethane to overcome the risk of tumor ingrowth of uncovered self-expandable metal stents. To evaluate the success and the effectiveness of the new membrane-covered self-expandable metal stent (covered modified Gianturco biliary stent), we studied patients with biliary obstruction caused by biliopancreatic carcinoma. PATIENTS AND METHODS We retrospectively evaluated 47 patients with malignant biliary obstruction to receive either a newly developed self-expandable metal stent covered with polyurethane (21 cases) or an uncovered metal stent (Strecker stent or Wallstent, 26 cases) by the endoscopic transpapillary route. RESULTS The success rate of stent insertion and drainage effect of stent showed no statistical difference in patients with a new membrane-covered self-expandable metal stent compared with those with an uncovered metal stent (90.4% vs. 88.5%, P > 0.05; and 100% vs. 95.6%, P > 0.05, respectively). The median patency of the stent was slightly prolonged in patients with a membrane-covered self-expandable metal stent, but there was no statistical difference between two groups (267 vs. 233 days, P > 0.05). The rate of early complication related to stent insertion showed no significant difference between the two groups. During the follow-up period, stent occlusion due to tumor ingrowth occurred in two patients (10.5%) in the membrane-covered, self-expandable stent group, compared with six patients (26.1%) in the uncovered metal stent group. The membrane-covered metal stent was removed successfully and a polyethylene stent was reinserted in one patient who had developed tumor overgrowth. CONCLUSIONS A new, membrane-covered, self-expandable metal stent has a tendency towards better long-term patency than the uncovered metal stent, and it can effectively prevent tumor ingrowth into the stent. Also it is possible to remove an occluded membrane-covered stent. However, a case-controlled study, including a larger patient number, and long-term follow-up are needed.

Abstract: A method of repairing fractures of the bone utilizing expanded metal or similar openwork metal sheeting as a fracture fixation device. Where possible the sheeting is wrapped around the bone, extending on opposite sides of the fracture site, and fastened. For other fractures a strip of the sheet material is secured to the bone on opposite sides of the fracture site or inserted within the medullary cavity. The fixation device holds the bone immobilized while permitting knitting and, at the same time, the surrounding tissue grows into and through the many fenestrations of the metal sheeting to permanently fix the device to the fractured bone.

Abstract: A composite sliding member includes a metal wire mesh or expanded metal impregnated and covered with a composition of 0.1-50% by volume of one or more of PFA, FEP and EPE, and 0.1-50% by volume of at least one of oxybenzoyl polyester, polyphenylene sulfide, thermosetting resin, metal lubricant, metal oxide, composite metal oxide, metal sulfide, metal fluoride, carbon-based self lubricant, fiber material, and ceramics, with the remainder being substantially PTFE.