TECHNICAL FAILURE OF BILIARY METAL STENT DEPLOYMENT IN A SERIES OF 116 APPLICATIONS

Biliary metal stents are thought to offer improved longterm palliation of malignant biliary obstruction due to a lower incidence of migration and clogging. Placement of these stents is technically more complicated than that of plastic endoprostheses and requires two experienced physicians. We report the incidence and reasons for apparent malfunction of expandable metal stent deployment (Wallstents(R) and Strecker(R) stents). In 116 applications of 82 Wallstents(R) (endoscopic approach: n = 33, transhepatic approach: n = 49), we observed 19 cases of stent malfunction due to technical problems of stent delivery. In 13 cases (15.8 %), the restraining membrane of the Wallstent(R) could not be retracted sufficiently to deliver the stent. There were 6 (17.6 %) failures in 34 cases of Strecker(R) stent deployment. In 3 cases, we noted difficult balloon removal, including avulsion of the balloon catheter shaft within the endoscope during attempted baloon removal in one case. In one case, the Strecker(R) stent could only be released partially, requiring subsequent endoscopic extraction. In two patients, only partial expansion of one end of the Strecker(R) stent could be achieved. Given the significant malfunction rate of expandable metal stents during stent delivery, further improvements in the delivery system of the metal stents are required.