Inward and Outward Migration of Covered Metallic Stent in Patients with Unresectable Malignant Distal Biliary Obstruction

Inward and Outward Migration of Covered Metallic Stent in Patients with Unresectable Malignant Distal Biliary Obstruction Hiroyuki Isayama, Yousuke Nakai, Osamu Togawa, Toshihiko Arizumi, Saburo Matsubara, Hiroshi Kogure, Yukiko Ito, Natsuyo Yamamoto, Naoki Sasahira, Kenji Hirano, Takeshi Tsujino, Nobuo Toda, Yutaka Komatsu, Minoru Tada, Haruihiko Yoshida, Takao Kawabe, Masao Omata Background & Aim: Endoscopic or transhepatic biliary stenting has become widely accepted as a standard procedure for palliation of jaundice in patients with malignant biliary obstruction. Recently, various types of metallic stents, including polyurethane-covered Wallstent (PCW), polyurethane-covered Diamond stents (PCD) and silicone covered-Wallstent (SCW), are available. We have reported that covered metallic stents have longer patency to prevent tumor ingrowth (Gastrointest Endosc 2002, Gut 2004). More recently, however, disadvantages characteristic of those stents are noticeable. Of those, stent migration is one of the most common and serious ones. Therefore, we conducted the present study to elucidate the clinical features in cases with migration. Patients & Methods: From August 1997 to August 2004, we managed 180 patients with unresectable malignant distal biliary obstruction treated with covered metallic stent (pancreatic cancer 109, bile duct cancer 34, gallbladder cancer 7, papillary cancer 8 and metastatic nodes 22). PCW, PCD and SCW were used in 21, 57 and 102 patients, respectively. Their Medical records were retrospectively reviewed. We defined the stent migrated above the stricture was ‘‘inward migration’’ and distally migrated into the duodenum was ‘‘outward’’. Results: Twenty patients developed migration 2.5 months in mean after stent insertion. Nine had inward migration and 11 outward. All the patients with inward migration were accompanied by cholestasis or cholangitis. Inward migration seems to be mainly due to inappropriate designing of stent length and placement site. Stents were more shortened than expected. On the other hand, among 11 patients with outward migration, none showed cholangitis or cholestasis. The migration was accidentally found by follow-up abdominal X-ray. Nine with outward migration had favorable response to anticancer. Of those, 4 did not show symptoms even after stent was detached. Conclusions: Inward migration was associate serious symptomatic complications such as cholangitis. However, this type of migration may be avoided by directing careful attention to designing stent length and placement site. On the other hand, outward migration occurred in patients with favorable response to anticancer treatment and might not lead to more serious condition.