Initial Experience with a New, Partially Covered Wallstent for Malignant Biliary Obstruction

Abstract

Covering biliary metal stents is a potential solution to prevent tissue ingrowth. However, current prototypes need to be improved in order to achieve this goal.

A prospective randomised study of "covered" versus "uncovered" diamond stents for the management of distal malignant biliary obstruction

“…Subsequently, Gore-Tex, 11 silicone, 24 and polyurethane [25][26][27][28][29][30] were evaluated as materials for the covered membrane. Miyayama et al, using polyurethane covered Gianturco stents, reported that the stent occlusion rate was only 5% due to tumour overgrowth above the stent edge and that no tumour ingrowth was observed.…”

“…26 However, other studies suggested that a covering membrane was not effective in preventing tumour ingrowth and did not improve stent patency. [27][28][29] Hausegger et al, using polyurethane covered Wallstents, reported that the obstruction rate of those covered EMS was 33%, mainly due to tumour ingrowth, concluding that covered EMS were not superior to uncovered EMS. 29 More recently, we published a prospective consecutive study using handmade polyurethane covered Wallstents.…”

“…We used a membrane of 40-50 mm in thickness in that study while those used in the other studies were 15 mm thick. [27][28][29] We were convinced that covered EMS could overcome tumour ingrowth if the membrane was of sufficient thickness. Therefore, we conducted the present study with membranes of 50-60 mm thick.…”

Cost-Effectiveness Decision Analyses Comparing Covered to Uncovered Self-Expandable Metal Stents to Elective or on Demand Polyethylene Stent Changes in Patients with Distal Malignant Biliary Obstruction

“…The extended patency of U-SEMS is associated with several benefits inc1uding: 1) a better quality of life for patients not only because of avoidance ofunnecessary procedures but also due to increased syrnptom-free period [B-IS]; 2) improved survival because it could prevent life-threatening conditions such as acute cholangitis and procedure-related complications [38]; 3) lower costs because of avoidance of repeated ERep. unexpected greater complication rate attributed to migration, cholecystitis and pancreatitis [39,40]. Regardless, the superior effectiveness of both SEMS is offset by significant higher up-front costs compared to PE stents.…”

Safety and Efficacy of Percutaneous Biliary Covered Stent Placement in Patients with Malignant Biliary Hilar Obstruction; Correlation with Liver Function

“…In patients with obstruction at the hilar portion or above, which is difficult to approach using an endoscopic method, percutaneous approaches have a higher rate of success than endoscopic approaches, especially when self-expanding metallic stents are used [8,9]. Stent occlusion due to bile sludge formation and tumor out-and ingrowth interferes with stent patency; therefore, covered metal stents have been introduced to improve the patency and efficacy [5,[10][11][12][13][14]. But, the major concerns that may occur during covered biliary stent placement are biliary complications such as cholecystitis or cholangitis [5,15,16].…”