Plastic or Metal Stents for Benign Biliary Obstructions? A Systematic Review of the Literature

Abstract

Introduction and Aim: Benign biliary strictures occur as a consequence of surgical procedures, chronic pancreatitis or iatrogenic ampullary lesions. Stents are increasingly being used for this indication however it is not clear which type of stent to use for which indication. Methods: A systematic review of the literature on stent placement for benign biliary obstructions was performed after searching PubMed and EMBASE databases. A total of 85 studies on outcome of stent placement in 2265 patients were identified. No randomized controlled trials (RCTs) and two non-randomized comparative studies were found. A total of 83 case-series evaluated 1409 patients with recurrent single plastic stents 329 patients with recurrent multiple plastic stents, 386 patients with uncovered self-expanding metal stents (uSEMS) and 93 with covered SEMS (cSEMS). In most studies plastic stents were electively exchanged every 3 months. Stent exchange was not performed with uSEMS and cSEMS. Data were evaluated and pooled for technical success, clinical success, defined as relief of (obstructive) symptoms and/or a significant decrease in bilirubin, and complications. Results: Indications for stent placement were biliary strictures following surgery (40.0%), chronic pancreatitis (20.2%), liver transplantation (24.3%) or others (15.4%). Median stenting time was longest for uSEMS (20 months (range 0.5-60)) followed by multiple plastic stents (11.8 months (range 4.6-14)), single plastic stent (11.6 months (range 0.3-24)) and cSEMS (4.0 months (range 1-28)). Technical success was 98.5% for uSEMS, 97.6% for multiple plastic stents, 96.5% for cSEMS and 94.1% for single plastic stent placement. Overall clinical success was highest after placement of multiple plastic stents (87.5%) followed by placement of cSEMS (75.0%), uSEMS (62.4%) and single plastic stent (61.2%). Clinical success in chronic pancreatitis was highest after uSEMS placement, whereas after liver transplantation and following surgery, clinical success was highest after placement of multiple plastic stents. Complications occurred least frequently after multiple plastic stent placement (18.5%) followed by single plastic stent (36.5%), cSEMS (39.6%) and uSEMS (49.6%) placement. Conclusion: Based on clinical success and risk of complications, placement of multiple plastic stents seems currently the best choice. The evolving role of cSEMS placement for this indication needs further elucidation in a RCT comparing them with multiple plastic stents.