Prospective pilot study of fully covered self-expandable metal stents for refractory benign pancreatic duct strictures: long-term outcomes

Endoscopic placement of a single plastic stent (PS) to the main pancreatic duct (MPD) is awidely accepted treatment method for symptomatic strictures in patients with chronic pancreatitis [1,2]. Although adequate stent placement in the dominant stricture will relieve pain in the majority of patients [3–5], stents cannot be definitively removed in approximately one-third of patients because of persistent or recurrent strictures [6– 9,10]. In such refractory cases, placement of multiple PSs has been reported to be feasible and effective for obtaining enduring resolution of strictures and preventing pain [11]. With their large diameters, self-expandable metal stents (SEMS) have emerged as an option for the durable resolution of refractory MPD strictures, as with the biliary tract [12]. However, uncovered SEMS placement must be discouraged for benign conditions because of the high dysfunction rate and the inability to remove the SEMS because of tissue hyperplasia through the wire mesh [13]. Tissue hyperplasia should be prevented by fully covered SEMS (FCSEMS). However, FCSEMS have been thought to be associated with risks of pancreatitis and pancreatic sepsis caused by occlusion of side branches of the pancreatic duct and stent migration. Contrary to these concerns, several pilot studies have recently shown favorable results with temporary FCSEMS placement for benign refractory pancreatic duct strictures without severe complications [14–19]. To date, temporary FCSEM placement is regarded as an alternative to multiple PSs for benign refractory pancreatic duct strictures due to chronic pancreatitis [20,21]. However, there are few data regarding short-term results of FCSEM placement, and no data regarding long-term outcomes of FCSEM application. The aim of this prospective studywas to investigate the feasibility, safety, efficacy, and long-term outcomes after temporary placement of an FCSEM for refractory benign MPD strictures due to chronic pancreatitis.