Fully covered self-expandable metal stents in biliary strictures caused by chronic pancreatitis not responding to plastic stenting: a prospective study with 2 years of follow-up.

Chronic pancreatitis can be complicated by benign biliary stricture in about 5-40% of the patients[1]. The severity of this biliary narrowing varies with patients having a wide range of presentation ranging from asymptomatic elevation of liver enzymes to deep jaundice and cholangitis. It is important to treat biliary obstruction, as long standing biliary stricture can lead on to secondary biliary cirrhosis[1,2]. Surgery, because of effective long lasting results, is the treatment of choice for benign biliary strictures due to chronic pancreatitis[3]. However, surgery is associated with significant morbidity and hence there have been increasing attempts to develop non surgical methods of relief of obstruction of the biliary tract[4]. Endoscopic biliary stenting is an attractive, minimally invasive, non surgical method of relief of biliary obstruction. The stenting in benign diseases has been traditionally done with plastic stents and they have been demonstrated to offer satisfactory short term biliary drainage, but long term results are not so impressive because of stent clogging or migration and thus poor long term efficacy[1,5]. To improve upon the long term results of plastic stents, insertion of multiple plastic stents have been suggested as an option. Although it results in more durable response, it requires multiple endoscopic sessions[6]. Uncovered self-expandable metallic stents (SEMS), although result in a longer and effective relief of biliary obstruction, are not considered in benign disease because of technical difficulties associated with its removal. Hence, partially covered SEMS were developed and one of their important attributes was the ability of removability, which could offer the possibility of removal of the stent once the stricture has resolved. Partially covered SEMS may also clog because of tissue in growth, thereby decreasing its patency rates. To overcome this problem of tissue in growth, fully covered biliary SEMS (FC SEMS) have been developed. They seem to be an attractive therapeutic modality in patients with benign biliary stricture due to chronic pancreatitis, but limited data is available.