Metallic Stents for Benign Extrahepatic Biliary Stricture: In Praise of Self-Expansion?

Abstract

Benign biliary strictures are often safely and successfully treated with removable indwelling biliary stents with stricture resolution in 75-90 % of all cases. There is no consensus on the optimal time to remove the stent, and this typically varies from 3 to 12 months [1,2], depending upon the pathology of the stricture and the clinical setting. For example, shorter dwell times are recommended for post-orthotropic liver transplant (OLT) strictures in the setting of immunosuppression. Resolution of the stricture must be balanced against the complications of stent migration and of cholangitis.In this issue of Digestive Diseases and Sciences, Saxena et al. [3] collected retrospective data from the endoscopic databases of five US tertiary referral centers, identifying patients with benign biliary strictures treated with covered self-expandable metal stents. Stricture etiologies included biliary calculi, chronic pancreatitis, post-OLT, primary sclerosing cholangitis, and other benign indications. The authors evaluated pre-and post-procedural characteristics to identify predictive factors associated with stricture resolution and adverse events. On analysis of 123 patients, the stricture resolution rate was 81 % after a mean stent dwell time of 6.1 months with a corresponding cholangitis rate of 4.1 %. Stricture resolution was associated with longer stent dwell times (24.4 vs 13 weeks, P = 0.02), but stricture etiology, prior plastic stenting, duration of stricture prior to stenting, stricture length, stricture dilatation, and brand of stent (Wallflex Ò vs Viabil Ò ) did not predict stricture resolution [3]. The data may have been biased by its retrospective design and the use of mean rather than the preferred nonparametric median to describe dwell time. Nevertheless, a stent dwell time of *6 months appeared to be near optimal, allowing adequate time to ensure scar remodeling with a relatively low complication rate, including cholangitis. Liver function testing was advocated at 3-month intervals to provide an early indication of stent obstruction and migration. A previously published prospective multicenter study by Devière et al.[1] reported a stricture resolution rate of 75 % and cholangitis rate of 13.9 % after a median stent dwell time of 11.3 months. Saxena's study adds to the data from prior case series, supporting the assumption that temporary stenting is safe and effective for treating benign strictures of various aetiologies (Table 1), even though one death occurred from cholangitis. Other stenting-related complications in this and other case series include post-sphincterotomy hemorrhage, pain, and stent migration [3,4].Potential flaws of the study include its retrospective nature with variable lengths of follow-up, heterogeneity of stricture etiology, and the tertiary hospital case mix, all factors that may reduce generalizability. The strength of the study is that it suggests that a 6-month stent dwell time may be optimal.Self-expanding metal stents have been increasingly used in preference to plastic stents....

Surgical Procedures for Biliary Stricture in Chronic Pancreatitis

“…Recent studies have focused on the choice of stent (plastic or metal (SEMS)), and in the case of the metal one it is important to choose whether the stent is coated or not [2][3][4][5][6][7], there are also isolated reports of much rarer causes BG, such as the stone of the main pancreatic duct (GLP), which caused biliary obstruction [8]. The degree of success (resolution of stricture) and failure (stent migration, recurrence of stricture) and complications varies between studies.…”