5.1　Plastic Stent

Usually，the plastic biliary stents are inserted for a duration of at least a year and exchanged at 3-4 months intervals to avoid problems of stent clogging and cholangitis.In patients with recurrent or persistent biliary stricture，surgical drainage should be considered.Patients with pancreatic head calcifications do poorly with biliary stenting，with the need for repeat endotherapy or surgery（Kahl et al.2003）.

While the technical success of biliary stent insertion is more than 90%in most cases，the long-term success from a single biliary stent insertion is generally poor，ranging from 10 to 32%，after a stent duration of 9-21 months.In some series，up to 49%of patients required surgical drainage（Dumonceau et al.2012）.However，Vitale et al.reported a high long-term successrate（80%）of the single biliary stent approach in a group of patients with a low prevalence of chronic calcific pancreatitis（Vitale et al.2000）.

Table 9.5　Indications for biliary drainage in benign biliary stricture secondary to chronic pancreatitis(https://www.daowen.com)

The multiple side-by-side biliary stents approach have better long-term success rates，ranging from 44 to 92%，after a stent duration of 14-21 months.However，up to 13%may still require surgical drainage（Dumonceau et al.2012）.