5.2　SEMS

The use of the wider diameter covered SEMS for a period of 3-6 months is associated with long term success rates of 50-80%（Dumonceau et al.2012）.Problems with stent migration is reduced when the partially covered SEMS is used instead of the fully covered SEMS（Cahen et al.2008；Behm et al.2009）.However，when compared with other causes of benign biliary strictures，chronic pancreatitis is associated with a lower success rate for stricture resolution despite the use of SEMS（Poley et al.2012）.(https://www.daowen.com)

While biliary stenting provide immediate improvement of jaundice in most patients，longterm ductal patency after stent removal remains a significant issue in most patients with chronic calcific pancreatitis.In patients with poor compliance to regular stent exchanges，endotherapy may not be advisable due to the significant septic complications that may occur.Also，although promising，SEMS placement remains investigational and no comparison studies between insertion of SEMS，plastic stents or surgical drainage have been concluded.