2.3　Endotherapy

Within a few days of the ESWL session，endotherapy is performed to remove the stone fragments and to ensure good ductal drainage.Selective cannulation of the pancreatic duct is achieved by aiming for the 1-2 o'clock position of the major papilla.Contrast instillation allows for delineation of the ductal morphology and anatomy（Fig.9.2）.The guidewire may then be maneuvred safely to reach the distal upstream pancreatic duct，with particular attention to avoid forceful wire manipulation should it enter a side branch.This reduces the risk of side branch injury causing leakage of pancreatic juice and subsequent pancreatitis.

Pancreatic sphincterotomy is then performed to facilitate easy access of instruments and removal of stone fragments.Stone fragments may then be removed by trawling with wire-guided balloon or basket.Subsequently，a pancreatic ductal stent may then be inserted if a stricture is present or if some stone fragments remain.

Although there has been no consensus on the use of prophylactic antibiotics，some endoscopists would prescribe a short-course of oral fluoroquinolone.Follow-up procedures are then performed at 3-month intervals to assess for ductal improvement，with a stent-free trial commenced when ductal clearance and pancreatic outflow is satisfactory.(https://www.daowen.com)

ESWL and endotherapy provide pain relief in 60-85%of patients.Table 9.2 summarises selected series in the last two decades.Subsequent to initial endotherapy，repeated sessions may be required in 20%of patients and surgery in up to 25%of patients（Dumonceau et al.2012）.Complications include bleeding，luminal perforation，pancreatitis and pancreaticobiliary sepsis（Tandan et al.2010，2013；Hu et al.2015；Tadenuma et al.2005；Delhaye et al.1992，2004；Brand et al.2000；Costamagna et al.1997；Sauerbruch et al.1992）.

Fig.9.2　Pancreatography of a patient with chronic pancreatitis，with a dilated pancreatic duct and stones in the head and body regions.There is relative narrowing of the distal common bile duct due to chronic pancreatitis，with upstream ductal dilation