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Page 2 of 9 Okano et al. Mini-invasive Surg 2021;5:29 https://dx.doi.org/10.20517/2574-1225.2021.15

POST-ERCP PANCREATITIS
Post-ERCP pancreatitis (PEP) can be fatal. In a systematic review that included 21 retrospective studies, the
incidence rate of PEP was 3.5%, the incidence rate of severe pancreatitis was 0.4%, and the mortality rate
was 0.11% .
[1]

The risk factors for PEP can be patient-related or procedure-related. Patient-related risk factors include
sphincter of Oddi dysfunction, female sex, history of pancreatitis, young age, non-extrahepatic bile duct
dilation, non-chronic pancreatitis, and normal serum bilirubin. Procedure-related risk factors include pre-
cut sphincterotomy, pancreatic duct injection, 5 or more cannulations, pancreatic sphincterotomy, papillary
balloon dilation, and endoscopic papillectomy. Furthermore, in a recent systematic review, history of PEP is
[2]
proposed as a risk factor . These factors must be considered while performing ERCP and other related
procedures.

Pancreatic stent placement
There are many reports on the usefulness of pancreatic stent placement to prevent PEP. Mazaki et al.
[3]
performed a meta-analysis of 14 randomized controlled trials and reported a significant reduction in PEP
incidence in the prophylactic pancreatic stent placement group with respect to the group without stent
[3]
placement. The authors concluded that pancreatic stent placement was useful in the prevention of PEP .
[4]
Mine et al. also recommended prophylactic pancreatic stent placement in patients at high risk of PEP. The
[4]
stents used were spontaneous dislodgement pancreatic stents . Regarding stent diameters,
[5]
Zolotarevsky et al. confirmed that the placement success rate was higher with 5Fr than that with 3Fr
stents, but there was no difference in the PEP prevention effects according to the size. Because a 3Fr stent
requires a 0.018-inch guidewire, manipulations may be difficult and fluoroscopy results can be poor. With a
5Fr stent, the procedure can be performed with a small guide wire and placement takes less time. Therefore,
5Fr pancreatic stents are recommended . That said, adverse events related to pancreatic stents may occur,
[6]
including damage to the pancreatic duct, inward migration of the stent, and pancreatitis due to stent
[7-8]
occlusion . Because there is a risk of pancreatitis onset if the pancreatic stent does not spontaneously
[9]
dislodge, the stent should be endoscopically removed in such cases . Of note, approaching the pancreatic
duct again to place a pancreatic stent after treating the bile duct may actually increase the risk of PEP.
Pancreatic stents should be aggressively placed if a guide wire is located in the pancreatic duct, such as
during pancreatic duct injection of a contrast or pancreatic guide wire cannulation. However, when only the
bile duct is treated, whether to place pancreatic stents should be considered on a case-by-case basis.

Wire-guided cannulation
Because the injection of a contrast agent into the pancreatic duct may be a risk factor for PEP, wire-guided
cannulation (WGC), wherein a guide wire is cannulated into the bile duct without injection of a contrast
agent, was developed. It is reported to be associated with lower PEP incidence compared to conventional
[10]
contrast-enhanced methods and increased rate of deep bile duct cannulation . It is widely used in the
Western countries as the standard procedure for bile duct cannulation. Meanwhile, a multicenter, joint
randomized controlled trial in Japan showed no significant difference in the PEP incidence and deep bile
duct cannulation rate between the WGC method and conventional contrast-enhanced method . However,
[11]
further studies will be needed in the future on the selection of cases indicated for the WGC method. If the
bile duct cannulation is challenging, we recommend that a prompt switch to another method to help
prevent the onset of PEP.