ERCP appears to be technically difficult and challenging in children because of their narrow airways and smaller anatomical dimensions compared to adults [5]. Improved designs of endoscopes and associated accessories have facilitated the development of ERCP procedures in children [1]. We found that diagnostic and therapeutic ERCP procedure could be successfully performed in childhood, even at three months of age. The only severe complication noted after ERCP was common bile duct injury; there were no cases of severe pancreatitis, bleeding, or perforation.

Our complication rate 1.5% (1/65) was lower than 7.7% incidence typically reported in pediatric large case series [6, 7]. Pediatric ERCP was performed by the most skilled gastroenterologist in our institution, and the use of PJF-7.5 (tip outer diameter, 7.8 mm; channel diameter, 2.0 mm; Olympus) may have avoided unnecessary pressure on the pancreatic duct and thus avoided post-ERCP pancreatitis.

Endoscopic biliary drainage with a temporary stent is adequate for symptomatic relief of CBD. We previously reported that endoscopic short-tube stenting is beneficial in children because it does not require tube management [3]. In our present study, ERCP for biliary tract disease was highly successful and effective. Four patients had unsuccessful stenting, but one patient had symptomatic improvement with guidewie manipulation. Thus, three (5.8%) of the 52 biliary disease cases failed to be treated by ERCP owing to difficulties encountered in cannulation, when the narrow segment was right-angled, or the body size of the patient was too small for the procedure. Percutaneous transhepatic biliary drainage may be useful when stent tube placement is unsuccessful. It has been reported that early biliary decompression should be performed when symptoms persit, but no definite protocol has been established [3, 8]. It is not necessary to perform ERCP in all symptomatic CBD patients, as symptoms may improve with fasting alone. Although there is certainly no statistical evidence to suggest the usefulness of our current treatment strategy for preoperative management of CBD (Fig. 1), our strategy is very safe and effective in carefully selecting patients for ERCP with few complications and safe surgery.

In this study, patients who underwent ERCP for determination of the cause of and treatment for pediatric pancreatitis were also evaluated. ERCP was useful for understanding pancreatic duct anatomy. MRCP can reportedly be evaluated in the same way as ERCP [9]; however, in our experience, the images were unclear and difficult to evaluate. ERCP evaluation in children should be strongly considered because minor artifacts, as seen on MRCP, make evaluation difficult.

We reported four cases of pancreatitis after congenital duodenal atresia/stenosis surgery. Duodenal atresia and stenosis are often accompanied by pancreaticobiliary anomalies due to developmental reasons [10–12]. Growth may also lead to impaired pancreatic drainage due to ductal angulation. Detailed examination of pancreatitis after duodenal atresia associated with an annular pancreas can lead to the diagnoses of pancreaticobiliary maljunction, pancreas divisum, and CBD requiring surgical treatment in some patients [10–12]. Since a wide variety of anatomical abnormalities have been observed, there is a need to carefully search for underlying causes and to develop treatment strategies for pancreatitis after congenital duodenal atresia/stenosis surgery. In Case 2, a pancreatic duct stent was emplaced because the Wirsung duct was bent, and in Case 3, a pancreatic duct stent was placed in the dominant dorsal duct from the accessory papilla. These results suggested that stenting of the pancreatic duct should be useful for improving the angulation and drainage of the pancreatic duct.

In our study, EPS for chronic pancreatitis improved the stenosis that had caused acute exacerbations and, eventually, patients were followed up after repeated stenting without recurrence of pancreatitis. Endoscopic treatments for chronic pancreatitis have been reported to be effective, and favorable results have recently been reported with EPS [5, 13]. EPS can be performed safely even in pediatric patients, and is often the first choice for endoscopic treatment.

In addition, the indications for endoscopic minor papilla sphincterotomy can be decided by placing a pancreatic duct stent in patients with pancreatic divisum and setting the follow-up period. Endoscopic minor papilla sphincterotomy encompasses risk for certain complications such as perforation, bleeding, and acute pancreatitis, and incomplete incision may result in scar stenosis and impaired drainage [14]. Since there is no evidence recommending the direction and extent of the incision, the policy adopted at our institution is to consider minor papillotomy in patients aged 2 years or older (the JF-240 body size that allows the endoscope to be inserted). Thus, the indications for papillotomy should be carefully considered. These experiences suggest that our diagnosis and treatment strategies for pancreatitis in children (Fig. 2) are effective.

In conclusion, ERCP and transendoscopic therapy are sufficiently feasible in pediatric patients and should be actively introduced for the investigation and treatment of pancreaticobiliary diseases.