Endoscopic retrograde cholangiopancreatography consultation after digestive tract reconstruction and risk factors for complications
Endoscopic retrograde cholangiopancreatography (ERCP) has been clinically applied since the 1960s and has become an indispensable minimally invasive technique that integrates both diagnosis and treatment in hepatobiliary surgery, gastrointestinal surgery, and digestive internal medicine . ERCP offers advantages such as being minimally invasive and having minimal impact on the internal environment, making it the preferred option for assisting in the treatment of biliary and pancreatic diseases. For patients with normal gastrointestinal anatomy, the success rate of intubation during ERCP can reach 90.0–95.0% , with stone removal success rates ranging from 80.0 to 90.0%. In patients with gastrointestinal reconstruction, the altered endoscopic path can lead to difficulties in locating the duodenal papilla or anastomosis, difficulty in cannulation, and tissue injury resulting in edema and bleeding. These factors increase the difficulty of therapeutic procedures and lead to lower success rates of intubation, cannulation, and therapeutic interventions, as well as a higher incidence of complications. This paper conducts a retrospective analysis of a large sample of clinical data, statistically analyzing the success rates of intubation, cannulation, and therapeutic procedures during ERCP in patients after gastrointestinal reconstruction. It also explores the risk factors for postoperative complications to reduce their incidence, which will help assess the efficacy and safety of ERCP in this patient group. 

Materials Clinical data This human research project was approved by the Ethics Committee of Zhongnan Hospital of Wuhan University (Ethics Approval No.: 2024181K). Clinical data were collected from 522 patients who underwent ERCP for diagnostic and therapeutic purposes after gastrointestinal reconstruction surgery at the Digestive Endoscopy Center of Zhongnan Hospital of Wuhan University from January 2017 to December 2023. Inclusion criteria: 1. patients who had previously undergone Billroth I or Billroth II gastrectomy, Roux-en-Y gastric bypass, biliary-enteric anastomosis, gastrojejunostomy Roux-en-Y, pancreaticoduodenectomy, or liver transplantation and 2. patients requiring ERCP for diagnosis or treatment.3.Patients with complete medical history and surgical data. Exclusion criteria: 1 unknown surgical procedures; 2. abnormal coagulation function (INR ≤ 1.5, platelet count ≥ 50 × 10^9, APTT within normal range, or fibrinogen ≥ 1.5 g/L); and 3. patients unable to cooperate during the procedure. Observation index Procedure-related success rates : 1. Intubation success : successful advancement of the endoscope to the duodenal papilla or anastomosis. 2. Cannulation success : successful cannulation and contrast injection. 3. Therapeutic success rate : successful removal of stones, balloon dilation, stent placement, drainage, etc. ERCP-related complications : 1. Post-ERCP pancreatitis (PEP) : clinical symptoms of pancreatitis lasting for more than 24 h after ERCP, with serum amylase levels greater than three times the normal upper limit. 2. Post-ERCP hyperamylasemia (PEH) : elevated serum amylase levels without clinical signs of pancreatitis. 3. Bleeding : includes both early and delayed bleeding. Early bleeding refers to active bleeding during or immediately after the procedure that does not stop spontaneously, requiring hemostatic intervention. Delayed bleeding refers to upper gastrointestinal bleeding symptoms occurring hours or even weeks after the procedure. 4. Gastrointestinal perforation : severe abdominal pain within 24 h after the procedure, with free gas seen under the diaphragm or retroperitoneal on abdominal X-ray or CT scan. ERCP preparation and procedure 1. Preoperative preparation and postoperative treatment : Patients were instructed to fast and withhold water for 6–8 h before the procedure. One hour before the procedure, 0.1 mg of octreotide acetate was administered subcutaneously (to inhibit pancreatic enzyme secretion, reduce pancreatic injury, and prevent biliary sphincter spasm). Ten minutes before the procedure, 10 mg of morphine was injected subcutaneously (for pain relief), 5 mg of hyoscine-N-butylbromide was administered intramuscularly (to relax the bile ducts and Oddi’s sphincter, reduce bile duct and pancreatic duct pressure, and provide analgesia), and 10 mg of diazepam was given intravenously (for sedation and to reduce anxiety). The procedure was performed using small-bowel endoscopes (SIF-H290S, SIF Q260, Olympus), long-type colonoscopes (CF HQ290L/I, Olympus), gastroscopes (GIF HQ290, Olympus, Tokyo, Japan), duodenoscopes (Olympus TFJ-260, Olympus-FJ260), and standard colonoscopes (CF HQ290L/I, Olympus). A transparent cap was attached to the tip of the endoscope to improve visibility. A Philips Easy Diagnost system (Netherlands) was used for fluoroscopy, and iodixanol or iohexol was selected as the contrast agent. After the procedure, patients were kept fasting and given proton pump inhibitors for acid suppression, somatostatin to inhibit pancreatic enzyme secretion, and intravenous fluids. Blood amylase and lipase levels were checked at 2 and 24 h postoperatively. 2. Operation procedure : Once the endoscope reached the duodenal papilla or anastomosis, selective bile duct cannulation was performed. Based on the clinical condition, treatments such as endoscopic nasobiliary drainage (ENBD), endoscopic retrograde biliary drainage (ERBD), biliary and pancreatic duct stent placement, stone removal, or lithotripsy were performed (Fig. ). Statistical analysis Data were analyzed using SPSS 27.0. For continuous variables (age), the Shapiro–Wilk test was used to assess normality. If the data were not normally distributed, the median and interquartile range were reported. Categorical data were presented as frequency and percentage, and analyzed using the χ 2 test or Fisher’s exact probability method. The variance inflation factor (VIF) was used to assess multicollinearity between factors associated with failed intubation. For variables with statistically significant differences, logistic regression analysis was conducted for multivariate analysis. A P value of < 0.05 was considered statistically significant. 

Clinical data This human research project was approved by the Ethics Committee of Zhongnan Hospital of Wuhan University (Ethics Approval No.: 2024181K). Clinical data were collected from 522 patients who underwent ERCP for diagnostic and therapeutic purposes after gastrointestinal reconstruction surgery at the Digestive Endoscopy Center of Zhongnan Hospital of Wuhan University from January 2017 to December 2023. Inclusion criteria: 1. patients who had previously undergone Billroth I or Billroth II gastrectomy, Roux-en-Y gastric bypass, biliary-enteric anastomosis, gastrojejunostomy Roux-en-Y, pancreaticoduodenectomy, or liver transplantation and 2. patients requiring ERCP for diagnosis or treatment.3.Patients with complete medical history and surgical data. Exclusion criteria: 1 unknown surgical procedures; 2. abnormal coagulation function (INR ≤ 1.5, platelet count ≥ 50 × 10^9, APTT within normal range, or fibrinogen ≥ 1.5 g/L); and 3. patients unable to cooperate during the procedure. Observation index Procedure-related success rates : 1. Intubation success : successful advancement of the endoscope to the duodenal papilla or anastomosis. 2. Cannulation success : successful cannulation and contrast injection. 3. Therapeutic success rate : successful removal of stones, balloon dilation, stent placement, drainage, etc. ERCP-related complications : 1. Post-ERCP pancreatitis (PEP) : clinical symptoms of pancreatitis lasting for more than 24 h after ERCP, with serum amylase levels greater than three times the normal upper limit. 2. Post-ERCP hyperamylasemia (PEH) : elevated serum amylase levels without clinical signs of pancreatitis. 3. Bleeding : includes both early and delayed bleeding. Early bleeding refers to active bleeding during or immediately after the procedure that does not stop spontaneously, requiring hemostatic intervention. Delayed bleeding refers to upper gastrointestinal bleeding symptoms occurring hours or even weeks after the procedure. 4. Gastrointestinal perforation : severe abdominal pain within 24 h after the procedure, with free gas seen under the diaphragm or retroperitoneal on abdominal X-ray or CT scan. ERCP preparation and procedure 1. Preoperative preparation and postoperative treatment : Patients were instructed to fast and withhold water for 6–8 h before the procedure. One hour before the procedure, 0.1 mg of octreotide acetate was administered subcutaneously (to inhibit pancreatic enzyme secretion, reduce pancreatic injury, and prevent biliary sphincter spasm). Ten minutes before the procedure, 10 mg of morphine was injected subcutaneously (for pain relief), 5 mg of hyoscine-N-butylbromide was administered intramuscularly (to relax the bile ducts and Oddi’s sphincter, reduce bile duct and pancreatic duct pressure, and provide analgesia), and 10 mg of diazepam was given intravenously (for sedation and to reduce anxiety). The procedure was performed using small-bowel endoscopes (SIF-H290S, SIF Q260, Olympus), long-type colonoscopes (CF HQ290L/I, Olympus), gastroscopes (GIF HQ290, Olympus, Tokyo, Japan), duodenoscopes (Olympus TFJ-260, Olympus-FJ260), and standard colonoscopes (CF HQ290L/I, Olympus). A transparent cap was attached to the tip of the endoscope to improve visibility. A Philips Easy Diagnost system (Netherlands) was used for fluoroscopy, and iodixanol or iohexol was selected as the contrast agent. After the procedure, patients were kept fasting and given proton pump inhibitors for acid suppression, somatostatin to inhibit pancreatic enzyme secretion, and intravenous fluids. Blood amylase and lipase levels were checked at 2 and 24 h postoperatively. 2. Operation procedure : Once the endoscope reached the duodenal papilla or anastomosis, selective bile duct cannulation was performed. Based on the clinical condition, treatments such as endoscopic nasobiliary drainage (ENBD), endoscopic retrograde biliary drainage (ERBD), biliary and pancreatic duct stent placement, stone removal, or lithotripsy were performed (Fig. ). 

This human research project was approved by the Ethics Committee of Zhongnan Hospital of Wuhan University (Ethics Approval No.: 2024181K). Clinical data were collected from 522 patients who underwent ERCP for diagnostic and therapeutic purposes after gastrointestinal reconstruction surgery at the Digestive Endoscopy Center of Zhongnan Hospital of Wuhan University from January 2017 to December 2023. Inclusion criteria: 1. patients who had previously undergone Billroth I or Billroth II gastrectomy, Roux-en-Y gastric bypass, biliary-enteric anastomosis, gastrojejunostomy Roux-en-Y, pancreaticoduodenectomy, or liver transplantation and 2. patients requiring ERCP for diagnosis or treatment.3.Patients with complete medical history and surgical data. Exclusion criteria: 1 unknown surgical procedures; 2. abnormal coagulation function (INR ≤ 1.5, platelet count ≥ 50 × 10^9, APTT within normal range, or fibrinogen ≥ 1.5 g/L); and 3. patients unable to cooperate during the procedure. 

Procedure-related success rates : 1. Intubation success : successful advancement of the endoscope to the duodenal papilla or anastomosis. 2. Cannulation success : successful cannulation and contrast injection. 3. Therapeutic success rate : successful removal of stones, balloon dilation, stent placement, drainage, etc. ERCP-related complications : 1. Post-ERCP pancreatitis (PEP) : clinical symptoms of pancreatitis lasting for more than 24 h after ERCP, with serum amylase levels greater than three times the normal upper limit. 2. Post-ERCP hyperamylasemia (PEH) : elevated serum amylase levels without clinical signs of pancreatitis. 3. Bleeding : includes both early and delayed bleeding. Early bleeding refers to active bleeding during or immediately after the procedure that does not stop spontaneously, requiring hemostatic intervention. Delayed bleeding refers to upper gastrointestinal bleeding symptoms occurring hours or even weeks after the procedure. 4. Gastrointestinal perforation : severe abdominal pain within 24 h after the procedure, with free gas seen under the diaphragm or retroperitoneal on abdominal X-ray or CT scan. 

1. Preoperative preparation and postoperative treatment : Patients were instructed to fast and withhold water for 6–8 h before the procedure. One hour before the procedure, 0.1 mg of octreotide acetate was administered subcutaneously (to inhibit pancreatic enzyme secretion, reduce pancreatic injury, and prevent biliary sphincter spasm). Ten minutes before the procedure, 10 mg of morphine was injected subcutaneously (for pain relief), 5 mg of hyoscine-N-butylbromide was administered intramuscularly (to relax the bile ducts and Oddi’s sphincter, reduce bile duct and pancreatic duct pressure, and provide analgesia), and 10 mg of diazepam was given intravenously (for sedation and to reduce anxiety). The procedure was performed using small-bowel endoscopes (SIF-H290S, SIF Q260, Olympus), long-type colonoscopes (CF HQ290L/I, Olympus), gastroscopes (GIF HQ290, Olympus, Tokyo, Japan), duodenoscopes (Olympus TFJ-260, Olympus-FJ260), and standard colonoscopes (CF HQ290L/I, Olympus). A transparent cap was attached to the tip of the endoscope to improve visibility. A Philips Easy Diagnost system (Netherlands) was used for fluoroscopy, and iodixanol or iohexol was selected as the contrast agent. After the procedure, patients were kept fasting and given proton pump inhibitors for acid suppression, somatostatin to inhibit pancreatic enzyme secretion, and intravenous fluids. Blood amylase and lipase levels were checked at 2 and 24 h postoperatively. 2. Operation procedure : Once the endoscope reached the duodenal papilla or anastomosis, selective bile duct cannulation was performed. Based on the clinical condition, treatments such as endoscopic nasobiliary drainage (ENBD), endoscopic retrograde biliary drainage (ERBD), biliary and pancreatic duct stent placement, stone removal, or lithotripsy were performed (Fig. ). 

Data were analyzed using SPSS 27.0. For continuous variables (age), the Shapiro–Wilk test was used to assess normality. If the data were not normally distributed, the median and interquartile range were reported. Categorical data were presented as frequency and percentage, and analyzed using the χ 2 test or Fisher’s exact probability method. The variance inflation factor (VIF) was used to assess multicollinearity between factors associated with failed intubation. For variables with statistically significant differences, logistic regression analysis was conducted for multivariate analysis. A P value of < 0.05 was considered statistically significant. 

Patient characteristics A total of 522 patients who underwent ERCP after gastrointestinal reconstruction were included in the study, including 382 males (73.18%) and 140 females (26.81%). The age range was 18–88 years, with a mean age of (57.50 ± 21) years. The procedures included Billroth II (129 cases), Billroth I (7 cases), Roux-en-Y gastrojejunostomy (16 cases), total gastrectomy (15 cases), biliary-enteric anastomosis (53 cases), pancreaticoduodenectomy (56 cases), and liver transplantation (246 cases). Therapeutic procedures included endoscopic sphincterotomy (EST) in 81 cases, endoscopic papillary balloon dilation (EPBD) in 188 cases, endoscopic pancreatobiliary lithotripsy (EPLBD) in 4 cases, lithotripsy in 18 cases, stone removal in 213 cases, endoscopic retrograde biliary drainage (ERBD) in 179 cases, endoscopic biliary metal stenting (EMBE) in 25 cases, endoscopic retrograde pancreatic drainage (ERPD) in 19 cases, endoscopic nasobiliary drainage (ENBD) in 183 cases, biliary stent placement in 14 cases, pancreatic stent placement in 6 cases, stent removal in 107 cases, and cell brush cytology in 7 cases. Clinical outcomes The overall success rates for intubation, cannulation, and therapeutic procedures were 96.93% (506/522), 92.09% (466/506), and 95.28% (444/466), respectively (Table ). These rates were higher than those reported in related studies, which reported success rates of 89.4% (126/141), 85.7% (108/126), and 75.2% (106/141). In the study by Gao Zhuqing et al., the patients included were primarily those who had undergone Billroth I ( n = 33, 23.4%), Billroth II ( n = 74, 52.5%), biliary-enteric anastomosis ( n = 32, 22.69%), and pancreaticoduodenal anastomosis ( n = 2, 1.41%). In contrast, in this study, 47.12% of the patients had undergone liver transplantation. Among the 246 liver transplant recipients, 241 patients had direct anastomosis between the recipient’s bile duct and the donor’s bile duct, which allowed successful access to the duodenoscope through the esophagus, stomach, and duodenum. The duodenal papilla was located, and cannulation, contrast injection, and therapeutic procedures were successfully performed. This pathway had a higher success rate for intubation, cannulation, and overall ERCP success. The remaining 5 patients underwent biliary-enteric Roux-en-Y anastomosis, which increased the difficulty of the ERCP procedure. The operators used a short-arm enteroscope to navigate through the pylorus, continue through the Roux-en-Y anastomosis, and proceed further to reach the biliary-enteric anastomosis, where cannulation, contrast injection, and therapeutic interventions were then carried out. ERCP‐complications Acute pancreatitis (13/522, 2.49%), hyperamylasemia (67/522, 12.84%), acute cholangitis (3/522, 0.57%), hemorrhage (3/522, 0.57%) and perforation (2/522, 0.38%) were among the postoperative complications that occurred following the successful intubation of ERCP in patients with gastrointestinal reconstruction. Risk factors for failure in ERCP In the univariate analysis of factors associated with intubation failure in patients after gastrointestinal reconstruction, the use of a forward-viewing endoscope, duodenoscope, gastrojejunostomy, and total gastrectomy showed statistically significant differences (Table ). The multicollinearity test for risk factors associated with intubation failure is shown in Table . Due to the variance inflation factor (VIF) of the duodenoscope being greater than 5, this variable was excluded in the multivariate analysis of risk factors for intubation failure. The results, shown in Table , indicate that total gastrectomy, gastrojejunostomy, and the use of a forward-viewing endoscope were independent risk factors. Common causes of intubation failure typically include repeated cannulation failures, anastomotic stricture, difficulty in navigating through twisted or deformed enteral loops, difficulty in identifying the direction of the enteral loop, and failure to locate the duodenal papilla. In this study, patients who had undergone total gastrectomy or Roux-en-Y gastrojejunostomy mainly faced issues in identifying the enteral loop and the multiple 180° angles between the enteral and afferent loops, making intubation extremely difficult and complicating passage through the anastomosis, leading to ERCP failure. The forward-viewing endoscope, compared to the duodenoscope and enteroscope, has a smaller field of view, which leads to blind spots and increased difficulty in operating within the confined space. Risk factors for ERCP‐complications In the univariate analysis of factors influencing the occurrence of post-ERCP hyperamylasemia in patients with gastrointestinal reconstruction, a history of cholecystectomy showed a statistically significant difference ( P = 0.042, OR = 1.800, 95% CI 1.015–3.193) (Table ). This is consistent with the findings of Seleem et al , who reported that a history of cholecystectomy increases the difficulty of cannulation and stone removal, leading to prolonged ERCP procedure times and an associated increased incidence of post-ERCP pancreatitis (PEP) and hyperamylasemia. Among the 3 patients with bleeding, one had bile duct bleeding after nasobiliary catheter placement, one had biliary bleeding after papillotomy along the guidewire, and one had bleeding after biliary stent removal in a patient with a history of pancreatitis. In the univariate analysis of postoperative bleeding, a history of pancreatitis showed a statistically significant difference ( P = 0.040, OR = 42.75, 95% CI 3.399–537.620) (Table ). Other factors, including potential procedural errors, were not excluded. This conclusion is consistent with the findings of Zhang Hongzhao et al., who suggested that patients with a history of pancreatitis may experience pancreatic swelling due to prior inflammation, which compresses the biliary system and impairs bile drainage, leading to secondary cholangitis. This can cause atrophy, degeneration, and even necrosis of the bile duct tissue, making it more fragile and prone to bleeding. In the univariate analysis of postoperative acute pancreatitis, only repeated cannulation showed a statistically significant difference ( P = 0.000, OR = 47.619, 95% CI 13.317–170.275) (Table ). This conclusion aligns with the findings of Freeman et al., who reported that difficult cannulation can cause mechanical damage to the papilla and pancreatic duct opening, leading to local edema and poor drainage due to obstruction . The incidence of postoperative perforation was 0.38% (2/522). One case involved perforation after papillectomy, while another case involved perforation of the enteral loop during repeated intubation due to a large angle of the intestinal lumen. Both cases were immediately managed with endoscopic suturing to close the perforations. The incidence of acute cholangitis was 0.57% (3/522). For patients with biliary obstruction, nasobiliary drainage was performed, which helped reduce the incidence of acute cholangitis . 

A total of 522 patients who underwent ERCP after gastrointestinal reconstruction were included in the study, including 382 males (73.18%) and 140 females (26.81%). The age range was 18–88 years, with a mean age of (57.50 ± 21) years. The procedures included Billroth II (129 cases), Billroth I (7 cases), Roux-en-Y gastrojejunostomy (16 cases), total gastrectomy (15 cases), biliary-enteric anastomosis (53 cases), pancreaticoduodenectomy (56 cases), and liver transplantation (246 cases). Therapeutic procedures included endoscopic sphincterotomy (EST) in 81 cases, endoscopic papillary balloon dilation (EPBD) in 188 cases, endoscopic pancreatobiliary lithotripsy (EPLBD) in 4 cases, lithotripsy in 18 cases, stone removal in 213 cases, endoscopic retrograde biliary drainage (ERBD) in 179 cases, endoscopic biliary metal stenting (EMBE) in 25 cases, endoscopic retrograde pancreatic drainage (ERPD) in 19 cases, endoscopic nasobiliary drainage (ENBD) in 183 cases, biliary stent placement in 14 cases, pancreatic stent placement in 6 cases, stent removal in 107 cases, and cell brush cytology in 7 cases. 

The overall success rates for intubation, cannulation, and therapeutic procedures were 96.93% (506/522), 92.09% (466/506), and 95.28% (444/466), respectively (Table ). These rates were higher than those reported in related studies, which reported success rates of 89.4% (126/141), 85.7% (108/126), and 75.2% (106/141). In the study by Gao Zhuqing et al., the patients included were primarily those who had undergone Billroth I ( n = 33, 23.4%), Billroth II ( n = 74, 52.5%), biliary-enteric anastomosis ( n = 32, 22.69%), and pancreaticoduodenal anastomosis ( n = 2, 1.41%). In contrast, in this study, 47.12% of the patients had undergone liver transplantation. Among the 246 liver transplant recipients, 241 patients had direct anastomosis between the recipient’s bile duct and the donor’s bile duct, which allowed successful access to the duodenoscope through the esophagus, stomach, and duodenum. The duodenal papilla was located, and cannulation, contrast injection, and therapeutic procedures were successfully performed. This pathway had a higher success rate for intubation, cannulation, and overall ERCP success. The remaining 5 patients underwent biliary-enteric Roux-en-Y anastomosis, which increased the difficulty of the ERCP procedure. The operators used a short-arm enteroscope to navigate through the pylorus, continue through the Roux-en-Y anastomosis, and proceed further to reach the biliary-enteric anastomosis, where cannulation, contrast injection, and therapeutic interventions were then carried out. 

Acute pancreatitis (13/522, 2.49%), hyperamylasemia (67/522, 12.84%), acute cholangitis (3/522, 0.57%), hemorrhage (3/522, 0.57%) and perforation (2/522, 0.38%) were among the postoperative complications that occurred following the successful intubation of ERCP in patients with gastrointestinal reconstruction. 

In the univariate analysis of factors associated with intubation failure in patients after gastrointestinal reconstruction, the use of a forward-viewing endoscope, duodenoscope, gastrojejunostomy, and total gastrectomy showed statistically significant differences (Table ). The multicollinearity test for risk factors associated with intubation failure is shown in Table . Due to the variance inflation factor (VIF) of the duodenoscope being greater than 5, this variable was excluded in the multivariate analysis of risk factors for intubation failure. The results, shown in Table , indicate that total gastrectomy, gastrojejunostomy, and the use of a forward-viewing endoscope were independent risk factors. Common causes of intubation failure typically include repeated cannulation failures, anastomotic stricture, difficulty in navigating through twisted or deformed enteral loops, difficulty in identifying the direction of the enteral loop, and failure to locate the duodenal papilla. In this study, patients who had undergone total gastrectomy or Roux-en-Y gastrojejunostomy mainly faced issues in identifying the enteral loop and the multiple 180° angles between the enteral and afferent loops, making intubation extremely difficult and complicating passage through the anastomosis, leading to ERCP failure. The forward-viewing endoscope, compared to the duodenoscope and enteroscope, has a smaller field of view, which leads to blind spots and increased difficulty in operating within the confined space. 

In the univariate analysis of factors influencing the occurrence of post-ERCP hyperamylasemia in patients with gastrointestinal reconstruction, a history of cholecystectomy showed a statistically significant difference ( P = 0.042, OR = 1.800, 95% CI 1.015–3.193) (Table ). This is consistent with the findings of Seleem et al , who reported that a history of cholecystectomy increases the difficulty of cannulation and stone removal, leading to prolonged ERCP procedure times and an associated increased incidence of post-ERCP pancreatitis (PEP) and hyperamylasemia. Among the 3 patients with bleeding, one had bile duct bleeding after nasobiliary catheter placement, one had biliary bleeding after papillotomy along the guidewire, and one had bleeding after biliary stent removal in a patient with a history of pancreatitis. In the univariate analysis of postoperative bleeding, a history of pancreatitis showed a statistically significant difference ( P = 0.040, OR = 42.75, 95% CI 3.399–537.620) (Table ). Other factors, including potential procedural errors, were not excluded. This conclusion is consistent with the findings of Zhang Hongzhao et al., who suggested that patients with a history of pancreatitis may experience pancreatic swelling due to prior inflammation, which compresses the biliary system and impairs bile drainage, leading to secondary cholangitis. This can cause atrophy, degeneration, and even necrosis of the bile duct tissue, making it more fragile and prone to bleeding. In the univariate analysis of postoperative acute pancreatitis, only repeated cannulation showed a statistically significant difference ( P = 0.000, OR = 47.619, 95% CI 13.317–170.275) (Table ). This conclusion aligns with the findings of Freeman et al., who reported that difficult cannulation can cause mechanical damage to the papilla and pancreatic duct opening, leading to local edema and poor drainage due to obstruction . The incidence of postoperative perforation was 0.38% (2/522). One case involved perforation after papillectomy, while another case involved perforation of the enteral loop during repeated intubation due to a large angle of the intestinal lumen. Both cases were immediately managed with endoscopic suturing to close the perforations. The incidence of acute cholangitis was 0.57% (3/522). For patients with biliary obstruction, nasobiliary drainage was performed, which helped reduce the incidence of acute cholangitis . 

ERCP in patients with gastrointestinal reconstruction presents technical challenges and a higher risk of complications . The challenges faced by endoscopists mainly include correctly identifying the enteral loop, sharp angles at the anastomosis or enteral loop, overly long enteral loops, changes in the position of the duodenal papilla, lack of appropriate endoscopic equipment and instruments, and postoperative adhesions in the peritoneal cavity . There are many related studies aimed at improving the success rate of ERCP in gastrointestinal reconstruction patients. For example, Wang Hao et al . Recommended the use of an enteroscope in patients who have undergone total gastrectomy or gastrojejunostomy, as using the appropriate endoscope and performing contrast injection under X-ray fluoroscopy can help in identifying the direction of the enteral loop and locating the duodenal papilla, thus improving the success rate of ERCP. When cannulation difficulties arise, Fan Ling et al.  reported that auxiliary cannulation techniques such as pancreatic duct stent-assisted guidewire cannulation, pre-cutting of the pancreatic sphincter, and pre-cutting of the papilla or fistula can increase the cannulation success rate to 95%. When encountering difficulty due to anastomotic stricture during the procedure, Tian Wenjie et al.  suggested that techniques such as magnetic anastomosis, percutaneous transhepatic biliary endoscopy with guidewire blunt-tip breakthrough, endoscopic balloon dilation combined with multiple stent placements, and others can be significantly effective. When therapeutic procedures fail, alternatives like endoscopic ultrasound-guided biliary drainage (EUS-BD) and endoscopic ultrasound-guided antegrade biliary drainage (EUS-AG) can be considered . In terms of auxiliary equipment, the introduction of scissors knives, tapered sheaths, auxiliary enteroscopes, and laparoscopic support has the potential to improve the diagnostic and therapeutic success rates of ERCP . Our center’s clinicians take various measures before and during the procedure to improve the success rates of intubation, cannulation, and therapy, as well as to reduce the occurrence of complications. Preoperatively, the surgeon reviews the patient’s medical history and surgical records in detail and draws a schematic diagram of the gastrointestinal anatomy to plan the intubation route. During the procedure, the appropriate endoscopic assistance is selected according to the patient type (e.g., duodenoscope for Billroth I and Billroth II patients, enteroscope for pancreaticoduodenectomy and total gastrectomy patients, and enteroscope or duodenoscope for biliary-enteric anastomosis patients), which can help improve the success rate of ERCP . Furthermore, the use of transparent caps and the introduction of single-balloon enteroscopes (SBE) in our center have shown improvements. Studies have reported that the SBE, with its new design features such as high force transmission and passive curvature, helps achieve smoother intubation and clearer high-definition imaging, enhancing visualization . The use of double-guidewires and pre-cut techniques also significantly improves the success of difficult cannulation. The mechanism is to place the guidewire into the duct, using gravity or a range effect to separate the bile duct and catheter, which helps to stabilize the papilla and straighten the common bile duct and pancreatic duct axis . When the procedure fails, percutaneous transhepatic cholangiography (PTCD) is often used as an alternative therapy in our center. The occurrence of postoperative complications in patients with gastrointestinal reconstruction undergoing ERCP is inevitable, and prevention of these complications is a key issue for clinicians. To reduce the risk of bleeding, Freeman et al. suggested that gentle handling during the procedure, appropriate use of electrosurgical cutting and coagulation, and stepwise dissection, as well as discontinuation of anticoagulants for more than a week, are effective preventive measures . To prevent PEP and hyperamylasemia, Hu Shiping et al. recommended using guidewire-assisted cannulation, early pre-cutting, pancreatic stent placement, endoscopic nasobiliary drainage, and papillary balloon dilation to reduce injury to the papilla, assist in cannulation, and ensure proper pancreatic fluid drainage . In addition, pharmacological preventive measures such as somatostatin, proton pump inhibitors, antibiotics, and NSAIDs have been shown to be effective . At our center, most patients undergo preoperative administration of octreotide acetate to inhibit pancreatic enzyme secretion, reduce pancreatic injury, and prevent biliary sphincter spasm. Intraoperatively, we use guidewire-assisted cannulation, perform pre-cutting in 5 cases, and carry out procedures such as EPBD (188 cases), ENBD (183 cases), and pancreatic stent placement (6 cases). Postoperatively, we routinely administer somatostatin to inhibit pancreatic enzyme secretion and proton pump inhibitors for acid suppression, which has been effective in reducing the incidence of PEP and hyperamylasemia. In conclusion, performing ERCP in patients with gastrointestinal reconstruction presents increased challenges compared to patients with normal gastrointestinal anatomy. Clinicians must possess proficient ERCP skills, understand the patient’s altered gastrointestinal anatomy preoperatively, and select the appropriate endoscope to improve the success rate. Patients with a history of pancreatitis are more prone to secondary bile duct fragility and bleeding. Gentle handling during the procedure can reduce the incidence of postoperative bleeding. Guidewire-assisted cannulation and pre-cut techniques can improve cannulation success and avoid repeated cannulation to reduce the incidence of postoperative acute pancreatitis and hyperamylasemia. Based on the findings from this study and numerous related studies, ERCP holds a promising future as a safe and effective diagnostic and therapeutic procedure. Although significant progress has been made, there is still potential for further improvement, such as the development of specialized equipment and the creation of training programs for clinicians. Recent research has also shown that 3D printing technology can be used to create silicone simulators for ERCP training , helping operators accumulate rich experience. This study is retrospective, with strict inclusion and exclusion criteria, and cases lacking research factors were excluded to control selection bias. Some patients underwent multiple ERCP procedures, which may have influenced the overall success rate. This limitation could be addressed by conducting high-quality randomized controlled trials to validate the analysis of risk factors in future research. 

