Endoscopic retrograde cholangiopancreatography (ERCP) in patients with Roux-en-Y anatomy

INTRODUCTION — 

Endoscopic retrograde cholangiopancreatography (ERCP) is an advanced endoscopic procedure that is often used for biliary interventions (eg, removal of bile duct stones, relief of biliary obstruction). For patients without surgically altered anatomy, a side viewing upper endoscope (ie, duodenoscope) is used to visualize the ampulla of Vater, followed by accessing the common bile duct with selective biliary cannulation.

For patients with Roux-en-Y anatomy, establishing biliary access is technically challenging. Roux-en-Y gastric bypass (RYGB) (figure 1) is a common bariatric surgical intervention, and it may result in rapid weight loss that increases the risk of gallstone formation. Thus, gallstones are common in patients who have undergone RYGB, and ERCP is often indicated in such patients who develop choledocholithiasis. (See "Bariatric procedures for the management of severe obesity: Descriptions", section on 'Roux-en-Y gastric bypass'.)

In addition to RYGB, Roux-en-Y anatomy may result from:

●Gastric resection (figure 2 and figure 3) – (See "Partial gastrectomy and gastrointestinal reconstruction" and "Total gastrectomy and gastrointestinal reconstruction".)

●Pancreaticoduodenectomy (figure 4 and figure 5) – (See "Surgical resection of lesions of the head of the pancreas" and "Surgical resection of lesions of the body and tail of the pancreas".)

●Liver transplantation – (See "Living donor liver transplantation in adults".)

●Other biliary tract surgeries, such as repair of bile duct injuries or as part of the treatment of cholangiocarcinoma, resulting in the formation of a hepaticojejunostomy (figure 6) or choledochojejunostomy – (See "Repair of common bile duct injuries", section on 'Repair options' and "Adjuvant and neoadjuvant therapy for localized resectable cholangiocarcinoma", section on 'Overview of surgical treatment and prognosis'.)

This topic will review endoscopic techniques for accessing the biliary or pancreatic duct in patients with Roux-en-Y anatomy. General issues related to upper endoscopy in patients with surgically altered anatomy are discussed separately. (See "Gastrointestinal endoscopy in patients who have undergone bariatric surgery".)

Endoscopic management of biliary tract conditions is discussed separately:

●Choledocholithiasis – (See "Endoscopic management of bile duct stones".)

●Malignant biliary strictures – (See "Endoscopic stenting for malignant biliary obstruction".)

●Biliary adverse events related to surgery – (See "Liver transplantation in adults: Endoscopic management of biliary adverse events" and "Endoscopic management of postcholecystectomy biliary complications".)

Other aspects of ERCP, including patient preparation and anesthesia, are discussed separately. (See "Overview of endoscopic retrograde cholangiopancreatography (ERCP) in adults" and "Anesthesia for gastrointestinal endoscopy in adults".)

POST-SURGICAL ANATOMY IMPACTING BILIARY ACCESS — 

In patients with Roux-en-Y anatomy (figure 1), it is frequently challenging or impossible to access the native papilla in the second portion of the duodenum using a standard duodenoscope due to the length and angulation of the intestinal tract that must be traversed. For patients with Roux-en-Y gastric bypass, an endoscope advanced through the "anatomic route" must traverse the esophagus, gastric pouch, and Roux limb (typically 100 to 150 cm in length), and then navigate the acute angle at the jejunojejunostomy into the biliopancreatic limb up to the papilla (an additional 80 to 100 cm). Moreover, in patients with a native papilla, the papilla appears to be rotated from the usual location because the endoscope approaches the papilla from a distal location (Roux limb) rather than from the typical proximal direction (picture 1). (See 'Issues related to ductal cannulation' below.)

To overcome these issues, specialized endoscopic approaches, accessories, and innovative techniques have been developed to achieve biliary access in patients with Roux-en-Y anatomy. When endoscopy-guided access is not possible, alternative methods include the following, provided that such interventional expertise is available:

●Percutaneous transhepatic cholangiography – (See "Percutaneous transhepatic cholangiography in adults".)

●Percutaneous transhepatic cholangioscopy – (See "Percutaneous transhepatic cholangioscopy".)

PREPROCEDURE EVALUATION

Review anatomy of Roux-en-Y — Prior to attempting ERCP in patients with Roux-en-Y anatomy, we review the surgeon’s operative note or, if possible, discuss the expected anatomy with the surgeon. Specifically, we review details about the anatomic resection, type of reconstruction, the excluded (remnant) stomach, length of the limbs, and types of anastomoses (eg, end-to-side, side-to-side). We also review whether the patient has a native papilla. In addition, we review relevant postoperative imaging studies, especially magnetic resonance cholangiopancreatography (MRCP), if available.

Review timing of ERCP — We measure the time interval between Roux-en-Y surgery and the expected date of the endoscopic procedure. If Roux-en-Y surgery was recent (eg, within the previous four weeks), we weigh the potential benefits of gaining biliary access with the risk of endoscopy-related injury to the anastomoses [1]. The risk of disrupting the gastrojejunal anastomosis and jejunojejunal anastomosis is related to pressure and shearing forces from the endoscope and to bowel stretching caused by looping.

Preprocedure testing — For patients with Roux-en-Y anatomy, preprocedure testing is similar to the evaluation for all patients prior to endoscopic procedures (eg, assess cardiopulmonary risk). These issues are discussed separately. (See "Anesthesia for gastrointestinal endoscopy in adults", section on 'Preprocedure evaluation'.)

SELECTING A TECHNIQUE

Factors that guide decision-making — For patients with Roux-en-Y anatomy in whom endoscopic access to the common bile duct or pancreatic duct is needed, selecting an access method is individualized and informed by the following:

●Patient anatomy:

•Whether the patient has a native papilla or a bilioenteric/pancreatoenteric anastomosis. (See 'Patients with native papilla' below and 'Patients without native papilla' below.)

•Length of the Roux (alimentary) limb and the biliopancreatic limb (shorter Roux limbs are generally <100 cm).

•Whether the patient has an excluded (remnant) stomach (figure 1).

●Other patient characteristics:

•The indication for ERCP, including the likelihood of requiring repeat procedures for therapeutic intervention. As an example, the common bile duct can often be completely cleared during the index endoscopic session in patients with choledocholithiasis. However, patients with malignant biliary obstruction may require repeat endoscopy to manage recurrent obstruction related to stent occlusion. For such patients with a history of Roux-en-Y gastric bypass (RYGB), endoscopic ultrasound (EUS)-directed transgastric ERCP (EDGE) may be a good option, if available. (See "Endoscopic stenting for malignant biliary obstruction" and 'Patients with native papilla' below.)

•The patient's surgical risk. (See "Preoperative evaluation for noncardiac surgery in adults".)

•Whether the patient has another indication for surgery. As an example, if the patient is undergoing laparoscopic cholecystectomy and needs ERCP for bile duct stone clearance, we may perform laparoscopy-assisted ERCP because stone clearance can be achieved intraoperatively and during a single procedural setting. (See 'Surgical access via the excluded stomach (or small bowel)' below.)

●The available resources, including expertise in device-assisted small bowel enteroscopy, EUS, laparoscopic surgery, and hepatobiliary surgery.

Issues related to ductal cannulation — Selective ductal cannulation is more challenging with a forward-viewing endoscope (eg, device-assisted ERCP) and when approaching the native papilla from a distal location than with a side-viewing duodenoscope. (See 'Device-assisted ERCP (balloon enteroscopy)' below.)

When the forward-viewing endoscope reaches the native papilla, the working channel of the endoscope is rotated such that the papilla appears in the six to nine o’clock position rather than the usual 12 o’clock position (picture 1) [2]. A short, distal attachment cap fitted on the endoscope may facilitate visualization of the papilla and may sometimes be used to “tip” the ampulla toward the endoscope.

Patients with native papilla — In patients with a native papilla, we typically select a technique that allows for the use of a side-viewing upper endoscope (ie, duodenoscope) (algorithm 1). We prefer to use a duodenoscope because the native papilla remains in the 12 o’clock position, which increases the likelihood of successful selective cannulation of the bile and/or pancreatic ducts. However, advancing the duodenoscope using a transoral approach through the anatomic route may be successful only in patients with a shorter Roux limb (<100 cm). (See 'ERCP using standard duodenoscope' below.)

For patients with a native papilla and longer Roux limb (as in most patients with RYGB), options for performing ERCP with a standard duodenoscope involve accessing the excluded stomach through an endoscopically placed internal stent or by establishing percutaneous access:

●Use of an internal stent – EUS-directed methods involve creating a gastrogastric or jejunogastric fistula via EUS-guided placement of a lumen-apposing metal stent (LAMS) into the excluded stomach (figure 7 and figure 8) [3,4]. A duodenoscope can then be passed through the metal stent, into the excluded stomach, and then into the duodenum followed by ERCP. Several factors play a role in whether the ERCP should be performed on the day of stent placement (versus letting the tract mature and epithelialize), including the urgency of the biliary intervention, size and location of stent placement, fixation techniques, and orientation of the stent. (See 'EUS-directed approaches' below.)

●Percutaneous access – Options for percutaneous access to the excluded stomach include laparoscopic creation of a gastrostomy tract (also referred to as laparoscopy-assisted [LA]-ERCP) or open surgical gastrostomy (figure 9). (See 'Percutaneous access methods' below.)

Techniques for establishing access to the excluded stomach are increasingly used for patients with RYGB anatomy who may need more than one ERCP (eg, those with biliary malignancy who require stenting, those with bile leaks who require temporary stenting, those with pancreatic duct stricture or stones).

Patients without native papilla — For patients with bilioenteric and/or pancreatoenteric anastomoses (figure 4 and figure 5), forward-viewing endoscopes are usually adequate for establishing access to the bile or pancreatic ducts because the patient lacks a native papilla. (See 'Patients with native papilla' above.)

Selecting an endoscopic technique is further informed by length of Roux limb that is anastomosed to the biliary or pancreatic access point:

●Shorter Roux limb – For patients with a shorter Roux limb (<75 cm), we may use a small bowel enteroscope (working length 200 cm) or a small caliber colonoscope (working length 168 cm with an outer diameter ranging from 9.7 to 11.7 mm). (See 'ERCP techniques without device assistance' below.)

●Longer Roux limb – For patients with a longer Roux limb (≥75 cm), we typically use device-assisted small bowel enteroscopy techniques such as balloon-assisted enteroscopy. (See 'Device-assisted ERCP (balloon enteroscopy)' below.)

SPECIFIC ENDOSCOPY-GUIDED TECHNIQUES

EUS-directed approaches

EUS-directed transgastric ERCP (EDGE) — EUS-directed transgastric ERCP (EDGE) is a technique that uses EUS-guided placement of a lumen-apposing metal stent (LAMS) between the gastric pouch (or jejunum) and the excluded stomach to facilitate a transoral antegrade ERCP using a duodenoscope (figure 7 and figure 8).

●Efficacy – Experience with EDGE in patients with Roux-en-Y gastric bypass anatomy has been very promising, with technical success rates comparable to those reported for laparoscopy-assisted ERCP [3-8]. (See 'Percutaneous access methods' below.)

Multicenter studies involving EDGE suggested high rates of technical success and clinical success [4]. In a retrospective study including 172 patients with Roux-en-Y gastric bypass (RYGB) who underwent EDGE, the technical success rate related to LAMS placement was 99  percent and the clinical success rate for biliary intervention was 95 percent [4]. ERCP with stent placement was performed in a single session in 75 patients (44 percent). In a meta-analysis of 16 studies comparing EDGE with laparoscopy-assisted ERCP and balloon enteroscopy-assisted ERCP, rates of technical success using EDGE were comparable to laparoscopy-assisted ERCP and higher than balloon enteroscopy assisted-ERCP (95 percent versus 95 and 66 percent, respectively) [5]. In addition, EDGE was associated with shorter procedure times compared with laparoscopy-assisted-ERCP (mean difference: -78 minutes, 95% CI -105 to -51 minutes) and compared with enteroscopy assisted-ERCP (mean difference -31 minutes, 95% CI -41 to -21 minutes).

●Adverse events – Potential adverse events with EDGE include stent migration, postprocedure weight gain related to the indwelling stent, and persistent fistula following stent removal. In a study including 172 patients with RYGB and pancreatobiliary disease who underwent EDGE and were followed for a mean of six months, the mean weight gain was 12 pounds (5.4 kg), although nearly 60 percent of patients gained less than 5 pounds (2.3 kg) [4]. Among 62 patients evaluated for fistula closure following stent removal, 19 patients (31 percent) had persistent gastric fistula. Stent dislodgement or migration was reported in 28 patients (16 percent), and most cases occurred peri-procedurally and were managed endoscopically.

EUS-directed transenteric ERCP (EDEE) — EUS-directed transenteric ERCP (EDEE) is a transoral technique involving EUS-guided placement of a LAMS between the duodenum and the Roux limb (ie, creating an enteroenteric anastomosis). EDEE has been studied mostly in patients with Roux-en-Y anatomy that is not related to gastric bypass [9]. In a retrospective study including 18 patients with surgically altered anatomy (Roux-en–Y hepaticojejunostomy or pancreaticoduodenostomy in 16 patients [89 percent]), creation of an enteroenteric anastomosis using EUS-guided LAMS placement was successful in all patients, while subsequent ERCP with intervention (eg, stone removal) was successful in 17 patients (94 percent) [9]. One patient had a stricture distal to the enteroenteric anastomosis; thus ERCP could not be completed. The adverse event rate was low, with one patient (6 percent) reporting mild post-procedure abdominal pain that was medically managed. Use of transluminal EDEE may be feasible for patients with Roux-en-Y anatomy if additional studies can validate these results and help define optimal timing for LAMS removal [10].

Other EUS-directed methods — EUS-guided hepaticoenterostomy has also been described in patients with surgically altered anatomy. This approach typically entails puncturing a branch of the left intrahepatic duct under EUS-guidance and then placing a biliary stent transmurally into the intrahepatic biliary system [11]. EUS-guided hepaticoenterostomy is typically reserved for palliation of malignant biliary obstruction. More data are needed to determine the safety and efficacy of this approach in benign disease.

Device-assisted ERCP (balloon enteroscopy) — Device-assisted ERCP refers to using deep small bowel enteroscopy techniques such as double-balloon enteroscopy (figure 10) or single-balloon enteroscopy (figure 11) to perform ERCP. Technical details and adverse events related to device-assisted enteroscopy are discussed separately. (See "Overview of deep small bowel enteroscopy".)

While deep enteroscopy techniques represent a significant advancement for performing ERCP in patients with surgically altered anatomy, they are not widely performed outside of specialized centers. Limitations of this approach are mostly related to the use of a forward-viewing enteroscope, including restricted maneuverability of the scope (related to looping, adhesions, sharp angulations, and depth of scope insertion), unfavorable orientation of the native papilla, lack of an instrument elevator, and relatively few enteroscope-compatible ERCP accessories [4]. (See 'Issues related to ductal cannulation' above.)

●Double balloon enteroscope-assisted ERCP – In several case series involving patients with Roux-en-Y anatomy who underwent double balloon enteroscopy-assisted ERCP, rates of achieving biliary access via the native papilla (or bilioenteric/pancreatoenteric anastomosis) ranged from 80 to 96 percent, and rates of successful selective ductal cannulation were over 80 percent (figure 10) [12-18].

As with other approaches using forward-viewing endoscopes, cannulation of the native papilla may be difficult with double balloon enteroscopy. (See 'Post-surgical anatomy impacting biliary access' above.)

An additional problem when performing double balloon technique is the limited number of biliary accessories that are compatible with a double balloon enteroscope due to its length. However, this issue can be addressed with the use of a "short" double balloon enteroscopy system that has a working channel length of 152 cm and is compatible with standard biliary accessories [14,19]. In a study including 36 patients with Roux-en-Y total gastrectomy who underwent a total of 55 procedures using the "short" double balloon enteroscope, successful bile duct cannulation was achieved in 50 procedures (91 percent) [19]. Multiple therapeutic maneuvers were performed, including sphincterotomy, stone extraction, balloon dilation, and the insertion of plastic stents, metal stents, and nasobiliary drainage tubes.

●Single balloon enteroscope-assisted ERCP – Use of single balloon enteroscope-assisted ERCP in patients with Roux-en-Y anatomy has been associated with diagnostic success rates ranging from 60 to 80 percent (figure 11) [20-26]. In a systematic review of 15 studies with 461 patients with surgically altered anatomy who underwent single balloon enteroscope assisted-ERCP, the pooled rates of technical success (ie, reaching the papilla or biliary anastomosis), diagnostic success (ie, obtaining cholangiogram), and therapeutic success were 81, 69, and 62 percent, respectively [27]. Among 489 procedures, 32 adverse events (6.5 percent) occurred. Serious adverse events related to ERCP included pancreatitis, bleeding, and perforation.

ERCP techniques without device assistance — Transoral, device-unassisted approaches to ERCP involve the use of duodenoscopes, small caliber colonoscopes, or enteroscopes that are advanced through the mouth and the anatomic route.

ERCP using standard duodenoscope — We reserve the transoral approach using a standard duodenoscope for patients with a shorter Roux (alimentary) limb (eg, <100 cm) [28]. In general, we prefer to use a side-viewing endoscope (duodenoscope) for cannulating the native papilla. (See 'ERCP using an enteroscope or colonoscope' below and 'EUS-directed approaches' above.)

However, the duodenoscope-only approach is frequently unsuccessful, as shown in one small series of six patients with Roux-en-Y anatomy in which ERCP was successfully performed in only two patients (33 percent) [29].

ERCP using an enteroscope or colonoscope — A small bowel enteroscope or small caliber (ie, pediatric) colonoscope may be an option for managing a longer Roux limb during ERCP when using a duodenoscope is not feasible. (See 'ERCP using standard duodenoscope' above.)

The likelihood of reaching the bile and pancreatic ducts depends on the length of the Roux limb. In one series, 18 patients with Roux-en-Y anatomy underwent a total of 25 attempted ERCPs using a small caliber colonoscope (164 cm working length) and/or an enteroscope (240 cm working length) [30]. The endoscope was successfully advanced to the papilla or the bilioenteric/pancreatoenteric anastomosis in 84 percent of procedures. Biliary cannulation was then successful in 94 percent of procedures (including five of six procedures performed in patients with intact native papilla).

For patients with a native papilla, selective biliary or pancreatic duct cannulation may be more difficult when using a forward-viewing endoscope that lacks an elevator mechanism. In addition, a small bowel enteroscope or colonoscope may have limited maneuverability due to torsion of the endoscope shaft and loop formation. Finally, deflection of the scope tip can make introducing accessories through the working channel technically challenging or impossible. To overcome these issues, forward-viewing endoscopes can be used initially to navigate the anatomic route. Once the papilla is reached, a guidewire is placed, and the forward-viewing endoscope is removed. Then, the duodenoscope is inserted over the guidewire and advanced to the region of the papilla [31].

PERCUTANEOUS ACCESS METHODS

Surgical access via the excluded stomach (or small bowel) — For patients with Roux-en-Y anatomy related to Roux-en-Y gastric bypass, an alternative to using a transoral, endoscopic approach is to establish percutaneous access to the excluded stomach or to the small bowel (eg, jejunum) (figure 9). Options for securing percutaneous access typically include laparoscopic surgery (also referred to as laparoscopy-assisted [LA]-ERCP) or open surgery [32-36]. After a trocar is surgically placed through the abdominal wall, through the gastric wall, and into the lumen of the excluded stomach, a side-viewing duodenoscope is inserted through the trocar and advanced to the native papilla. The ERCP is usually performed intraoperatively (ie, immediately after trocar placement), but it may also be performed at a later date if necessary. A large bore feeding tube (eg, a 32 French gastrostomy tube) can maintain patency of the tract if repeated endoscopic procedures are anticipated [37].

This approach has advantages, including providing efficient, reliable access to the duodenum and facilitating the use of a side-viewing duodenoscope in addition to standard biliary accessories [38].

For patients with a native papilla, the papilla remains in the typical 12 o'clock position when visualized with the side-viewing duodenoscope. Conversely, when a forward-viewing endoscope is used, the papilla appears rotated to another position (eg, 6 o’clock) because the endoscope approaches the papilla from a distal location (biliopancreatic limb) rather than from the typical proximal direction. When the papilla appears rotated, cannulation of the bile duct is technically challenging and requires specialized endoscopic accessories. (See 'Issues related to ductal cannulation' above.)

Approaches involving percutaneous access may have the following disadvantages:

●Surgical access is more invasive than endoscopy-directed approaches and carries additional risks such as wound infection.

●Surgical access requires sterile instruments and sterile technique.

●Surgical access is usually more resource-intensive and requires close coordination between surgical and therapeutic endoscopy teams.

Establishing percutaneous access to the excluded stomach via a surgical procedure appears to be effective and safe in patients with Roux-en-Y anatomy who require ERCP. In a systematic review of 26 studies including 509 patients with Roux-en-Y gastric bypass who underwent ERCP via percutaneous access to the excluded stomach, bile duct cannulation was achieved in 98 percent of patients [36]. Percutaneous gastrostomy was successfully placed in all patients using methods such as laparoscopic surgery, open surgery, or endoscopic ultrasound. Wound infection was the most common gastrostomy-related adverse event (19 patients [4 percent]), and post-ERCP pancreatitis was the most common ERCP-related adverse event (seven patients [1 percent]). In one study comparing laparoscopy-assisted-ERCP with balloon enteroscopy-assisted ERCP in 56 patients, laparoscopy-assisted-ERCP was associated with higher rates of reaching the papilla (100 versus 72 percent), successful biliary cannulation (100 versus 59 percent), and successful therapeutic intervention (100 versus 59 percent) [39].

Other percutaneous methods — Another percutaneous option is percutaneous-assisted transprosthetic endoscopic therapy (PATENT), although this technique has not been widely used in clinical practice (figure 12) [40-42]. PATENT involves the use of device-assisted (balloon) small bowel enteroscopy or EUS to access the excluded stomach followed by placement of a percutaneous gastrostomy tube [40]. Next, a self-expandable metal stent is deployed within the gastrostomy tract, and then antegrade ERCP is performed through the stent during the same endoscopic session.

SOCIETY GUIDELINE LINKS — 

Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Endoscopic retrograde cholangiopancreatography (ERCP)".)

SUMMARY AND RECOMMENDATIONS

●Background – For patients with Roux-en-Y anatomy (figure 1) who have indications for ERCP, it is frequently challenging or impossible to access the native papilla in the second portion of the duodenum using a standard side-viewing duodenoscope due to the length and angulation of the intestinal tract that must be traversed. To overcome these issues, specialized endoscopic approaches, accessories, and innovative techniques have been developed to achieve access to the bile ducts and/or pancreatic duct in patients with Roux-en-Y anatomy. (See 'Post-surgical anatomy impacting biliary access' above.)

●Preprocedure evaluation – Preprocedure evaluation includes (see 'Preprocedure evaluation' above):

•Review anatomy – Prior to attempting ERCP in patients with Roux-en-Y anatomy, we review the operative note or, if possible, discuss the expected anatomy with the surgeon.

•Review timing of ERCP – If Roux-en-Y surgery was recent (ie, within the previous four weeks), we weigh the potential benefits of endoscopic biliary access with the risk of injury to the anastomoses.

•Preprocedure testing – Preprocedure testing is similar to the evaluation for all patients prior to endoscopic procedures (eg, assess cardiopulmonary risk). These issues are discussed separately. (See "Anesthesia for gastrointestinal endoscopy in adults", section on 'Preprocedure evaluation'.)

●Selecting a technique – For patients with Roux-en-Y anatomy in whom endoscopic access to the common bile duct or pancreatic duct is needed, selecting an access method is informed by the following (algorithm 1) (see 'Selecting a technique' above):

•Patient anatomy:

-Whether the patient has a native papilla or a bilioenteric/pancreatoenteric anastomosis

-Roux (alimentary) limb length (shorter Roux limbs are <100 cm)

-Whether the patient has an excluded (remnant) stomach

•Other patient characteristics:

-Indications for ERCP, including the likelihood of requiring repeat procedures

-The patient's surgical risk (see "Preoperative evaluation for noncardiac surgery in adults")

-Whether the patient has another indication for surgery (eg, cholecystitis)

•The available resources including expertise in EUS, device-assisted enteroscopy, laparoscopic surgery, and hepatobiliary surgery

●Patients with native papilla – For patients with a native papilla and a longer Roux limb (as in most patients with Roux-en-Y gastric bypass), we typically use one of the following techniques (see 'Patients with native papilla' above):

•EUS-directed transgastric ERCP (EDGE) (figure 7 and figure 8)

•Laparoscopy-assisted ERCP (LA-ERCP) (figure 9)

Techniques involving direct endoscopic access to the excluded stomach provide an efficient, reliable method for reaching the descending duodenum and visualizing the native papilla in the usual orientation (ie, 12 o’clock position) while using a standard duodenoscope and related accessories (eg, sphincterotome). (See "Endoscopic biliary sphincterotomy".)

●Patients without a native papilla – For patients without a native papilla (ie, patients with a bilioenteric/pancreatoenteric anastomosis), selecting a technique is generally informed by the length of the Roux limb (see 'Patients without native papilla' above):

•Shorter Roux limb – For patients with a shorter Roux limb (<75 cm), we typically use a forward-viewing endoscope such as a small caliber (pediatric) colonoscope or enteroscope to reach the anastomosis. (See 'ERCP using an enteroscope or colonoscope' above.)

•Longer Roux limb – For patients with a longer Roux limb, we use device-assisted ERCP (balloon enteroscopy). (See 'Device-assisted ERCP (balloon enteroscopy)' above.)

●Managing biliary tract conditions – Endoscopic interventions for biliary tract conditions are discussed separately:

•Choledocholithiasis – (See "Endoscopic management of bile duct stones".)

•Malignant biliary strictures – (See "Endoscopic stenting for malignant biliary obstruction".)

•Biliary adverse events related to surgery – (See "Liver transplantation in adults: Endoscopic management of biliary adverse events" and "Endoscopic management of postcholecystectomy biliary complications".)