Biliary cannulation is a fundamental technique in endoscopic retrograde cholangiopancreatography (ERCP) and is essential for all therapeutic and diagnostic procedures associated with ERCP. ERCP‐related procedures have made remarkable progress over more than 50 years since their development, benefiting from innovations in techniques and device development [1, 2]. However, failure to achieve biliary cannulation renders further procedures impossible. Prolonged biliary cannulation time is a high‐risk factor for post‐ERCP pancreatitis (PEP) and may adversely affect patient prognosis [3].
Therefore, mastering biliary cannulation is the primary objective for endoscopists performing ERCP; however, it remains a significant challenge, and achieving a success rate exceeding 95% remains unresolved. With increasing experience, most endoscopists can eventually succeed in biliary cannulation. However, endoscopists who perform biliary cannulation without establishing a strategy and without evidence will never be able to overcome difficult cases. Cannulation of a native or intact papilla fails in approximately 5%–11% of cases, even in experienced hands [4, 5].
One of the main reasons for this challenge is the lack of a standardized technique and uniform teaching methods for biliary cannulation. Cannulation techniques include contrast‐assisted, guidewire‐assisted, and hybrid approaches. When initial attempts fail, multiple rescue techniques such as the double‐guidewire (DGW) technique or precut sphincterotomy can be employed. Preferences for these techniques vary among both trainees and trainers, resulting in a biased and heterogeneous transfer of skills. This variability makes the creation of comprehensive, universally accepted guidelines difficult, and such guidelines remain insufficient.
In latest digestive endoscopy, new guidelines led by the World Endoscopy Organization (WEO), involving expert panels from Asia, Europe, and the United States, have been published [6]. The most distinctive feature of this guideline is their aim to provide globally applicable clinical recommendations, regardless of available resources or expertise. The guideline developers paid particular attention to integrating all available techniques for biliary cannulation, making it a clinically practical and useful resource worldwide.
The document is structured around four major themes: prevention of PEP, biliary cannulation techniques, endoscopic sphincterotomy and balloon dilation, and cannulation in special situations. Fourteen clinical questions (CQs) were formulated, each accompanied by a statement and supporting evidence. Although the explanations are concise, they incorporate extensive evidence, providing valuable insights into the current evidence‐based status of biliary cannulation.
One of the most appealing features of these guidelines is the comprehensive summary of meta‐analyses of randomized controlled trials (RCTs) presented as Supplementary Tables in Crinò et al. [6]. These tables alone are highly educational and essential reading. Moreover, the guidelines report the proportion of “strongly agree” and “agree” responses among WEO Research Committee members, illustrating the degree of consensus. Notably, some statements have over 90% “strongly agree,” while others are as low as 20%, reflecting the inherent variability and diversity in biliary cannulation techniques.
Overall, the statements are clinically acceptable and provide evidence to support many real‐world techniques that have traditionally been performed based on experience rather than data.
The guideline also highlights future research priorities. Focusing specifically on biliary cannulation, several key issues are worth mentioning:
Efficacy and safety of the “hybrid” cannulation technique compared with guidewire‐assisted cannulation.
In difficult cannulation cases, the hybrid technique involves contrast injection to delineate the intrapapillary bile duct anatomy, followed by scope and guidewire manipulation based on this information to achieve successful cannulation. This method is widely used in clinical practice and is clearly beneficial. On the other hand, non‐contrast wire‐guided cannulation (WGC) is an established technique, and its usefulness has been widely reported. Should an RCT be conducted comparing contrast‐enhanced WGC with non‐contrast WGC, the results would be intriguing. However, in actual clinical practice, non‐contrast WGC is often attempted first for biliary cannulation, with contrast‐enhanced WGC employed when the initial attempt fails. Therefore, contrast use and WGC should be appropriately combined according to the case, and the question of which is superior is not particularly clinically relevant.
Comparison of pancreatic guidewire‐assisted cannulation and precut techniques in unintended pancreatic duct (PD) cannulation.
No clear evidence currently supports the superiority of transpancreatic sphincterotomy (TPS) or DGW over each other in this setting. Several RCTs have been conducted with inconsistent results [7, 8, 9]. The variation in precut techniques likely contributes to these discrepancies. Future RCTs using standardized precut methods are warranted.
Comparison of repeat ERCP versus percutaneous or EUS‐guided rendezvous, and precut versus rendezvous techniques.
While EUS‐guided rendezvous has great potential due to its reliability, its global adoption remains limited, as it requires specialized expertise and equipment. Therefore, designing RCTs that reflect real‐world feasibility will be challenging.
Comparison of cannulation techniques in patients with periampullary diverticula.
In this scenario, the two‐devices‐in‐one‐channel method can be useful but is technically demanding [10]. Realistically, the optimal technique will depend on the individual endoscopist's skill set.
ERCP in patients with surgically altered anatomy using new endoscopes, and comparison of LA‐ERCP versus EDGE after Roux‐en‐Y gastric bypass.
Management of concurrent gastric outlet obstruction (GOO) and malignant biliary obstruction using different endoscopic approaches.
These techniques are highly specialized and not universally available. As evidence accumulates through future RCTs, the importance of timely referral to high‐volume centers for these complex procedures will likely increase.
As content not included in these guidelines, further research priorities include the following:
The importance of preoperative preparation.
Where there is a history of successful cannula insertion via ERCP, referencing images or videos from that procedure provides a wealth of information. Attempting biliary cannula insertion without thorough preoperative assessment should be avoided. Skilled endoscopists habitually gather comprehensive patient‐specific information, including anatomical findings and outcomes of previous procedures, to formulate their strategy. This preparatory work itself constitutes a technical skill. Regardless of experience, some practitioners fail to adopt this habit. The ability to consistently perform sincere and detailed preoperative preparation is a decisive factor for cannula insertion success and for becoming a truly proficient endoscopist in the pancreatobiliary tract. While objectively evaluating its effectiveness is challenging, elucidating the consequences of inadequate preparation remains an important area for future research.
Scope shape and its relation to biliary cannulation.
When visualizing the papilla, scope shape may be straight or angulated, influencing the cannulation approach. Future research is expected to elucidate the optimal scope position for different papillary morphologies.
How should biliary cannulation be taught?
Currently, there are numerous excellent educational resources available concerning ERCP, including textbooks, demonstrations, and hands‐on workshops. However, the optimal integration of these educational tools remains underexplored. Generating evidence on structured and effective teaching strategies is an important responsibility for our field.
The fundamental principles of biliary cannulation are clear. The process begins with thorough preparation to maximize success before scope insertion, followed by gentle scope insertion. Upon reaching the papilla after scope stretching, it is essential to secure an optimal frontal view of the papilla and carefully observe both the papilla and the oral protrusion to visualize the invisible confluence of the bile and pancreatic ducts. Furthermore, the endoscopist must assess the scope's shape and, in accordance with guideline statements, approach the papilla gently.
As the guideline authors emphasize, the recommendations must be interpreted in the context of each individual patient, and not all statements are universally applicable.
Above all, gentle and careful manipulation is paramount. Although it may not be feasible to evaluate the importance of gentle handling through an RCT for ethical reasons, its clinical importance is beyond question.
Author Contributions
Mamoru Takenaka: drafting the manuscript. Masatoshi Kudo: critical revision of the manuscript for important intellectual content.
Funding
The authors have nothing to report.
Conflicts of Interest
The authors declare no conflicts of interest.
Linked Article
This article is linked to Crinò et al. papers. To view this article, visit https://doi.org/10.1111/den.15060.
Takenaka M. and Kudo M., “What Are the Future Research Priorities Regarding Biliary Cannulation? How Can It Be Mastered? What Is the Most Crucial Factor?,” Digestive Endoscopy 38, no. 2 (2026): e70093, 10.1111/den.70093.
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