Difficult Biliary Access at ERCP




Endoscopic retrograde cholangiopancreatography allows intervention for a variety of diseases of the biliary tract. Cannulation of the bile duct is the prerequisite step for biliary intervention. Although obtaining biliary access is straightforward in many cases, it can occasionally be challenging. Multiple devices, all with additional wire-guided techniques, have been developed to aid cannulation. More advanced techniques have also been developed to aid biliary access if it is unsuccessful with standard devices. Multimodality techniques can be used if other approaches fail. This article provides an evidence-based discussion of these approaches, and provides insight into their appropriate application.


Key points







  • •

    Multiple devices aid cannulation, including rotatable and steerable sphincterotomes and ultratapered cannulas, any of which can incorporate wire-guided techniques.


  • •

    Pancreatic duct guidewire or stent-assisted biliary access is increasingly used in advanced techniques.


  • •

    Pancreatic stent placement is often required to reduce risk of post-ERCP pancreatitis in difficult access.


  • •

    Precut biliary sphincterotomy and transpancreatic septotomy are generally considered only when prior are not feasible or successful.






Introduction


Establishing biliary access during endoscopic retrograde cholangiopancreatography (ERCP) requires deep cannulation and guidewire access, and is a prerequisite to successful biliary therapy. Achieving such access can be a challenge for experts and novices, and many accessories and techniques have been developed to aid biliary cannulation. Success at biliary cannulation can be enhanced by using such devices as papillotomies, guidewires, cannulas, and precut papillotomes. Similar techniques can also be applied to pancreatic access, which then allows instrumentation and protective stenting of the pancreatic duct. Some endoscopists may be unfamiliar with some of the newer devices and techniques. Many of these techniques can be successfully applied, and disagreement as to the most appropriate technique may exist even among experts. This is further amplified by lack of comparative data available to generalize various techniques outside of centers where such studies are performed. Inferences about relative safety and efficacy of one technique over another are limited because complications can depend on patients’ susceptibility as much as the specific technique used by the endoscopist. In this article judgment is avoided as to which method is preferable, and mention of any specific manufacturers is omitted because it is impossible to list them in entirety. A comprehensive list of devices for biliary cannulation and sphincterotomy was published in Gastrointestinal Endoscopy in 2010.




Introduction


Establishing biliary access during endoscopic retrograde cholangiopancreatography (ERCP) requires deep cannulation and guidewire access, and is a prerequisite to successful biliary therapy. Achieving such access can be a challenge for experts and novices, and many accessories and techniques have been developed to aid biliary cannulation. Success at biliary cannulation can be enhanced by using such devices as papillotomies, guidewires, cannulas, and precut papillotomes. Similar techniques can also be applied to pancreatic access, which then allows instrumentation and protective stenting of the pancreatic duct. Some endoscopists may be unfamiliar with some of the newer devices and techniques. Many of these techniques can be successfully applied, and disagreement as to the most appropriate technique may exist even among experts. This is further amplified by lack of comparative data available to generalize various techniques outside of centers where such studies are performed. Inferences about relative safety and efficacy of one technique over another are limited because complications can depend on patients’ susceptibility as much as the specific technique used by the endoscopist. In this article judgment is avoided as to which method is preferable, and mention of any specific manufacturers is omitted because it is impossible to list them in entirety. A comprehensive list of devices for biliary cannulation and sphincterotomy was published in Gastrointestinal Endoscopy in 2010.




Determining the success of cannulation


The clinical success of a procedure is determined by the balance between clinical efficacy, technical success, and adverse events. Reported complications are highly variable because of differences in definition and rates of detection. Complications are most widely defined by consensus criteria established in 1991, which incorporate interventions and duration of hospital stay. The rates of complications are determined by patient characteristics as much as by the technical aspects of the procedure. Younger patients, those without obstructive jaundice, and patients with sphincter of Oddi dysfunction are known to be at higher risk for complications, although expeditious cannulation and pancreatic stents are protective.


Success rates at biliary cannulation can be difficult to measure because the procedure is performed for a variety of indications, at different centers, and by endoscopists with various levels of expertise. The decision to use various techniques, such as precut sphincterotomy, can be influenced by the patient’s anatomy and the relationship between the frequency of its application and the total number of cannulation attempts. In addition, failed precut sphincterotomy requiring repeat procedures has not been consistently defined as failed cannulation.


Expert endoscopists are expected to be successful at biliary access in 95% to 100% of attempts, a goal that is supported by the literature. Community success rates should exceed 90%. Trainees are deemed competent to perform endoscopic procedures independently when a success rate of 80% to 90% is achieved. A direct association between the case volume, local expertise, endoscopic training, and practice setting has been demonstrated in multiple studies. ERCP is a technically demanding procedure with many levels of complexity. A five-point scale, which was later revised to three points, has been proposed to describe the difficulty of the procedure. The rates of technical success are inversely proportional to the difficulty of the procedure even at expert centers. Given the potential risks, a possibility of failure, and limited success in some settings, ERCP should only be considered when therapeutic intervention is necessary. The advent of modern, noninvasive, or minimally invasive imaging modalities, such as Magnetic resonance cholangiopancreatography and endoscopic ultrasound, in combination with careful clinical assessment should help limit ERCP to patients in whom the need for intervention is almost certain.




What makes a cannulation difficult?


There are many reasons for difficult cannulation ( Box 1 ). In some cases, the papilla may be flat and small. One example is sphincter of Oddi dysfunction. Although the anatomy is preserved, cannulation may be challenging because the sphincter is often stenotic. The papilla can be difficult to locate in the setting of tumor infiltration of the papilla or the duodenum, or pancreatitis that causes duodenal edema and distortion. Adequate duodenoscope positioning may be challenging in a patient with a large duodenum where the papilla has to be approached from a cephalad or distant position. Intradivertiucular or peridiverticular papillas are other well-known causes for difficult cannulation. Patients with surgically altered anatomy, such as post–Billroth II or post–Roux-en-Y, present particular challenges because the papilla is approached either from the opposite direction or using a forward-viewing endoscope that lacks the advantage of an elevator. Patient cooperation is essential when maneuvers as precise as biliary cannulation are attempted. Nurse-administered sedation or monitored anesthesia care can make bile duct access much more challenging and result in failed cannulation in up to 5% of cases. Finally, the endoscopist may just be having a “bad day.” Involving a colleague or postponing a procedure for a different day (if feasible) can be the best approach.



Box 1





  • Small papilla



  • Normal anatomy with stenotic sphincters



  • Difficult (cephalad or distant) approach to papilla



  • Tortuous (“elephantine”) papilla



  • Intradiverticular or peridiverticular papilla



  • Malignant infiltration or distortion of papilla



  • Duodenal edema or distortion caused by pancreatitis, tumor, and so forth



  • Surgically altered anatomy (Billroth II, Roux-en-Y)



  • Poorly controlled patient sedation or anesthesia



  • “Bad day” for the endoscopist



Possible causes of difficult cannulation




Devices and techniques for endoscopic bile duct access


Principle approaches to cannulation and difficult bile duct access techniques are shown in Box 2 . Visual illustrations are also available from several online resources, including the DAVE project ( http://daveproject.org ). ASGE DVD learning library ( http://www.asge.org/ell_list.aspx ) contains a number of video resources available for purchase. In particular, ASGE DV035: Biliary Access Techniques for ERCP: From Basic to Advanced has been developed by the corresponding author and Dr Kapil Gupta, and presents a comprehensive overview of biliary access techniques ranging from basic to very advanced. All of the issues presented in this article are addressed in a video format.



Box 2





  • Standard techniques




    • Catheters



    • Standard



    • Ultratapered (5F-4F-3F)



    • Steerable (swing tip) catheter




  • Papillotomes




    • Single lumen or multilumen



    • Rotatable




  • Guidewire cannulation in conjunction with catheters and papillotomes




    • Standard



    • Nitinol



    • Hybrid



    • Hydrophilic




  • Placement of pancreatic guidewire or stent to assist biliary cannulation



  • Precut “access” papillotomy




    • Needle-knife




      • Freehand starting at orifice



      • Freehand “fistulotomy” starting above orifice



      • Over pancreatic stent




    • Traction papillotome



    • Papillary roof incision



    • Transpancreatic (pancreatic sphincterotomy)




Principle ERCP biliary cannulation techniques


Standard and newer techniques for accessing the bile duct are shown in Figs. 1–13 . Most catheters used for ERCP are 5F to 7F in diameter and can accept guidewires up to 0.035 in in diameter. Simultaneous use of a guidewire and contrast injection can be accomplished through a triple-lumen catheter or a side arm adaptor. 5-4-3F ultratapered catheters are often used for biliary and pancreatic access through small or stenotic papillas, but require the use of smaller guidewires, such as 0.018 in. Standard catheters have never been compared with ultratapered cannulas in head-to-head studies. Regular cannulas with or without guidewires can be difficult to use because the angle of approach cannot be varied. Standard papillotomes are widely used for cannulation. This device can be bowed up to vary the vertical angle of approach and engage the papilla. The bow can then be relaxed to achieve deep cannulation of the bile duct (see Figs. 3 and 4 ). A randomized trial comparing the success of biliary access using a sphincterotome with that of a regular cannula found, in 100 patients, that a sphincterotome without a guidewire was successful in 84% using a sphincterotome compared with 62% using a standard cannula ( P <.05). Crossover to the sphincterotome resulted in a cannulation rate of 94%. There was no difference in the rate of complications. These findings were confirmed in another randomized trial in which biliary cannulation was successful in 97% of patients using a sphincterotome compared with 67% using a standard catheter ( P = .09). The use of a sphincterotome was associated with fewer cannulation attempts and shorter cannulation times. The study was not powered to assess for complications. Swing tip is a cannula that can be flexed upward and downward, the latter particularly valuable in unusual anatomy, such as Billroth II or distorted intradiverticular papilla (see Fig. 1 ). Standard cannula, sphincterotome, and a steerable catheter (swing tip) were prospectively compared in a randomized trial of 312 patients. End points included deep cannulation and time to cholangiography, number of pancreatic injections, number of attempts, and success of the procedure. Both the sphincterotome and the steerable catheter were superior to regular cannula (88% and 84%, respectively, vs 75%; P = .038). Successful cannulation using a sphincterotome or a steerable catheter was achieved in 26% of patients when cannulation with a regular catheter failed. The bile duct was successfully cannulated using advanced techniques (eg, precut) if all three methods failed. Although the study was not powered to assess for overall complications, pancreatitis occurred in 5.3% of patients. The angle of approach to the papilla varies with biliary anatomy, endoscopes, and consistency in device manufacturing. The ability to change the angle of approach by rotating the sphincterotome has therefore been a long time goal. Manual grooming of the sphincterotome has been shown to be effective in this setting, but is time consuming and imprecise. Rotatable papillotomes are widely used now, which allow the endoscopist to match of the angle of approach of the papillotome to the specific course of the bile duct within the papilla. These devices may improve cannulation in surgically altered anatomy, distorted and peridiverticular papillas, or unusual angulation of the bile duct.




Fig. 1


Swing tip cannula flexed upward ( A ) and downward ( B ).



Fig. 2


Guidewire cannulation showing wire in pancreatic duct ( A ) and bile duct ( B ).



Fig. 3


Papillotome with flexed papillotome entering bile duct with puckered distal duct.



Fig. 4


Relaxation of the bow to achieve straightened alignment with the distal bile duct.



Fig. 5


Fluoroscopic view of dual wire cannulation (biliary and pancreatic guidewires).



Fig. 6


Pancreatic stent inserted with biliary wire still in place.



Fig. 7


( A ) Needle knife precut papillotomy over pancreatic stent. ( B ) Extent of the incision ( C ) after deep cannulation of bile duct with extension of sphincterotomy.



Fig. 8


Guidewire cannulation.



Fig. 9


Dual wire cannulation (pancreatic wire followed by biliary wire).

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Sep 12, 2017 | Posted by in GASTOINESTINAL SURGERY | Comments Off on Difficult Biliary Access at ERCP

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