Needle-Knife Papillotomy

G&H What is needle-knife papillotomy?

JB Needle-knife papillotomy (NKP) is a technique used during endoscopic retrograde cholangiopancreatography (ERCP) to facilitate access to the common bile duct or pancreatic duct (PD) when standard cannulation techniques have failed. NKP can also be used to selectively ablate the biliary and pancreatic sphincters, usually after the placement of a protective PD stent.

G&H Why should this technique only be performed by experienced endoscopists?

JB Compared to standard endoscopic sphincterotomy, NKP is considered a free-hand technique. As such, its success is much more operator-dependent. This technique is associated with a significant risk of serious complications—including bleeding, perforation, and pancreatitis—if used incorrectly. Even when performed by experienced endoscopists, the procedure-related pancreatitis (PEP) rate for NKP has consistently remained at approximately 15% in the published literature, a rate 2–3 times the expected PEP rate for standard therapeutic interventions. Used appropriately, NKP is a valuable tool; used without an appreciation for its risks and limitations, however, it is a dangerous tool. Endoscopists should never use a needle-knife papillotome without having undergone supervised training with a skilled mentor.

G&H How many supervised NKP procedures are required to achieve competence?

JB This question is difficult to answer because it depends upon how NKP is being used. A small incision made down onto a PD stent to create a pancreatic sphincterotomy carries a relatively low risk of complications, whereas a free-hand incision of the roof of the bile duct (eg, fistulotomy) to obtain deep access is technically more demanding and risky. To the best of my knowledge, the American Society for Gastrointestinal Endoscopy has not released formal guidelines for supervised training in NKP. My recommendation for achieving competence is to perform a minimum of 5 free-hand bile-duct accesses and 5 NKP procedures with the protection of a previously placed stent. Some trainees will require additional practice to become competent with this technique; if they fail to master the procedure after a reasonable time period, they should be advised to avoid NKP in their ERCP practice.

G&H Why is NKP associated with a high post-ERCP pancreatitis rate?

JB NKP is too often used as the last resort for facilitating cannulation when standard techniques have failed. By this time, multiple attempts have already been made to enter the duct of choice, often with guidewire probing or blind contrast injection. It is hardly surprising that pancreatitis develops after repeated manipulation of the papilla; therefore, this result should not be attributed to the needle knife alone. To minimize the risk of PEP, conventional cannulation failure should be recognized and acknowledged early in the procedure, so that the needle knife can be used before post-ERCP pancreatitis becomes inevitable. Several experts use NKP from the beginning of the procedure if they think that cannulation will be diffi-cult; however, endoscopists must be very experienced and confident of their abilities to do this. Certain situations lend themselves to NKP, such as the incision of an obvious choledochocele (type III choledochal cyst; Figure 1) and the release of a stone impacted in the ampulla of Vater in gallstone pancreatitis.

G&H What other risks accompany NKP?

JB Due to the very high current density at the tip of the needle knife, NKP involves rapid cutting, with little time for cautery, which can lead to bleeding. Unless carefully applied, the rapid cutting may result in unintended deep incisions, which may cause perforations (typically retroduodenal). This may be immediately recognized by contrast extravasation into the retroperitoneum or by the appearance of retroperitoneal air. A late finding may be subcutaneous emphysema, the result of retroperitoneal air tracking into the neck through the mediastinum. A properly executed NKP should never result in perforation of the back wall of the bile duct, the usual cause of this complication. One of the great proponents of NKP, Dr. Kees Huibregtse of the University of Amsterdam, The Netherlands, has often said that the needle-knife papillotome should be used like a paintbrush. Light strokes are the key to safe NKP; because the needle knife penetrates tissue as easily as a hot knife through butter, pressure should never be applied with this tool.

G&H What other procedural tips can increase the safety and success of NKP?

JB One might assume that an understanding of papillary anatomy would be basic to NKP technique, but many endoscopists launch into NKP without any inkling of how to expose, or “de-roof,” the bile duct. A skilled manipulator of the needle knife can expose the choledochus before incising it for access, thus maintaining tight control of the entire procedure. In contrast, inexperienced ERCP endoscopists attempting to perform NKP often make either ineffective, superficial cuts or crude, deep incisions in the papillary fold in the hopes of stumbling across the bile duct. Endoscopists should never attempt blind biliary access with a needle knife without observing several of these procedures performed by an expert and then having supervised experience in additional cases. Mentoring NKP is a stressful experience for most ERCP experts because many complications can occur very quickly. Typically, supervised NKP is reserved for trainees who have demonstrated skill at standard ERCP techniques and who can be trusted to follow instructions. Some trainees never achieve this level of expertise; I advise these individuals never to perform NKP in their postfellowship practice.

G&H Do you foresee NKP remaining a procedure that only experts should undertake?

JB Even experts have to begin somewhere. That “somewhere” is a teaching center with a sufficient volume of cases to allow the talented ERCP trainee to gain skill and confidence in advanced techniques, including NKP, under expert supervision. It is unlikely that any trainee can acquire these skills within the confines of a standard 3-year gastroenterology fellowship, however, which is why 4th-year fellowships were established in the United States more than a decade ago for advanced endoscopic training. There is growing pressure from gastroenterology trainees to “roll back” these 4th-year programs, with demands that every procedural skill—including therapeutic ERCP—be taught during a 3-year fellowship. However, there is not enough time in the already overcrowded curriculum to teach therapeutic ERCP in the last year of a standard gastroenterology fellowship. Apprenticeship has, it appears, become unpopular in procedural training, but it is the time-honored method through which ERCP experts have always learned their skills. There is no substitute for significant supervised experience.

The tools that endoscopists have used for over 30 years for performing NKP are very crude. The standard needle-knife papillotome, for example, consists of bare wire sticking out of the end of a plastic sheath. In these days of natural orifice transluminal endoscopic surgery (NOTES) and other sophisticated endoscopic microsurgeries, surely specialized tools can be developed for NKP as well? Exposing the roof of the bile duct would be much safer with a ceramic ball-tip papil-lotome, which would prevent the dangerous tunneling that occurs so readily with existing devices. Other tools to aid dissection of the tissue planes, such as devices to inject air, water, or gels submucosally, are already in use in the NOTES arena. For reasons difficult to fathom, the technical challenges surrounding NKP have been virtually ignored by accessory manufacturers but it is time that they stepped up to help make NKP a mainstream ERCP procedure. When failure to cannulate is not an option, NKP is an invaluable tool. NKP has been limited to endoscopists with superior ERCP skills for too long, but I believe that NKP can be made much safer if industry and ERCP endoscopists work together.

Figure 1.

The endoscopic view of a choledochocele (type III choledochal cyst) bulging into the duodenum of a 7-year-old boy (A). The post–needle-knife papillotomy view, showing a large black (pigmented) stone sitting within the lumen of the choledochocele. The roof of the choledochal cyst had been opened with the needle knife and the stone subsequently extracted (B).