|Home | About | Journals | Submit | Contact Us | Français|
G&H Could you describe the needle knife sphincterotomy technique as it is utilized in clinical practice?
CG Needle-knife sphincterotomy or needle-knife papillotomy is a cutting method that uses a straight, fine, wire-type needle, referred to as a needle knife, to incise the papilla as well as the overlying and deeper tissues, opening the sphincter itself. The needle knife utilizes electrocautery to aid in cutting. The use of electrocautery in this procedure varies among individual clinical practices from a pure cutting current to a mixture of cutting and coagulation current. The purpose of needle knife sphincterotomy is to cut into the sphincter area and facilitate entry into either the common bile duct or pancreatic duct. Pure coagulation is not used, in order to avoid the edematous effects that may make these procedures more difficult.
G&H What are the indications for this procedure?
CG Needle-knife sphincterotomy is typically performed when access into either the common bile duct or the pancreatic duct cannot be obtained through conventional methods such as direct catheter cannulation, cannulation with a sphincterotome, or guidewire-assisted cannulation with either of these two devices. If these approaches fail, it is fairly common practice to employ needle-knife sphincterotomy to gain entry into one or the other duct. It is becoming increasingly common when utilizing needle-knife sphincterotomy in the biliary tree that a prophylactic stent be placed in the pancreatic duct before the incision is made toward the biliary tree, in an effort to reduce the complications of needle-knife pancreatitis. Prophylactic pancreatic stenting prior to needle-knife pancreatic sphincterotomy is well established.
Another indication for needle-knife sphincterotomy is in the approach to the minor papilla in patients with pancreatic divisum, as these patients typically have a structure that is small and extremely difficult to access utilizing a conventional sphincterotome. In these cases, the needle knife is applied to the minor papilla, almost always with the combined use of a small stent, in order to prevent perforation, due to the small size of the minor papilla and its location.
An excellent indication for needle-knife entry is in the setting of an impacted stone. When a stone is impacted in the papilla and the overlying duodenal hood, it can rotate the papilla and the duodenal hood with the opening in an extreme downstream-facing position, which makes access by cannulation methods extremely difficult, particularly if the stone is truly impacted and partially protruding from the orifice of the papilla. In this setting, when there is an impacted stone in the orifice of the papilla or a very obvious, bulging papilla and overlying duodenal hood, direct needle-knife entry and release of the stone is a much-preferred method that is used by many endoscopists.
Finally, the needle knife can be utilized in the patient who has distal or very distal obstruction of the papilla in the ampullary region that is neoplastic, rather than actual stone. A needle knife can directly enter the bulging common bile duct above the level of a very focally obstructing neoplastic lesion. Rather than an incision, this procedure constitutes more of a drilling or boring of the needle-knife wire into the bulging duct, until there is a sudden release of bile, at which point there can be either a further cephalad incision with the needle knife or placement of a sphincterotome inside the duct with extension of the incision. The needle knife can also be applied to enter pseudocysts. This is a nonpapillary use of the needle knife directed into and through a bulging segment of the stomach or the duodenal wall, to enter and attempt drainage of pseudocysts or pancreatic necrotic collections.
G&H What are the concerns surrounding utilization of needle-knife sphincterotomy in general endoscopic practice?
CG Concerns regarding needle-knife sphincterotomy are not associated with the technique itself, but rather with the question of who is qualified to perform it. There is no doubt that it is one of the highest-risk procedures that is performed during routine endoscopic retrograde cholangiopancreatography (ERCP). The most prevalent risk in needle-knife sphincterotomy is perforation from cutting too deep or extending too long of an incision cephalad. There are no ideal anatomic indicators that can guarantee safe needle-knife sphincterotomy when performed by less practiced endoscopists. It is performed slowly and carefully with a sense of how deep to cut, how long to cut, and a tremendous amount of experience and understanding of the papillary and ampullary anatomy.
The highest risk of bleeding occurs when a greater proportion of cutting current or pure-cut electrocautery is used. Obviously, patients who are predisposed toward bleeding—those with abnormal international normalized ratios, those on antiplatelet medication, or those with coagulopathy or thrombocytopenia—are going to be at greater risk in these procedures.
Another risk in performing needle knife sphincterotomy arises in a situation that is not common but can occur, when there is considerable edema, to the point where the operator loses his or her sense of direction within the edematous anatomy. Perforation and bleeding can occur in this situation as well. Sometimes the procedure must be aborted and resumed the next day.
G&H Are there limitations in terms of who is allowed to perform these procedures?
CG Within the practice of gastroenterology, there is a debate among leaders in the field of ERCP, many of whom feel very strongly that needle-knife sphincterotomy should only be performed by the most skilled ERCP endoscopists. They feel that the procedure should be limited to referral centers or referral practice-based individuals as opposed to a community gastroenterologist, who may perform only a limited number of ERCP procedures per year.
G&H How can less experienced endoscopists be safely trained in this procedure?
CG It is extremely difficult to train fellows in this procedure. In our practice, we do not allow general gastrointestinal fellows to consider performing needle-knife sphincterotomy in their 3-year gastroenterology program. We have advanced endoscopy fellows who spend a year doing ERCP and it is only after the first 6 months of this period that many of us feel comfortable allowing them to attempt a simple needle-knife sphincterotomy procedure in a patient presenting with a papilla overlying a long duodenal hood, which is easy to access and has the highest margin of safety.
Fellows in our advanced endoscopy program perform approximately 600 ERCPs during their year of training, which is an adequate volume of procedures to acquire advanced skills. However, we as instructors must make a judgement in terms of when they have reached a level of control and mastery in approaching the papilla and surrounding anatomy that allows them to attempt an initial needle-knife sphincterotomy.
G&H Are there methods of training available beyond the performance of the actual procedure?
CG Instructors in our own practice, as well as through the American Society of Gastrointestinal Endoscopy (ASGE), are using ex vivo animal parts to model the ERCP procedure. Pig organs with intact liver, bile duct, and papilla can be utilized to practice ERCP techniques. However, the pig anatomy is not well suited for needle-knife sphincterotomy because of the flat presentation of the papilla. Dr. Jonathan Cohen, a gastroenterologist at New York University Medical Center, Dr. Jonathan Cohen, who, working with a fellow, has developed a model using a chicken heart sewn into the pig duodenum, to simulate the papilla. This can be a teaching model for learning the needle-knife technique. However, it is very difficult to find an ideal model that would allow this technique to not only be demonstrated but taught in a fashion that the instructor would feel comfortable allowing a fellow to perform the actual procedure.
G&H Are there emergency situations where a community gastroenterologist may not have time to refer the patient to a specialty center and would be called upon to perform needle-knife sphincterotomy himself or herself?
CG The immediate need for a needle-knife procedure might arise in a patient presenting with an impacted stone. As mentioned above, emergency ERCP is often performed in patients who are acutely ill and an impacted stone is detected. The needle-knife procedure is designed for these cases and under these circumstances it can be safely performed incising the distended overlying tissue while using the impacted stone as a protective backdrop.
G&H Could you share your personal approach to training in needle-knife procedures?
CG Every instructor has a training method that he or she utilizes to reduce the number of issues with complications. I have fellows perform needle-knife sphincterotomy using an ERBE electrosurgical generator with the endocut mode active; this is a very specific type of blended current that allows for a careful, layer-by-layer dissection. I tell my fellows to think of themselves as trying to cut through the shell of an egg without cracking it. That is how delicately the cutting needs to be done. This method of layer-by-layer dissection cuts first through the mucosa and then slowly down to the sphincter muscle itself.
Utilizing this method, the endoscopist can actually dissect down and visualize the sphincter muscle to precisely incise and access the desired duct. This is the method that I attempt to use when performing needle knife sphincterotomy and it is how I train our fellows. It requires extra time and considerable patience but it allows the endoscopist to recognize the anatomy very clearly and to understand where he or she is going and how to get there.