Access (Precut) Papillotomy

Indication for Precut Papillotomy

Biliary cannulation is one of the key components of ERCP (see Chapter 14 ), with success related to factors that include patient anatomy, endoscopist experience, and the availability of alternative accessory devices and alternative access techniques, such as percutaneous and EUS-guided approaches (see Chapter 32 ). Initial failure can occur even in the most experienced hands, and it is in these situations that alternative approaches are required. Precut papillotomy encompasses a variety of techniques, often reserved for the experienced endoscopist as a last resort, given the concerns about its risk profile as an independent risk factor for post-ERCP pancreatitis (PEP) in early studies. However, when repeated instrumentation of the pancreatic duct occurs during attempted selective biliary cannulation, precut must be considered. It is important to change one's approach to cannulation rather than persisting with the same technique and/or accessory. Increasingly the recent literature points to the early adoption of an alternative technique that has not been shown to increase the risk of adverse events. Early adoption of an alternative approach should be undertaken before traumatizing the ampulla and repeatedly passing guidewires and/or injecting contrast into the pancreatic duct. Before deciding to perform precut, two alternative techniques may be considered. It is our practice that if the pancreatic duct is selectively cannulated with a guidewire, a double-guidewire approach (DGT) is used, whereby a guidewire is advanced into the pancreatic duct and the catheter withdrawn. The sphincterotome or cannula preloaded with a second guidewire is advanced alongside the indwelling pancreatic duct wire to cannulate the bile duct. The pancreatic duct wire straightens the intraampullary portion of the distal bile duct to allow successful cannulation. If the DGT approach fails after several attempts, a small-caliber (3 or 5 Fr) pancreatic stent is placed and additional attempts to cannulate the bile duct above the stent are made. If deep cannulation is still not achieved, a precut papillotomy is performed.

The decision to proceed with a precut when standard techniques fail depends on several factors, which include the indication for ERCP, the expertise of the endoscopist, and the availability of alternative options for gaining biliary access (e.g., interventional radiology, EUS techniques). Marked variation exists in use of precut sphincterotomy, with reported rates between 1% and 38% of cases. The initial success rates of precut sphincterotomy in the setting of difficult cannulation range from 70% to 90%, and the rates of cannulation at subsequent ERCP are nearly 100%.

Alternative approaches after failed cannulation with standard techniques include stopping the procedure and reattempting cannulation at another session by the same endoscopist, or referring the patient to another, more experienced endoscopist at the same or a different center. Techniques such as percutaneous and EUS rendezvous techniques are alternatives for achieving deep biliary cannulation. However, in most situations in which standard biliary cannulation techniques have failed, a precut papillotomy is attempted before considering these alternative techniques. It is important that the endoscopist attempting a precut is experienced and comfortable with the technique. If not, it is best to abort the procedure and explore other options for gaining access ( Box 15.1 ).

Precut Accessories

It is vital that appropriate equipment to perform a precut papillotomy is available for all ERCP procedures. The most commonly used accessory is the needle-knife sphincterotome. The key design feature is the retractable electrosurgical wire, which is controlled through the catheter handle. The wire is projected forward from the distal aspect of the catheter tip and its length can be adjusted. The wire is used to create an incision in the overlying mucosa via electrosurgical current and movement of the catheter via the elevator and/or the big wheel of the endoscope, which controls tip deflection. Needle-knife sphincterotomes are available in variable tip lengths (4 to 7 mm) and wire diameters and can be single, double, or triple lumen. The advantage of a double-lumen or triple-lumen configuration is that it allows a guidewire to be preloaded in the catheter to enable gentle wire probing of the incised area without having to exchange instruments. An insulated-tip needle knife designed to protect the papillary orifice also exists and has been found to be equivalent in terms of efficacy and safety to the more commonly used catheter; however, it is not yet widely available. Another type of precut papillotome is the Erlangen-type sphincterotome, which has similarities to the standard traction sphincterotome. It has an ultrashort 5-mm-long monofilament cutting wire and a less-than-1-mm catheter tip distal to the wire.

During precut, soft-tipped hydrophilic guidewires are essential to facilitating cannulation. We recommend the use of electrosurgical units with pulsed modes, which have a microprocessor-controlled generator in which the cutting and coagulation currents alternate and are automatically adjusted according to tissue resistance. This allows for stepwise cutting and precise control of the incision direction, depth, and length. A 20-mL syringe filled with 1 : 20,000 epinephrine concentration can be used to irrigate the incision site through the wire or contrast port if bleeding occurs and obscures visualization.

Techniques

The principle of precut sphincterotomy to gain deep cannulation is to unroof the duodenal portion of the ampulla, thereby exposing the biliary orifice. In contrast, the purpose of traditional biliary sphincterotomy is to widen the biliary orifice for therapeutic purposes, such as stone extraction and stent placement. The precut was designed purely for biliary and occasionally pancreatic access ( Box 15.2 ).

Before undertaking a precut sphincterotomy, it is vital that the three-dimensional anatomy of the ampullae of Vater is understood. The terminal portion of both the biliary and pancreatic ducts tapers before entering the medial wall of the duodenum. The ampullary segment itself consists of the pancreatic, biliary, and ampullary sphincters that envelop the tapering biliary and pancreatic ducts in order to control the flow of their secretions. The duodenal mucosa and submucosa overlay this ampullary segment. There are several anatomic variations of how the terminal portions of the biliary and pancreatic duct enter the medial duodenal wall. Most commonly, the ducts join to form a common channel of approximately 5 mm in length before entering the duodenum. In the majority of patients, the pancreatic duct enters the ampulla in a straight fashion at the 1 o'clock position, resulting in straightforward cannulation ( Fig. 15.1 ). The bile duct runs more superficially and parallel to the duodenal wall, where it enters the ampullae at the 11 to 12 o'clock position. As the precut technique involves freehand cutting, it is imperative to understand this three-dimensional anatomy ( Box 15.3 ).

Needle Knife From the Orifice

The most widely practiced precut method is the freehand needle-knife technique, in which the incision is made starting at the orifice and extending upward to the roof of the papilla ( Fig. 15.2 ; Cases 15.1 and 15.2 ). Initially, a “sham” precut is performed with the needle retracted. A few practice maneuvers are performed to ensure that the incision will be performed in the intended direction (similar to practice swings in golf before striking the ball). The direction of the cut is the most critical aspect of the procedure and determines its success or failure. Originally the technique was described by using an upward motion with the elevator. It has been suggested by Howell that improved control and safety can be achieved by “loading” the needle knife through upward traction of the endoscope reference: Desilets DJ, Howell DA. Precut sphincterotomy: another perspective on efficacy and complications. Available at: www.uptodateonline. com . Accessed 11-1-2004. The length of the fully exposed needle is 4 to 7 mm, but we usually expose only 2 to 3 mm of the cutting wire. The tip of the needle is positioned at the upper lip or rim of the papillary orifice, current is applied, and a 2-mm to 5-mm incision is made on the papillary bulge. The length and depth of the incision depend on the size and configuration of the papilla and the length of the intraduodenal segment. We recommend that the incision be made in short increments, with repeated gentle strokes opening the papilla gradually, layer by layer. When current is applied, the needle should be in continuous motion to avoid deeper thermal damage. Once the mucosa is separated, the mucosal edges should be pushed aside with the catheter to expose the sphincter muscle. Gentle suction often amplifies the sphincter and may promote bile drainage. The site is carefully examined, looking for nodularity of biliary epithelium, which usually appears as a pink or brownish nodule. The area is gently probed with the precut catheter and/or guidewire while the needle is retracted. It is very important that the incision is probed gently without contrast injection unless deep cannulation has been achieved endoscopically or fluoroscopically, because submucosal injection can compromise further cannulation attempts. We prefer to explore the precut site with a hydrophilic-tipped guidewire. Once deep access has been achieved, the sphincterotomy can be completed by changing to a standard sphincterotome. If cannulation is still not successful and the patient is stable, the procedure is aborted and a repeat attempt can be made 48 to 72 hours later. By that time the edema has subsided, and the biliary orifice is easily identified. The success rate for repeat attempts ranges from 80% to 100%. However, depending on the clinical situation and especially if biliary drainage is urgent (e.g., severe cholangitis), placement of a percutaneous wire and/or drain or an EUS-guided approach may be required. The latter can be undertaken at the same procedure if expertise is available.

Case 15.1

Fistulotomy: Ampullary Tumor

Case 15.2

Precut From Above the Orifice

Needle Knife Above the Papillary Orifice (Fistulotomy)

As in many tertiary units, we prefer to perform a needle-knife fistulotomy, particularly when prior pancreatic duct stenting is not possible. This is also the preferred technique for cases of large-stone impaction at the papillary orifice. The advantage is avoidance of thermal injury to the pancreatic orifice, which theoretically reduces the risk of pancreatitis. This technique is most useful in patients with a dilated intraduodenal segment of the bile duct. The fistulotomy variation can be performed upward (cutting toward the duodenal wall from above the papilla) or downward (cutting toward the papilla from the duodenal wall) depending on the anatomy of the papilla, location of the initial entry point ( Fig. 15.3 ), and operator preference. We perform the fistulotomy beginning 2 mm above the ampullary orifice and extend the cut upward toward the transverse fold. When the downward approach is chosen, the initial incision is made just below the transverse fold of the mound at the 11 to 12 o'clock position and extended downward until it stops just short of the papillary orifice. The depth and direction of the incision are again achieved through the combined movement of the endoscope, large wheel, and elevator. In individuals with small papillae, this may be the preferred method because the upper extent of the cut is predefined and it theoretically minimizes the risk of duodenal perforation. When performing these freehand techniques, it is important to avoid making the incision outside of the 11 to 12 o'clock corridor, which can result in retroperitoneal perforation. Clear visualization is essential, which if compromised by bleeding can be improved through the use of dilute epinephrine (1 : 20,000) irrigation through the injection port of the needle knife in order to achieve hemostasis and clear the field. Submucosal injection of epinephrine, as is done to treat bleeding in other situations, should be avoided because it results in distortion of the anatomy.

Data comparing the various precut techniques are limited. The first study, a prospective randomized trial, evaluated fistulotomy and precut involving the papillary orifice in 103 patients. Although there was no significant difference in rates of successful biliary cannulation (91% with fistulotomy vs 89%), the fistulotomy technique resulted in a lower rate of pancreatitis (0% vs 7.59%, p < 0.05). The second study involved a retrospective cohort and assessed three variations of the precut technique: fistulotomy, precut from the ampullary orifice without pancreatic duct stenting, and precut with pancreatic duct stenting. Although there was no significant difference in cannulation rates, there was a trend toward lower rates of pancreatitis in the fistulotomy group (0%, 6%, and 3%, respectively). The third study, again a retrospective design, assessed three strategies, precut from the papillary orifice, fistulotomy, and transpancreatic sphincterotomy, in 283 patients. Again, although no significant differences were observed in cannulation rates, the overall adverse event profile and specifically the rates of PEP were lower in the fistulotomy group (3% fistulotomy, 21% precut from the orifice, 22% transpancreatic sphincterotomy).