Biliary Sphincterotomy

Instruments

The type of sphincterotome should be selected according to the individual anatomic situation and the preference of the endoscopist. Sphincterotomes differ in the diameter and length of the tip, length and characteristics of the cutting wire, and shaft stiffness, which are described in detail in Chapter 4 and in a recent review. Tapered devices, which require smaller wires (0.025-inch diameter or less), can be easier to insert into the papilla but are also more prone to cause tissue trauma and submucosal injection than those with a more blunted tip.

Modern sphincterotomes provide a lumen for insertion of a guidewire and an integrated hub for contrast injection. These devices allow for injection of contrast media without the need for guidewire removal. This approach can be very helpful in difficult cannulation for visualization of the ductal anatomy or in targeting ductal strictures with the wire under cholangiographic guidance. Sphincterotomes preloaded with a guidewire are convenient for the assistant and may accelerate the procedure ( Fig. 17.1 ). Devices that allow the use of short guidewires are also helpful, because they reduce the length of over-the-wire exchange to a fraction of the total device length while locking the wire to reduce the risk of losing access. In addition, these short-wire systems offer the option of guidewire manipulation by the endoscopist, which can be advantageous depending on the expertise of the operator and the assistant. A short, 15-mm to 20-mm cutting wire can be precisely controlled, but it tends to orient the cutting direction toward the 2 o'clock position. Contact with the sphincter may be inadequate, thus making the cutting difficult in some situations. However, the advantage of short cutting wire over a 30-mm-long wire is the reduced risk of an uncontrolled large cut when inserted too deeply into the bile duct. In addition, the proximal part of a long cutting wire may come into contact with the elevator of the duodenoscope or overhanging duodenal folds; the former causes wire breakage when electrocautery current is applied. This problem can be overcome by use of a sphincterotome that is insulated on the proximal part of the cutting wire ( Fig. 17.2 ). However, a recent prospective randomized controlled trial showed no significant difference between insulated and standard sphincterotome wires in terms of bleeding rates or other adverse events. A thin monofilament wire provides a clean, sharp cut but may break more easily than a braided wire during application of electrocautery. On the other hand, braided wires are rarely used because they induce more thermal injury. There are no formal trials that compare the efficacy and safety of these different devices. As the endoscopists' experience grows, specific preferences develop for maintaining a limited array of accessories based on expertise, skill of assistants, and patient selection. The use of special sphincterotomes can be limited to particular cases. A device with a 4.0-Fr ultratapered tip is useful after failed cannulation using standard techniques in the setting of a small papilla, suspicion of a narrow ductal orifice, or difficulty in achieving proper cutting orientation. The latter problem can be overcome also by the use of a rotatable sphincterotome, which utilizes a specially designed handle that allows controlled tip rotation. Sphincterotomes with a tip length of more than 5 mm can occasionally be helpful when there is difficult access to the papillary orifice, as seen in patients with a juxtapapillary duodenal diverticulum or altered surgical anatomy. Push-type or sigmoid-shaped sphincterotomes have been developed for EST in patients with Billroth II anatomy. A recently introduced sphincterotome combines the two steps of sphincterotomy and sphincteroplasty (balloon dilation) into one endoscopic device, which promises to simplify and accelerate the treatment of larger bile duct stones ( Fig. 17.3 ). Malfunction of sphincterotomes infrequently occurs but can usually be managed without major adverse events.

Procedure

The papilla is usually approached with the sphincterotome from a distance so that its precurved distal part can be seen exiting the endoscope. Alternatively the tip of the sphincterotome is gently introduced into the papillary orifice. A short, straight position of the duodenoscope facilitates precise control of the device. Subsequent bowing of the tip usually allows its insertion toward 11 o'clock into the opening of the common bile duct ( Fig. 17.4, A, B ). Straightening the tip and gently withdrawing the endoscope results in overcoming the sigmoid-type shape of the distal part of the common bile duct. A guidewire should then be gently passed in the direction of the bile duct under endoscopic and fluoroscopic guidance without contrast injection. For this approach, guidewires with a soft, preferably hydrophilic, tip should be used to reduce the risk of ductal injury ( Fig. 17.5, A–E ; Video 17.1 ). Trials comparing different-diameter guidewires and straight or angle-tipped wires do not show significant differences in cannulation rates and incidence of PEP. The unbowed sphincterotome can then be further advanced to achieve deep cannulation. Such a smooth, direct approach may fail and the procedure can become difficult and frustrating. Careful injection of contrast may allow visualization of the biliary anatomy for targeted guidance of the tip of the sphincterotome or insertion of a guidewire. However, repeated injections may induce edema of the papilla and increase the likelihood of PEP. Cannulation of the bile duct with a sphincterotome with or without use of a guidewire should succeed in approximately 90% of cases. Failures are mainly caused by difficult access to the papilla because of anatomic variation or previous gastroduodenal surgery. Ampullary tumors or impacted stones creating a bulging papilla can also impair the approach to the papillary orifice or deep ductal cannulation. For these cases, lifting the roof of the papilla with the adjustable tip of the sphincterotome and using a hydrophilic guidewire are helpful in selective cannulation and controlled cutting.

When standard cannulation fails, a variety of additional techniques have been established. In case of unintended repeated cannulation of the main pancreatic duct, a guidewire with a hydrophilic tip can be inserted in the pancreas, which may facilitate straightening of an angulated course of a common channel or the distal part of the common bile duct ( Fig. 17.6, A–E ; Video 17.2 ). The wire can then be locked for removal and reinsertion of the sphincterotome alongside the pancreatic duct wire for further attempts to cannulate the bile duct (see Chapters 14 and 15 ). Alternatively, a 5-Fr pancreatic stent can be placed to facilitate biliary access ( Fig. 17.7, A–D ).

Precutting should be limited to cases in which there is difficult biliary cannulation and the absence of unintentional main pancreatic duct access or failure of pancreatic guidewire-assisted biliary cannulation. There are three main types of precutting: needle-knife papillotomy over a pancreatic stent, or freehand without pancreatic stent placement; suprapapillary fistulotomy; and transpancreatic sphincterotomy. Details of these methods are described in Chapter 15 . Precutting or persistent cannulation attempts present similar success and overall complication rates. The incidence of PEP does not increase or is even less frequent when early precut is performed.

The appropriate use of these advanced techniques allows access to the biliary system in nearly all cases. A recent prospective cohort study of a single tertiary-care center demonstrated that the overall success of ERCP-guided cannulation was 99.4% of 518 patients in whom the ampulla was reached. However, the risk of adverse events increases, in particular when “access” papillotomy is performed, which should therefore be limited to experienced endoscopists who achieve selective biliary cannulation with standard cannulation techniques in more than 80% of cases.

After deep cannulation has been confirmed by contrast injection, a guidewire should be advanced to the proximal biliary system in order to secure ductal access for subsequent maneuvers and exchange of accessories. Short-wire technology allows fixation of the wire with the locking device attached to the duodenoscope. The tip of the sphincterotome is then slightly bowed so that it is in contact with the roof of the papilla. Stiff shaft guidewires deeply inserted into the biliary tree may limit bowing of the cutting wire. This infrequent problem can be overcome by withdrawing the guidewire until its flexible tip approaches the papilla, without losing biliary access. When performing the sphincterotomy, 5 mm or less of the cutting wire should be inside the papilla so that only a small amount of tissue will be cauterized. This approach enhances the incision and avoids a rapid, large incision (“zipper cut”) that can occur when pure cutting current is used. The use of newer electrosurgical generators (see Chapter 11 ) has largely eliminated zipper cuts. Most sphincterotomes have endoscopically visible markers positioned at the distal part of the catheter, which allow one to determine the depth of insertion of the cutting wire into the bile duct. It is generally believed that orientation of the cutting wire between the 11 o'clock and 1 o'clock positions reduces the likelihood of bleeding and perforation. In spite of great efforts by accessory manufacturers to develop sphincterotomes with cutting wires that automatically cut along these directions, the devices may sometimes still orient in a 2 o'clock direction. In selective cases, a rotatable sphincterotome is helpful in achieving proper orientation. For appropriate cutting direction, the papilla has to be placed on the left side, preferably along the 11 o'clock position. This maneuver can be facilitated in difficult cases by rotating the left-right dial to the left while advancing the duodenoscope slightly into the “long” endoscope position ( Fig. 17.8, A–D ; Video 17.3 ). Alternatively the endoscope can be carefully withdrawn along with rotation to the left side (see Fig. 17.4, B ).

The choice of electrosurgical current for EST is a source of controversy. The combination of high cutting current with low coagulation current is most frequently used. Creation of edematous, extensively whitened or blackened tissue during EST is evidence of suboptimal cutting and may increase the risk of PEP or sphincter stenosis. Excessive cautery also occurs when an excessive amount of cutting wire is inside the papilla and/or contact of the wire with the tissue of the papillary roof is inadequate. Previous trials suggest that pure-cut electrocautery current is safer than blended current in terms of PEP without increasing the bleeding rate. However, a recent meta-analysis of four randomized controlled trials showed that there was no significant difference between the rate of PEP when pure current was used and when blended current was used. Pure cutting current was associated with more episodes of bleeding. When pure cutting current is used by less-experienced hands, there may be a higher risk of bleeding and perforation, especially when a longer part of the cutting wire is inside the papilla, which can lead to a fast, uncontrolled large cut (i.e., zipper cut). In a small trial, the combined technique of beginning the incision using cutting current and finishing using blended current was not associated with a decrease in the risk of PEP. An alternative electrocautery option is the use of the Endocut mode (ERBE, Tübingen, Germany) or Pulsecut mode (Olympus, Tokyo, Japan) using electrosurgical generators, in which cutting and coagulation current are alternated in short bursts by intrinsic software (see Chapter 11 ). A potential advantage of this technology is a stepwise cutting action that allows precise control of the direction and length of the incision. This replaces the technique in which current is applied in short pulses controlled by foot pedal activation and is recommended for pure-cut or conventional blended current to reduce the risk of a zipper cut. A large retrospective analysis suggested that microprocessor-controlled EST is associated with a significantly lower frequency of intraprocedural bleeding but had no impact on clinically evident bleeding. On the other hand, a recent randomized controlled study of EST in 360 patients showed no significant difference between the Endocut mode and conventional blended cut mode in terms of success, adverse events, and procedural duration.

The size of EST can vary and depends on the diameter of the distal portion of the common bile duct and the indication for sphincterotomy. During cutting, pressure on the papillary roof should be applied by upward lifting of the slightly bowed sphincterotome or by maneuvering the tip of the duodenoscope. EST should be continued only when the wire can be clearly seen and when it is directed between the 11 and 1 o'clock positions. Guidance and repositioning of the device should be mainly controlled with the tip and the shaft of the endoscope, which is maneuvered with the right hand of the operator like the handle of a knife. A small incision seems to be appropriate for stent placement in the setting of malignant biliary obstruction, whereas complete splitting of the sphincter should be attempted for treatment of bile duct stones and sphincter of Oddi dysfunction (SOD) to decrease the risk of recurrences and EST-related stenosis of the papilla. However, there are no data demonstrating a correlation between the length of cutting and the incidence of early or late adverse events of EST. Biliary sphincterotomy should be limited to the junction between the duodenal wall and the intraduodenal portion of the papilla of Vater, which is sometimes difficult to determine because there is no reliable endoscopic landmark. The incision is also complete if the inner lumen of the bile duct is completely visible or the bowed tip of the sphincterotome can be pulled through the papilla without resistance. In view of modern techniques of lithotripsy and the option to combine EST with large-diameter sphincteroplasty, a large, potentially hazardous EST is not required. If a wide opening to the common bile duct is needed, it may be safer to perform a small to moderate-sized incision and then dilate the orifice with a balloon catheter rather than to increase the size by cutting ( Video 17.4 ) (see Chapter 18 ). Compared with other indications, the risk of adverse events of EST is usually low in patients with a dilated common bile duct and in the presence of ductal stones, especially when the papilla is large and protruding because of an impacted stone.

Extension of a previous biliary sphincterotomy may be required for the treatment of recurrent bile duct stones or recurrence of symptoms after SOD. The technique of EST in this setting does not differ from when EST is performed initially. Data from anecdotal reports and small case series suggested that the incidence of bleeding was increased during a postsphincterotomy period of approximately 1 week because of a resultant increased vascularity. However, large prospective studies did not show extension of a previous EST to be an independent risk factor for hemorrhage. Nevertheless, the risk of severe bleeding or duodenal perforation should be considered. Although it may not be related to previous EST, extension of the incision should be carefully performed in a stepwise manner. Sphincteroplasty could be a safer alternative, at least in cases with a difficult orientation and control of the cutting wire.

EST in Patients With Difficult Anatomy

Juxtapapillary duodenal diverticula are found in 10% to 20% of patients undergoing ERCP. Depending on the location of the papilla, cannulation of the bile duct can be difficult and may require special techniques, such as insertion of the tip of the endoscope into the diverticulum, use of a sphincterotome with a long nose, or pulling the papilla out of a diverticulum with biopsy forceps or a second catheter. Pancreatic duct stent placement and precut sphincterotomy or needle-knife fistulotomy are suitable alternative options to achieve cannulation. After successful biliary access, it is strongly recommended to perform EST with a biliary guidewire in place. This facilitates cutting in the direction of the bile duct, which may otherwise be difficult to determine because of the altered anatomy. Moderate bending of the tip of the sphincterotome with a few millimeters of the cutting wire inside the papilla exposes the papillary roof to allow for a controlled incision. Any direction of the cutting wire toward the base of the diverticulum should be avoided (see Fig. 17.5, D ). Data from a large retrospective analysis suggested that juxtapapillary duodenal diverticula is an independent risk factor for bleeding after EST.

The approach to patients with postsurgical anatomy is discussed further in Chapter 31 . Use of a duodenoscope in patients with Billroth II anatomy allows better visualization of the papillary roof and improves the maneuverability of accessories because of the availability of the elevator ( Fig. 17.9, A ). Precurved sphincterotomes should not be used for initial cannulation of the bile duct in these patients because they direct the tip of the catheter toward the pancreatic duct orifice. This is because the papilla is rotated 180 degrees compared with native anatomy. A straight, previously unused ERCP cannula and a straight guidewire with a hydrophilic tip aim in the direction of the bile duct and facilitate entry into the biliary orifice (see Fig. 17.9, B, C ; Video 17.5 ). After successful placement of guidewire, a rotatable push-type or sigmoid-shaped sphincterotome can be used for EST. In spite of use of these special accessories, the correct direction of the cutting wire toward the desired 5 o'clock position (in this situation) can remain difficult because of the reversed anatomic orientation (see Fig. 17.9, D, E ). It is usually easier to place a straight 7-Fr biliary stent and to sever the papillary roof with a needle-knife incision using the stent as a guide. A combination of limited EST with a large papillary balloon dilation seems to be effective and safe in Billroth II patients for removal of bile duct stones (see Fig. 17.9, F ; see Video 17.4 ). A similar approach is required when performing EST in the setting of loop gastrojejunostomy (used for patients with duodenal or pyloric obstruction).

Reaching the papilla with a duodenoscope in patients with Roux-en-Y anatomy is usually not possible. The approach in these patients is to use a pediatric colonoscope or a balloon-assisted enteroscope. However, therapeutic interventions are impaired because of the limited transmission of manipulations via the long insertion tube and the limited array of available accessories for these endoscopes based upon length and diameter of the working channel.

If the papilla is inaccessible because of altered anatomy or cannot be cannulated even after precut techniques, a rendezvous method should be considered. For a percutaneous route a transhepatic tract is established with placement of a 7-Fr catheter into the common bile duct. Thereafter, duodenoscopy is repeated. A percutaneously inserted 400-cm-long guidewire is antegradely passed through the papilla and grasped endoscopically with a snare passed through the endoscope. In cases where there is a long afferent loop, this technique allows one to pull the tip of the endoscope toward the papilla by applying tension on the guidewire simultaneously from the percutaneous portion of the wire and the wire exiting the endoscope. The sphincterotome is passed over the guidewire for subsequent EST. In selected cases, the sphincterotome can be percutaneously inserted for the performance of antegrade sphincterotomy under endoscopic retrograde visualization. EUS-guided biliary drainage ( Chapter 32 ) offers an effective and safe alternative to percutaneous procedures, with technical success rates ranging from 70% to 100% and adverse event rates of 3% to 77%. Comparative studies of percutaneously assisted and EUS-guided procedures for achieving biliary access after failed ERCP show conflicting results. The selection of the appropriate method should be made with respect to local expertise and availability.

In rare cases, even rendezvous methods do not allow an endoscopic approach to the papilla. Antegrade sphincterotomy under percutaneous transhepatic cholangioscopic and fluoroscopic guidance can be performed, though this technique is potentially hazardous and should be restricted to centers with extensive expertise in percutaneous transhepatic interventions.