Endoscopic Sphincterotomy 

Updated: Feb 21, 2020
Author: Priya A Jamidar, MD, FACG, FASGE; Chief Editor: Kurt E Roberts, MD 

Overview

Background

Endoscopic biliary sphincterotomy was first reported in 1974. Approximately 150,000 patients undergo endoscopic biliary sphincterotomy in the United States each year. Sphincterotomy is a complex procedure that incorporates the use of endoscopic as well as fluoroscopic guidance. The technique involves deep cannulation of the bile duct followed by severance of the sphincter of Oddi with the electrocautery. This topic focuses on preparation for, as well as the technique involved in, endoscopic biliary sphincterotomy.

Indications

The primary indications for endoscopic sphincterotomy include the following:

  • Extraction of common bile duct (CBD) stones [1]
  • Treatment of papillary stenosis or type I (elevated liver biochemical markers with concomitant dilated CBD) sphincter of Oddi dysfunction
  • Facilitation of endotherapy (eg, stent placement, tissue sampling, and stricture dilation)

Endoscopic sphincterotomy has been used in conjunction with endoscopic balloon dilatation in the treatment of choledocholithiasis.[2, 3] Guidelines addressing the use of this procedure in this setting have been published by the European Society of Gastrointestinal Endoscopy[4] (ESGE) and the American Society of Gastrointestinal Endoscopy[5] (ASGE).

Endoscopic sphincterotomy has been employed in the treatment of postcholecystectomy abdominal pain potentially attributable to type III (without elevated biochemical markers or CBD dilation) sphincter of Oddi dysfunction. However, the EPISOD (Evaluating Predictors and Interventions in Sphincter of Oddi Dysfunction) study, which assessed 103 such patients with little or no objective evidence of biliary obstruction, found endoscopic sphincterotomy to be no better than sham treatments in this setting.[6]

Contraindications

Contraindications for endoscopic sphincterotomy include the following:

  • Severe cardiopulmonary disease
  • Recent attack of acute pancreatitis (unless there is concomitant cholangitis or persistent biliary obstruction)
  • Contrast dye exposure causing anaphylaxis
  • Uncorrected severe coagulopathy, thrombocytopenia, or both

Outcomes

Park et al carried out a meta-analysis aimed at assessing the relative efficacy of various endoscopic techniques for removal of CBD stones, including endoscopic sphincterotomy, endoscopic papillary balloon dilatation (EPBD), and endoscopic sphincterotomy with balloon dilatation (ESBD).[7] ​ They noted the following:

  • ESBD was more efficacious in stone removal during the first endoscopic session
  • Pancreatitis tended to be less common with endoscopic sphincterotomy and ESBD than with EPBD, though the difference was not statistically significant
  • The risk of bleeding was higher with endoscopic sphincterotomy and ESBD than with EPBD
 

Periprocedural Care

Equipment

Papillotomes

Papillotomes come in a number of different configurations, broadly grouped into the following three types:

  • Pull
  • Push
  • Needle-knife

The most commonly used papillotome is the pull-type version, also known as Erlangen. This consists of a wire-loop partially enclosed in a Teflon catheter. The wire exits the catheter roughly 3 cm before its distal end and reenters the catheter roughly 3 mm from its tip. The portion of catheter distal to the reentry point is referred to as the nose. The catheter becomes bowed when the wire is tightened, allowing the exposed wire to be brought away from the catheter.

Several ways exist for distinguishing the various pull-type sphincterotomes, including the following:

  • Nose length
  • Length of the diathermy wire
  • Number of lumens

The nose length can be further divided into short and long, though long-nose devices are rarely used today. The short-nose devices are more responsive to bowing, which translates into more control during sphincterotomy; however, they are more likely to become inadvertently dislodged from the bile duct.

The diathermy wire varies with regard to the length of wire exposed (range, 15-40 mm). Longer-wire devices are more likely to enter the papilla in the correct orientation by following the natural curve of the endoscope. The ideal transfer of energy occurs when a shorter segment of wire is applied to the sphincter tissue; therefore, one must select an optimal length that allows adequate entry into the papilla while maintaining the proper transfer of energy to effectively cut. The authors favor a 30-mm cutting wire.

Finally, multilumen sphincterotomes have been developed, providing a major advance. With double-lumen sphincterotomes, contrast is injected in the second lumen, which also functions as a port for guide-wire insertion. The triple-lumen variety allows contrast to be injected without removal of the guide wire.

Guide wires

Wires commonly used for sphincterotomy include the inexpensive Teflon-coated guide wire, the basic Teflon-sheathed wire (glide wire), and other Teflon-sheathed wires (including the Zebra, Visi-Glide Jaguar, Hydra-Jag wires, and Metro wires). Teflon-sheathed wires are preferred to Teflon-coated wires because they may be less likely to short-circuit.[8]

A theoretical concern exists regarding metal-core guide wires, in that they have the potential to produce unacceptably high current levels when damaged.[9] However, no convincing evidence has shown that non–wire-guided sphincterotomy is safer than wire-guided sphincterotomy.[10]

Electrosurgical generators

In order to perform sphincterotomy, an electrical current must be applied to the diathermy wire. This is achieved through a standard electrosurgical cautery generator. High-frequency current is required for sphincterotomy. This may be applied as either pure cut, pure coagulation, or a combination of the two. Most endoscopists choose a blend of the two because pure cut or pure coagulation alone may increase the risk of pancreatitis or a higher rate of bleeding, respectively.

Conventional generators

Conventional electrosurgical units (ESUs) use constant wattage. Variations in voltage from these devices may lead to complications, in that voltage is the primary determinant of thermal damage. At this point, it is worthwhile to review Ohm’s law, which states the following:

  • Power = Voltage × current (P = V × C)

and

  • Current = Voltage/resistance (C = V/r)

Therefore,

  • P = V × V/r

or

  • V 2 = r × P

The ESUs function using constant power. As the wire begins to coagulate tissue, the tissue resistance will rise. From the equations above, it is important to note the direct relation between resistance and voltage (ie, as resistance rises, so will voltage). The units may thus deliver low voltage at low resistance and high voltage at high resistance.

By bowing the sphincterotome, higher amounts of voltage are applied by creating tension. Once the wire breaks through, there is a short period during which the wire is cutting through low resistance tissue at high voltage, and this may lead to a "runaway cut."

Excessive thermal injury may occur. As noted above, current is equal to voltage divided by resistance (C = V/r); thus, resistance is inversely proportional to current, whereas voltage is directly proportional. The current level must be high at the start in order to ensure the necessary electrical arcs to cut tissue. As the cut continues, the current should decrease. Unfortunately, with conventional units, the voltage variation, which is unavoidable, can cause excessive coagulation leading to thermal injury.

A randomized prospective study found that a pure-cut current was associated with a lower frequency of pancreatitis than a blend current was.[11] No difference in the relative risk of bleeding was reported, possibly because of an insufficient number of patients studied.

Constant-voltage generators

Unlike conventional ESUs, some units (eg, VIO; Erbe USA, Marietta GA) use constant voltage rather than constant wattage. In this way, they disallow fluxes in voltage based on tissue impedance. Thus, such units will deliver more predictable and reproducible cutting effects with less overall thermal injury.

The energy is delivered with fractionated, intermittent pulses of current. This allows cutting with periods of hemostasis. The generator will automatically shut on and off, which maintains the cut in short stages. It has thus been hypothesized that this so-called endocut mode will lead to a lower incidence of bleeding as well as pancreatitis, because rapid cutting and excessive coagulation are decreased, respectively.[12]

In review of the literature, several studies suggest an advantage of Erbe generators over conventional generators.[13, 14]  A randomized study involving 100 patients demonstrated a decreased risk of bleeding as compared with conventional units; however, no clear difference existed in the incision length or risk of pancreatitis.[13]

One large study involved 2711 consecutive sphincterotomies. Specifically, the authors compared 1218 sphincterotomies using the Valleylab conventional generator and 1091 sphincterotomies using the Erbe generator.[15] They found an increase in bleeding using the Valleylab generator; however, this was endoscopically observed, and they did not find a significant difference in clinically apparent bleeding. Again, no difference in pancreatitis between groups was discovered.

Patient Preparation

With a skilled nurse or anesthesiologist present, sedation is provided with a combination of meperidine, fentanyl, midazolam, or propofol. Vital signs, including blood pressure, heart rate, and pulse oximetry, are monitored throughout the procedure.

Endoscopic retrograde cholangiopancreatography (ERCP) is generally performed with the patient prone or semiprone.

 

Technique

Incision of Sphincter of Oddi

Endoscopic sphincterotomy (see the video below) is typically performed with the endoscope in the short position. Bowing the sphincterotome is usually necessary, which allows the wire to be forced upward toward the roof of the papilla. Using the elevator and the up-down deflecting knobs may facilitate the latter bowing technique. Sometimes, performing sphincterotomy in the long position is preferred; in this case, less bowing is required.

This video, captured via endoscopic retrograde cholangiopancreatography, shows sphincterotomy being performed. Sphincter of Oddi is being cut with electrocautery applied to biliary cannulation catheter. Video courtesy of Dawn Sears, MD, and Dan C Cohen, MD, Division of Gastroenterology, Scott & White Healthcare.

The location of the sphincterotomy should be between the 11 o'clock and 1 o’clock positions. Deep cannulation is then facilitated. Once deep cannulation is achieved, the endoscopist can withdraw the sphincterotome tailored to the desired incision length. Generally speaking, approximately one half to two thirds of the wire should be visible in the duodenum.

One potential complication during the procedure is a retroperitoneal perforation that results from an uncontrolled "zipper-cut." This complication can be avoided by ensuring that enough wire is withdrawn from the papilla.

The incision length should be based on the following:

  • Indication
  • Duct size
  • Surrounding anatomy

The incision should be directed along the longitudinal axis of the intramural segment of the common bile duct (CBD). The incision should never be continued beyond the junction of the intramural segment of the CBD and the duodenal wall. This junction is located by identifying where the superior margin of the bulging impression of the intramural bile duct meets the duodenal wall. The sphincterotomy size can be assessed by using a 75% bowed sphincterotome or an inflated stone balloon.[16]

The authors perform the first third of the sphincterotomy with the generator in the cut setting, the middle third with blended current, and the final third with coagulation current. The rationale for this approach is as follows. The risk of causing pancreatitis may be highest during the initial portion of the sphincterotomy, whereas the risk of causing bleeding may be highest near the apex of the sphincterotomy (because of the proximity of the pancreatic orifice and the blood vessels, respectively).

The cut setting is used initially to cut rapidly (and presumably with minimal thermal injury) away from the pancreatic orifice. Blended current is used for the middle portion of the cut because at this point, the risks of pancreatitis and bleeding may be lowest. The sphincterotomy is completed with coagulation current because at this point, the risk of bleeding is highest.

The above recommendations are based on the authors' experience. Many experts perform the entire sphincterotomy using only the blended current setting.

Special cases

Billroth II

In this case, the papilla is upside down. This location requires the catheter to be oriented in the 6 o’clock position to cannulate the bile duct. Two techniques are used in patients who have undergone Billroth II anastomoses. The first calls for stenting of the bile duct and then using a needle-knife to cut over the stent. The incision is carried along the stent toward the junction of the intramural segment and the duodenal wall, which translates to the 6 o’clock position.[17]

The second technique involves a reverse sphincterotome. These sphincterotomes are designed so that the diathermy wire is oriented in the 6 o’clock position. The authors prefer the free-hand technique as described above because in practice, the reverse sphincterotomes often do not orient correctly.

Finally, in difficult cannulations, a needle-knife fistulotomy can be created with subsequent antegrade passage of a wire across the ampulla.[18]

Periampullary diverticulum

In cases of a periampullary diverticulum, sphincterotomy may be more difficult. The incision can usually be continued to the edge of the diverticulum; however, the size of the sphincterotomy may have to be limited because it is difficult to visualize the incision in these cases.

Complications

Potential complications of endoscopic sphincterotomy include the following:

  • Bleeding [19]
  • Infection
  • Perforation [20]
  • Pancreatitis

The overall complication rate of ERCP varies according to patient- and procedure-related factors, but in general, it ranges from 5% to 10%. In particular, within 30 days of biliary sphincterotomy, ERCP carries a 2% risk of hemorrhage and up to a 5.4% risk of acute pancreatitis.[21, 22]

A large study from Japan found that hemodialysis, heparin replacement, and early hemorrhage were risk factors for delayed hemorrhage after endoscopic sphincterotomy.[23]  Placement of a covered self-expandable metallic stent may decrease the extent of bleeding after ensdoscopic sphincterotomy and reduce rebleeding.[24]

Over the long term, patients who have undergone endoscopic sphincterotomy appear to be at higher risk for acute pancreatitis and cholangitis than those who have not, but they are not at significantly higher risk for pancreaticobiliary malignancy.[25]

Overall, awareness of these patient- and procedure-related factors is essential for avoiding or minimizing complications. With regard to the risk of bleeding, the recommendation is to avoid endoscopic sphincterotomy in patients with uncorrected severe coagulopathies, especially those receiving antithrombotic agents in whom delay of intervention is not feasible. For example, in emergency ERCP (eg, for septic shock secondary to cholangitis), placement of a biliary stent alone is the preferred alternative.

Rectal indomethacin is a widely available, inexpensive, and relatively safe nonsteroidal anti-inflammatory drug (NSAID) that can significantly reduce the risk of post-ERCP pancreatitis.[26] Guidelines from the European Society of Gastrointestinal Endoscopy (ESGE) have advocated routine use of rectal indomethacin in all patients undergoing ERCP.[27] In the United States, the current practice is to administer indomethacin to high-risk patients, including those undergoing procedures with high procedure-related risk (eg, biliary sphincterotomy).