Endoscopic Papillosphincterotomy

Overview

Endoscopic retrograde cholangiopancreatography (ERCP) has now become a therapeutic treatment for a variety of pancreaticobiliary illnesses due to the utilization of magnetic resonance cholangiopancreatography and endoscopic ultrasonography with great accuracy in diagnosis. Biliary endoscopic sphincterotomy (EST) is used to either cure illnesses of the papilla of Vater, such as sphincter of Oddi dysfunction (SOD), or to assist later therapeutic biliary operations, such as stone removal, stenting, and so on.

What is Endoscopic Papillosphincterotomy?

Biliary endoscopic sphincterotomy (EST) is the cutting of the biliary sphincter and intraduodenal portion of the common bile duct after selective cannulation with a high frequency current administered with a sphincterotome introduced into the papilla. EST is used to either cure illnesses of the papilla of Vater, such as sphincter of Oddi dysfunction, or to assist later therapeutic biliary operations, such as stone extraction, stenting, and so on. It is a requirement for biliary therapies, thus any practitioner who does endoscopic retrograde cholangiopancreatography must be familiar with various procedures as well as clinical and anatomic characteristics linked to the procedure's efficacy and safety.

Endoscopic biliary sphincterotomy was described for the first time in 1974. Each year, around 150,000 patients in the United States have endoscopic biliary sphincterotomy. Sphincterotomy is a complicated treatment that requires both endoscopic and fluoroscopic guiding. Deep cannulation of the bile duct is used, followed by electrocautery severance of the sphincter of Oddi.

Indications of biliary EST

Biliary EST is the cutting of the biliary sphincter and intraduodenal portion of the common bile duct after selective cannulation with a high frequency current delivered with a sphincterotome inserted into the papilla. It was originally made available in Germany and Japan in 1974. Since then, it has been utilized to treat and relieve symptoms of a wide range of biliary and papillary illnesses, including bile duct stones, benign and malignant biliary strictures, SOD and bile leaks, among others. Furthermore, it may be utilized to facilitate diagnostic procedures such as transpapillary bile duct biopsy, papillary tumor biopsy, and cholangioscope insertion.

Indications of biliary endoscopic Spincterotomy

• Extraction of choledocholithiasis and/or intrahepatic stones
• Treatment of benign biliary/papillary strictures
• Palliation of malignant biliary strictures
• Treatment of SOD
• Treatment of bile leaks
• Gall bladder drainage
• Others: Biliary parasites, Sump syndrome, choledochocele

Contraindications of Biliary EST 

Biliary EST contraindications include standard ERCP contraindications such as an unstable or reluctant patient, as well as those particular to EST such as uncorrected coagulopathy and failure to position the cutting wire of the sphincterotome towards the axis of the common bile duct. Alternative procedures, such as balloon dilation, should be investigated in certain cases.

Biliary EST is a high-risk bleeding operation. Before the surgery, the platelet count and international normalized ratio (INR) should be evaluated. Platelet and fresh frozen plasma transfusions should be given to raise the platelet count to more than 50000/mm3 and lower the INR to 1.5. The risk of procedural bleeding versus thrombosis owing to cessation should be considered when discontinuing antiplatelet or anticoagulant therapy. In EST, aspirin monotherapy is safe.

In individuals with a low risk of thrombosis, clopidogrel and warfarin should be discontinued 5 days before EST. Direct oral anticoagulants including dabigatran, rivaroxaban, apixaban, and edoxaban should be discontinued at least 48 hours before EST. In patients at high risk of thrombosis, practitioners should follow guidelines for discontinuing antiplatelet medication, managing dual antiplatelet medicines, and initiating bridging anticoagulant therapy.

In individuals with chronic illnesses such as cirrhosis and chronic renal failure, biliary EST is not contraindicated. The literature on the safety of ERCP in cirrhotic individuals is perplexing. In 52 cirrhotic patients, a significant risk of death (12.5%) and morbidity (34.5%) was recorded within the first month following biliary EST. A large retrospective multicenter analysis of cirrhotic patients found a substantially higher incidence of post-ERCP pancreatitis (12.8%) and cardiac adverse events (3.5%). Furthermore, a recent large statewide database research of 2155 cirrhotic patients discovered a considerably higher incidence of bleeding and PEP following biliary EST.

Equipments specific to Biliary EST 

Sphincterotome and electrosurgical unit are the equipments specific to EST.

Sphincterotome

A sphincterotome is a catheter with a distal cutting wire. Sphincterotomes vary in length and cutting wire characteristics, length and diameter of the tip (portion of the catheter extending beyond the distal end of the cutting wire), and number of lumens. They are divided into three types: pull, push, and needle-knife.

A steel cutting wire is contained within a Teflon catheter in pull-type sphincterotomes. When the wire is tightened from the sphincterotome handle, it is drawn away from the catheter, stretching the catheter tip upward. This upward motion of the tip is significant because it promotes cannulation by pointing the sphincterotome tip towards the biliary sphincter while keeping the cutting wire in contact with the papilla.

When electricity is delivered, a cutting wire is attached to an electrode connection of a monopolar electrosurgical unit on the handle and operates as a knife. The cutting wires are mainly monofilament, and the length of the exposed area at the distal side of the sphincterotome ranges from 15 to 35 mm. The use of varied lengths of cutting wire has technical ramifications. Sphincterotomes with a short cutting wire, 15-20 mm, are easy to regulate and do not result in a severe incision when put too far into the bile duct; nevertheless, they tend to orient towards 2-3 o'clock.

Because the distance between the duodenoscope and the papilla is limited in juvenile patients with a narrow duodenum, sphincterotomes with a short cutting wire may be required while doing ERCP with adult duodenoscopes. Longer cutting wire sphincterotomes (25-30 mm) are more likely to orient towards the biliary sphincter. However, because all of the cutting wire should be out of the endoscope with just a little portion of it within the papilla during sphincterotomy, taking and maintaining a remote posture while utilizing them demands greater effort.

Furthermore, due to contact with the proximal portion of the cutting wire, this difficulty in placement may result in unintended thermal damage of the overhanging duodenal folds, which can be avoided by employing a sphincterotome that is insulated on the proximal section of the cutting wire.

The sphincterotomes' distal outer diameter is usually between 4.4-6 Fr. Patients with a tiny papilla may benefit from sphincterotomes with a smaller outer diameter (3.9-4 Fr) or a tapered tip. They do, however, necessitate thinner guidewires and may result in higher tissue stress during cannulation efforts. Sphincterotomes have tips that range in length from 3 to 20 mm. 

Smaller-tipped sphincterotomes may make cannulation easier because they can be orientated more readily towards the bile duct axis when the cutting wire is tightened. Longer-tipped ones may be easier to use in people with juxtapapillary diverticula. There are also various rotating sphincterotomes that allow the axis of cannulation or EST to be changed. They may be effective in individuals who have a papilla that is oddly orientated or who have had a Billroth II gastrectomy.

The number of lumens in a sphincterotome also varies. Sphincterotomes with a single lumen for cutting wire, a double lumen for cutting wire and guidewire insertion, or a triple lumen with an extra lumen for contrast injection are now available. Some sphincterotomes have short wire designs that reduce the time it takes to replace instruments and the danger of wire loss. They also allow the operator to manipulate the guidewire.

The cutting wire design of push-type sphincterotomes differs. Tightening the cutting wire causes it to create a bow and orient itself towards 5 to 6 o'clock. As a result, they are beneficial in individuals who have had a Billroth II gastrectomy. In patients with Billroth II gastrectomy, sigmoid-shaped sphincterotomes can also be utilized for EST.

An exterior Teflon catheter with an inner retractable cutting wire makes up a needle knife sphincterotome. The cutting wire measures 3-5 mm in length. When traditional cannulation procedures fail, they are most commonly utilized for pre-cut sphincterotomy to get access to the underlying bile duct. In patients with complex or changed anatomy, they may also be utilized for EST over a plastic stent put into the common bile duct.

Electrosurgical unit

Electrosurgical generators provide three types of electrical current: pure cut, coagulation, and mixed current. There are two types of mixed current: blended (which provides cutting and coagulating currents in the same waveform) and alternating (which is regulated by an intrinsic program and delivers cutting and coagulation currents one after the other in brief bursts). When pure electrosurgical current was compared to mixed electrosurgical current for endoscopic biliary sphincterotomy, pure cut current was linked with higher bouts of hemorrhage. 

Endoscopically detected moderate bleeding was considerably reduced following EST with mixed current in alternating mode (endocut) compared to blended mode. A short retrospective observational research in cirrhotic patients found that sphincterotomy with mixed current in the alternating mode (pulsecut) had a lower incidence of EST hemorrhage than blended mode.

Because software applies a consistent voltage, mixed current in alternating mode may be linked with fewer incidents of uncontrolled cutting (zipper). The majority of studies found a comparable incidence of post-ERCP pancreatitis in individuals who had EST utilizing pure cutting or mixed current. 

TECHNIQUES OF BILIARY EST

Standard sphincterotomy

Cannulation of the bile duct is required prior to therapeutic biliary procedures. Following cannulation, a cholangiography is performed to identify the biliary disease and select the next steps. Because the majority of ERCPs are performed for therapeutic purposes, EST is nearly always necessary, unless contraindicated. The sphincterotome is progressively removed after deep cannulation until 1/4 to 1/3 of its cutting wire remains inside the papilla.

Later, the tip of the sphincterotome is bent to make contact with the roof of the papilla and to orient it towards the biliary sphincter between 11 and 13 o'clock. Based on our experience, we believe that endoscopists should take the following precautions to reduce sphincterotomy-related complications:

• To begin, the duodenoscope should be positioned such that the endoscopist can clearly observe the beginning point, direction, and upper boundary of the sphincterotomy all at the same time, to ensure that the sphincterotomy is going in the correct direction.
• Second, the sphincterotome should not squeeze the overlaying tissue but rather cut with little contacts to avoid zipper cut.
• Third, in the short duodenoscope position, it is not always easy to orient the sphincterotome towards the axis of the bile duct.

In such circumstances, additional maneuvers such as rotating the scope to the left while simultaneously advancing to a long or semi-long position or moderate shortening while simultaneously rotating to the left are required for proper alignment.

After achieving the right location, it is essential to double-check the position of the cutting wire before beginning sphincterotomy. Inside the papilla, there should be no more than 5 mm of cutting wire. Otherwise, tissue resistance may grow, resulting in an uncontrolled big incision (zipper) and heat harm to the surrounding tissues, resulting in pancreatitis. In the short posture, contact with the roof of the papilla is maintained in many ways during sphincterotomy:

• Upward lifting of the tip of the sphincterotome with elevator, 
• Slightly pulling back the duodenoscope, 
• Tipping up the proximal end of the duodenoscope or 
• Counterclockwise rotation of the duodenoscope. 

EST can be extended down the bile duct axis to the confluence of the intraduodenal bile duct and the duodenum wall. This higher edge of sphincterotomy is sometimes difficult to identify. If a fully bent sphincterotome drawn back from the bile duct into the duodenum does not bulge the roof of the papilla, the lumen of the bile duct is totally visible, or the bowed sphincterotome slips smoothly through the opening, sphincterotomy should be ended. Sphincterotomies are divided into three sizes: small, medium, and big.

A little EST is described as sphincterotomy that reaches up to the transverse hood, whereas a big EST extends up to the upper edge of the intramural bile duct. There is no standard incision size that is good for all patients. Sphincterotomy size should be decided individually based on the indication. Due to safety considerations, the diameter of the distal common bile duct and technical challenges encountered during sphincterotomy also play a role in deciding the amount of sphincterotomy.

A modest EST, for example, may be sufficient to install a stent for palliation in a patient with a malignant biliary stricture, but big stones require a large EST. If maintaining optimal posture while extending sphincterotomy is problematic, like in a patient with periampullary diverticula who requires a big sphincterotomy, it may be better to discontinue EST early and transition to balloon dilation of the papilla. Finally, it is safe to prolong an existing EST. However, due to an increase in vascularity, there is a trend toward a greater risk of bleeding when re-EST is conducted soon after the first one.

Alternatives to Endoscopic Sphincterotomy

In patients with coagulopathy and changed (e.g., Billroth II gastrectomy) or unfavorable anatomy, balloon dilation of the papilla might be explored as an alternative to sphincterotomy. It is usually used to aid in the removal of common bile duct stones. Regardless of the common bile duct diameter, an 8 mm dilation balloon is indicated. There is no uniform methodology for the number and duration of dilations.

In the extraction of small to moderate-sized stones, balloon dilation is as effective as EST. However, additional treatments, such as mechanical lithotripsy, are usually required, particularly in the evacuation of big stones. Big-balloon dilatation (12 mm) in conjunction with a variable size of EST is a safe and successful approach for large stone extraction.

In the near run, balloon dilatation of the papilla is substantially related with more PEP and less hemorrhage than EST. Choosing a balloon diameter less than the overlaying common bile duct diameter, prolonging the time of balloon inflation, and conducting a little EST before dilatation may reduce the risk of PEP. Balloon dilation is linked with a decreased long-term risk of problems, such as stone recurrence, since maintaining sphincter function avoids duodenobiliary reflux and bacterial colonization of the bile duct.

What triggers the sphincter of Oddi pain?

• The smooth muscle that covers the terminal section of the common bile duct and pancreatic duct is referred to as the sphincter of Oddi. During a meal, this muscle relaxes to allow bile and pancreatic fluids to enter the gut.
• Sphincter of Oddi dysfunction is a medical disease in which the sphincter (smooth muscle) lacks its usual capacity to contract and relax. This may impede bile flow, causing biliary discomfort and obstructing pancreatic juice flow, leading to pancreatitis.

The etiology of this malfunction is unknown; however, numerous ideas propose that tiny stones in the bile and duodenal (part of the intestine) enlargement might be the culprits.

The most common symptom of this dysfunction is recurrent steady pain in the abdominal upper right area. 

• This ache may intensify after eating, especially fatty foods.
• Opioids and other pain relievers may potentially aggravate the situation.
• Following gallbladder removal, patients may have recurring chronic discomfort.
• For long-term pain alleviation, patients with sphincter of Oddi dysfunction may require a biliary endoscopic sphincterotomy.

What are the risks involved in a biliary endoscopic sphincterotomy?

Potential complications of endoscopic sphincterotomy include the following:

• Bleeding
• Infection
• Perforation
• Pancreatitis

The total complication rate of ERCP varies depending from patient and procedure-related variables, although it is typically in the 5-10% range. ERCP, in instance, entails a 2% risk of bleeding and a 5.4% risk of severe pancreatitis within 30 days post biliary sphincterotomy.

Hemodialysis, heparin replacement, and early bleeding were all identified to be risk factors for delayed hemorrhage following endoscopic sphincterotomy in a large Japanese research. The placement of a covered self-expandable metallic stent may lessen the degree of bleeding and rebleeding following endoscopic sphincterotomy.

Patients who have had endoscopic sphincterotomy appear to be at higher risk for acute pancreatitis and cholangitis than those who have not, but not for pancreaticobiliary cancer.

Overall, understanding these patient and procedure-related variables is critical for preventing or limiting problems. Regarding the danger of bleeding, the suggestion is to avoid endoscopic sphincterotomy in patients with uncorrected severe coagulopathies, particularly those receiving antithrombotic medications and for whom delaying action is not an option. For example, in an emergency ERCP (e.g., for septic shock owing to cholangitis), placing a biliary stent alone is the preferable option.

Rectal indomethacin is a nonsteroidal anti-inflammatory medicine (NSAID) that is widely accessible, affordable, and reasonably safe. It can dramatically lower the incidence of post-ERCP pancreatitis. The European Society of Gastrointestinal Endoscopy (ESGE) recommended that all patients undergoing ERCP be given rectal indomethacin or diclofenac. In the United States, indomethacin is now administered to high-risk patients, particularly those having operations with a high procedure-related risk (eg, biliary sphincterotomy).

What is the outcome after a biliary endoscopic sphincterotomy?

In most situations, a biliary endoscopic sphincterotomy can give significant relief from pain and other dysfunctional symptoms. This technique, however, is normally considered only after medical therapy has failed.

A biliary endoscopic sphincterotomy is a complicated surgery with a significant risk of complications. Consequences such as pancreatic enlargement affect between 5%-15% of individuals, however in certain situations, the complications are severe and may necessitate a lengthy hospital stay.

Conclusion 

Endoscopic Biliary Surgery Papillosphincterotomy is an important endoscopic retrograde cholangiopancreatography (ERCP) operation for the treatment and palliation of a wide range of biliary and papillary disorders. The muscle between the common bile duct and the pancreatic duct is severed during an endoscopic sphincterotomy. To remove gallstones or other obstructions, a catheter and a wire are used. It has several drawbacks and inconveniences.