In addition to the usual medications used for sedation (see Ch. 2.3), glucagon and secretin are sometimes use to aid identification of the major or minor papillae or assist cannulation.

1 Glucagon

Glucagon causes transient relaxation of the smooth muscles of the GI tract, thus decreasing motility. Glucagon has an onset of action of 1 min, with a duration of effect of 20–30 min. It should be avoided in patients undergoing sphincter of Oddi manometry.

10.4 Equipment

Summary

1. Endoscopes 373

2. ERCP equipment 373

3. Radiology suite and equipment 376

Key Points

• All equipment should be available in duplicate.

• A therapeutic duodenoscope is used for the majority of procedures.

• A forward viewing endoscope may be required in patients with altered anatomy.

• Short wire systems have been developed which allow for rapid exchange, control of the wire by the endoscopist and avoid the need for an experienced assistant.

• All baskets should be compatible with a lithotripter.

• High quality radiological equipment is essential.

1 Endoscopes

1.1 Video duodenoscope

• Almost all ERCPs are performed with a ‘therapeutic’ duodenoscope which has a 4.2 mm operating channel. This duodenoscope can be used for both diagnostic and therapeutic procedures. This size instrument channel allows insertion of all accessories and as well as performing cholangioscopy.

• A ‘diagnostic’ duodenoscope is thinner and has a smaller instrument channel. The instrument channel will only allow the passage of an

Fr stent. As their diameter is slimmer, they are useful where there is altered anatomy (i.e. Billroth I), a stricture, or if an ERCP is being performed in a child or young adult.

1.2 Forward viewing endoscope

• For patients with Billroth II, start with a standard duodenoscope; however, ensure that a forward viewing endoscope is available. Options include using an enteroscope by itself, or augmented enteroscopy with a single balloon, double balloon or Spirus overtube (see Ch. 5.2). A pediatric colonoscope can also be used.

2 ERCP equipment

2.1 Catheters

The choice of whether to start with a catheter or a sphincterotome is based on endoscopist preference, and also on whether a sphincterotomy is likely to be made. In cases where this is unlikely, or where a sphincterotomy has already been performed, a catheter is often used to cannulate. There are several types of catheters available. A standard catheter has a graduated, precurved tip with a single channel, which can be used for either contrast or a wire. A triple lumen catheter has two channels which allow contrast to be injected while keeping a wire in place. A taper-tip catheter has a shorter, 5 mm tip. The taper-tip catheter is sometimes useful for cannulating a stenosed or minor papilla. There is a slightly increased risk of submucosal injection with this type of catheter.

2.2 Sphincterotomes

The sphincterotome consists of a metal wire covered by an insulating sheath, with the distal 20–30 mm of wire exposed, and a short radio-opaque, tapered tip (5 mm). Cannulation is usually attempted with a sphincterotome if a sphincterotomy is likely. The angle of the tip of the sphincterotome can be altered, by asking the assistant to ‘tense’ the sphincterotome, which is also useful if cannulation is difficult.

Several different types of sphincterotomes are available. A double-lumen sphincterotome allows either injection of contrast or a guidewire (Fig. 1A). A triple lumen sphincterotome (Fig. 1B) allows injection of contrast without removing the guidewire. A tapered tip (5 mm tip) (Fig. 1D) is sometimes used if the papilla is stenotic or to cannulate the minor papilla. In patients in whom the orientation of the biliary and pancreatic ducts are reversed (i.e. Billroth II), a special sphincterotome is available which is orientated in the opposite direction to the regular sphincterotome (Fig. 1E). Where sphincterotomy fails, a needle-knife sphincterotome with a retractable wire or blade with guidewire option (Fig. 1C) can be used. Sphincterotomes with long cutting wires (Fig. 1G) are no longer used due to an increased risk of bleeding and perforation. The sphincterotome with a long tip nose (Fig. 1F) was used prior to guidewire cannulation, but is rarely used now.

Figure 1 Different types of sphincterotomes. (A) A double-lumen sphincterotome allows either injection of contrast or a guidewire. (B) A triple lumen sphincterotome allows injection of contrast without removing the guidewire. (C) A needle-knife sphincterotome with a retractable wire or blade. (D) A tapered tip (5 mm tip) is sometimes used if the papilla is stenotic or to cannulate the minor papilla. (E) In patients in whom the orientation of the biliary and pancreatic ducts are reversed (i.e. Billroth II), a special sphincterotome is available which is orientated in the opposite direction to the regular sphincterotome. (F) Sphincterotome with a long tip nose was used prior to guide wire cannulation, but is rarely used now. (G) Sphincterotomes with long cutting wires are no longer used due to an increased risk of perforation bleeding and perforation.

2.3 Balloon catheters

Balloon catheters are used to remove either small or medium-sized stones or sludge. They can also be used to obtain a cholangiogram where there is a very dilated duct or following a sphincterotomy. Balloon catheters come either in a single size or with three different attachments which alter the size of the balloon. They are also available as wire guided if required.

2.4 Brushes

Wire guided brushes are available and are used to obtain tissue from suspicious strictures.

2.5 Forceps

Regular biopsy forceps should be available. These can be used to biopsy the ampulla where an ampullary cancer is suspected or where autoimmune pancreatitis is a possibility. They can also be used to biopsy bile duct strictures after a biliary sphincterotomy. Pediatric biopsy forceps (6 Fr) are sometimes used. These are easier to insert into the bile duct than regular biopsy forceps; however, they provide smaller samples. There may be a slightly decreased risk of complications compared with paediatric biopsy forceps than with regular biopsy forceps.

Jumbo forceps should also be available. These are used to remove stents. Stents are easier to grasp with the jumbo forceps than a snare; however, the stent cannot be removed through the operating channel, necessitating removal and reinsertion of the duodenoscope.

2.6 Snare

A snare is used to remove stents. It takes a little more practice to use than the jumbo forceps; however, the stent can usually be removed through the instrument channel of a therapeutic duodenoscope avoiding removal and reinsertion of the duodenoscope.

Clinical Tip

How to remove a stent with a snare

Take time to position the scope. Insert the snare and open it just above or below the distal end of the stent. If you are going to remove it though the instrument channel, place the snare as close to the distal end of the stent as possible, close the snare and withdraw it through the instrument channel. If the stent has partially migrated out of the bile duct, grasp the side flap with the snare and gently push the stent back into the bile duct. Once this is done, the distal end of the stent can be snared and the stent removed.

2.7 Wires

Wires are an essential part of the ERCP armamentarium. A wire consists of a nitinol or stainless steel core with a smooth coating. The type of coating determines the performance characteristics of the wire. A hydrophilic wire consists of a nitinol core with a polyurethane coating covering the entire length of the wire. Hydrophilic wires are often used for difficult cannulations (i.e. stricture at the hilum). They are excellent at navigating tight, difficult strictures but their hydrophilic coating means that they are more difficult to handle for the assistant. Hybrid wires combine regular wire with a hydrophilic section. The aim of these wires is to give the ease of use of the non-hydrophilic wire, with the ability to traverse a tight stricture of the hydrophilic wires. PTFE or Teflon coated wires were used in the past, but are rarely used nowadays, as they must be removed prior to performing a sphincterotomy due to the risk of conducting current.

Wires come with a variety of tips. A straight tip is usually used; however, an angled tip is useful if a tight stricture is encountered. They also come in different widths: 0.035 inch is the most commonly used, though a 0.025 inch or 0.018 inch may be required to pass a tight stricture.

Clinical Tip

How do you exchange over a wire?

The endoscopist sets the pace of the exchange and watches the monitor to ensure that the wire does not move. The assistant should watch the hands of the endoscopist and move at the same speed. Most wires are made in two colors so that it is easy to see if the wire is moving. The distal end of the wire are often made of a different color (i.e. yellow and black with a pure black distal end) so that if a wire has moved significantly it will be obvious before it comes out of the duct. If it does move, stop, check the position of the wire with fluoroscopy, and once the wire is in a secure position, restart the exchange.

2.7.1 Short wire system

The classic system is a ‘long’ wire which is manipulated by an assistant. This is exchanged by the assistant advancing the wire at the same rate as the physician withdraws the instrument (see clinical tip box). With the long wire system, an experienced assistant is essential to the success of the procedure. Short wire systems have been developed which allow rapid exchange over the wire and give control of the wire to the endoscopist. The potential advantages of the short wire system include:

• Rapid exchange

• No need for an experienced assistant

• Control of the wire by the endoscopist.

They are three components to the short wire system:

• Short wires (185–270 cm vs 400–460 cm)

• Locking device for the wire

• Devices designed to be exchanged over the short wire platform.

There are currently three short wire systems. The V system (Olympus, Toyko, Japan), contains the ‘V’ locking device. This is an elevator with a V-shaped groove on the elevator, which acts as an internal wire lock (Fig. 2), securing the wire and allowing devices to be removed over the wire without exchanging with an assistant.

Figure 2 V-Scope. (A,B) Demonstrate how the V-shaped elevator captures the wire, allowing for rapid removal of devices without formal exchange with an assistant.

(From Shah R et al. Short-wire ERCP systems. Technology status evaluation report. Gastrointestinal Endoscopy 2007;66:650-655.)

Both the Fusion System (Cook Endoscopy; Winston Salem, NC) and the RX Biliary System (Boston Scientific, Natick, MA) consist of short wire systems with external wire locking systems. They both have specially designed biopsy caps, which prevent leaking of air or bile. The Fusion System incorporates a wire lock with port cap (Fig. 3B), while the RX Biliary System has a separate anti-leak biopsy cap, and a wire lock which is attached to the handle of the endoscope and allows fixation of two wires (Fig. 3A). A large variety of compatible devices are available (see Shah et al 2007, for information on available devices) including sphincterotomes and stents.

Figure 3 RX System and Fusion System. (A) The RX System has an anti-leak biopsy cap and wire locking device. (B) The Fusion System has a specially designed biopsy cap and a locking device which can hold up to two wires.

(From Shah R et al. Short-wire ERCP systems. Technology status evaluation report. Gastrointestinal Endoscopy 2007;66:650-655.)

3 Radiology suite and equipment

Ideally the ERCP room should be an integral part of the endoscopy suite, thus avoiding the need to move equipment and personnel. The ERCP room should be an adequate size to allow for the amount of equipment and personnel required, and should be provided with equipment to allow propofol or general anesthesia if necessary. It is essential that high quality radiological equipment is used. The ideal equipment is a digital remote-control table operated by a radiographer.

3.1 General radiology equipment

• Articulated arm supplying fluids and electrical current over the video console (with several power points, two suction inlets, one oxygen point, one nitrous oxide point)

• An X-ray generator with continuous and pulsed exposure capability (most now have high frequency generators which provide excellent exposure reproducibility and automatic brightness control)

• Bifocal X-ray tube

• Collimation and filtration

• High definition image intensifier

• Digital image recording and display using a minimum of two display screens

• The patient table should minimize X-ray attenuation while providing sufficient strength to support large patients. The configuration most commonly used in GI is a mobile C-arm with an under table X-ray tube

• Standard radiation protection aprons, eye shielding and standard radiation protection systems, including lead barriers between the patient and operator

• Foot pedal to acquire images.

Further Reading

Kethu SR, Adler DG, Conway JD, et al. ERCP cannulation and sphincterotomy devices. Gastrointest Endosc. 2010;71:435-445.

Shah RJ, Somogyi L, Petersen BT, et al. Short-wire ERCP systems. Technology status evaluation report. Gastrointest Endosc. 2007;4:650-657.

10.5 Checklist before starting an ERCP

Summary

1. Patient checklist 377

2. Endoscopist checklist 377

3. Patient positioning 377

Key Points

• Always ensure that you have reviewed the patient notes and imaging.

• Check the duodenoscope and equipment before starting.

2 Endoscopist checklist

• Check that the endoscope is aspirating, blowing air and water correctly, and that white balancing has been performed

• Make sure that endoscopy recording equipment is available and working.

3 Patient positioning

• The patient is placed in the left lateral decubitus position with their left arm at their back

• Patients should preferably be placed in a supine position, if access to the minor papilla is required or in cases of hilar stenosis, to allow optimal visualization of the biliary tree.

10.6 Basic ERCP technique

Summary

1. Inserting the duodenoscope and positioning over the papilla 378

2. Locating the papilla 378

3. Cannulating the major papilla 380

4. Failure to cannulate the desired duct 381

5. Cannulating the papilla beside a diverticulum 382

6. Cannulating a stricture 382

7. Cannulating the minor papilla 384

8. ERCP in patients with altered anatomy 384

9. Successful cannulation rate 390

10. ERCP in children 390

Key Points

• Patience is key to successful cannulation.

• The major papilla usually has a ‘neck tie’ appearance.

• The minor papilla is usually 2 cm proximal and anterior to the major papilla and is usually most easily identified and cannulated with the patient supine.

• ERCP in patients with altered anatomy is associated with lower success rates and higher complication rates. It is essential to know what type of surgery has been performed. Augmented enteroscopy, with single/double balloon or spiral enteroscopy, is sometimes required.

1 Inserting the duodenoscope and positioning over the papilla

How to intubate and position the duodenoscope in front of the papilla is illustrated in Figure 1. Gently insert the duodenoscope to the upper esophageal sphincter. The esophagus is intubated blindly with gentle forward pressure and slight clockwise rotation. If there is resistance STOP, and change to a forward viewing gastroscope to exclude anything which may cause difficulties with intubation (i.e. Zenker’s diverticulum/stricture). Due to the side-viewing nature of the duodenoscope, a full view of the esophagus is not possible. Once the duodenoscope passes the gastroesophageal junction, make a half turn clockwise and follow the lesser curve to the pylorus. As the duodenoscope is side viewing, the duodenum is entered by placing the pylorus in the ‘setting sun’ position, so that the upper half of the pylorus is visible at the 6 o’clock position. Check that the shaft of the scope is at the 12 o’clock position when intubating the pylorus as this ensures optimum positioning in front of the papilla. The duodenoscope is then inserted into the second part of the duodenum. Two maneuvers are performed in succession: first turn the big wheel anticlockwise and the small wheel clockwise, thus deflecting the tip of the scope up and right, then withdraw the endoscope to 50–70 cm from the incisors to reduce the gastric loop.

Figure 1 Inserting the duodenoscope and positioning over the papilla. (A) Duodenoscope advancing blind into the esophagus. (B) Advancing along the lesser curvature. (C) The endoscope rests on the greater curvature and faces the pylorus. (D) Deflection upwards, before advancing through the pylorus. (E) The apparatus advances to the superior flexure. (F) The endoscopist turns to his right through 90°. (G) The endoscopist has turned to his right through 90°. (H) Deflection upwards and to the right by turning the small wheel clockwise and the big wheel anti-clockwise. (I) Withdrawal of the endoscope to approximately 70 cm which removes the gastric loop.

1.1 Problems with intubation

• Unable to intubate the esophagus:

STOP. DO NOT PUSH. Withdraw the duodenoscope and insert a forward-viewing scope to exclude a pharyngeal pouch or stricture. A guidewire can be left in the stomach to guide insertion with the duodenoscope if required.

• The duodenoscope coils in the fundus:

Ensure the patient is fully in the left lateral decubitus position. If necessary, place a bolster under the patient. Withdraw to the cardia then deflect slightly to the right after advancing through the cardia once again. Follow the vertical folds along the lesser curvature to the pylorus.

Avoid over-inflating the stomach.

• The duodenoscope advances as far as the superior flexure of the duodenum facing upwards:

Rotate the scope to the right through 90°, by turning from facing the patient to facing the monitor video and be perpendicular to the patient (Fig. 7) patient. This will present the second part of the duodenum.

Figure 7 Cannulation of the bile duct. The bile duct is cannulated going from inferior to superior while directing the catheter towards 11 o’clock. The pancreatic duct is cannulated in an en face position, directing the catheter from left to right and towards 1 o’clock.

Box 1 Short versus long scope position

• In a short scope position, the duodenoscope is straight with no gastric loop, and is normally between 50 and 70 cm from the incisors.

• In the long scope, a gastric loop is left in the stomach with 70+ cm of the duodenoscope inserted.

2 Locating the papilla

The major papilla should now be in the field of vision. The major papilla consists of a frenulum, a hood, infundibulum, and orifice (Fig. 2). It is often a different color from the rest of the duodenum. The papilla should be inspected for evidence of stone passage (gaping or inflamed orifice), edema or papillary adenoma. The major papilla is then classified depending on its appearance (Fig. 3). This is important when assessing how far a sphincterotomy may be extended and to do a diathermic puncture of biliary infundibulum.

Figure 2 Normal papilla. (1) Papillary orifice. (2) Frenulum. (3) Hood. (4) Infundibulum.

Figure 3 Classification of the various types of infundibulum. Type 0: no infundibulum. Type 1: the infundibulum extends to the limit of visibility. Type 2: a prominent infundibulum. Type 3: a large infundibulum which covers the papilla.

2.1 Problems identifying the major papilla

The papilla is normally found on the medial wall of the duodenum, but can be located anywhere from the duodenal bulb to the mid-descending duodenum. If the papilla is not visible after performing the maneuvers described above, the following should be tried:

• Wait a little before changing position

• Improve visualization with antifoam solution (i.e. simethicone)

• Give glucagon to decrease duodenal motility

• Search for the papilla by gently lifting the mucosal folds with a catheter and look for the frenulum, infundibulum, or hood

• There is usually only one longitudinal fold in the second part of the duodenum – the major papilla is usually located at the end of this fold. This is often described as having a ‘neck tie’ appearance (Fig. 4)

• Occasionally, the papilla is located in the third part of the duodenum. This can be reached using the long scope position (>70 cm)

• The infundibulum can be divided into four types (Type 0–3; Fig. 3). This system is useful if a pre-cut sphincterotomy is required. A Type 0 infundibulum is not suitable for pre-cut, while Types 2 or 3 have the ideal configuration for pre-cut sphincterotomy.

Figure 4 Neck tie appearance of the major papilla (arrow).

In cases where there is difficulty identifying the major papilla, look for the ‘neck tie’ appearance with a longitudinal fold (Fig. 4) in the second part of the duodenum.

2.2 Locating the minor papilla

The minor papilla is smaller (Fig. 5), and is usually located 2 cm proximal and anterior to the major papilla in the second part of the duodenum. It can be difficult to locate. In these cases consider the following:

• Use a long scope position: this is usually the optimum position to see the minor papilla

• Place the patient in the supine position

• Give secretin. Some authors recommend spraying the second portion of the duodenum prior to giving secretin.

Figure 5 Minor papilla (arrow).

3 Cannulating the major papilla

Flush the catheter or sphincterotome with dye prior to commencing the procedure to prevent any injection of air. Prior to attempting cannulation, optimize conditions and ensure there is an adequate view of the papilla by ensuring:

• Duodenal hypotonia: give glucagon if necessary

• No bubbles or mucus: use antifoam solution (simethicone)

• Take time to optimally position the duodenoscope and ensure that the orifice is at the center of the image

• Wait a little for the orifice to open.

3.1 Cannulating the bile duct and pancreatic duct

To selectively cannulate the bile duct, the side-viewing duodenoscope should be placed below the major papilla. Place the catheter slightly below the papilla and direct the catheter vertically towards 11–12 o’clock (Fig. 6) in the right upper quadrant. Cannulation of the pancreatic duct requires the duodenoscope to be placed en-face, and slightly to the left of the papilla. The catheter should be placed on the right side of the papilla between 1 and 3 o’clock, with the catheter moving from left to right. If the os is difficult to catheterize, the catheter can initially be introduced a few millimeters, then directed towards the biliary or pancreatic orifice. The catheter is then introduced as far as possible into the chosen duct.

Figure 6 Orientation of the pancreatic and bile duct. Using the face of a clock for orientation, the pancreatic duct is found between 1 and 3 o’clock position, while the bile duct is found at 11 o’clock.

In obese patients, those with malignant pancreatic disease, particularly where there is a lesion in the genu of the pancreas, it can be difficult to properly centre the major papilla. In these cases, a long scope position may be required, and the endoscopist may need to position themselves in the opposite of the classic position (i.e. at 90° to the patient’s face).

Box 2 Role of a guidewire

• A wire allows the sphincterotome to be manipulated (i.e. withdrawn to just above the ampulla) without losing cannulation. This is very useful for people learning ERCP or after a difficult cannulation. It is also useful when the papilla is difficult to cannulate (i.e. stenotic os).

• It can be useful to determine whether the correct duct has been cannulated, thus avoiding repeated injection of contrast into the pancreatic duct. This is done by looking at the direction the wire follows (see Clinical Tip ‘How do I know which duct I am in’ below).

• The guidewire is also very useful where minimizing contrast injection is important, e.g. in a patient with cholangiocarcinoma.

4 Failure to cannulate the desired duct

• Check that the catheter is in the correct orientation to cannulate the desired duct:

Use fluoroscopy to check the position of the endoscope and the direction of the catheter. To cannulate the bile duct, check that the tip of the endoscope is slightly under the papillary orifice, with the catheter pointing towards 11 o’clock (Fig. 7). For the pancreatic duct, the tip of the endoscope should be placed in the same area as the papillary orifice, with the catheter directed towards 1–3 o’clock (Fig. 7).

• The pancreatic and biliary orifices are separate:

If the pancreatic duct is repeatedly cannulated, look above the cannulated orifice for the biliary orifice.

• The catheter is in the correct direction for the bile duct, but deep cannulation cannot be achieved:

This is because the catheter is up against the anterior wall of the ampulla or the common bile duct. Withdraw the endoscope slightly: when the papilla has disappeared from the visual field, push the catheter forward into the bile duct.

• Use a hydrophilic guidewire to cannulate the desired duct (Fig. 8).

• Change the catheter to a sphincterotome:

The sphincterotome can be tensed, which allows for maximum elevation to assist biliary cannulation.

• The papilla is stenotic:

A tapered catheter or sphincterotome is sometimes useful.

• If the pancreatic duct is repeatedly entered, a wire can be left in the pancreatic duct. This prevents further pancreatic duct cannulation. It also identifies the direction of the pancreatic duct. Once this is known, the direction of the bile duct can be determined. Alternatively, a pancreatic duct stent can be inserted, with subsequent cannulation of the common bile duct.

• Cholecystokinin can sometimes be used. This causes the gallbladder to empty with subsequent opening of the papillary orifice.

Figure 8 Selective cannulation with a wire. A wire can be used to selectively cannulate either the bile duct. (A) Note the position of the duodenoscope below the papilla or the pancreatic duct. (B) Once the correct duct has been cannulated with the guidewire, the sphincterotome is then inserted over it.

Needle knife pre-cut sphincterotomy should not be used to access the biliary or pancreatic duct, except in an emergency. If the above maneuvers fail, the procedure should be discontinued and a repeat attempt made 24–48 h later. This allows the edema to settle, and the second procedure is often successful.

5 Cannulating the papilla beside a diverticulum

Diverticulae frequently occur in the second part of the duodenum, especially in elderly individuals. In these cases, look for the papilla at the edges or inside the diverticulum (Fig. 9). Occasionally it is hidden by the duodenal folds, which should be lifted using a catheter. If the papilla cannot be identified, identify the frenulum and hence the papilla. Cannulating a papilla located at the edge, inside or in the middle of a diverticulum is usually possible. The difficulty arises when the papilla is located inside the diverticulum and with the os also facing towards the inside of the diverticulum. In these cases, the following can be tried:

• Evert the papilla by pressing with a catheter on the edge of the diverticulum without insufflating it too much.

• Saline has been used raise the papilla from the diverticulum (Fig. 10A,B); however, this can be associated with pancreatitis.

• Gently tease the papilla outside the diverticulum with a biopsy forceps (Fig. 10C).

• It is sometimes possible to place the tip of the endoscope into the diverticulum to center it.

• Percutaneous transhepatic wire can be inserted through the ampulla (see section 8.11).

Figure 9 Location of papilla in the presence of a diverticulum. The papilla is located at the left (A) or right (B) edge of a large diverticulum. This is the most common presentation. (C) Papilla between two small diverticula. (D) Papilla in the centre of large diverticulum.

Figure 10 Techniques for accessing a papilla located within a diverticulum. Saline can be injected (A) which raises the papilla from the diverticulum (B). However, this is associated with an increased risk of pancreatitis. Biopsy forceps can also be used to tease the papilla out of the diverticulum (C).

6 Cannulating a stricture

Traversing a difficult stricture requires patience, skill and optimum X-ray control. When a difficult stricture is encountered the following should be tried:

• Consider using a fully hydrophilic wire for difficult strictures (Fig. 11). Also an angled tip is sometimes useful. Repeat forward and back movements while simultaneously twirling the wire. Occasionally, a 0.025 or 0.018 inch guidewire is needed. An ultratapered sphincterotome or cure-tipped 5–6 Fr cannula may also be useful. Once the stricture has been traversed, the sphincterotome is advanced across the stricture and the guidewire should be exchanged for a regular guidewire as this facilitates dilation or stent placement.

• The left hepatic duct is usually more difficult to cannulate. Bounce the guidewire off the lateral wall to cannulate the left hepatic duct. A swingtip or Haber Ramp catheter is occasionally useful in difficult cannulation.

• Cannulate the right hepatic duct by placing the sphincterotome at the level of the bifurcation and direct towards the right hepatic duct.

• Distortion of the second part of the duodenum by tumour can hinder the correct centering of the papilla. If cannulation of the papilla is difficult, determine if this is a technical problem or a low stenosis. Review pre-ERCP imaging (ideally MRC or EUS) to determine whether there is a low stenosis near the papillary orifice. In this case, use a sphincterotome mounted on a guidewire to find the orifice of the stenosis. Pre-cut sphincterotomy or diathermy loop excision of the infundibulum may be necessary.

• Make a loop with the guidewire (Fig. 12). Once the loop moves in the desired direction, advance the sphincterotome over the guidewire to the apex of the loop. Then withdraw the guidewire until the wire is straight. Reinsert the guidewire, forming a loop if necessary. This is repeated until the stricture is traversed.

• Advance stepwise if the stenosis has several angulations. The guidewire is advanced to the end of the first angulation (Fig. 13A). The sphincterotome is advanced over the guidewire to this point (Fig. 13B). The guidewire is advanced to the end of the second angulation, followed by the sphincterotome (Fig. 13C). This is repeated until the stricture is crossed (Fig. 13D).

• Changing the patient position can help. For complex hilar strictures, placing the patient in the dorsal decubitus position is often useful.

• Placing an inflated retrieval balloon below the stricture can stretch the bile duct and alter the angle aiding guidewire cannulation.

Figure 11 Inserting a guidewire through a stricture. Strictures should be crossed initially using a guidewire. If the guidewire is hitting the side walls (A,B), withdraw the sphincterotome slightly (C). This maneuver allows optimal alignment of the guidewire with the stricture.

Figure 12 How to manipulate the wire into the correct hepatic duct. (A) Produce a loop with the guidewire. (B) Insert the catheter to the end of the loop. (C) Undo the loop formed by the guidewire. (D) Insert the guidewire through the catheter lying in the correct direction. Withdraw the guide catheter to change the direction of the guidewire if the guidewire fails to pass through the stenosis.

Figure 13 Inserting a guidewire through a complex stricture. The guidewire is advanced in a stepwise manner. The guidewire is advanced to the end of the first angulation (A). The sphincterotome is advanced over the guidewire to this point (B). The guidewire is advanced to the end of the second angulation, followed by the sphincterotome (C). This is repeated until the stricture is crossed (D).

7 Cannulating the minor papilla

The accessory or minor papilla is usually located 2 cm proximal and anterior to the major papilla in the second part of the duodenum. The os is often very small (2 mm), with the duct of Santorini running from the 5 o’clock to the 11 o’clock position. The easiest position to cannulate the minor papilla is in the ‘long’ scope position, with the patient supine. Patience is essential. Wait for the orifice to open before attempting cannulation. Cannulation is usually performed initially with wire, following with the sphincterotome once the duct has been cannulated. This is usually possible with a regular sphincterotome, however a tapered sphincterotome can be required if the os is very small or stenosed. Care should be taken to avoid submucosal injection. If the minor papilla is difficult to locate or cannulate, placing the patient in the supine position is often useful helpful. Secretin can be used to aid identification and to encourage the os to open.

8 ERCP in patients with altered anatomy

8.1 Post-surgical anastomoses

Performing ERCPs in patients who have undergone gastroenteric anastomoses is becoming increasingly common as more patients undergo gastric bypass surgery for obesity. It is important to know what type of surgery has been performed before commencing the ERCP, as this will determine the type of endoscope used, as well as the difficulty of the procedure. Some of these procedures, such as post-duodenopancreatectomy (Whipple’s) are technically demanding, and are often best referred to a tertiary referral centres.

8.2 Which endoscope to use?

A duodenoscope is usually used where possible, as the presence of the elevator facilitates cannulation. In addition, the side viewing assists location of the ampulla (Fig. 14A). However, it is sometimes not possible to reach the papillary area due to the length of the afferent loop. In these cases, a forward viewing scope should be used. Reaching the ampulla is often successful with a forward viewing scope; however, the ampulla can be more difficult to visualize (Fig. 14B), and the lack of an elevator can make cannulation or exchanging over a guidewire difficult. The choice of forward viewing scope depends on what is available in the unit and the experience of the endoscopist. Options include a pediatric colonoscope, a single or double balloon enteroscope, or an enteroscope with Spirus overtube. Where a forward-viewing endoscope is used, but cannulation has failed, it is possible to leave a wire and then backload this wire onto a duodenoscope.

Figure 14 View of the ampulla in a patient with altered anatomy with a duodenoscope or forward viewing scope. In patients with altered anatomy, the ampulla can be reached with a duodenoscope or a forward viewing endoscope. The duodenoscope is side viewing and allows good visualization of the ampulla (A). The ampulla can be slightly more difficult to visualize with a forward viewing endoscope (B).

8.3 Pyloroplasty and Billroth I surgery

The major papilla can be reached with a duodenoscope, and the common bile duct or pancreatic duct is cannulated as normal.

8.4 Gastroenteric anastomosis with a preserved pylorus

In cases of gastroenteric anastomosis, a duodenoscope can be used if the pylorus is patent. However, the pylorus often becomes stenosed. In these cases, the afferent loop should be used to access the papilla.

8.5 Choledochoduodenal anastomosis

For patients with a choledochoduodenal anastomosis (Fig. 15A), a forward-viewing endoscope is sometimes required. The anastomosis is usually located on the anterior side of the bulb. If the anastomosis is patent, the endoscope can be introduced into the bile duct. If it is an end-to-side choledochoduodenal anastomosis (Fig. 15B), i.e. if the segment underlying the anastomosis is closed, access to the papilla should be gained using a duodenoscope.

Figure 15 Choledochoduodenal anastomosis. (A) A side-to-side choledochoduodenal anastomosis. (B) An end-to-side choledochoduodenal anastomosis.

Clinical Tip

Sump syndrome

’Sump syndrome’ is a rare complication of a side-to-side choledochoduodenostomy (Fig. 15A). The common bile duct between the anastomosis and the ampulla of Vater acts as a reservoir in which debris and stones collect. This can result in abdominal pain, cholangitis, biliary obstruction or pancreatitis. ERCP findings include dilated bile or pancreatic duct, and signs of chronic pancreatitis.

8.6 Pancreaticoduodenectomy (Whipple’s)

The classic pancreaticoduodenectomy described by Whipple consists of removal of the pancreatic head, duodenum, first 15 cm of the jejunum, common bile duct, and gallbladder, as well as a partial gastrectomy (Fig. 16). There is a side-to-side gastrojejunostomy, often with a long afferent loop and a variety of placements for the pancreatico- and hepatico-jejunostomies. In a pylorus preserving pancreaticoduodenectomy, the gastric antrum, pylorus, and proximal 3–6 cm of the duodenum are preserved, with an end-to-side pylorojejunostomy. The pancreaticojejunostomy is usually located at the apex of the loop, with the hepatic-jejunotomy about half way down the afferent loop. In these patients, pancreatic and biliary anastomoses can rarely be reached with a duodenoscope and a forward viewing endoscope should be used.

Figure 16 Classic Whipple. This is a non-pylorus preserving pancreaticoduodenectomy. The head of the pancreas has been resected. There is a gastrojejunostomy, with an afferent and efferent limb. The afferent limb leads to the hepatico- and pancreaticojejunostomies. Note that the pancreaticojejunostomy is past the hepaticojejunostomy and is often found almost at the end of the afferent limb.

Box 3 The afferent loop

How to identify and enter the afferent loop

• The afferent loop is almost always more difficult to access than the efferent loop.

• The afferent loop is usually adjacent to the lesser curve.

• If it is not possible to intubate the afferent loop, place the patient to prone or supine position.

• A wire can be advanced into the correct loop, and the endoscope guided over the wire into the loop.

• If this fails, a CRE wire-guided balloon is sometimes useful. It can be inflated in the loop, and the endoscope then guided into the loop. These procedures should be performed under fluoroscopic guidance to avoid complications.

How do I know if I am in the afferent loop?

There are several tools you can use to determine if the endoscope is in the correct limb:

• Use fluoroscope to confirm that the endoscope is moving towards the right hypochondrium.

• The presence of bile.

8.7 Gastrojejunal anastomosis (Billroth II)

A Billroth II was often performed in patients with peptic ulcer disease or gastric antral carcinoma and consists of a partial gastrectomy with end-to-side gastrojejunostomy (Fig. 17). The operation may also be known as a Polya and Hoffmeister, depending on how the gastrojejunostomy is performed. A duodenoscope should be used initially. If this is unsuccessful, it can be exchanged for a forward viewing endoscope. There is a native papilla, but the pancreatico-biliary anatomy is reversed as described in the pancreaticoduodenectomy.

Figure 17 Gastrojejunal anastomosis. (A) Demonstrates the relationship of the afferent and efferent limbs in a gastrojejunal anastomosis (Finisterer type procedure). (B) Note the location of the afferent loop – it is at the top left under the fold and is the more difficult limb to enter.

Box 4 Jejunojejunal anastomoses

• Enteric anastomoses can either be in the ‘Y’ configuration, which presents the endoscopist with two lumens to choose from, or in a side-to-side anastomosis, which appears as three lumens.

• The afferent loop is usually the most difficult loop to enter.

8.9 Gastric bypass surgery

There are two types of gastric bypass surgery performed. In patients with gastric outlet obstruction, a side-to-side loop gastrojejunostomy is performed. Patients undergoing gastric bypass surgery as a treatment of obesity often have a gastric pouch which is separated from the rest of the stomach. The pouch empties into an end-to-side gastrojejunostomy. A jejunojejunostomy connects the other part of the stomach, duodenum and jejunum in a Roux-en-Y configuration. Although it is occasionally possible to reach the anastomosis with a duodenoscope, a forward viewing endoscope is usually required. There is a native papilla, but as with a Billroth II or pancreaticoduodenectomy, the anatomy is reversed with the bile duct between 5 and 6 o’clock.

Box 5 How to reach the papilla in a patient with an afferent limb

• The afferent limb should be approached in a similar manner to a colonoscopy, with repeated shortening of the endoscope and removal of loops.

• Contrast can be injected either through a catheter or a CRE balloon (if reflux of contrast is a problem). This is useful where there are sharp angulations to determine the direction of the afferent loop.

• External manual compression can be useful.

• Take care not to stretch the anastomosis, as perforation can occur.

8.10 Cannulating the bile duct and pancreatic duct in patients with Billroth II or Whipple’s procedure

In Billroth II the ampulla will be intact, while in a Whipple’s or other reconstructive surgery there will be a surgical anastomosis (i.e. choledochoenteric anastomosis), and the pancreatic and bile duct anastomoses are usually found separately in the jejunum. The pancreatic duct is often located just proximal to the end of the loop, while the biliary orifice is located proximal to the pancreatic orifice, on the anti-mesenteric wall. As the papilla has been reached retrograde through the afferent loop, the anatomy is reversed by 180° with the biliary orifice found between 5 and 6 o’clock rather than the normal 11 o’clock position (Fig. 18). A straight catheter can be used to cannulate the bile duct or pancreatic duct. It is helpful to maintain an en-face position and exaggerated distance away from the ampulla. A standard cannula is sometimes useful, as a standard sphincterotome may make biliary cannulation difficult in this situation due to its pre-curve. In our experience, guidewire cannulation is particularly useful in these circumstances.

Figure 18 Cannulating the papilla in a patient with a Billroth II. As the papilla has been reached retrograde through the afferent loop, the anatomy is reversed by 180° with the biliary orifice found between 5 and 6 o’clock rather than the normal 11 o’clock position.

• A guidewire is inserted percutaneously (Fig. 20). The guidewire is retrieved using a snare and gently pulled into the instrument channel. A sphincterotome is then inserted over the guidewire and a standard sphincterotomy is performed.

• A variation of this is where a catheter has been placed by radiology. Insert a guidewire through the catheter (Fig. 21). The percutaneous guidewire is retrieved using a snare and pulled out of the instrument channel. The guide catheter is mounted on the guide wire in the bile duct. The stent is pushed through the stenosis.

Figure 20 Rendezvous procedure. (A) Percutaneous insertion of a guidewire through the papilla. (B) Retrieval of the guidewire using a snare which is re-inserted in the operating channel. (C) A sphincterotome is inserted over the guidewire. (D) Biliary sphincterotomy is performed.

Figure 21 Alternative rendezvous technique for access to the papilla. (A) The percutaneous guidewire is recovered using a diathermy loop. (B) The guide catheter is mounted on the guidewire in the bile duct. (C) The stent is pushed through the stenosis. (D) Withdrawal of the guidewire before withdrawal of the catheters. (E) Stent in the hepatic parenchyma to be repositioned.

Warning!!

It is very important to work closely with radiology. Large catheters should not be removed without prior discussion with radiology, as these can cause bile to leak into the peritoneum.

Clinical tips for patients with a PTC

• If the sphincterotome is being advanced over the wire, a long wire (>450 cm) is required as it will need to pass from the liver, through the duodenoscope.

• Always manipulate the catheter/wire gently as liver laceration can occur.

• Some of the PTC catheters have a fixed pigtail to maintain their position in the duodenum. This must be either released or cut prior to removing the catheter or liver laceration can occur.

• It is advisable to insert a regular guidewire through the PTC catheter prior to manipulating it to minimize the risk of laceration.

PTC, percutaneous transhepatic cholangiogram.

9 Successful cannulation rate

Cannulation of the papilla is successful in 95–98% of cases when performed by an experienced endoscopist. The pancreatic ducts are opacified on average in 90–95% of cases and the bile ducts in 85–90%. Failures are due to duodenal stenosis, a papillary lesion, or the intradiverticular location of the papilla.

In patients with altered anatomy, success rates depend on the type of surgery. Patients with a pyloroplasty, Billroth I, or choledochoduodenal anastomosis, have a similar success rate to normal ERCP. Patients with a Roux-en-Y have lower success rates of between 60% and 75%, provided the afferent loop is not too long or located transmesocolically.

10 ERCP in children

ERCP in children should be undertaken under general anesthesia. A diagnostic side-viewing duodenoscope may be used from the age of 1 year upwards. A therapeutic duodenoscope can be used in children over 5 foot. A 7.5 mm diameter duodenoscope with a 2.0 mm operating channel is available for use in children under the age of 1. There are few indications: bile duct stones, jaundice due to bile duct malformation, recurrent pancreatitis, pancreatic trauma, bile stones.

10.7 Cytology, biopsies, and biochemical analysis

Summary

1. Cytology 391

2. Biopsies 391

3. Brushing 391

4. Biochemical examination of bile and pancreatic juice 391

Key Points

• Cytological analysis of bile and pancreatic juice have a sensitivity of between 35% and 70% and specificity of >90% for the diagnosis of cancer.

• Biopsies of the major papilla should be taken in all patients suspected of having autoimmune pancreatitis.

• Transpapillary biopsies can be performed following biliary sphincterotomy and have a similar sensitivity and specificity as cytology.

• The type of tumor and the number of passes made with a brush affect the sensitivity. Multiple passes should be made in a patient with a suspicious lesion.

1 Cytology

The cytological study of the bile or pancreatic juice can help to diagnose cancer of the bile ducts or pancreas and has a sensitivity of between 35% and 70%, with a specificity of >90%. Fluid can be collected by selective catheterization, or by collection of duodenal aspiration either after irrigation with saline or following stimulation with either CCK or secretin. Stents inserted into potentially neoplastic stricture should also be sent for cytological analysis.

2 Biopsies

Endoscopic transpapillary biopsies of a localized lesion or stenosis of the biliary or pancreatic ducts are more difficult, with a sensitivity of between 43% and 88% and a specificity of >90%. It is particularly difficult to introduce biopsy forceps through an intact papilla and to position them correctly within the lesion. Biopsies of the major papilla should be taken in patients who are suspected of having autoimmune pancreatitis.

3 Brushing

The sensitivity of endoscopic transpapillary brush cytology is dependent on the type of tumor, as well as the number of passes made with the brush. Thus, it is important to brush multiple times, and to repeat brushing if the patient returns for repeat ERCP. Tumors which compress the bile duct (i.e. pancreatic) have a lower sensitivity than primary biliary cancer. If a pancreatic neoplasm is suspected, endoscopic ultrasound should be considered as the initial procedure of choice to obtain tissue.

A new technique, inserting a guidewire through a stricture and collecting juice above the stricture, has a high sensitivity (93%) and specificity (100%) in a single study. Further studies are required to confirm these promising results.

4 Biochemical examination of bile and pancreatic juice

4.1 Collection of bile juice

The biochemical study of bile should be carried out before contrast is injected. Optimal collection requires deep biliary cannulation with a catheter with three lateral holes in its tip. The collection of pure bile samples is indicated in three circumstances:

• Severe cholangitis: Samples should be sent for culture and antibiotic sensitivity test

• Testing for lithogenic bile: Calcium bilirubinate crystals, bile pigments and cholesterol (Fig. 1) can be seen. This is used if microlithiasis is suspected in patients who have pancreatic or biliary clinical symptoms, and can be treated with ursodeoxycholic acid

• Pharmacokinetic study of drugs eliminated via the bile in relation to hepatobiliary disease.

Figure 1 Crystallography of bile. (A) Calcium bilirubinate crystals. (B) Bile pigments. (C) Cholesterol crystals (translucent, larger) and calcium bilirubinate crystals (yellow and brown) obtained by bile sampling.

4.2 Collection of pancreatic juice

Pure pancreatic juice can be collected for analysis of molecular markers as part of a research study. Pancreatic juice can also be collected after stimulation with secretin.

10.8 Pancreaticobiliary anatomy

Summary

1. Normal and variant biliary anatomy 393

2. Post-surgical anatomy 398

Key Points

• Understanding normal, variant and post-surgical pancreaticobiliary anatomy is essential.

• The Couinaud classification divides the liver into eight functionally independent segments.

• The most common variation of biliary anatomy is where the right posterior hepatic duct drains into the left hepatic duct, prior to its confluence with the right anterior hepatic duct.

• In patients undergoing laparoscopic cholecystectomy, surgeons should be informed of altered cystic duct anatomy.

• Pancreas divisum is the embryonic anomaly most commonly found in adults (5% of ERCP), characterized by the failure of the ventral and dorsal pancreatic ducts to fuse.

1 Normal and variant biliary anatomy

The Couinaud classification gives eight functionally independent segments, numbered I through VIII (Fig. 1). The segments are numbered in a clockwise manner starting with the caudate lobe (segment I). Each segment has its own vascular inflow, outflow, and biliary drainage. In the center of each segment there is a branch of the portal vein, hepatic artery, and bile duct. In the periphery of each segment, there is vascular outflow through the hepatic veins. The liver is divided by vascular structures. The right hepatic vein divides the right lobe into anterior and posterior segments. The middle hepatic vein divides the liver into right and left lobes, while the left hepatic vein divides the left lobe into medial and lateral parts. The portal vein divides the liver into upper and lower segments.

Figure 1 Normal segmental anatomy of the liver. This drawing shows normal biliary segmental anatomy, which is observed in 56% of individuals.

The biliary drainage runs in parallel to the portal venous supply. The right hepatic duct drains the segments of the right liver (V–VIII), with the right posterior duct draining the posterior segment (VI and VII), and the right anterior duct draining the anterior segments (V, VIII). The right posterior duct has an almost horizontal course, while the right anterior duct tends to have a more vertical course. The left hepatic duct is formed from tributaries draining segments II–IV. The common hepatic duct is formed by fusion of the right and left hepatic ducts. The duct draining the caudate lobe (I) usually joins the origin of the right or left hepatic duct. The cyst duct usually joins the common hepatic duct below the confluence of the right and left hepatic ducts (Fig. 2).

Figure 2 Extrahepatic biliary tree.

There are variations of this classic anatomy. The most common variant, which is present in up to 19% of the population, is where the right posterior duct drains into the left hepatic duct before its confluence with the right anterior duct (Fig. 3D). Another common variant, occurring in 12% of individuals, is where the right posterior duct empties into the right aspect of the right anterior duct. Another common variant is where the right anterior, posterior, and left hepatic ducts drain simultaneously into the common hepatic duct (Fig. 3A). In these individuals, the right hepatic duct is virtually non-existent.

Figure 3 Hepatic duct variation. Variant anatomy most commonly affects the right hepatic duct. (A) The right posterior (RP), right anterior (RA) and left hepatic duct (LHD) insert together. This occurs in 12% of individuals. (B) Segments II, III and IV join the right anterior and posterior ducts in 3% of people. (C) This is the most common anatomical variation, occurring in 16% of individuals, where the right anterior hepatic duct (RA) drains into the left hepatic duct (LHD), prior to its confluence with the right posterior hepatic duct (RP). Other variations include insertion of the left hepatic duct into the right posterior hepatic duct, prior to insertion of the right anterior hepatic duct (4%) (D); insertion of the right anterior hepatic duct into the left hepatic duct followed by a confluence with the right posterior hepatic duct (5%) (E); insertion of the right posterior hepatic duct into the left hepatic duct which then joins the right anterior hepatic duct (1%) (F); and (G) confluence of the left hepatic duct with the right posterior hepatic duct which then join the right anterior hepatic duct (1–2%).

Note

ERCP images can only be interpreted with the patient in dorsal decubitus position.

The cystic duct termination exhibits a number of variants. A common variation is where there is a low insertion of the cystic duct into the distal third of the common bile duct (9%) (Fig. 4). Another variation is where the cystic duct drains into the left side of the common hepatic duct.

Figure 4 Variations in cystic ductal anatomy. The cystic duct termination exhibits a number of variants. A common variation is where there is a low insertion of the cystic duct into the distal third of the common bile duct (9%) (C). Another variation is where the cystic duct drains into the left side of the common hepatic duct (D).

The common bile duct terminates at the ampulla of Vater, where it joins the main pancreatic duct (Wirsung’s duct) (Fig. 5). There are a number of variations in the communication between the common bile duct and Wirsung’s duct. It is important to be familiar with these variations when cannulating the papilla (Fig. 6). In the majority of cases (98%), the papilla has a single orifice (type I). The biliary duct and the pancreatic duct may have separate openings in the papilla (type II) (Fig. 7) or openings at different points in the duodenum (type III). There are two types of common opening (or common channel):

• Type 1a corresponds to a long common channel with extraduodenal confluence of the two channels (Fig. 8).

• Type 1b corresponds to a common channel confined to the mucosa and to the duodenal submucosa.

Figure 5 Ampulla of Vater with junction of the common bile duct and Wirsung’s duct. (1) Common sphincter. (2) Choledochic sphincter. (3) Wirsung’s duct sphincter.

Figure 6 Variations in the communication between the common bile duct and Wirsung’s duct. Type 1a has a long common bile duct (>1 cm) with one orifice. Type 1b has a short common bile duct with one orifice. Type 2 has a separate orifice for the bile and pancreatic ducts. Type 3 has separate orifices for the bile and pancreatic ducts at different points in the duodenum.

Figure 7 Type II opening with separate pancreatic (black arrow) and bile ducts.

Figure 8 Type 1a common channel. These images illustrate a type 1a, with a long common channel (arrow).

When the common channel is >15 mm long, the frequency of congenital anomalies of the bile ducts (choledochal cyst, Caroli disease) and cholangiocarcinoma is believed to be higher.

The arterial supply of the papilla exhibits numerous anatomical variations, which are determined by the retroduodenal artery and the branch of the upper pancreaticoduodenal artery. Significant bleeding can occur depending on the configuration of the blood vessels at the papilla (Fig. 9).

Figure 9 Arterial supply of the papilla. (A) This configuration is associated with a low hemorrhagic risk with sphincterotomy. (B) This configuration is associated with increased risk of bleeding due to a low arterial trunk which can be cut during sphincterotomy.

1.1 Normal pancreas and its variants

The main pancreatic duct rises steeply in the head, then crosses the upper abdomen horizontally or in a slightly ascending manner (Fig. 10). In healthy individuals, the shape of the pancreatic duct is variable, and diagnostic conclusions cannot be based on shape alone. Loops (ansa loops) may be observed, particularly in the isthmus (Fig. 11). The diameter of the pancreatic duct is on average 4 mm in the head of the pancreas, 3 mm in the body and 2 mm in the tail. The duct of Santorini usually connects the pancreatic duct to the accessory papilla. Collateral branches open perpendicular to the axis of the pancreatic duct. Their normal diameter should not exceed 1 mm. The diameter of the pancreatic duct increases with age. The aging of the pancreas is accompanied by irregularities in ductal diameter and may make differential diagnosis with incipient chronic calcifying pancreatitis difficult.

Figure 10 Normal pancreatic ductal anatomy. (1) Duct of Wirsung or pancreatic duct. (2) Duct of Santorini. (3) Secondary ducts. (4) Parenchyma.

Figure 11 Ansa pancreatica loop. A wire is in the pancreatic duct. Note where the tip of the sphincterotome is (arrow) there is an alfa loop consistent with ansa pancreatica but the wire is in the direction of the common bile duct. Ensure careful injection.

1.2 Congenital anomalies of the pancreatic ducts

Annular pancreas is characterized by a ring of pancreatic tissue surrounding the descending portion of the duodenum. It is thought to be due to incomplete rotation of the pancreatic ventral bud. It is a rare anomaly in adults (0.1% of ERCP).

Pancreas divisum (Fig. 12) is the embryonic anomaly most commonly found in adults (5% of ERCP), characterized by the failure of the ventral and dorsal pancreatic ducts to fuse. A definite diagnosis can be obtained only by cannulation of the major papilla and the accessory (minor) papilla.

Figure 12 Normal pancreatogram and pancreas divisum. (A) Normal pancreatogram. (B) Ventral duct (pancreas divisum). (C) Dorsal duct (pancreas divisum).

Cannulation of the major papilla opacifies the ventral pancreas (Fig. 12B). The ventral duct is short with a small diameter. The length varies from a few millimetres to 5 or 7 cm. If the duct is very short, injection of contrast medium results very quickly in acinarization, which must not be confused with a submucosal injection. If the duct measures 3 or 4 cm, complete occlusion of the head of the pancreas by cancer must be excluded. Opacification of the dorsal pancreas (Fig. 12C) should be performed to confirm the diagnosis of pancreas divisum if the ventral pancreas is completely atrophic and invisible after catheterization of the major papilla. Opacification also allows visualization of lesions in the dorsal pancreas. Incomplete forms of pancreas divisum exist (Fig. 13).

Figure 13 Variations in pancreatic anatomy.

2 Post-surgical anatomy

It is important to understand post surgical anatomy (see also Ch. 10.6), as it is encountered frequently due to the increase in obesity and gastric bypass surgery. Gastroduodenal anastomoses (Fig. 14) and certain types of choledochoduodenal anastomoses (Fig. 15) can usually be reached with a duodenoscope. The papilla is more difficult to reach in patients with Roux-en-Y anatomy (Fig. 16). A pediatric colonoscope, enteroscope or double/single balloon or spiral enteroscopy may be required to reach the papilla. The main problem in these patients is the length of small bowel that has to be traversed. The shortest distance is encountered with a Billroth II (Fig. 17), with the longest distance typically associated with Roux-en-Y, associated with gastric bypass. Whether the limb has been placed antero- or retrocolic can also affect the ability to reach the papilla (Fig. 18). Retrocolic is associated with acute turns which can be difficult to negotiate but it’s a short way to find papilla. Anterocolic is a long way to reach papilla.

Figure 14 Gastroduodenal anastomoses. (A,B) represent two different types of gastroduodenal anastomoses. A Pean (A) anastomosis is commonly found in Europe, while a Billroth I is seen more frequently in the USA (B). These types of surgery were often performed for treatment of peptic ulcer disease and are seen less frequently now due to eradication of H. pylori and use of proton pump inhibitors.

Figure 15 Choledochoduodenal anastomoses. (A) Side-to-side choledochoduodenal anastomosis. (B) End to side choledochoduodenal anastomosis. (C) Choledochojejeunal anastomosis with Roux-en-Y anastomosis.

Figure 16 Roux-en-Y. This is the classic Roux-en-Y configuration found in patients with Billroth II, Finsterer and Polya anatomy. Note that the Roux limb can be either antero- or retrocolic (as found in this figure). Retrocolic Roux limbs have greater angulation and can be more difficult to traverse.

Figure 17 Gastrojejunal anastomoses. These figures represent different types of gastrojejunal anastomoses. (A) Polya is found more commonly in Europe, while a Billroth II (B) is performed commonly in the UK and USA for patients with pancreatic cancer in the head. (C,D) represent a classic and an isoperistaltic Finsterer gastrojejunostomy. Note that the Roux limbs are labelled A and E. A represents the afferent limb, which contains the papilla or choledochoenterostomy. E is the efferent limb which leads to the remaining small bowel. It is very important to check what limb you are in. This is usually done by looking for bile (afferent limb) and by using fluoroscopy to check your position. The endoscope should be going in the direction of the right upper quadrant. If you are not, you may be in the efferent limb.

Figure 18 Roux limbs. In (A) the Roux limbs have been arranged in a classic omega pattern with a side-to-side anastomosis. The omega loop and retrocolic position make it difficult to reach the papilla. The configuration in (B) is better, as there is a relatively straight path to the papilla. (C) Demonstrates enterocolic Roux limb. Patients with this type of anatomy have less angulation of the bowel, compared with retro-colic Roux-limbs; however, the distance to the papilla is greater, which can make accessing the papilla challenging.

Box 1

Problematic surgical anatomy

• Partial gastrectomy with Billroth II gastrojejunostomy.

• Whipple resection with Roux-en-Y limb of jejunum anastomosed to the biliary and pancreatic ducts.

• Pylorus preserving Whipple resection with Roux limb of jejunum anastomosed to the duodenal cap.

• Gastrojejunal bypass for obesity with a Roux limb of jejunum anastomosed to a small gastric pouch.

• Resection of the bile duct with anastomosis of the common hepatic duct (choledochojejunostomy) or hilum (hepatico-jejunostomy) to a Roux-en-Y limb of jejunum.

• Biliary diversion procedure with a Roux limb of jejunum draining the gastric remnant after partial gastrectomy.

• Total gastrectomy with anastomosis of the esophagus to a Roux limb of jejunum.

From Haber GB. Double balloon endoscopy for pancreatic and biliary access in altered anatomy (with videos). Gastrointest Endosc 66(3 Suppl):S47–S50, 2007.

10.9 ERCP imaging technique

Summary

Introduction 400

1. Dilute or full strength contrast media? 400

2. How much contrast should be injected? 400

3. When and how many X-ray images should be taken? 400

4. Diagnostic problems and interpretation errors 400

Key Points

• It is essential that the highest quality radiographic images are obtained during ERCP.

• Full strength contrast is usually used, unless pancreatic or biliary stones are suspected.

• Images should be taken from different views to clearly define any abnormal area.

• Bubbles can be distinguished from stones by placing the patient in the reverse Trendelenburg position.

Introduction

It is very important that high quality radiographic images are obtained. The type of contrast used, the amount injected, and how to obtain good radiographic views are discussed below.

1 Dilute or full strength contrast media?

Contrast media can be used undiluted (300 mg iodine/mL), or diluted to 50%. In most cases, undiluted contrast is usually used. This provides excellent visualization of neoplastic stenoses or diseases of the small bile or pancreatic ducts. Diluted contrast is often used where biliary or pancreatic stones are suspected, as stones are often not seen if full strength contrast is used.

2 How much contrast should be injected?

Continue injecting until the intrahepatic bile ducts or the small pancreatic ducts are visible. Do not overfill the gallbladder (due to the risk of cholecystitis) or secondary pancreatic ducts (due to the risk of pancreatitis). Usually 3–5 mL of contrast medium is sufficient to opacify the pancreatic ducts, while 15–20 mL is required for the bile ducts. In patients who have a sphincterotomy, a balloon catheter may be required to allow adequate opacification of the ducts.

3 When and how many X-ray images should be taken?

X-rays should be taken at different stages. An image should be taken before injection and passing the endoscope, as well as in different stages of opacification (as you start injecting, once injection is completed and while contrast is emptying from the ducts). Images taken from different views (left lateral decubitus, dorsal decubitus with slight rotation to the right) can be used to clearly define abnormal areas, and to identify normal structures such as the cystic duct take off. An image of contrast emptying from the bile duct is taken after the duodenoscope has been removed. An image is often taken in the supine position after removing the duodenoscope to exclude perforation for medicolegal reasons. The pancreatic duct, however, empties quickly and images must be taken during the injection of the contrast medium.

4 Diagnostic problems and interpretation errors

Interpreting cholangiographic and pancreatographic images sometimes raises difficult problems, which should be borne in mind.

4.1 Stones or bubbles?

A filling defect corresponds in the majority of cases to a stone; however, occasionally it may be due to parasites (gallbladder with hydatid cyst, Ascaris, flukes), benign or malignant tumor fragments, hemobilia, or even air bubbles. To differentiate air bubbles from stones, tilt the table in such a way that the patient’s head is elevated (reverse Trendelenburg position). This will cause air bubbles to rise and stones to fall (Fig. 1).

Figure 1 Diagnostic dilemmas and interpretation errors. (A,B) Differentiation of a stone versus an air bubble. (A) A possible stone is present in the common bile duct. A stone generally rises towards the intrahepatic bile ducts with a patient prone. (B) Air bubbles do not usually rise. (C) Adenoma arising in the common bile duct appears as a fixed, non-moving object. (D) Hemobilia. (E,F) False underfilling: stone occluding the lower common bile duct (complete filling necessary before drawing conclusions).

Errors of interpretation can be reduced by some simple principles:

• Use contrast medium diluted to 75% if stones are suspected.

• Use undiluted contrast medium if a tumor is suspected (dense bile due to stasis prevents accurate assessment of the limit of the tumor).

• Catheterization of the bile and pancreatic ducts must be selective and deep to achieve correct opacification which is the key to the correct interpretation of the images.

• In the left lateral decubitus and ventral position, air bubbles remain in the lower common bile duct, while stones rise to the hilum. In the dorsal decubitus position, the opposite occurs.

• A close examination of all the images, including those taken in the dorsal decubitus position, is essential. This allows the following to be confirmed:

Correct drainage of the bile and pancreatic ducts

Opacification of the left intrahepatic bile ducts

A stone pushed by the injection into the intrahepatic bile ducts which has re-descended with the patient in dorsal decubitus.

• The catheter can be connected to a pump which injects contrast. This should be purged correctly with a constant drop-wise injection system to reduce the risk of injecting bubbles. A stone located in the papilla or in the bile duct may simulate the image of a tumor, by its immobility.

• A stone located in the papilla may not be identified and present a misleading tapered aspect. Images taken during emptying show the normal lower common bile duct with a tapered appearance varying over time, related to the alternate contraction and relaxation of the sphincter of Oddi. A stone or a tumor yields a fixed image.

• A normal dilated bile duct, without visible stones, does not automatically rule out the possibility of stones. Microlithiasis may be present, the stone may be hidden in contrast medium, or the stone may have migrated since the clinical event.

• An image in which contrast does not appear to fill beyond the bile duct may correspond to obstruction by a tumor or a false image due to incomplete opacification. This is also true for the left intrahepatic bile ducts, which fill only in excess pressure or in images taken with the patient in dorsal decubitus.

• The benign or malignant nature of a biliary stenosis is sometimes difficult to determine from the radiological appearance alone.

• Obstruction of the intrapancreatic bile duct may correspond to cancer of the pancreas or of the common bile duct.

• Dilation of the bile duct does not always correspond to sphincter of Oddi stenosis, particularly in elderly or cholecystectomized individuals.

• Cancer in the region of the ampulla of Vater infiltrating the ampulla is not endoscopically visible and may appear as irregular stricture of the lower common bile duct during opacification.

• Minor anomalies during pancreatography are difficult to interpret. They may correspond to incipient chronic pancreatitis or to a normal pancreas, particularly in the elderly.

• Compression of bile duct by the gallbladder may be secondary to cholecystitis, a stone impacted in the cystic duct or a tumor lesion (gallbladder cancer).

• Incomplete stenosis of the pancreatic duct may correspond to cancer or to pancreatitis.

• Complete stenosis of the pancreatic duct may be due to cancer, pancreatitis or to a technical fault (injection of air bubbles or incomplete opacification which must not be confused with pancreas divisum).

• Normal pancreatography does not rule out incipient chronic pancreatitis or cancer of the peripheral pancreas.

• Incorrectly filled intrahepatic bile ducts should be distinguished from sclerosing cholangitis.

Most of these diagnostic problems can be resolved by correct catheterization technique, rigorous analysis of the radiological images and precise knowledge of the limits of ERCP.

10.10 Abnormal imaging: classification and etiology

Summary

1. Cystic dilation of the bile duct 403

2. Cholangiocarcinoma 403

3. Gallbladder cancer 406

4. Primary sclerosing cholangitis 406

5. Other causes of biliary dilation 406

6. Intrahepatic cholestasis 406

7. Chronic pancreatitis 407

8. Pancreatic tumors 408

Key Points

• A knowledge of abnormal imaging is essential for anyone undertaking ERCP.

• Hilar cholangiocarcinoma is classified into four types depending on its extent into the intrahepatic biliary tree.

• Gallbladder cancer can present with Mirizzi’s syndrome.

• Alternating stricturing and dilation is classic for primary sclerosing cholangitis.

1 Cystic dilation of the bile duct

Congenital cysts of the bile duct are rare. They are classified depending on their location in the biliary tree (Table 1, Figs 1–4). They can be associated with jaundice, abdominal discomfort, cholelithiasis, cholangitis, hepatic abscesses, recurrent pancreatitis, cirrhosis, portal hypertension, portal vein thrombosis, and are associated with an increased risk of cholangiocarcinoma.

Table 1 Classification of congenital bile duct cysts (Todani classification)

Type of cyst	Definition	Comment
I	Dilatation of the entire common hepatic or common bile duct or segments of each	Account for 80–90% of cysts. Treatment of choice is excision of the cyst and Roux-en-Y biliary-enteric anastomosis.
II	Diverticulum in the CBD	Surgical excision and primary closure over a T-tube.
III (choledochocele)	There is a dilatation of the intraduodenal portion of the CBD (Figs 2, 3)	<3 cm in diameter treat with sphincterotomy. ≥3 cm requires surgery.
IVa	Multiple dilatations of the intra- and extrahepatic biliary tree (Fig. 4)	Excision of the cyst and Roux-en-Y biliary-enteric anastomosis. No specific treatment of intrahepatic cysts. If disease is limited to specific intrahepatic segment these can be considered for surgical resection.
IVb	Multiple dilatations of the extrahepatic biliary tree
V (Caroli disease)	Single or multiple intrahepatic cysts	If disease is limited to a single hepatic lobe, surgical resection can be considered. Transplantation can be considered in patients with decompensated cirrhosis.

Figure 1 Classification of congenital bile duct cysts (Todani classification). Type I: Dilation of the entire common hepatic or common bile duct or segments of each. Type II: CBD diverticulum. Type III: Dilation of the intraduodenal portion of the CBD. Type IV: Dilation of the intra and extrahepatic biliary tree (Type IVa). Type IVb demonstrates dilation of the extrahepatic biliary tree alone. Type V: Single or multiple intrahepatic cysts.

Figure 2 (A,B) Type III cyst (choledochocele). Note the dilatation of the intraduodenal portion of the CBD (arrow).

Figure 3 Type III cyst (choledochocele). (A) Appearance of the second duodenum. (B) Incision of the choledochocele. (C) Opening with a sphincterotome. (D) Appearance after opening with a sphincterotome.

Figure 4 Type IVa cyst. This image demonstrates cystic dilation of the common bile duct and intrahepatic bile ducts

2 Cholangiocarcinoma

Cholangiocarcinoma can be classified into three types based on its radiographic appearance (Fig. 5):

• Type I: complete stenosis (Fig. 6)

• Type II: incomplete stenosis (Fig. 7)

• Type III: filling defect.

Figure 5 Cholangiocarcinoma. Cholangiocarcinoma can be classified based on its radiographic appearance: Type I, complete stenosis of the bile duct; Type II, incomplete stenosis and Type III, filling defect is present.

Figure 6 Type I cholangiocarcinoma. Note the complete obstruction of the bile duct.

Figure 7 Type II cholangiocarcinoma. Note the irregular stenosis (arrow) with upstream dilation of the biliary tree.

In Type I, there is complete obstruction of the bile duct. In Type II, there is a stenosis of variable length with smooth or irregular contours with upstream dilation of the biliary tree. This is the most common type. Type III presents as a filling defect or as a fixed sessile or pedunculated lesion arising from the wall. This appearance may be confused with a stone; however, unlike a stone the tumor is immobile.

3 Gallbladder cancer

Gallbladder cancer can also be classified based on its radiographic appearance into types I–IV (Fig. 9). It is rare to find an irregular filling defect in the gallbladder without alteration of the common bile duct (Types I and II). Gallbladder cancer can present with Mirizzi’s syndrome (Type III). This radiographic appearance can also be due to cholecystitis, a stone impacted in the cystic duct or hepatic metastasis.

Figure 9 Classification of gallbladder cancers.

4 Primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) causes diffuse strictures of the common bile duct and intrahepatic bile ducts. Alternating stenosis and dilation is characteristic. It is important to emphasize the difficulty of diagnosing diffuse bile duct cancer in this group of patients, thus, the importance of histological and cytological samples. Strictures of the pancreatic duct are rarer in PSC, occurring in 8% of patients, while cystic duct involvement occurs in 18%. PSC can be classified into four intrahepatic and four extrahepatic types depending on the radiographic features (Fig. 10).

Figure 10 Radiographic classification of primary sclerosing cholangitis.

4.1 Intrahepatic radiographic changes in PSC

• Type 1: There is slight irregularity of ductal contour, localized stricture, no post-stenotic dilation. These features are often found at the bifurcation.

• Type 2: There is diffuse filiform stricture, alternating with moderate interstenotic dilations or with a normal ductal diameter. The strictures are predominant at the bifurcation, with reduced arborization.

• Type 3: There is complete occlusion of the peripheral ducts with multiple cystic, fusiform, sac-like dilations of the central ducts; there are strictures between dilations giving a string-of-pearls appearance.

• Type 4: There is diffuse ductal occlusion with stenoses of the remaining ducts; only the central ducts are filled with contrast medium. Large spaces are empty of any ducts.

4.2 Extrahepatic radiographic changes in PSC

• Type 1: There are moderate irregularities of the contours with no segmental or total stenosis without distinct strictures.

• Type 2: There is segmental stenosis of the common bile duct with irregular or regular edges, sparing part of the duct.

• Type 3: There is diffuse stricture with a string-of-pearls appearance along its length.

• Type 4: This has very irregular edges with alternating strictures and dilations, giving the appearance of a pseudodiverticulum.

5 Other causes of biliary dilation

• Sphincter of Oddi (see also Ch. 10.18) dysfunction (SOD) can be associated with a stricture of the sphincter, with diffuse dilation of the bile duct and pancreatic duct

• Postoperative stenoses (following cholecystectomy, liver transplantation, sphincterotomy) yield images of complete or incomplete stenosis which are short, and may be associated with stones. The bile duct are not diluted upstream of the obstacle (at an early stage).

• AIDS-related cholangiopathy.

6 Intrahepatic cholestasis

A diagnosis of intrahepatic cholestasis is made by demonstrating normal opacification of the whole bile duct with no filling defects, in particular by good filling of the intrahepatic bile ducts. Only deep, selective catheterization can yield complete images of the intrahepatic bile ducts.

7 Chronic pancreatitis

7.1 Pancreatographic alterations

The main duct is often normal initially, with a few collateral branches demonstrating localized dilation. CT, functional and pancreatic tests are usually normal at this stage. Endoscopic ultrasound may show changes within the parenchyma before any ductal changes appear. The diagnosis of chronic pancreatitis in the advanced form is rarely difficult: the main duct is dilated, tortuous and with defects (stones and protein deposits), stenosis and areas where the duct is disrupted. ERCP is useful in managing the complications of chronic pancreatitis. Chronic pancreatitis is usually graded using the Cambridge criteria (Table 2). Other classification systems used include the Kasugai classification (Box 1), and Crémer’s classification (Fig. 11).

Table 2 Cambridge criteria for grading chronic pancreatitis

Grade	Main pancreatic duct	Side branches
Normal	Normal	Normal
Equivocal	Normal	>3 abnormal
Mild	Normal	>3 abnormal
Moderate	Abnormal	>3 abnormal
Severe	Abnormal with at least one of the following:	>3 abnormal
	Large cavity (>10 mm)
	Duct obstruction
	Intraductal filling defects
	Severe dilation or irregularity

Figure 11 Crémer’s classification of chronic calcifying pancreatitis.

Box 1 Kasugai’s classification of chronic pancreatitis

Kasugai’s classification distinguishes between three forms of the disease:

• Minor forms: a few collateral branches are abnormal and the pancreatic duct is normal

• Moderate forms: in addition to the above lesions, there are images of pancreatic duct irregularities

• Major forms: stenosis of the pancreatic duct, with pancreatic stones, pseudocysts, and common bile duct stenosis.

7.1.1 Crémer’s classification

• Type 0: The pancreatic duct is normal and a few secondary ducts are abnormal. This form is difficult to distinguish from age-related changes in the ducts

• Type I or minor pancreatitis: This is divided into two subtypes. Type IA where the pancreatic duct has irregular contours and a few secondary ducts are altered or dilated; type IB where all the secondary ducts are abnormal

• Type II or focal pancreatitis: This predominantly affects the head or the tail with macrocystic dilation of one or more secondary ducts. The morphology of the ducts in unaffected segments is normal

• Type III or diffuse pancreatitis: The pancreatic duct shows one or more stenoses (IIIB or IIIA) without marked dilation upstream. The secondary ducts are always abnormal

• Type IV or cephalic pancreatitis: The pancreatic head shows segmental stenosis with dilation upstream of all the ducts. This type can be seen in cancers

• Type V or pancreatitis with cephalic filling limit: The contrast medium does not fill the cephalic segment of the pancreatic duct. This image suggests cancer of the head of the pancreas.

Chronic pancreatitis can also affect the bile duct (Figs 12, 13). This can be classified into types I–IV depending on the radiographic appearance.

• Type I is the commonest alteration of the bile duct. There is an elongated, regular stenosis of the retropancreatic path of the common bile duct with or without dilation upstream and a gaping papilla.

• Type II corresponds to a stricture at the sphincter of Oddi with dilation upstream.

• Type III corresponds to an hourglass-shaped stenosis at the upper edge of the pancreas.

• Type IV, which may also be seen in pancreatic cancer, corresponds to localized lateral or anteroposterior compression of the intrapancreatic common bile duct (Type IVb).

Figure 12 The cholangiographic appearance of the pancreatic pathology can be classified into Types I–V (Caroli–Sarles classification).

Figure 13 Changes in the bile duct and chronic pancreatitis. (A) Type I has an elongated stenosis. (B) Type II presents as a stricture at the sphincter of Oddi. (C) Type III has a stricture with an hour-glass appearance. (D) Type IVa there is compression by a pancreatic pseudocyst.

8 Pancreatic tumors

The image of both biliary and pancreatic stenosis is characteristic of pancreatic cancer. In typical cases, stenosis is present in the upper part of the intrapancreatic common bile duct with the same image shown in the cephalic pancreatic duct. The pancreatic ductal changes are shown in Figure 15 and can be classified as shown below. Types I and II are the most frequent. The other forms of pancreatic cancer are far less common.

• Type I: There is complete stenosis of the pancreatic duct, with irregular, tapering stricture, or cystic dilation indicative of tumor necrosis.

• Type II: There is localized stenosis of the pancreatic duct with dilation of the ducts upstream.

• Type III: Infiltrating form. There is diffuse infiltration form, with a narrow, irregular pancreatic duct.

• Type IV: There are changes in the secondary ducts which show amputation, stenosis and dilation. The pancreatic duct is normal.

• Type V: There is dilation of the pancreatic duct and one or more branches, which contain radiotransparent filling defects which correspond to mucoid masses. This type is characteristic of adenomatous tumors of the pancreatic duct.

Figure 15 Radiographic changes of the pancreatic duct associated with pancreatic cancer.

The bile duct can also be affected by pancreatic cancer. The radiographic appearances are discussed below, with stenotic and obstructive types being the commonest seen.

• Stenotic type: There is incomplete stenosis in the upper part of the head of the pancreas, away from the papilla, with marked dilation and horizontalization of the common bile duct, which is engulfed by the tumor. This appearance is characteristic of cancer of the head of the pancreas (Type V of the Caroli–Sarles classification) (Figs 12, 14).

• Obstructive type: This involves complete stenosis of the common bile duct in the upper part of the head of the pancreas.

• Angular type: The bile duct is engulfed in the upper edge of the pancreas and shows angulation with rigid walls without proximal dilation (Type IVb of the Caroli–Sarles classification) (Fig. 12).

Figure 14 Type V, cholangiographic appearance of pancreatic cancer.

Figure 16 Appearance of the papilla in a patient with IPMN. The presence of mucin in the papilla is classic for IPMN.

Further Reading

Cremer M, Toussain J, Hermanu A, Deltenre M, de Toeuf J, Engelholm L. Les pancréatites chroniques primitives. Classification sur base de la pancreatographie endoscopique Acta, Gastroenterol Belg. 1976;39:522-546.

Liguory CI, Canard JM. Tumors of the biliary system. Clinics in Gastroenteroly. 1983;12(1):265-291.

Sarles H, Sarles JC, Guien C. Study of pancreatic and bile ducts in chronic pancreatitis. Arch Mal App Dig. 1958;47:664-683.

Ohto M, Ono T, Tsuchiya Y, Saisho H. Cholangiography and pancreatography. Tokyo New York: Ed. Igaku-Shoïn; 1978. pp 155-159

10.11 Endoscopic sphincterotomy

Summary

Introduction 410

1. Indications 410

2. Biliary sphincterotomy technique 410

3. Pancreatic sphincterotomy technique 410

4. Special situations 414

5. Sphincterotomy in difficult cases 415

6. Endoscopic balloon dilation of the Sphincter of Oddi 418

Key Points

• The biliary orifice should be cut between the 11 o’clock and 12 o’clock position.

• The pancreatic orifice should be cut between the 1 o’clock and 3 o’clock position.

• The minor papilla is cut in from the 5 o’clock to 11 o’clock direction.

• Pre-cut sphincterotomy and fistulotomy should only be performed by an experienced endoscopist.

• Complications of sphincterotomy include perforation, bleeding, and pancreatitis.

Introduction

Endoscopic sphincterotomy is commonly performed as part of the treatment of biliary and pancreatic diseases. The success and complication rate depend not only on having appropriate equipment, but also on the experience and frequency with which the endoscopist performs sphincterotomies.

2 Biliary sphincterotomy technique

2.1 Standard technique

The standard technique was developed by Classen and Demling and consists of five steps:

1. The bile duct is cannulated deeply (Figs 1A, 2A)

2. Confirm that the sphincterotome is in the correct duct:

• Contrast is injected to confirm that the correct duct has been cannulated and to confirm the diagnosis. It is important to look for and confirm the presence of stones, even if they have been demonstrated on recent imaging, as they may have passed spontaneously.

3. Place the sphincterotome in the cutting position:

• This is achieved by withdrawing the sphincterotome until approximately half of the metal wire appears outside the papilla (Figs 1B, 2A). The wire should be positioned in the direction of the bile duct between 11 and 12 o’clock (Figs 1C, 2B).

4. Sphincterotomy

• The sphincterotome is connected to the electrocautery unit. This should be done just before the endoscopist is ready to perform the sphincterotomy to avoid accidentally cutting the bile duct with the sphincterotome.

• The papilla is cut using endo-cut mode. Cutting is carried out in a stepwise fashion.

5. Radiographic images

• Images should be taken in the ventral and dorsal decubitus position. If sphincterotomy has been performed correctly, the bile duct drains completely into the duodenum on the images in dorsal decubitus. Images taken in dorsal decubitus should always be checked to confirm the absence of retro-pneumoperitoneum, which would indicate a perforation.

Figure 1 Performing an endoscopic sphincterotomy. (A) Catheterization of the bile duct. (B) Withdrawal of the sphincterotome from the papilla. The cutting wire is tensioned. (C) Cutting. (D) Sphincterotomy with a view of the posterior side of the lower common bile duct. (E) Sphincterotomy on day 15.

Figure 2 Biliary sphincterotomy. (A) Correct position of the sphincterotome before tensioning the cutting wire. (B) The sphincterotome should be directed between the 11 and 12 o’clock position (shaded area). (C) Sphincterotomy.

3 Pancreatic sphincterotomy technique

• If both biliary and pancreatic sphincterotomies are required, commence with the pancreatic sphincterotomy (Figs 3, 4). If the pancreatic orifice cannot be located, biliary sphincterotomy may be performed initially. This may then help to locate the pancreatic orifice.

• The pancreatic duct is cannulated with a sphincterotome and a 0.035 inch guidewire. Some practitioners use a smaller calibre wire to cannulate the pancreatic duct (0.025 inch wire), as theoretically this may decrease trauma to the pancreatic duct.

• A pancreatogram should be obtained. Inject contrast gently to avoid acinarization, which increases the risk of pancreatitis.

• A 3–4 mm cut is made directing the sphincterotome towards the 1 o’clock position. An alternative technique is to place a stent and perform needle-knife sphincterotomy cutting down onto the stent. One study has shown that this decreases the rate of pancreatitis in patients with sphincter of Oddi dysfunction; however, it is technically demanding and should only be performed by experienced endoscopists.

• Minor papilla sphincterotomy can be performed using a sphincterotome, cutting in the 5 to 11 o’clock direction.

Figure 3 Pancreatic sphincterotomy. (A) The sphincterotome should be angled towards the 1 to 2 o’clock position. (B,C) Sphincterotomy performed. (D) Following pancreatic sphincterotomy, look for the biliary orifice between the 11 and 12 o’clock position.

Figure 4 Indications for pancreatic sphincterotomy. (A) Removal of a pancreatic stone (arrow). Note the position of the prior pancreatic sphincterotomy towards 1 o’clock. (B) Stenosis of the main pancreatic duct in the head, with an upstream stone which caused a fistula following distal pancreatectomy. (C) Incomplete retrieval of the pancreatic stone. (D) Follow-up after complete removal of the stone: the fistula resolved 72 h later.

3.1 Problems with sphincterotomy

• The sphincterotome is not cutting properly:

Check that you do not have too much of the sphincterotome within the infundibulum. The ideal cutting position is with the proximal one-third of the sphincterotome.

Withdraw the sphincterotome a few millimeters to reduce the cutting wire surface area in contact with tissues (Fig. 5).

• I cannot orientate the sphincterotome in the 11–12 o’clock position. Try the following:

Adjust your position using right/left wheel.

Unbow the sphincterotome and advance it into the bile duct and withdraw it.

Go to a long scope position.

Alter your body position, by rotating your shoulders left or right. This will alter the position of the sphincterotome and will often allow you to perform a sphincterotomy using the edge of the wire.

• How far can I cut and how big should I make a biliary sphincterotomy?

The average size of a sphincterotomy is between 10 and 15 mm. The papilla and the whole infundibulum (Figs 1D, 1E) should be cut until the lumen of the lower common bile duct is visible and/or air appears in the bile.

The length of the incision depends on the endoscopic anatomy, the diameter of the bile duct, the length of the infundibulum (Figs 6) and if you are removing stones, their size.

• How do I know if the biliary sphincterotomy is adequate?

There are several methods to assess the adequacy of a biliary sphincterotomy. There should be rapid emptying of contrast from the bile duct into the second portion of the duodenum on imaging.

The biliary sphincter can sometimes be seen on imaging as a smooth tapering just above the papilla. This disappears as the sphincter is cut.

Another method of assessing the size of the sphincterotomy is to insert the sphincterotome into the bile duct. Fully bow the sphincterotome and withdraw it. If it is easy to withdraw a fully bowed sphincterotome through the papilla this suggests that a generous sphincterotomy has been performed.

• How far can I cut and how big should a pancreatic sphincterotomy be?

As with a biliary sphincterotomy, the length of the incision depends on the endoscopic anatomy, the diameter of the pancreatic duct, the length of the infundibulum and if you are removing stones, their size.

• How do I know if the pancreatic sphincterotomy is adequate?

The adequacy of the sphincterotomy depends on why it is being performed (i.e. to remove stones, etc.). Some general tips are:

• The length of the incision depends on the diameter of the bile duct, the length of the infundibulum and the size of the stones (if you are removing stones). When the size of the stones is bigger than the maximum potential diameter of the sphincterotomy, you can dilate the sphincterotomy to 15 mm (see section 7 below).

• After performing a sphincterotomy, check fluoroscopy to see if contrast is draining from the duct or if there is a rapid drainage of bile. If it is not, you may need to extend the sphincterotomy.

• Look for the loss of the sphincter on fluoroscopy. The sphincter is seen as a smooth tapering of the distal CBD, and is lost following sphincterotomy.

• Check the size of the sphincterotomy by seeing if it will allow a fully bowed sphincterotome through.

Figure 5 Wire position is critical to successful sphincterotomy. (A) Sphincterotome introduced too deeply into the bile duct; the current leaks away without cutting, with the resulting risk of rough cutting with hemorrhage and perforation. (B) Sphincterotome in the correct position.

Figure 6 The size of the sphincterotomy can be affected by the type of infundibulum.

4 Special situations

4.1 Sphincterotomy in patients with a gastroenteric anastomosis (Billroth II/Whipple)

In patients with a gastroenteric anastomosis, the papilla is accessed through the afferent loop. As the papilla is approached through the afferent loop, the anatomy is reversed with the bile duct between 5 and 6 o’clock. Sphincterotomy is difficult to perform but extraction of stones is, by contrast, easier because it is done along the axis of the bile duct.

Techniques

• The standard technique described above can be used (Fig. 7), however caution must be used as the sphincterotome tends to cut in the direction of the pancreas (Fig. 8). Sphincterotomy should be performed towards the 5–6 o’clock position (Fig. 9), i.e. THE OPPOSITE OF NORMAL.

Figure 7 Altered anatomy. This is a diagram of a Finsterer operation, which is a variation of a Roux-en-Y. (A) Demonstrates centering the papilla. (B) After centering the papilla, the endoscope is withdrawn to allow cannulation in the direction of the bile duct, with the aid of a guidewire. (C) The same procedure performed using of a forward-viewing endoscope.

Figure 8 Incorrect orientation of the sphincterotome in a patient with a Roux-en-Y anastomosis (B). The sphincterotome tends to align in the direction of the pancreatic, rather than bile duct in patients with gastrojejunal anastomosis. Sphincterotomy should be performed towards the 5 or 6 o’clock position.

Figure 9 Endoscopic sphincterotomy in a patient with Billroth II gastrectomy. (A) Sphincterotome in position through a papilla open due to the passage of a stone. (B) Sphincterotome cutting wire tensioned. (C) Sphincterotomy completed. (D) Extraction of the stone.

Equipment

Equipment is determined by which endoscope is used.

• Duodenoscope: Standard or specialized equipment. Special sphincterotomes can be used where the cutting wire is directed towards the bile duct.

• 160 cm enteroscope: Standard or specialized equipment

• >160 cm enteroscope: Standard ERCP equipment (sphincterotome, balloon, etc.) are not long enough to be used with these enteroscopes. A bespoke special length sphincterotome can be made.

• In difficult cases, a biliary stent can be placed. A pre-cut sphincterotomy can then be performed cutting down onto the stent.

4.2 Sphincterotomy in children

Sphincterotomy should not be performed in children unless there is a definite indication. If a sphincterotomy is performed, it should be generous to decrease the risk of subsequent stricture formation.

5 Sphincterotomy in difficult cases

In about 10% of cases, deep biliary cannulation is impossible and sphincterotomy cannot be performed. In these cases, the following techniques may be used in order of preference, depending on the anatomical conditions.

5.1 Sphincterotomy over a guidewire

Where cannulation is difficult, a triple lumen sphincterotome is used to cannulate the bile duct with a guidewire (Fig. 10). Once the guidewire is deeply inserted into the duct, contrast is injected to confirm the correct duct. The sphincterotome is then advanced over the guidewire into the duct and sphincterotomy performed as described above.

Figure 10 (A) Initial cannulation of the bile duct with a wire. (B) Successful deep cannulation achieved by guiding the sphincterotome over the guidewire.

5.2 Pre-cut

In a pre-cut sphincterotomy the bile duct is identified by opening it from the papillary orifice. This can be performed using a regular sphincterotome; however, a short tip sphincterotome may be useful in these cases. This technique is used in the absence of an infundibulum or when a neoplastic lesion causes bile duct obstruction.

Technique

• Insert the sphincterotome into the papillary orifice. The sphincterotome rapidly comes up against the papillary orifice after a few millimeters (Fig. 11).

• Ensure that the electrocautery unit is set to use of pure cutting current.

• Tense the cutting wire.

• Using stepwise cuts, the sphincterotome is advanced in the direction of the bile duct.

• Try to locate the bile duct after each cut.

• When the bile duct has been located, cannulate the bile duct, and perform a standard sphincterotomy.

Figure 11 Pre-cut sphincterotomy using a sphincterotome. (A) Insert sphincterotomy as far as you can into the papilla. (B) Tense the cutting wire and perform a sphincterotomy on the section you can visualize. (C) Repeat the procedure until deep cannulation of the bile duct is achieved.

Warning!

BEWARE! Pancreatitis and perforation are more common with pre-cut sphincterotomy due to cutting in the wrong direction.

5.3 Needle knife infundibulotomy

This involves cutting through the infundibulum to the bile duct. This technique should be used with a Type II or III infundibulum and should not be performed in a Type I or 0 infundibulum (Fig. 12). The ideal indication is a stone impacted in the papilla of Vater, where the stone serves as a block on which to open the infundibulum.

Figure 12 Classification of different types of infundibulae. Type 0: No infundibulum; Type 1: Infundibulum at the limit of visibility; Type 2: Projecting infundibulum; Type 3: Large infundibulum covering the papilla.

Technique (Figs 13, 14)

• Optimize conditions by ensuring complete duodenal hypotonia.

• Ensure that the electrocautery unit is set to pure cutting current.

• The needle is advanced 3–5 mm and the guard fixed. The needle is then withdrawn into the catheter and the catheter inserted into the instrument channel.

• Take time to locate the optimal site. Practice the maneuver you are going to use once or twice. Use the elevator to control the needle. The aim of the technique is to gently cut down into the bile duct as if it were an onion where you are peeling back the layers.

• Advance the needle and cut down into the infundibulum in a stepwise manner. The cut can be made starting at the top and cutting down towards the os or from the os cutting up. The dissection is performed in a stepwise fashion, layer by layer. Wash generously to ensure adequate visualization. After each cut, try to locate the bile duct which has a white pearly appearance, before continuing.

• A flow of bile is proof that the bile duct has been cut. Do not cut any further, wash the area and try to identify and cannulate the biliary orifice. Once the bile duct has been cannulated, the sphincterotomy is extended with the aid of a standard sphincterotome.

• Do not proceed if you cannot see the bile duct after deep dissection, as it has probably been cut.

Figure 13 Needle knife infundibulotomy.

Figure 14 Needle knife infundibulotomy. (A) Examine the infundibulum to locate the optimal site. (B) Using the tip of the needle knife catheter, palpate the infundibulum to locate the optimum site. (C,D) Cut down into the infundibulum in a stepwise manner. Start slightly above the optimal site cutting from the top down. The dissection is performed in a stepwise fashion, layer by layer. (E) Cannulate the bile duct.

There is a high risk of perforation associated with this procedure. In this situation is better to stop and repeat the ERCP 24 hours later after the edema has receded.

Clinical Tip

• Pre-cut sphincterotomy or infundibulotomy should only be attempted when there is a definite therapeutic indication based on other imaging and never during diagnostic ERCP.

• This procedure is associated with an increased risk of perforation, bleeding, and pancreatitis, and should only be performed by an experienced endoscopist.

• It is often better to stop and repeat the ERCP 24 h later after the edema has resolved.

In cases where deep cannulation of the bile duct is difficult, a rendezvous procedure can be performed followed by biliary sphincterotomy.

6 Endoscopic balloon dilation of the Sphincter of Oddi

Endoscopic balloon dilation (EBD) of the biliary sphincter is an alternative to biliary sphincterotomy. The potential advantages of EBD over sphincterotomy are that it preserves the biliary sphincter, and also reduces the risk of bleeding compared with a biliary sphincterotomy. However, a single multi-center study in 237 patients randomized to either endoscopic sphincterotomy or balloon dilation was stopped early due to increased rates of pancreatitis (15.4% vs 0.8%), with two deaths due to pancreatitis in the dilation group. EBD can be considered as an alternative to endoscopic sphincterotomy in patients at high risk for endoscopic sphincterotomy such as those with a bleeding disorder, altered anatomy (i.e. Billroth II), or difficult anatomy such as a periampullary diverticulum. In patients with large CBD stones with a prior sphincterotomy, EBD can also be used as an alternative to extending the sphincterotomy. EBD is performed as follows:

• Cannulate the bile duct

• Confirm that the correct duct has been cannulated

• Insert an 8 mm biliary balloon over a guidewire

• Position the balloon so that the waist of the balloon is within the sphincter

• Inflate the balloon until the waist is no longer present under fluoroscopy and then deflate the balloon

• A guidewire should be maintained in the bile duct as access can occasionally be difficult following EBD.

Further Reading

Disario JA, Freeman ML, Bjorkman DJ, et al. Endoscopic balloon dilation compared with sphincterotomy for extraction of bile duct stones. Gastroenterology. 2004;127(5):1291-1299.

Kethu SR, Adler DG, Conway JD, et al. ERCP cannulation and sphincterotomy devices. Gastrointestinal Endoscopy. 2010;71:435-445.

http://daveproject.org. This is an excellent site which provides videos on how to perform a sphincterotomy in normal, as well as altered, anatomy.

10.12 Biliary and pancreatic stone extraction techniques

Summary

Introduction 419

1. Bile duct stones 419

2. Pancreatic duct stones 420

3. Equipment 420

4. Technique 420

5. Lithotripsy 424

Key Points

• The choice of which method to use is determined by the experience of the endoscopist and the size of the stones.

• Very small stones (<5 mm) often pass spontaneously or can be removed with a balloon.

• Stones measuring 5–15 mm can be removed either with a balloon or a basket.

• Giant stones (>1.5 cm) usually require mechanical lithotripsy to break them into smaller pieces before they can be removed.

• It is important to correctly align the duodenoscope for successful stone removal.

• When multiple stones are encountered, commence by removing the most distal stone.

• Once stones have been captured in a basket, the basket is withdrawn without closing it.

• A Dormia basket is usually used first to extract stones which are <1.5 cm. A basket with lithotripsy capability should always be used.

• Ensure that all the equipment required (Dormia basket, balloon, mechanical lithotripter, nasobiliary drain, etc.) is available prior to commencing an ERCP.

Introduction

Gallstones affect 10–20% of the Caucasian population while 10–15% of patients with symptomatic cholelithiasis will also have bile duct stones.

Transabdominal ultrasound is the least sensitive method for detecting bile duct stones. Helical contrast-enhanced CT has a sensitivity of between 71% and 73% and specificity of 98–97% for intrahepatic and extrahepatic gallstones, respectively. A systematic review comparing EUS and magnetic resonance cholangiogram (MRC) for the diagnosis of bile duct stones found that EUS had a sensitivity of 93%, specificity of 96%, compared with a sensitivity of 85%, specificity 93% for MRC. ERCP has a sensitivity of 79–90% and specificity of 92–100%. Intraoperative cholangiogram has a false positive rate of up to 5%. The sensitivity of MRC decreases when the bile duct is dilated (>10 mm) or when the stone measures <6 mm. False negative results occur in ERCP with small stones located within a dilated biliary duct, while false negative results for EUS occur in stones located in the upper portion of the common hepatic duct or within the intrahepatic ducts.

1 Bile duct stones

Box 1 Extraction of bile duct stones is successful in almost all cases

• 65–0% in a single session.

• 85% with multiple sessions.

• 95–99% with lithotripsy.

Box 3

Predictors of choledocholithiasis

Very strong

• Common bile duct stone on transabdominal US.

• Clinical ascending cholangitis.

• Bilirubin >4 mg/dL.

Strong

• Dilated common bile duct on US (>6 mm with gallbladder in situ).

• Bilirubin level 1.8–4 mg/dL.

Moderate

• Abnormal liver biochemical test other than bilirubin.

• Age older than 55 years.

• Clinical gallstone pancreatitis.

Assigning a likelihood of choledocholithiasis based on clinical predictors

• Presence of any very strong predictor: High.

• Presence of both strong predictors: High.

• No predictors present: Low.

• All other patients: Intermediate.

(Reproduced with permission from Maple JT, Ben-Menachem T, Anderson MA et al. The role of endoscopy in the evaluation of suspected choledocholithiasis. Gastrointestinal Endoscopy 2010.)

ERCP is the most common method for treating bile duct stones. Several methods can be used to remove stones; the choice of which method to use is determined by the experience of the endoscopist and the size of the stones. Very small stones (<5 mm) often pass spontaneously or can be removed with a balloon. Stones measuring between 5 and 15 mm can be removed either with a balloon or a basket. Giant stones (>1.5 cm) usually require mechanical lithotripsy to break them into smaller pieces before they can be removed. When stones are large, or where the patient’s anatomy makes stone extraction difficult, electrohydraulic or laser lithotripsy may be required. Laparoscopic bile duct exploration is an alternative to ERCP (Fig. 1). Prophylactic cholecystectomy should be offered to all patients following clearance of their bile duct, unless they are poor operative candidates.

Figure 1 (A) Standard treatment of choledocholithiasis. (B) Specialized treatment of difficult bile duct stones

(With permission from Ginsberg G, Kochman ML, Norton I, et al, editors. Clinical gastrointestinal endoscopy, Saunders, 2005, London, p 677.)

Clinical Tip

Gallstones

• Cholesterol gallstones

Round and golden in color.

• Calcium bilirubinate (pigment) gallstones

Black, round and hard, contain calcium bilirubinate.

• Primary bile duct stones

Brown and shapeless stones. Consist of a mixture of calcium salts, unconjugated bilirubin, protein, bacteria and cholesterol.

• Risk factors for gallstone development:

Age, female sex, pregnancy, multiparous, genetic (Native Americans, Chileans)

Obesity, diabetes, weight loss

Drugs (exogenous estrogens, clofibrate, long-term octreotide), TPN

Diseases: Terminal ileal resection/disease (impaired enterohepatic circulation), gallbladder stasis, cirrhosis, hemolytic disease (pigment stones), hypertriglyceridemia (cholesterol stones), gallbladder stasis (diabetes mellitus, TPN, post-vagotomy, octreotide, somatostatinoma, spinal cord injury)

Biliary bacterial colonization (brown pigment stones)

Reduced exercise (men).

Box 4 Indications for stone removal

ERCP in acute pancreatitis

• There are four randomized trials of ERC compared with conservative management in patient’s acute pancreatitis.

• ERC is indicated in patients with severe pancreatitis and evidence of biliary obstruction within 24–72 h of admission.

2 Pancreatic duct stones

Approximately one-third of patients with chronic pancreatitis have pancreatic duct stones. It is unclear whether pancreatic stones worsen the clinical course of chronic pancreatitis and glandular destruction. There is, however, evidence that they may contribute to pain associated with chronic pancreatitis due to increased intrapancreatic pressures.

Indications for pancreatic duct stone removal include:

• Patients with symptomatic chronic pancreatitis. The most suitable patients are those with ≤3 stones measuring <10 mm, located in the head or body with no downstream strictures or impacted stones.

• Patients with pancreatic pseudocyst.

3 Equipment

• Guidewire

• Sphincterotome

• Dormia basket with lithotripsy capability

• Biliary balloon

• Biliary and pancreatic stents

Specific equipment is required for lithotripsy, which is discussed later in this chapter.

4 Technique

A balloon or Dormia basket can be used to extract most stones. The decision of which to use is based on personal preference and experience; however, many experienced ERCPists use a Dormia basket first, with a balloon used where residual stones remain following a pull through with a Dormia basket, for the extraction of small stones, or small fragment following lithotripsy.

4.1 Balloons

Balloons are used exclusively for small stones, or after a Dormia basket has been used. A selection of balloons are available in different sizes. A balloon is ideal for small (<5 mm) stones, or to remove small fragments after mechanical lithotripsy, but can be difficult to use in a large, dilated bile duct as the stone can slide past the balloon.

4.1.1 Balloon technique

• The balloon is inserted above the stone. If there are several stones, the stones are removed one at a time, starting with the stone closest to the papilla.

• Modern balloons can be inflated to several different sizes using the same balloon. The size of the bile duct should be estimated and a balloon should be chosen that is the same size or slightly larger than the width of the duct.

• A balloon can be used to remove intrahepatic stones. Place a guidewire above the stones and then insert the balloon over the guidewire. The size of the duct is assessed and the balloon inflated to a similar diameter. Take care to ensure that the diameter of the balloon is not too large as there is a risk of perforation of the bile duct.

• The balloon is inflated above the stone and is gently pulled as far as the papilla.

• It is important to ensure that the duodenoscope is correctly aligned to successfully remove the stone through the sphincterotomy. Check the position of the scope – the balloon/bile duct should be aligned at 90° to the scope. The tip of the duodenoscope should be positioned directly below the papillary orifice abutting the opening. Often the scope will need to be inserted slightly, the tip deflected downwards and right. If this is not successful, gently turn the shaft of the scope clockwise while keeping constant pressure on the balloon.

• If this fails, the balloon may need to be deflated slightly to allow it to pass through the sphincterotomy.

In cases where there is a large stone but it is not possible to extend the sphincterotomy, a balloon sphincteroplasty can be used to dilate the os to allow the stones to be removed (see Chapter 10.11, Section 11.6).

4.2 Stone extraction with a basket

Baskets are available in a variety of sizes and configurations. ‘Memory’ or non-deforming baskets are also available which return to their original shape, facilitating capture of stones. Wire-guided baskets also exist. It is important to ensure that the basket is compatible with a mechanical lithotripter so that stones can be crushed if required.

4.2.1 Basket technique

• Assess the number and size of the stones. The stones must be small enough to pass through the distal duct and sphincterotomy to prevent stone impaction.

• The closed basket covered by its plastic sheath is inserted over the stones. If this is difficult, a guidewire can be placed above the stones and the basket inserted over the guidewire.

• The basket is opened and the stone snared by opening and closing the basket. Sometimes vigorous shaking of the fully open basket inside the bile duct may help to bring the stones into the basket. Take care when opening the basket not to displace stones into the intrahepatic ducts.

• The basket is gently withdrawn as far as the papilla without closing it (Figs 2, 3). It is important to ensure that the duodenoscope is correctly aligned as described above to successfully remove the stone through the sphincterotomy.

• If the stone continually slips out of the basket, then the basket can be closed gently around the stone.

• Where there are multiple stones, commence by removing the most distal stone.

• Abundant lavage will help to remove small stones or fragments, and even to mobilize very large stones and remove them. If the stones are very large, they may be broken mechanically by the Dormia basket.

Figure 2 Removal of stones using a Dormia basket. (A) Stones in the common bile duct. (B) Extraction of stones using a Dormia basket. (C) Clear bile duct at the end of the procedure.

Figure 3 Removal of distal CBD stones. (A) Large stone (arrow) in the lower common bile duct. (B) A large sphincterotomy was performed, followed by retrieval of the stone with a Dormia basket. (C) Bile duct with no evidence of stones at end of the procedure.

Common bile duct stones are often very friable. Once the large stones have been removed with the basket, a balloon catheter is sometimes required to remove small stone fragments and to obtain an occlusion cholangiogram demonstrating a clear biliary tree.

4.2.2 Problems with the Dormia basket

The stone is snared in the basket, which is impacted in the sphincterotomy opening.

There are several solutions.

• Withdraw the endoscope gradually and firmly, maintaining firm traction on the basket so that the endoscope and basket are integral. This may allow the stone to pass through the sphincterotomy orifice.

• Advance the endoscope so that the tip of the endoscope is against the papilla. Force the basket into the operating channel. The basket will close as it is withdrawn into the operating channel, crushing the stones (Fig. 4).

• The basket should be attached to a lithotripter and the stones crushed (see Lithotripsy technique without withdrawal of the endoscope, below).

Figure 4 Wedged Dormia basket with stone. The endoscope is advanced so that the tip of the endoscope is against the papilla. The basket is forced into the operating channel. The stones are crushed as the basket closes as it is withdrawn into the operating channel.

Other options include extending the sphincterotomy, intra- or extracorporeal lithotripsy.

In cases where this fails, which is extremely rare, a nasobiliary drain can be inserted (see Chapter 10.19). The Dormia catheter is exteriorized like the nasobiliary drain. By pulling on it slightly every day, the stone and the Dormia become disimpacted within 48–72 h when the edema around the sphincterotomy subsides.