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.

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.