ERCP


8
ERCP


Brian S. Lim1,2, Joseph Leung3,4, and Wei‐Chih Liao5,6


1 University of California School of Medicine, Riverside, CA, USA


2 Department of Gastroenterology, Kaiser Permanente Riverside Medical Center, Riverside, CA, USA


3 University of California Davis School of Medicine, Sacramento, CA, USA


4 VA Northern California Health Care System, Mather, CA, USA


5 National Taiwan University Hospital, Taipei, TW, China


6 National Taiwan University, College of Medicine, Taipei, TW, China


Introduction to ERCP training


The need for training


Endoscopic retrograde cholangiopancreatography (ERCP) is an established diagnostic and therapeutic modality for patients with pancreaticobiliary diseases. Although its role as a diagnostic tool is partially replaced by magnetic resonance cholangiopancreatography (MRCP), ERCP remains the gold standard for the diagnosis of suspected pancreaticobiliary pathologies, including ductal stones and strictures. Therapeutic ERCP is preferred as a nonoperative alternative to surgical treatment for the management of bile duct stones and for the palliation of malignant obstructive jaundice. More recently, prolonged biliary stenting with multiple plastic stents and/or fully covered self‐expandable metal stent (fcSEMS) has offered significant benefits in patients with benign bile duct strictures [1].


ERCP is one of the most challenging endoscopic procedures performed by gastroenterologists. Optimal performance requires broad knowledge of pancreaticobiliary anatomy/pathologies, considerable manual dexterity, a thorough understanding of the equipment being used, and familiarity with alternative diagnostic and therapeutic approaches [2]. It carries substantial risks even in the hands of experts. For these reasons among others, it has become very clear that one should be properly trained and be competent with ERCP to improve success and minimize risks to the patients.


The format of training


Traditional ERCP training takes the form of the teacher–apprentice system with supervised hands‐on practice on patients. The trainees learn the basic and advanced skills under the tutelage of the ERCP trainer and perform procedures with the help of a trained GI assistant. Sometimes, the trainee or trainer would serve the role of an assistant. Many trainees receive ERCP training as part of a 3‐year GI fellowship program, usually in their senior year after mastering the techniques of upper and lower GI endoscopy. Because of a lack of patients, many training programs cannot offer sufficient ERCP training to the trainees enrolled in fellowship training. Instead, ERCP training is now being offered to a selected few in many programs as an advanced fellowship where trainees spend an additional (fourth) year in special ERCP training.


The types of training—from clinical to simulation


Clinical experience is gained by performing procedures on patients using real duodenoscope and accessories. This is the traditional way by which many endoscopists learn and master the ERCP skills. Supervised hands‐on practice offers learning opportunities but the limited number of patients has restricted trainees’ access to patients and thus practice opportunities. Because of the high risks and complications involved with therapeutic ERCP procedures, many trainers are reluctant to allow trainees to perform these invasive procedures independently. Although many trainees have admitted to not completing the required number of ERCPs [as recommended by the American Society for Gastrointestinal Endoscopy (ASGE) or Accreditation Council on Graduate Medical Education (ACGME)] before graduation, a majority of them want to practice ERCP, hoping that they will improve their imperfect skill with practice on patients in the daily unsupervised practice. This poses increased risks to patients as failure and complications tend to increase with inexperienced endoscopists.


Trainers have resorted to alternative methods to provide trainees with hands‐on experience and more practice learning opportunities. Such practice settings include the use of the live anesthetized animal model, the ex vivo porcine stomach model, mechanical simulators, and computer simulators. The details of these simulators are discussed later in the chapter.


Prerequisite for training


Trainee—level of skill and expertise


Following are the trainee prerequisites set forth by the latest ASGE guidelines for advanced endoscopic training [3]:



  1. Trainees who are seeking to acquire skills in advanced endoscopic training must have completed standard endoscopy training during an approved GI fellowship (or equivalent training) and have documented competence in general routine (i.e., not advanced) endoscopic procedures.
  2. Trainees must have good understanding of the normal anatomy/physiology of the pancreatobiliary system and epidemiology, pathophysiology, diagnosis, and treatment involving this system.
  3. The trainee must understand the cognitive as well as technical component of the procedures, including appropriate indications for and the contraindications to performing these procedures. They should have knowledge of pre‐ and post‐procedure evaluations as well as managing procedure‐related complications that may occur. The trainee should have the ability to explain the procedure to the patient, including obtaining informed consent. Furthermore, trainees must know that the usage of a side‐viewing duodenoscope changes the orientation of the endoscopic image, although the basic controls are similar. Trainees should receive orientation for the basics of ERCP, including didactic talks on organization of the ERCP room and radiological interpretation of cholangiogram and pancreatogram to help them understand the clinical procedure. Although technical skill is gained through practice, trainees should have a good grasp on the cognitive aspect of different ERCP procedures and understand the technical component as well as clinical applications even prior to getting hands‐on training.

Setting—case load


The experience gained by the trainee is affected by the clinical case load (and complexity) in individual training centers. The ASGE stated that trainees should perform a minimum of 180 cases with at least 50% of procedures containing a therapeutic component to achieve competency [4]. A higher expectation on trainees’ performance exists in other countries, e.g., Australia. To provide adequate training, the training institution should have cases or referrals more than the minimum number required by fellowship training as there may be difficult cases that the trainees cannot handle, especially at the start of their training. Except for large academic centers, many training programs do not have adequate number of patients for training and many trainees have graduated without meeting the minimum standard. Yet, in a previous survey of 69 graduates from US fellowship programs, 91% were planning to perform ERCP in their practice despite one‐third of them stating that their training was inadequate [5].


Trainer—a skilled endoscopist may not be a good teacher


There are certain prerequisites for a trainer, namely clinical and teaching experience. ERCP trainers have different teaching styles; no two trainers agree on everything and there is no standard of reference. However, a skilled endoscopist may not necessarily be a good teacher if he/she cannot communicate effectively with the trainees. Allowing the trainee to struggle by trial and error may not be in the best interest for the patient. The ability to recognize the errors made by the trainees and to correct their mistakes, giving them specific instructions to complete a procedure without taking away the endoscope would be ideal. Yet, this may be difficult to accomplish. Often, the trainer may have to take over the instrument and demonstrate to the trainee how to complete a certain step of the procedure and then allow the trainee to continue. Patience in coaching and allowing the trainees to practice without taking the scope away from them is an important quality for the trainer who must balance trainee training with the safety of the patient.


Advice for trainers


It is necessary to ensure that trainees understand the fundamentals and basic technique of ERCP. The emphasis is on proper understanding of the nature of the procedure, the technique involved, and the risk of complications that could be detrimental to the patient. ERCP is very different to upper or lower endoscopy and certain interventions can result in serious complications if not performed properly. Trainees need to understand the essence of an ERCP procedure, the need for proper and good (controlled) coordination in accessory exchanges, in performing a papillotomy and in deploying a stent (especially a SEMS) because precision matters. Such teaching involves understanding of the anatomy regarding axis of the different ductal systems, control in manipulation of the scope for proper orientation, and alignment with the respective ducts (or stricture) to ensure success. Trainers need to be watchful especially when inexperienced trainees are performing the procedure, ready to offer clear instructions and correct any mistake or error before it happens, and do not hesitate to take over the scope to keep the situation under control for completion of the procedure. It is important to allow trainees to practice but they should be ready to admit if they do not understand or know what to do. Trainees are not allowed to fumble with trial and error, which can potentially hurt the patient. It is important to emphasize on the need for a team of trained assistants to assist with the procedure. Trainees also need to be oriented to the job of an assistant to appreciate the team work and trainers should not hesitate to offer help in difficult settings. It requires a higher level of vigilance, commitment, and coaching to produce an experienced trainee and quality service for the patient.


ERCP training


Cognitive and technical aspects


ERCP skill can broadly be divided into two components: the cognitive and the technical aspects. Technical skills can be learned with understanding the function and operation of the endoscope and different accessories and practicing coordination between the endoscopist and the assistant. In principle, many accessories have similar basic design, i.e., exchange over a guide wire, so good coordination as a team is necessary to facilitate the ERCP procedure.


Clinical experience comes with hands‐on practice and is acquired with repeat performance on patients with different clinical problems. The number of procedures performed has traditionally been used as a surrogate for the trainees’ experience. However, it is important to realize that an inexperienced trainee endoscopist could “waste” much of the clinical time if they have difficulty and struggle in handling the different ERCP accessories, thus missing the opportunity to learn the clinical application of the procedure in the management of the patient.


In addition to the technical skills, trainees must have the ability to recognize the different endoscopic pathologies and understand the choice of different accessories. ERCP involves monitoring the position of accessories and manipulating them under fluoroscopic control. Radiological interpretation of ERCP images is therefore necessary to enable the trainees to recognize the different pathologies, for example, how to differentiate between a stone and an air bubble in the bile duct and diagnosing a benign stricture versus a malignant one. This is of crucial importance since many clinical decisions are made at the time of ERCP using the fluoroscopic information to guide subsequent therapy. This is very different to the traditional interpretation of radiological imaging because the decision to proceed with subsequent therapy cannot wait until one receives the radiology report. Thus, the trainee needs to be trained to make such clinical decisions (independently) based on proper interpretation of fluoroscopic images.


Equipment—scope, accessories, and diathermy


ERCP utilizes the side‐viewing duodenoscope to provide proper orientation and alignment with the papilla. Although the channel size of different ERCP scopes can vary, it is preferable to use the large (4.2 mm) channel therapeutic scope as it can accommodate larger 10 or 11.5 Fr size accessories and allow more options for endoscopic intervention. Further scope modification includes the V‐system with a small V‐notch on the elevator (Olympus Medical System, Tokyo) for holding the guide wire to facilitate the exchange of accessories over a special short guide wire. Further adaptation involving the use of wire locks such as the Rapid Exchange (Boston Scientific, Natick, MA, USA) or Fusion System (Cook Endoscopy, Winston Salem, NC, USA) allows anchoring of the short (or long) guide wire to facilitate exchange of accessories over a stable guide wire. If possible, trainees should become familiar with both long‐ and short‐wire exchanges and manipulation.


Accessories can be separated into diagnostic and therapeutic categories


A simple catheter or wire‐guided papillotome is used for injection of contrast medium and to achieve diagnostic cannulation of the bile or pancreatic duct. Traction on the papillotome cutting wire helps to deflect the tip of the papillotome and facilitates selective cannulation of the bile duct. Curving the tip of the catheter can also facilitate biliary cannulation. Instead of injecting contrast, a flexible hydrophilic tip guide wire can be used for selective cannulation, avoiding the risk of overfilling the pancreas in repeat attempts at common bile duct (CBD) cannulation.


Therapeutic accessories include the papillotome, stone extraction balloon or baskets, dilation catheter or balloon, brush cytology catheter, and plastic or self‐expandable metal stents. For large stones, one can consider using the mechanical lithotripter or intraductal lithotripsy methods such as electrohydraulic lithotripsy (EHL) and laser lithotripsy.


Diathermy is generally achieved using monopolar electrocautery via electrosurgical generators such as the ValleyLab (Boulder, Colorado, USA) and Olympus (Olympus Co, Tokyo, Japan) diathermy units. The energy levels (cutting and coagulation) can be preset or adjusted on the machine as well as the wave form (pure cutting, coagulation, or a blended mode). Cutting is controlled by activating the foot pedal. The ERBE (Tuebingen, Germany) unit has a microcomputer control that automatically allows a stepwise cutting (alternating coagulation and cut) of the papilla. Trainees need to be well versed with the setup and desired electrocautery settings of the generator in their unit.


Performance—key steps to technique and trick of trade


Scope handling


Unlike performing upper and lower GI endoscopy where there may be considerable hand and body movement, ERCP requires a steady position of the tip of the duodenoscope to facilitate the procedure. In this setting, the endoscope resembles a launching platform where different accessories are used to achieve cannulation and therapy within the pancreas or the biliary system. It is important to minimize body movement that may be transmitted to the tip of the endoscope (Figure 8.1). In addition, the scope shaft should be held with third, fourth, and fifth digits using only the index finger for both the air and suction button (as opposed to using the index finger for suction and middle finger for air while holding the shaft with two fingers as many endoscopists prefer during colonoscopy). This puts less strain on the base of the thumb when moving the elevator (Figure 8.2). This three‐finger technique also allows the left little finger to be used for gripping and stabilizing the guide wire during exchange when using the long‐wire method.

Photo depicts using one finger to control the air and suction button allows easy control of the elevator. Left wrist rotation can alter the scope tip position and change the orientation with the papilla in the duodenum.

Figure 8.1 Using one finger to control the air and suction button allows easy control of the elevator. Left wrist rotation can alter the scope tip position and change the orientation with the papilla in the duodenum.

Photo depicts holding the ERCP scope with two fingers on the air and suction buttons will limit the left thumb movement and use of the elevator.

Figure 8.2 Holding the ERCP scope with two fingers on the air and suction buttons (as in a colonoscopy procedure) will limit the left thumb movement and use of the elevator. This will also put unnecessary strain on the base of the thumb when using the elevator.

Schematic illustration of a combination of 12 different scope maneuvers to position the catheter for selective cannulation.

Figure 8.3 A combination of 12 different scope maneuvers to position the catheter for selective cannulation (air insufflation and suction are not shown).


In terms of scope manipulation, basically, there is a combination of 12 different maneuvers—up/down, left/right tip deflection (angulations), left/right scope tip rotation by the left wrist, pulling/pushing of the scope, up/down control of the elevator, and finally air insufflation and suction—to change the position of the scope tip in relation to the papilla in order to achieve and maintain a good orientation and alignment for diagnostic and therapeutic manipulations (Figure 8.3). These can be combined with traction and relaxation of the cutting wire when a papillotome is used. The wheels should be freed when performing insertion and positioning of the endoscope and locked subsequently to allow a more stable position for fine adjustment and manipulation of accessories. A combination of the different maneuvers will serve to position the papilla in the middle of the endoscopy field. In some cases, it may be necessary to reverse some of these manipulations or repeat them to regain a proper position for correct alignment.


Cannulation—selective


Selective cannulation of the bile duct and pancreatic duct is achieved using a diagnostic catheter or a wire‐guided papillotome. For CBD cannulation, the tip of the scope is inserted further into the duodenum with the catheter approaching the papilla from below and directing toward the 11–12 o’clock position. It is important to avoid impacting the catheter and forceful injection of contrast to prevent submucosal injection, which may traumatize the papilla. Cannulation of the pancreatic duct is achieved by directing the catheter in the 1–2 o’clock position and going slightly more horizontal, i.e., perpendicular to the duodenal wall.


c08i001c08i001The use of a papillotome allows tip deflection with traction on the cutting wire to align with the biliary axis. If multiple pancreatic injections occur in attempted CBD cannulation, it may be easier to change to the use of a guide wire for selective CBD cannulation. Gentle probing is performed with 5 mm of the tip of the guide wire protruding from the papillotome to aid selective cannulation (see Videos 8.1 and 8.2). It is important to note that even though most guide wires have atraumatic flexible tips, they are quite stiff when restrained by the catheter, and forceful manipulation can still lead to trauma and edema of the papilla. Gentle probing in the respective axis of the bile or pancreatic duct while altering slightly the direction of approach if attempts fail will facilitate cannulation. As most papillotomes tend to deviate to the right when traction is applied, it may be necessary to shape the tip of the papillotome to change the orientation of the tip and thus alignment of the guide wire (see Video 8.3). The use of a rotatable papillotome may achieve similar results (see Video 8.4).


c08i001 c08i001c08i001Successful deep cannulation of the bile or pancreatic duct depends on proper alignment of the accessory with the axis of the distal ductal anatomy. It is not uncommon to see that the tip of the catheter or guide wire is abutting against the wall of the ampullary portion of the distal bile duct and further advancement of the accessory is not possible. It is helpful to perform further manipulation under fluoroscopic control to change the alignment of the distal tip of the accessory. Sometimes, dropping the elevator, pulling back the tip of the scope, and gentle rotation to the left will change the accessory orientation and bring back the alignment with the axis of the distal bile duct to facilitate further advancement (see Video 8.5). Similarly, manipulation of the scope tip can facilitate deep cannulation of the pancreas, which is more easily achieved using a flexible tip guide wire. There is a suggestion that the use of a loop‐tip guide wire (Cook Endoscopy, Winston Salem, NC, USA) (which is less traumatic than a pointed tip guide wire) may facilitate cannulation [6]. Other techniques utilized for difficult selective biliary cannulations include wire‐guided cannulation following initial guide wire placement into the pancreatic duct and using a second guide wire for cannulation (double wire technique), or after placement of a small diameter pancreatic duct stent to straighten the common channel (see Videos 8.6 and 8.7). With difficult or angulated distal CBD or stricture, shaping the tip of the guide wire (by creating varying degree of curves at the tip) enables the wire tip to form a loop to negotiate an angulated passage. This can be a single or C‐loop or a double curve or a S‐loop (Video 8.8).


Advanced techniques to overcome difficult biliary cannulation


Selective cannulation and access to the biliary system (in particular) can avoid unnecessary post‐ERCP pancreatitis. Although wire‐guided cannulation or double wire technique improves the success of selective biliary cannulation, access to the bile duct can be achieved with precut papillotomy with or without the use of pancreatic stenting.


Precutting with the (regular) wire‐guided papillotome along the biliary axis


When deep cannulation with the guide wire fails after injection of contrast into the distal CBD, precut papillotomy can be performed by impacting the regular papillotome against the papilla and cutting the biliary orifice. Gentle traction and pressing the papillotome against the wall allow the cut in the direction of the bile duct (unroofing the papilla) and gain access into the distal CBD for proper positioning to complete the papillotomy and placement of the guide wire.


Precutting with regular papillotome positioned in pancreatic axis/duct (septostomy)


When deep CBD cannulation fails despite repeat cannulation and injection of the pancreatic duct, it may be helpful to insert a guide wire into the main PD and position the tip of the papillotome cutting wire in the common channel and cut toward the biliary axis. In doing so, it opens the common channel and exposing the biliary orifice (which is often seen as a bile stained orifice on the left side of the precut papillotomy), to facilitate subsequent CBD cannulation.


Precutting with needle knife alongside an indwelling pancreatic stent


In the setting when CBD cannulation fails, a small PD stent can be inserted over a guide wire positioned in the main PD to straighten/open the common channel and at the same time protects the pancreatic orifice. A needle knife is then used to cut alongside the indwelling PD stent in the direction of the CBD until the biliary orifice is identified.


Fistulotomy with needle knife


When guide wire fails to cannulate both bile and pancreatic ducts, cutting with a needle knife onto the bulge of the papilla at 11‐o’clock direction proximal to the papillary orifice can create a fistula and access into the distal bile duct.


Papillotomy—standard


Before performing papillotomy, one should review the indication and contraindications for the procedure. Different diathermy units are available, and each has a slightly different design in terms of power (energy) setting and performance (cutting or blended modes), and it is safer to use a unit that one is familiar with.


Papillotomes are designed in a very similar way with the cutting wire controlled by varying traction on the handle that changes the tension applied to the wire (bowing) and cutting when the electrical circuit is completed using the foot pedal. The length of the exposed wire also affects the papillotomy.


Prior to performing the cut, it is important to assess the anatomy of the papilla and adjacent structures such as periampullary diverticulum. The “perfect” axis for a biliary papillotomy is along the axis of the distal bile duct and intraduodenal portion of the papilla and this is usually considered the 11–12 o’clock orientation in relation to the papillary orifice (often representing the bulge of the papilla), and not simply the 11–12 o’clock direction as seen on the endoscopy monitor [7]. Similarly, the pancreatic axis is along the 1–2 o’clock direction. It is important to remember that the alignment of the scope tip with the papilla can change because of scope manipulation but the “perfect” axis will not since this is an anatomical landmark.

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Jul 31, 2022 | Posted by in GASTOINESTINAL SURGERY | Comments Off on ERCP
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