Fig. 4.1
Patient being positioned semi-prone in the operating room for ERCP
Other positions that are used for ERCP include left lateral and supine. Although the left lateral position is preferred for esophagogastroduodenoscopy, it is not ideal for ERCP due to the unusual projection of the radiologic image obtained during fluoroscopy. The directions taken by the opacified bile and pancreatic ducts are unfamiliar in the left lateral projection; the author confesses to once having placed a stent in the bile duct when he thought it was in the main pancreatic duct. The left lateral position has one particular use that is worth remembering: if a large, J-shaped stomach makes it difficult to access and intubate the pylorus with the duodenoscope, repositioning the patient to the left lateral position will often work. After the tip of the scope is safely in the second part of the duodenum and the control wheels locked to maintain that orientation, the patient should be returned to the previous semi-prone/prone position for a more familiar view of the papillary fold. The supine position is the most difficult position in which to access the descending duodenum for ERCP. The supine position may be requested by the anesthesia provider for a morbidly obese patient because in the event of respiratory depression or a code, it is difficult to roll a very obese patient from prone to supine quickly for resuscitation. With the patient supine, and the endoscopist facing the patient and the endoscopy monitor in the usual fashion, the control section of the duodenoscope is rotated 180° from its normal position, which is an unfamiliar and uncomfortable way to do ERCP for many. However, if the endoscopist rotates 90 degrees to the right (i.e., away from the patient), he or she can hold the duodenoscope in the more familiar and comfortable position. If the patient is undergoing surgery immediately before ERCP, then the supine position is inevitable. However, if ERCP is performed first, the option exists to position the patient as you prefer. This requires the agreement and cooperation of the operating room staff, including the surgeon. In my experience, the best results are obtained when the patient undergoes ERCP in the semi-prone position.
If the patient is having a prolonged procedure under anesthesia, hypothermia may be a problem, especially if the room is cold as many operating rooms are intentionally kept cool. A heating blanket helps prevent this problem. If the patient is under general anesthesia, the endotracheal tube (ET) may be conveniently routed through a side hole in the bite block, which slides over it. For this maneuver, the ET is briefly disconnected from the bag or machine being used to ventilate the patient. The ET should not apply pressure to the lip or the corner of the mouth. Your patient will not thank you for a swollen lip or another sore place in their mouth after ERCP! Care should be taken to ensure the correct positioning of the bite block, so that the teeth are gently holding it in place. The pre-procedure evaluation should have included careful inspection of the teeth, but this should be repeated at the time of placing the bite block. Loose, usually carious, teeth create a risk for aspiration should they be dislodged during instrumentation. If loose teeth are detected at pre-procedure screening in clinic, the patient should be asked to have them removed by a dentist before returning for ERCP. Unfortunately, patients with poor dentition may be uninsured and unable to pay for dental extractions. A social worker or other patient advocate may help identify indigent dental care locally to address this problem. Complete or partial dentures that are not “cemented” in place should be removed before endoscopy . Finally, many anesthesia providers like the patient’s head supported by a foam block.
The electrocautery grounding pad should be applied to an area of skin well away from any metallic implants like a hip prosthesis or pacemaker and connected to the electrosurgical unit in preparation for use during the procedure. It is recommended that the active cord (often a red or black cord linking the electrosurgical unit to the accessory) not be connected until the endoscopist is ready to use the device. This reduces the risk of unintended activation of electrocautery by, for example, the endoscopist stepping on a foot pedal that he or she thinks controls fluoroscopy rather than electrocautery.
Until 1990, when the author and colleagues from Duke University published the first small case series of pregnant women undergoing ERCP [6, 7], this procedure was considered too risky to attempt (Chap. 19). There was concern that complications of ERCP, especially pancreatitis, could put the lives of both the mother and fetus at risk. In the last 25 years, it has been demonstrated repeatedly that if the patients are chosen carefully, for appropriate indications, ERCP in pregnancy is safe and effective. Appropriate precautions must be taken to screen the fetus from X-rays used for fluoroscopy. This is achieved by shielding the mother’s abdomen with a lead apron, which needs to be pulled up at least to the level of the top of the uterine fundus. Minimal fluoroscopy is used to confirm positioning of the catheter in the bile duct, and taking pictures is avoided as this will add to radiation exposure. A radiation dosimeter can be placed over the uterus under the lead apron to measure fetal exposure during ERCP; this should be minimal. Pregnant women in the second and third trimesters should NOT be placed in the supine position for ERCP. Lying on the gravid uterus may compress the inferior vena cava, reducing venous return to the heart, and result in supine hypotension syndrome that causes syncope and sometimes seizures (Fig. 4.2) [8]. It is best to perform ERCP with the mother in the left lateral position during the second and third trimesters, which is not ideal for imaging but a necessary compromise for safety and comfort.
Fig. 4.2
Inferior vena cave ( IVC) compression by third trimester gravid uterus in supine position ( schematic)
Equipment
All the equipment required for the procedure should be available at the beginning. It is inefficient, time-consuming and frustrating for all concerned when your assistants must leave the room to find missing accessories. Time-outs are invaluable, but planning for ERCP has to start well before the endoscope is passed. You should meet with your ERCP room staff at the beginning of a list of procedures to discuss the cases and identify specific needs you anticipate, such as having a mechanical lithotripter or a metal stent available. Where I currently work, we have a mobile cart for endoscopic accessories that is easily moved from room to room. Your cannula of choice should be removed from its package and prepared for use by flushing with contrast medium that has already been drawn up. In addition to having an automated water jet (activated by a foot pedal) connected to the duodenoscope, I like to have a 60 cc syringe with a metallic tip that fits snugly in the instrument channel for applying high pressure lavage. The ERCP nurse or technician should ensure that the duodenoscope is fully functional before handing it to you. If necessary, they should use a check list to ensure that a suction source is attached and operating, air and water are available for insufflation and lens cleaning, the light source has been switched on, and the elevator is functional. It is also important that electrocautery connections are checked before the start to avoid delays when sphincterotomy is needed. Accessories that may be used, but not definitely, should be nearby in their packaging. As most ERCP accessories including catheters, wires, baskets, stents are expensive and single-use, opening but not using them is a waste of money. Some devices are reusable, but must be re-sterilized first. Ensure that equipment you use is replaced. Many endoscopic accessories are expensive enough that they are often bought one at a time to avoid large inventories. The use of an expandable metal stent (or a nasobiliary drain or a needle knife papillotome, etc.) should trigger a same-day order preferably by overnight or 2-day express delivery for replacement. Most accessory manufacturers are happy to set up a reordering mechanism to accommodate these requests. It is helpful to review the ERCP accessory inventory regularly with your endoscopy staff. Most endoscopists have a relatively small number of accessories that they use on a regular basis. Although it is necessary to have a range of stent lengths and calibers to address different uses and types of strictures, maintaining a large inventory is wasteful and expensive. When devices reach their sell-by date, they can no longer be used for patient procedures or be returned for credit. It is common practice now in larger endoscopy units for new devices and accessories to undergo committee review before they are approved for purchase. A new device that is significantly more expensive than the existing one must demonstrate some additional benefit in terms of safety and/or efficacy to justify the added expenditure. Many endoscopists find such restrictions irksome, as they like to have the latest and greatest equipment available. However, the fiscal reality is that ERCP frequently loses money for institutions, making financially responsible choices imperative when it comes to purchasing equipment.
Special tools for ERCP, such as choledochoscopes, intraductal ultrasound probes, and biliary manometry systems, are expensive items. It is difficult to justify their purchase if they will only be used a few times each year. In the community, who has the latest ERCP technology appears more important than the skill level of the operator when it comes to directing referrals. Tertiary centers with deep pockets (a rarity these days) may have the volume of challenging cases to justify these purchases, especially if their use generates additional revenue.
The middle of a complex procedure is not the time for assistants to learn how to deploy a new (unfamiliar) stent, or assemble a lithotripsy device for the first time. If an experienced assistant cannot be available, it is wise to request an in-service from the equipment company representative ahead of time. Unfortunately, in my experience one in-service may be inadequate as it may take your assistants repeated use of a new device to become familiar and comfortable using it. It is very important to develop a cadre of experienced assistants for ERCP work. If you have to perform ERCPs in a surgical operating room with duty surgical technicians assisting, at certain times of day and especially during weekends, no one with ERCP experience may be on duty. In that event, it may be better to transfer a sick patient requiring urgent ERCP to a referral center which is suitably staffed rather than attempt a difficult procedure without experienced support staff.
An important piece of equipment for all endoscopy units is an electronic reporting system to generate endoscopy reports. A number of these are available for purchase, several through major endoscope suppliers. Electronic record keeping is here to stay, especially with the introduction of the Affordable Care Act. However, many small endoscopy units still rely on physician dictations and printouts of endoscopic images. This is not a sustainable mechanism for producing medical records. Not only is it difficult to search these records, but prospective or retrospective review of large numbers for quality assurance becomes a daunting task. Carbon dioxide (CO2) used for insufflation during endoscopy reduces gaseous distension of the bowel from prolonged procedures and hastens recovery [7]. It is common for patients who have undergone long ERCP procedures to have significant gaseous distention of the bowel, resulting in post-procedure pain and delayed recovery. This pain may masquerade as PEP in evolution. Substituting CO2 for air for insufflation effectively addresses this problem, as unlike air CO2 rapidly diffuses across the bowel wall into the circulation for rapid excretion by the lungs. For a relatively small investment in a CO2 tank connected to the air pump, post-procedure recovery times after endoscopy can be significantly shortened. Early concerns that CO2 insufflation of this type might lead to problems with hypercapnia have proved groundless. When ERCP is performed in the operating room immediately before laparoscopic cholecystectomy for suspicion of a retained bile duct stone, gaseous distension of the small bowel can create problems for the surgeon. CO2 insufflation prevents this problem.
Execution: The Procedure
Passing the Duodenoscope
Modern duodenoscopes are sophisticated devices that have undergone considerable evolution since ERCP was first introduced in the late 1960s. The current duodenoscopes are much more flexible with a smaller external diameter but a larger caliber instrument channel than their predecessors. The “quantum leap” in endoscopic imaging arrived with the change from fiberoptics to electronic [charge coupled device (CCD)] technology [8]. The only part of a modern endoscope that employs fiberoptics is the light guide used for illumination. It may be a cliché, but it is not an exaggeration to say that the original duodenoscopes were primitive and crude compared to the precision tools of today (in terms of automotive development, Model T Fords compared to Rolls Royces!) Part of the unavoidably long learning curve required for ERCP involves gaining familiarity and comfort handling duodenoscopes, which are decidedly differently from all other endoscopes. Detailed descriptions of the modern duodenoscope are available elsewhere [9]. What matters most when passing the duodenoscope into the duodenum is an understanding of the various axes of motion of the scope, and how they are used to obtain the best position for cannulating. The axes of motion are push-pull, twist (torque on the shaft) right and left, and tip deflection (up/down and right/left, controlled by the dials on the control head). In addition, the “angle of attack” of the catheters and other accessories passed through the instrument channel can be varied using the elevator, a small moveable ramp at the bottom of the instrument channel controlled by a lever on the control head. Positioning the duodenoscope tip in front of the papillary fold on the medial wall of the second part of the duodenum is achieved by advancing it through the hypopharynx into the esophagus, through the stomach, exiting out of the pylorus and passing into second/third part of the duodenum. At this point the duodenoscope is in the long position, which is unfavorable for cannulation. To achieve correct orientation, the right–left control wheel is locked in the full-right position and the scope gently pulled back to remove the gastric loop. When done correctly, the major duodenal papilla almost always pops into view directly ahead with this shortening maneuver. Small adjustments are usually necessary to fine tune the position, and a motility-control agent, such as glucagon, may have to be administered to inhibit peristalsis.
Passing the duodenoscope through the patient’s mouth into the hypopharynx and then through the upper esophageal sphincter (UES) into the esophagus merits further review. The tip of the duodenoscope is rounded, so it can be passed “blind” with modest pressure. Experienced ERCP endoscopists can interpret the side-viewing images during intubation, but they usually confuse beginners, who are determined to see where the duodenoscope is going. I tell my trainees not to overthink the process. Provided that the lubricated duodenoscope tip is passed over the back of the tongue and maintains a posterior track, it will almost always pass smoothly through the UES into the esophagus. Some endoscopists teach their trainees to lock the tip controls for intubation to maintain curvature on the end of the duodenoscope, but I consider this a potential risk for injury and discourage it. Modest—but not major—forward pressure on the duodenoscope shaft is needed to advance the instrument. If resistance is encountered, it is always best to pull back and try again rather than risk traumatizing the fragile hypopharynx. Neck positioning may influence the ease or difficulty of scope passage, and occasionally cervical spine bone spurs may provide resistance. If a few gentle attempts to pass the duodenoscope fail, I recommend passing a standard gastroscope to assess the local anatomy. If no obvious cause for failing to pass the duodenoscope is identified, you can try to advance it over a guidewire. A long 0.035-in. guidewire can be placed into the stomach using the gastroscope, which is then removed while maintaining the wire position. The wire is captured into a cannula advanced down the instrument channel of the duodenoscope, and finally the duodenoscope is advanced over the wire into the esophagus. I have used this technique successfully a number of times. Another option is to pass the duodenoscope using the blade of a laryngoscope for visualization and guidance. Anesthesia providers are happy to assist you with a laryngoscope. Patients who have had prior head and neck surgery for cancer (and often radiation therapy) require particular care, as they often have altered anatomy that makes passing adult caliber duodenoscopes difficult or impossible. Unsuspected esophageal webs, rings, and strictures can all interfere with duodenoscope passage, as well as the possibility of a Zenker’s diverticulum catching the duodenoscope tip.
Negotiating the pylorus is often an adventure too! In patients with a large, J-shaped stomach, it is usual to run out of duodenoscope before reaching and traversing the pylorus due to the formation of a large loop in the stomach. The way to manage this is first to remove as much air as possible (consistent with maintaining an adequate view) in order to collapse the stomach. If this does not allow the duodenoscope tip to access the pylorus, move the patient from semi-prone into the left lateral position (warning: this may make you unpopular in the operating room, where the patients are usually taped or strapped tightly in position, but it is necessary!). In most cases, this maneuver allows you to intubate the duodenum through the pylorus. The patient can then be repositioned semi-prone and the shortening maneuver undertaken to visualize the major papilla.
Accessing the major duodenal papilla is rendered difficult by benign or malignant stenoses of the gastric outlet or duodenal sweep, as may occur in cancers of the duodenum and head of the pancreas (Fig. 4.3). Dilation of strictures with or without subsequent metal stenting may be necessary to access the papilla. EUS-guided biliary access techniques may be used to overcome stenoses involving the vicinity of the major duodenal papilla: for example, a dilated bile duct may be accessed through the duodenal bulb by EUS-guided needle puncture and subsequent guidewire placement (Fig. 4.4a, b, c, d and Chap. 34) [10]. However, this remains an experimental technique for experts only at present, due to the risk of retroperitoneal leaks and perforations [11]. It is anticipated that EUS-guided biliary access will become more widely available when suitable tools have been developed to minimize these risks. Combined radiologic-endoscopic procedures (“rendezvous”) were used to deal with difficult cannulation situations 20 years ago, but have gone out of fashion due to the increased morbidity associated with them (Fig. 4.5) [12]. Endoscopists try very hard to avoid subjecting their patients to percutaneous biliary procedures, because of the inevitable inconvenience and discomfort associated with them. Unfortunately, these combined procedures were frequently used as an alternative to skill at biliary cannulation, to the patients’ detriment.
Fig. 4.3
Malignant stenosis at junction of 1st and 2nd part of duodenum preventing access to duodenal papilla for ERCP
Fig. 4.4
Endoscopic ultrasound ( EUS) access for difficult biliary cannulation. a After needle puncture through the posterior duodenal bulb, a contrast cholangiogram is obtained. b Using the same needle, a 0.025-in.-diameter guidewire is passed down the bile duct and into the duodenum. c Endoscopic view of the papillary area showing the guidewire exiting. d Using the guidewire, which is grasped with a basket and pulled up the instrument channel of the EUS scope, an expandable metal mesh biliary stent was placed in the standard fashion
Fig. 4.5
External-internal biliary drain placed as prelude to a combined radiologic-endoscopic (“rendezvous”) procedure
Altered surgical anatomy, including Billroth II (BII) partial gastrectomy and Roux-en-Y diversions, creates other difficulties (Chap. 17). Provided that the afferent limb of the BII anatomy is relatively short, most experienced ERCP endoscopists have little difficulty finding it. This requires a special technique for retrograde (compared to the usual route) access to the papilla up the blind-ending afferent limb. The major duodenal papilla is upside down from the perspective of the endoscopist, which requires modification of cannulation technique. If the tip of the duodenoscope cannot be torqued into a position in which a papillotome, which has a gently curved tip, can be advanced into the duct of choice, a straight catheter may work better. The need to access a surgical Roux limb of small bowel has increased considerably recently with the introduction of bariatric surgery. The most common type of Roux diversion currently in vogue creates considerable difficulty for ERCP, as the Roux limb is usually too long for a standard duodenoscope. Even when the papilla is reached using a colonscope or enteroscope and special long accessories, it can be technically very difficult to perform the standard therapeutic ERCP maneuvers using an endoscope without an elevator. An alternative approach involves shortening the distance needed for duodenoscope insertion by bypassing the esophagus. This can be accomplished by creating a gastrostomy track with percutaneous endoscopic gastrostomy (PEG) [13] or using a laparoscopic trochar. The disadvantage of the PEG technique is that 6 weeks are required to allow the gastrostomy track to mature, so this approach does not help when the patient needs urgent ERCP. A more elegant approach is to combine laparoscopic access to the gastric remnant with ERCP performed through the laparoscopy trochar [14]. Following laparoscopic puncture of the gastric remnant by the surgeon, the cannula of the trochar is removed and replaced with the duodenoscope, which is just small enough in caliber to pass through it. The papilla can be reached through the pylorus after which ERCP is performed in the standard fashion. I have performed this procedure on numerous occasions and found it a nice solution to a difficult problem in patients with post-bariatric surgery anatomy needing urgent ERCP.
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