Approaching 50 Years

SECTION I

General Topics

1  Approaching 50 Years: The History of ERCP Lee McHenry and Glen Lehman

Endoscopic retrograde cholangiopancreatography (ERCP) has been a remarkable technological advance that has evolved over its nearly 50 years in the field of gastrointestinal endoscopy and has redefined the medical and surgical approach to patients with pancreatic and biliary tract diseases. Since its inception in 1968, the medical community has witnessed significant achievements by the pioneers in endoscopy who incrementally advanced ERCP techniques from their infancy to maturity. The infancy focused on diagnoses, the adolescence on therapies of common biliary tract diseases such as bile duct stones and malignant strictures, the early adulthood on therapy for diseases of the pancreas and prevention of pancreatitis, and now the mature adulthood focuses on continued refinement of techniques to make ERCP safer and more effective. The pioneers in the ERCP field are numerous and have played significant roles in developing new techniques and novel instrumentation, spearheaded innovative techniques to reduce adverse events, and effectively trained future generations of endoscopists to safely perform ERCP. We are now approaching a 50-year milestone, and as we look back, we can recall a journey in ERCP that has been enjoyable, exciting, and replete with enthusiastic innovation, and in the end has benefitted many patients (Box 1.1). It would encompass an entire book to incorporate all of the important contributions made by the many ERCP endoscopists over the past 50 years. We apologize in advance to individuals who have advanced the field and are not mentioned in this brief summary of the history of ERCP.

ERCP IN ITS INFANCY: 1968 TO 1980 In the 1920s, bile duct imaging was performed by surgeons Evarts Graham and Warren Cole with the use of intravenously administered iodinated phenolphthalein that was selectively excreted into the bile and recorded radiographically. Oral cholecystography and percutaneous skinny “Chiba” needle cholangiography were additionally developed to improve the visualization of the bile duct.1,2 What defied the clinician was a nonoperative technique to image the pancreatic duct. In 1965 two innovative radiologists, Rabinov and Simon,3 fashioned a bendable catheter that was inserted through a per oral basket catheter. The medial duodenal wall was “blindly scratched” with the tip of the catheter and the first pancreatogram was successfully obtained nonoperatively. In eight attempts, an interpretable pancreatogram was obtained in two patients. The gastrointestinal endoscopist now entered the arena. In 1968 William McCune and his surgical colleagues at George Washington University were credited with the first report of endoscopic cannulation of the ampulla of Vater in living patients.4 McCune used an Eder fiberoptic

duodenoscope (Eder Instrument Company, Chicago, IL), which had both a forward and side lens and an endotracheal-type cuff placed on the scope just beyond the lens. The balloon was inflated and deflated to enable adequate focal length for mucosal visualization. McCune taped a small-diameter plastic tube that served as a tract to the endoscope that could house a bendable cannula. The cannula was advanced to the major duodenal papilla under endoscopic guidance. In his report of 50 patients, McCune’s duodenal intubation success rate was only 50%, with only 25% pancreatic duct opacification. As stated in his discussion: “Anyone who looks through one of these instruments has to have 2 personality characteristics. First, he has to be honest, and second, must have an undying, blind, day and night, uncompromising persistence.” ERCP was now born, and it slowly grew to an established technique as a result of the honesty and persistence of the pioneers of endoscopy. In March 1969 in Japan, Oi (Fig. 1.1) and colleagues—in close collaboration with Machida (Machida Endoscope, Ltd., Tokyo, Japan) and Olympus corporations (Olympus Optical Co., Ltd., Tokyo, Japan)— developed a side-viewing fiberoptic duodenoscope with a channel and an elevator lever to enable manipulation of the cannula. Initially, Oi visualized the ampulla in about half of 105 cases.4 In a subsequent report, Oi cannulated the papilla in 41 of 53 patients (77%) without significant morbidity.5 By 1972, Jack Vennes and Steven Silvis of the University of Minnesota published the experience in their first 80 attempts at cannulation of the bile and pancreatic ducts, paving the way for acceptability in the American endoscopic wilderness6 (Table 1.1).7,8 Over the next 5 years, pioneers such as Safrany, Cotton, Geenen, Siegel, Classen, and Demling and the Japanese groups embraced this new technique and reported on the successes (cannulation rates of >90%) (Fig. 1.2), the shortcomings (e.g., post-ERPC pancreatitis [PEP]), the nuances (variety of cannula types, cannulation angles), and the practical application of ERCP in our understanding of biliary and pancreatic disorders.9–15 But what could we as endoscopists do with this new-found knowledge? Simultaneously in 1973, in separate regions on the globe, ERCP investigators conceived the concept of a therapeutic application of ERCP. The sphincter of the intact papilla served as a barrier to reflux of duodenal contents into the bile and pancreatic duct and was an impediment to removal of stones from the bile duct. Independently, Demling and Classen in Erlangen, Germany, and Kawai in Kyoto, Japan, developed similar techniques to split the sphincter. Demling and Classen developed a high-frequency diathermy snare, the Demling-Classen probe consisting of a Teflon catheter with a thin steel wire that could be protruded to create a “bowstring” that would sever the papillary muscle (Fig. 1.3).15–17

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SECTION I  General Topics

BOX 1.1  History of ERCP: Five Decades, Decade by Decade 1970s: Diagnosis and Therapy • Locating the ampulla • Biliary and pancreatic duct cannulation • Interpretation of cholangiography and pancreatography, identifying pathology • First reports of biliary sphincterotomy • Developing the instruments: balloon extraction of bile duct stones and stent placement 1980s: Slowly Shifting from Surgery to Endoscopic Management of Pancreaticobiliary Disorders • Refinement of accessories, improvements in radiographic imaging • Reporting adverse events of sphincterotomy • Biliary stent placement for obstructive jaundice and shift from palliative surgery • Introduction of the teaching head: “seeing is believing” • Acceptance of ERCP by the medical community • Management of CBD stones shifts from surgery to endoscopy • ERCP training gets its start for physicians and ERCP nurses • Basic threshold numbers for competence 1990s: Training and Expanding Our Therapies • More emphasis on advanced training • Endoscopic photography and videography: sharing images with others • Referring MDs, patients, and industry • Comparison of one procedure to another • Teaching and training • “Theater presentations” of ERCP • Therapies for pancreatic disorders: chronic pancreatitis, pseudocysts, and necrosis • Era of laparoscopic cholecystectomy and bile duct injuries

• Safer sphincterotomy: monofilament wires and computer-regulated blended current • Self-expandable metallic stents • Complementary pancreaticobiliary techniques developed • Endoscopic ultrasonography (EUS) and magnetic resonance cholangiopancreatography (MRCP) 2000s: Prevention, Pulverizing, and Peculiar Pancreas Diseases • Pancreatic stents and post-ERCP pancreatitis prevention • Improved techniques for extraction of “large” bile duct stones are implemented • Papillary balloon dilation • Single-operator system for intraductal lithotripsy • Intraductal papillary mucinous neoplasm (IPMN) and autoimmune pancreatitis (AIP) recognized • “Hands-on” courses • EUS and ERCP therapeutic interface 2010s: Refinements of ERCP Techniques and New Treatments • Pharmacologic agents (rectal NSAIDs) for post-ERCP prevention • Revised recommendations for sphincter of Oddi dysfunction diagnosis and therapy • ERCP scope infections are revisited and rigorous cleaning processes of ERCP scopes are revised • Novel ERCP treatments for cholangiocarcinoma, including photodynamic therapy and radiofrequency ablation, are introduced • Charge-coupled device (CCD) imaging improves intraductal cholangioscopy and pancreatoscopy

TABLE 1.1  ERCP in Its Infancy: Cannulation Rates Around 1972 Group

Total

Overall Success (%)*

Selective Success Pancreatic (%)

Selective Success Biliary (%)

Ogoshi Oi Kasugai Cremer Cotton Classen Safrany Vennes

283 310 270 144 132 541 145 80

88 81 74 76 83 86 94 75

68 78

63 73

*Generally defined as entry into either duct. From Cotton PB. Progress report: cannulation of the papilla of Vater by endoscopy and retrograde pancreatography (ERCP). Gut 1972;13:1014–1025.

Canine experiments ensued and demonstrated that a papillotomy could be performed safely without bleeding or perforation. An added benefit of the Demling-Classen probe was that contrast dye could be instilled while the catheter was in place. In Japan, Kawai developed a papillotomy device consisting of two separate 2-mm-long diathermy knives that protruded from the catheter tip and could be used to incise the papillary sphincter, similar to the present-day needle knife technique.15 This device was particularly useful in patients with impacted stones at the papilla. The Erlangen probe, because of a perceived reduction in the risk of perforation, was more accepted in the West, and sphincterotomy as a technique was born. The initial concern of postsphincterotomy scarring was postulated, but the incidence was found to be infrequent. The first

therapeutic application during ERCP, with incumbent well-chronicled risks, was gradually adopted by endoscopists around the world. Bile duct stones were accurately diagnosed at the time of cholangiography, biliary sphincterotomy was performed, and the stones were left in the bile duct to pass on their own. This clinical problem needed a solution, and as is true with the many endoscopic techniques, the fundamental elements for major endoscopic technological advances were borrowed heavily from other fields (i.e., urology: basket, stent, and balloon technology; radiology: catheter and guidewire technology; cardiology: catheters and metallic stents). To solve the clinical problem of removing stones from the bile duct, in 1975 Zimmon and colleagues18 in New York reported removal of bile duct stones with balloon-tipped catheters, a

CHAPTER 1  Approaching 50 Years: The History of ERCP technique that further expanded the endoscopist’s therapeutic armamentarium. Long, flexible balloon-tipped catheters, basket catheters, stone-grasping forceps, and endoscopic laser or ultrasound stone disintegrators were miniaturized to fit through the endoscope working channel, and removal of bile duct stones no longer required surgical laparotomy and open choledochotomy.

FIG 1.1  One year after Dr. William McCune successfully performed the first ERCP at George Washington University, in Japan Dr. Itaru Oi, with his chief, Dr. Takemoto, performed endoscopic cholangiopancreatogram (ECPG), as it was called, with a Machida scope in 1969.5 The method used was almost the same as Dr. McCune’s method of using a prolonged gastrofiberscope. In close collaboration with the Machida and Olympus corporations, Oi developed a side-viewing fiberoptic duodenoscope with a channel and an elevator lever to enable manipulation of the cannula. (Photo courtesy Dr. Peter Cotton, Medical University of South Carolina.)

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The 1970s were an exciting time for ERCP, but many physicians (gastroenterologists and surgeons) were appropriately concerned about the dangers of the procedure, particularly PEP, bleeding, and biliary sepsis. In 1976, Bilbao and colleagues19 surveyed 402 U.S. owners of side-viewing duodenoscopes who had collectively performed 10,435 ERCPs. The procedure failed in 30%, adverse events occurred in 3%, and death occurred in 0.2%. Pancreatitis was associated with injection into the pancreatic duct and sepsis with injection into an obstructed bile duct. Inexperience led to a fourfold increase in failures (62%) and twice the rate of adverse events (7%). ERCP was the riskiest procedure for the endoscopist, yet was gradually embraced, and the physicians who had the willingness and ability to perform ERCP forged ahead. In looking back in ERCP history over the past 5 decades, the gastroenterology community was aware of the high incidence and potentially severe adverse events associated with ERCP; however, the absolute requirement of advanced training and expertise before subjecting patients to this potentially lethal procedure was understated, minimized, and inadequately addressed. These should serve as reminders and lessons for the future as new endoscopic procedures are introduced. Malignant bile duct obstruction posed a problem to the ERCP physician in the 1970s. Endoscopic cannulation of the bile duct introduced bacteria-laden contrast dye into an obstructed biliary tree, and endoscopic sphincterotomy alone would not provide adequate biliary drainage except in the most distal bile duct or ampullary cancers. Percutaneous transhepatic methods for biliary drainage were commonly employed preoperatively in patients with deep jaundice or for palliation, and the first report of a percutaneous transhepatic cholangiography (PTC)-guided internal bile duct prosthesis was reported by Burcharth et al. in 1979.20 In 1980, the ERCP groups in England (Laurence and Cotton21) and Germany (Soehendra and Reynders-Frederix22) reported the early cases of internal decompression of malignant biliary obstruction by ERCP-directed biliary endoprosthesis placement (Fig. 1.4). The initial methods relied on “borrowed” technology and reported the uses of a 7-Fr nasobiliary drain fashioned from an angiographic catheter and a “pigtail” stent cut from a 7-Fr Teflon catheter. Over the next 30 years, with the aid of industry and ingenuity, biliary endoprosthesis design continued to advance from the back table of the craftsman/endoscopist to the precision engineering of multisized polyethylene stents and

FIG 1.2  In the early days: First ERCP by Dr. Ogoshi at the Niigata Cancer Center Hospital, Japan, in 1970. Radiographs showing complete pancreatography (left) and the distal bile duct (right). Note the long scope position to obtain pancreatography. (Photo courtesy Dr. Peter Cotton, Medical University of South Carolina.)

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SECTION I  General Topics

FIG 1.3  The endoscopic and fluoroscopic images from the first sphincterotomy performed by Drs. Nakajima and Kawai in Kyoto, Japan, in 1974. Clockwise from left: The fluoroscopic images on the left show the distal bile duct calculus (arrow) with upstream filling of the bile duct. The catheter was used for cannulation and sphincterotomy. On the right, the cholangiogram and pancreatogram revealing bile duct clear of filling defect. In the bottom middle is the limited field of view of the duodenal papilla on the left and the papilla after sphincterotomy on the right. (Photo courtesy Dr. Peter Cotton, Medical University of South Carolina.)

self-expandable metallic stents. Effective palliation of malignant biliary obstruction was wrestled from the surgeon and radiologist, and planted for good into the endoscopist’s hands.

THE SECOND DECADE: 1980 TO 1990 Over the next 10 years from 1980 to 1990, medicine witnessed an explosion in the number of ERCPs performed throughout the world. However, this explosion did not occur in a vacuum and was fueled by burgeoning technology in other medical disciplines such as radiology, anesthesia, pathology, and surgery. In 1979, the Nobel Prize in Medicine was awarded jointly to Godfrey N. Hounsfield (U.K.) and Allan McLeod Cormack (Tufts University, Medford/Somerville, MA) for independently inventing the computerized axial tomography (CAT) scanner. Assessment of the patient with pancreatobiliary disease was transformed from physical examination, ultrasound, and plain radiographs, and their inherent limitations to precise computed tomography (CT) characterization and localization of the problem at hand. Improved perioperative management and anesthesia care made the ERCP procedure more acceptable to patients. Pathologic interpretation of endoscopic biopsies and cytologic assessment of brushings continued to improve, with increased number of specimens and physician experience allowing tissue diagnosis to be made nonoperatively. The surgeon’s role evolved from exploration for diagnosis with its inherent morbidity and mortality to a more focused therapeutic operation that would lead to improved patient outcomes. Industry played a major role in the close collaboration with endoscopists in designing improved versions of ERCP accessories, including cannulas, sphincterotomes, and endoscopic stents, which led to improved therapeutics and improved patient outcomes. Companies such as Wilson-Cook (now Cook Endoscopy, Winston-Salem, NC), Olympus (Center Valley, PA, and Tokyo, Japan), Bard (now ConMed, Utica, NY), and Microvasive (now Boston-Scientific, Marlborough, MA) and many

others forged tight, long-lasting relationships with the pioneers in ERCP, which accelerated innovation in the field (Fig. 1.5). Both ERCP endoscopists and patients benefited from increased cannulation rates, improved sphincterotomies, and reliable prostheses. The domain of bile duct stones and palliation of malignancies shifted from surgeons to endoscopists. One of the recurring themes in endoscopic advances is the importance of close collaboration of engineers and clinicians to attempt to solve clinical problems. Fiberoptic endoscopy was the platform for the ERCP gastroenterologist in the 1970s and posed a challenge for performance of and training and reporting in ERCP. Documenting endoscopic findings was limited in quality, as the camera head attachment was bulky and, when affixed, precluded real-time visualization of the endoscopy image. To share the endoscopy experience, a teaching head apparatus would connect to the endoscope to allow a second observer (an ERCP trainee or procedural nurse) to visualize the endoscopic image. The major drawbacks were halving of the light transmitted through the fibers to the eyepiece, allowing only one observer on the teaching head, and limiting the nurse to the use of only one hand to perform important functions such as wire advancement while holding the teaching head with the other hand. The first videoendoscope had a small television camera in the tip of the endoscope (charge-coupled device [CCD]) and was connected to a computer capable of transforming electronic signals into a recognizable image. Sivak and Fleischer23 in the United States and Classen and Phillip24 in Germany reported on their first experiences in 1984. Videoendoscopy had transformed the ERCP experience for the performing physician, the trainees, and the ERCP nurses to a more dynamic, less solitary experience and launched ERCP training to a new level.

THE THIRD DECADE: 1990 TO 2000 In the decade of 1990 to 2000, several breakthrough technologies in radiology, endoscopy, and surgery were introduced that would impact

CHAPTER 1  Approaching 50 Years: The History of ERCP

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resonance cholangiopancreatography (MRCP) to image noninvasively the bile and pancreatic ducts.26,27 Endoscopic ultrasonography (EUS), originally described in 1980 by DiMagno et al.,28 was introduced with the radial scanning echoendoscope, which became a staple for clinical care in the late 1980s. Linear endosonography followed in 1994 and had the added advantage of diagnostic fine-needle aspiration. Laparoscopic cholecystectomy was first performed in 1987 by Mouret (unpublished) and reported in 1989 in Europe by Dubois et al.29 and Perissat et al.30 and in the United States by Reddick and Olsen.31 Laparoscopic cholecystectomy transformed the practice of ERCP, with more reliance on endoscopists to remove bile duct stones preoperatively or postoperatively.32

ERCP IN THE NEW MILLENNIUM

FIG 1.4  ERCP-directed bile duct drainage using biliary stents was introduced by Soehendra and Reynders-Frederix from Hamburg, Germany, in 1979, adding to the armamentarium of therapeutic ERCP. The team used a 20-cm-long, 7-Fr radioopaque angiographic catheter with 12 side holes inserted over a guidewire with a single pigtail that allowed it to be fixed inside the bile duct. (Photo courtesy Dr. Peter Cotton, Medical University of South Carolina.)

FIG 1.5  Industry played a pivotal role in the field of ERCP. The Olympus duodenoscope model JF (pictured here with camera attached) was introduced in 1971. The JF duodenoscope was fiberoptic, had a 65-degree view angle, and was fitted with an elevator. The channel size was <2 mm diameter, limiting the size of catheters that could be used and making suctioning around the catheter problematic. (Photo courtesy Dr. David Barlow, Olympus Corporation.)

the field of pancreaticobiliary disease and the ERCP endoscopist. These technologies blossomed and ultimately transformed the indications for ERCP from a diagnostic/therapeutic procedure to a predominately therapeutic one.25 This transformation was driven in part by the introduction of magnetic resonance imaging (MRI)/magnetic

In the fourth and fifth decades, ERCP as an endoscopic procedure was widely available and practiced by many gastroenterologists in nearly every hospital with more than a 50-bed capacity. In the earlier decades of ERCP, the technique was adopted initially based on logic and began to grow based on cannulation success and eventually therapeutic success. There were few prospective, controlled, randomized, outcome-based studies in the early years, in part because of the excitement and enthusiasm of innovation and the lack of funding (and applications for funding) for endoscopic studies. The growth of ERCP decade by decade was in part attributable to the continued refinement of techniques and introduction of new innovations. In the new millennium, the “science of ERCP” has now become the focus. Prospective scientific studies have flourished since the year 2000, including studies evaluating the role of ERCP in gallstone pancreatitis,33 malignant biliary obstruction (preoperative endoscopic drainage followed by pancreaticoduodenectomy compared with primary pancreaticoduodenectomy alone),34 and sphincter of Oddi dysfunction (National Institutes Health–sponsored EPISOD trial) comparing sham therapy to manometrically directed sphincterotomy),35 and studies using pancreatic stents and pharmacologic agents to prevent PEP.36 Comparative trials evaluating novel therapies for cholangiocarcinoma, including photodynamic therapy (PDT) and radiofrequency ablation (RFA), emerged. With the benefit of hindsight, in the 5-decade history of ERCP we could pose the following: What were the shortcomings of the incorporation of this technology into standard clinical practice? The risks of ERCP were underrecognized and underreported, particularly with respect to pancreatitis and perforation.37 An attempt to stratify patients at the greatest risk for PEP was not addressed until the fourth decade by Freeman and colleagues in 2001.38 Informed consent for ERCP was cursory, and in many instances, full disclosure of the potential risks and severity of adverse events was not provided to patients. Self-training was the norm in the first decade of ERCP, but advanced training became more readily available in the 1980s and 1990s. The endoscopy societies were lax in guiding ERCP training programs and community hospitals in the number of ERCPs necessary to attain a base level of competence. The Gastroenterology Core Curriculum of the Gastroenterology Leadership Council (joint effort of the American Association for the Study of Liver Diseases [AASLD], American College of Gastroenterology [ACG], American Gastroenterological Association [AGA], and American Society for Gastrointestinal Endoscopy [ASGE]) in 1996 did not recommend a specific number of ERCPs necessary to assess competence. An early ASGE guideline recommended 100 ERCP procedures (75 diagnostic and 25 therapeutic) as the minimum number of ERCPs before one could assess competency. The threshold still remains unclear, with the suggestion that at least 180 procedures are necessary.39 Yearly ERCP volume by the endoscopist practicing ERCP has not been established to guide credentialing agencies.

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SECTION I  General Topics ERCP CASES OVER 25 YEARS INDIANA UNIVERSITY GI DIVISION 3500 2840

3000

3069

2495

2500 # ERCPs

THE FUTURE OF ERCP

2000

1658

1500

1153

1000 500

550 150

0 1983 1988 1993 1998 2003 2008 2010

FIG 1.6  ERCP case volume over 25 years at the Indiana University Division of Gastroenterology.

A “shift” of high-risk, complicated ERCP procedures to referral centers is reflected in the growing number of ERCPs performed at our institution over the past 15 years (Fig. 1.6). Hands-on training opportunities for practicing gastroenterologists to improve ERCP skills are scarce, and real-life simulators for ERCP are still not available.

As we look back at the history of ERCP, we can take time to speculate about ERCP in the future. Capsule cameras and remote-guided cameras may complement or replace handheld gastroscopy, enteroscopy, and colonoscopy, but we foresee that endoscopic cannulation of the pancreaticobiliary system will remain the standard. Improvements with CCDs, even smaller-diameter choledochoscopes, and pancreatoscopes are eagerly awaited and should soon become a practical reality. However, optimal view, steerability, and durability remain as challenges. Hands-free manipulation of endoscopes, similar to robotic-assisted surgery, is anticipated with the advantages of reduced endoscopist fatigue, improved ability to train endoscopists, and more refined movement of accessories. Pancreaticobiliary tumor diagnosis and tissue sampling will undoubtedly improve with advances in intraductal endoscopy. Endoscopic pancreatic cancer screening of high-risk groups may become a reality. Pancreatitis management may benefit from a more defined endoscopic role. Dissolution of intraductal pancreatic stones may be possible with the aid of endoscopically placed catheters. Studies of pancreatic juice may provide predictors of recurrent pancreatitis, pancreatic cancer risk, and response to chemotherapy. Continued effort is needed to make ERCP safer and more effective. Advanced training programs must continue to ensure that ERCP endoscopists are adequately trained and skilled in the performance of this procedure. The complete reference list for this chapter can be found online at www.expertconsult.com.

KEY POINTS • In the early years of ERCP in the 1970s, pioneers such as McCune, Oi, Classen, Kawai, Cotton, Vennes, Silvis, Geenen and others established a new technology. • Close collaboration was vital between the endoscopist and industry to design new instrumentation, leading to higher cannulation rates, improved sphincterotomy, more effective drainage techniques, and improved outcomes. • The early adopters of ERCP were self-taught, and subsequent trainees were schooled using the apprentice model. Training accelerated with

introduction of videoendoscopy. Minimum qualifications for ERCP competency were poorly defined. • In the new millennium, ERCP endoscopists have emphasized scientific rigor with several prospective, outcome-based studies. Newer techniques such as prophylactic pancreatic stent placement were adopted to make ERCP safer in high-risk patients.

CHAPTER 1  Approaching 50 Years: The History of ERCP

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22. Soehendra N, Reynders-Frederix V. Palliative bile duct drainage: a new endoscopic method of introducing a transpapillary drain. Endoscopy. 1980;12:8–11. 23. Sivak MJ, Fleischer DE. Colonoscopy with a video-endoscope: a preliminary experience. Gastrointest Endosc. 1971;18:66. 24. Classen M, Phillip J. Electronic endoscopy of the upper GI tract: initial experience with a new type of endoscope that has no fiberoptic bundle for imaging. Endoscopy. 1984;16:16. 25. Sherman S, Lightdale CJ, editors. Endoscopic therapy of pancreatic disease. Gastrointest Endosc Clin North Am. 1998;8:1–272. 26. Wallner BK, Schumacher KA, Weidenmaier W, et al. Dilated biliary tract: evaluation with MR cholangiography with a T2-weighted contrastenhanced fast sequence. Radiology. 1991;181:805–808. 27. Fulcher AS, Turner MA, Capps GW, et al. Half-Fourier RARE MR cholangiopancreatography: experience in 300 subjects. Radiology. 1998;207:21–32. 28. DiMagno EP, Buxton JL, Regan PT, et al. Ultrasonic endoscope. Lancet. 1980;1:629–631. 29. Dubois F, Berthelot G, Levard H. Cholecystectomies par coelioscopie. Presse Med. 1989;18:980–982. 30. Perissat J, Collet DR, Belliard R. Gallstones: laparoscopic treatment, intracorporeal lithotripsy followed by cholecystostomy or cholecystectomy—a personal technique. Endoscopy. 1989;21(suppl):373–374. 31. Reddick EJ, Olsen DO. Laparoscopic laser cholecystectomy: a comparison with mini-lap cholecystectomy. Surg Endosc. 1989;3:131–133. 32. NIH Consensus Conference. Gallstones and laparoscopic cholecystectomy [review]. JAMA. 1993;269:1018–1024. 33. Attasanaranya S, Fogel EL, Lehman GA. Choleledocholithiasis, ascending cholangitis, and gallstone pancreatitis. Med Clin North Am. 2008;92:925–960. 34. van der Gaag NA, Rauws EA, van Eijck MD, et al. Preoperative biliary drainage for cancer of the head of the pancreas. N Engl J Med. 2010;362:129–137. 35. Cotton PB, Durkalski V, Orrell KB, et al. Challenges in planning and initiating a randomized clinic study of sphincter of Oddi dysfunction. Gastrointest Endosc. 2010;72:986–991. 36. Elmunzer BJ, Scheiman JM, Lehman GA, et al. A randomized trial of rectal indomethacin to prevent post-ERCP pancreatitis. N Engl J Med. 2012;366:1–9. 37. Cotton PB, Lehman G, Vennes J, et al. Endoscopic sphincterotomy complications and their management: an attempt at consensus. Gastrointest Endosc. 1991;37:383–391. 38. Freeman ML, DiSario JA, Nelson DB, et al. Risk factors for post-ERCP pancreatitis: a prospective, multicenter study. Gastrointest Endosc. 2001;54:425–434. 39. Jowell PS. Quantitative assessment of procedural competence: a prospective study of training in ERCP. Ann Intern Med. 1996;125: 937–939.