Current Indications and Methods

243

Review

Interventional Endoscopy Ducts: Current Indications David

J. Ott,1

John

H. Gilliam

111,2Ronald

of the Biliary and Methods

J. Zagona,1

and Garret

The use of interventional endoscopy of the biliary and pancreatic ducts has increased dramatically in recent years. Although choledocholithiasis is the most common reason for endoscopic treatment, other indications include pancreatolithiasis, cholangitis, biliary pancreatitis, papillary stenosis, sphincter of Oddi dysfunction, and benign or malignant ductal strictures. Endoscopic sphincterotomy is the cornerstone of therapeutic endoscopy and often precedes the use of balloon and basket stone extractors and placement of stents and endoprostheses. Other endoscopic methods include the use of lfthotripsy, placement of drainage and infusion catheters, and coupling with percutaneous techniques. Radiologists need to be aware of the expanding indications and va#{241}ety of endoscopic methods available for treating biliary and pancreatic disorders so that they can understand when the procedures are indicated.

ERCP was introduced more than 20 years ago as a diagnostic examination to evaluate pancreaticobiliary disease. Within a short time, endoscopic sphincterotomy was descnbed, and therapeutic applications of this technique developed rapidly. Interventional endoscopy of the biliary and pancreatic ducts has expanded dramatically in recent years, while its diagnostic uses have decreased with the continued advancements in cross-sectional imaging of the liver, biliary tree, and pancreas. Combined percutaneous and endoscopic manipulation of the biliary tract also has become an important therapeutic option in managing difficult or complicated biliary problems. This review provides an update of the current indications and methods of interventional endoscopy of the

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1992

0361

-803X/92/1

582-0243

© American

Roentgen

and Pancreatic

P. Young1

and pancreatic ducts, with emphasis on endoscopic sphincterotomy as the cornerstone of many of these therapeutic applications. biliary

Indications The indications for interventional endoscopic techniques in the biliary and pancreatic ducts include choledocholithiasis, pancreatolithiasis, suppurative cholangitis, biliary pancreatitis, papillary stenosis, sphincter of Oddi dysfunction, and benign or malignant ductal strictures. The most common indication is choledocholithiasis, in part, because the reported morbidity and mortality rates from endoscopic treatment are lower by at least half than those described for surgical exploration of the common bile duct and stone extraction [1]. Endoscopic intervention is the treatment of choice for retained or recurrent stones in the common bile duct in patients who have had cholecystectomy, and is successful in 86-98% of attempted cases, with complete clearance of stones in the common bile duct in 85-90% of those patients [2]. However, endoscopic management of choledocholithiasis in patients with intact gallbladders remains controversial, although there is agreement that endoscopy is indicated in patients more than 50 years old or in patients at increased risk for surgery [3]. Only a minority of elderly patients need cholecystectomy after successful endoscopic clearance of ductal stones [4]. Endoscopic treatment of choledocholithiasis is not recommended in patients less than 50 years old who have intact

Received May 3, 1991; accepted after revision October 7, 1991. ‘Department of Radiology, Bowman Gray School of Medicine, Wake Forest Wiversty, requests to D. J. Ott. 2Department of Medicine, Bowman Gray School of Medicine, Wake Forest 1.kiiversity, AJR

Article

Ray

Medical

Center Blvd., Winston-Salem,

Winston-Salem, Society

NC 27157-1088.

NC 27157-1088.

Address

reprint

244

OTT

gallbladders because of the potential long-term risks. Endoscopic sphincterotomy reduces the bile-salt pool, most likely by increasing enterohepatic cycling of bile salts and decreasing the fraction of the pool stored in the gallbladder [5]. Conversely, in patients who have had cholecystectomy and who already have a smaller total bile acid pool, sphincterotomy produces no further reduction. Bacterial colonization of the gallbladder and bile ducts after endoscopic biliary intervention is common, but is probably not important in the absence of ductal obstruction. These considerations are thought to be less critical in older patients, although in general long-term risks are most likely small [6-8]. The impact of laparoscopic cholecystectomy on the endoscopic treatment of ductal gallstones relative to the age of the patient and status of the gallbladder remains to be clarified [9]. Acute suppurative cholangitis and acute biliary pancreatitis with rapid clinical deterioration are more emergent indications for endoscopic intervention [1 0]. Severe sepsis can be reversed and surgical risk improved in severely ill patients by endoscopic drainage. In some patients, simple placement of a nasobiliary drain without sphincterotomy can relieve biliary sepsis [1 1 1. Also, dramatic clinical improvement in acute biliary pancreatitis may follow sphincterotomy [1 2]. An impacted ampullary stone is seen as a firm bulging ampulla, often with necrotic ulceration at its apex. When cannulation of the bile duct is impossible, electrocautery can be used directly over the stone to achieve an adequate sphincterotomy and promote ductal drainage. Papillary stenosis is an increasingly common indication for endoscopic treatment and is thought to occur after repeated passage of small biliary calculi, after surgical manipulation with Bakes dilators, or in association with periampullary diverticula [13, 14]. Endoscopic visualization can exclude ampullary carcinoma, and directed biopsies and cytologic brushing may be done at the time of ERCP. Endoscopic sphincterotomy has largely replaced operative sphincteroplasty for treating papillary stenosis, and both techniques achieve similar results. Papillary stenosis recurs in about 1 0% of patients treated by endoscopy, but is managed easily by repeating the procedure [2]. A variety of postcholecystectomy syndromes can be diagnosed by using biliary manometry and can be treated by endoscopic methods [1 3, 14]. The mechanisms of sphincter of Oddi dysfunction are poorly understood. Patients can have sphincter spasm, papillary stenosis, relapsing pancreatitis, periampullary diverticula, or abnormal motility of the sphincter of Oddi. Biliary manometry is done with a special catheter passed through the duodenoscope. The catheter is attached to a low-compliance water-perfused system by using three ports, each 2 mm apart at the tip. The catheter is placed in the distal portion of the common bile duct, then slowly withdrawn while pressure readings are obtained. The average normal pressure in the sphincter of Oddi is 8 mm Hg greater than the intraduodenal pressure. Patients with pressure differentials of 40 mm Hg or more between the sphincter and duodenum are defined as having sphincter of Oddi dysfunction [14]. When combined with symptoms of biliary colic, biliary tract dilatation with delayed emptying after cholangi-

ET AL.

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ography, elevations in alkaline phosphatase or bilirubin levels, or a combination of these features, biliary manometry can be used to diagnose sphincter of Oddi dysfunction. An unusual group of patients with sphincter of Oddi dysfunction has only idiopathic relapsing pancreatitis. Properly selected patients with any of these varied conditions may respond favorably to endoscopic

intervention

[13-15].

Benign or malignant strictures of the biliary and pancreatic ducts can be treated with endoscopic methods, which may be combined with percutaneous techniques. Benign biliary strictures

usually

result

from

injury

to the

bile duct

during

cholecystectomy and ductal exploration and, less frequently, from inflammatory disease due to stones and sclerosing cholangitis. Malignant biliary obstruction is most often caused by carcinoma of the pancreas. Endoscopic sphincterotomy is done to facilitate placement of indwelling stents and nasobiliary catheters in patients with biliary obstruction [1 6, 17]. Hydrostatic balloon dilators and tapered dilators can be passed

through

benign

or malignant

strictures.

Nonsurgical

palliation and preoperative biliary decompression are options for relieving jaundice and its accompanying symptoms. Often the choice between endoscopic or surgical biliary decompression is difficult, and the age and physical condition of the patient, location of the lesion, expected survival, and costs must be considered [18].

Methods

A variety of interventional developed

and include

endoscopic

endoscopic

methods

sphincterotomy,

have been various

balloons and baskets, intraluminal lithotnpsy, laser applications, assistance of extracorporeal lithotnpsy, catheters and infusions, stents and endoprostheses, and coupling with percutaneous cornerstone

procedures. of these

Endoscopic sphincterotomy is the therapeutic techniques [2, 4] (Fig. 1).

The side-viewing duodenoscope is passed into the second portion of the duodenum and aligned directly over the ampulla. A cholangiogram and a pancreatogram are obtained. If a sphincterotomy is definitely indicated, a sphincterotome is passed through the duodenoscope and advanced deeply into the common bile duct. Fluoroscopic confirmation that the sphincterotome is in the distal common bile duct is mandatory. A variety of sphincterotomes are available, all of them contaming 20 or 30 mm of exposed wire for electrocautery (Fig. 2). Once

positioning

in the

common

bile duct

is confirmed,

the sphincterotome is withdrawn until one half to one third of the wire is left in the ampulla. It is partially “bowed” by tightening the wire loop, and a sequential cut is made along the apex of the intramural segment of the intraduodenal portion of the choledochal sphincter and distal common bile duct. The length of the cut varies, according to the indication for sphincterotomy. When endoscopic sphincterotomy is done for choledocholithiasis, an attempt is made to size the opening to allow stone extraction. Bile duct stones are usually less than 10 mm in diameter, and a sphincterotomy incision of this size is needed [19]. Stones 10-15 mm in diameter require a longer

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ENDOSCOPY

OF BILIARY

Fig. 1.-Drawings show technique for endoscopic sphlncterotomy. aphincterotome is advanced fully into common bile duct, it is withdrawn until one half to one third of wire loop is Inserted. B, Sphincterotome is lifted upward, and wire loop is slightly bowed to begin cut. C, Sphlncterotomy Is continued until hooding fold is reached. D, En face view of a completed sphincterotomy shows orientation of cut along apex of ampullary fold. A, After

B

AND

PANCREATIC

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245

cut is done in the same manner and continued until a gush of bile is seen. This indicates that the sphincter fibers are fully cut. A long cut is not needed for these indications. When the reason for endoscopic sphincterotomy is facilitation for interventionaltherapy of benign or malignant strictures, the sphincterotome cut can be even shorter, just to allow passage of 10-French or 1 1 .5-French stents or dilating catheters. Complications of endoscopic sphincterotomy vary with the techniques used and the experience of the operator, and can be classified into early and late types [20]. Early types include hemorrhage, pancreatitis, cholangitis, perforation, and basket impaction. Late complications are cholecystitis if the gallbladder is intact, cholangitis, stone recurrence, and restenosis of the sphincteric region. In general, the overall complication rate has been 8-1 0%. Early complications in a compiled series of 7729 attempted sphincterotomies included hemorrhage, 3%; pancreatitis, 2%; cholangitis, 2%; and perforation, 1% [20]. In that same series, the mortality rate was 1%. Retroduodenal perforation occurs most often, and treatment of the perforation is controversial although fatalities have occurred [20]. Intraperitoneal perforation is rare. Late complications are more difficult to determine because follow-up may be incomplete, and treated asymptomatic patients are restudied rarely. The usual method of removing stones after endoscopic sphincterotomy is by balloon extraction or metal baskets [21] (Fig. 3). Currently available extraction balloons inflate from 8 to 14 mm in diameter and can be used to estimate the size of the sphincterotomy incision and to remove stones (Fig. 4). A balloon may not be effective in extracting stones if the duct is too dilated and the stone slips around the inflated balloon. Another potential problem is that balloons are fragile and may break. Baskets are the major alternative to balloon catheters for extracting stones (Fig. 5). Balloon dilators are also available for treatment of strictures, especially before stent placement, and for sphincter of Oddi dysfunction that may be affecting the biliary and pancreatic ductal orifices. The Dormiatype basket or a variation of it is most often used to capture the stone. Stones can be difficult to trap, particularly if large, and impaction of the basket can occur, but this is infrequent and rarely a serious complication. Intraluminal lithotripsy and extracorporeal shock-wave Iithotnpsy (ESWL) also have been used to manage choledo-

Fig. 2.-Available sphincterotomes include ball-tip cannula (A), conecannula (B), over-the-wire sphlncterotome (c), ball-tip sphlncterotome (D), precut sphincterotome (E), and push-hp sphincterotome designed for Blllroth II anatomy (F).

tip

incision but can usually be extracted. Stones larger than 20 mm need to be fragmented before extraction, as an incision ofthis length cannot be performed safely. The sphincterotomy incision can be sized by withdrawing the flexed sphincterotome through the opening or by passing balloon stone extractors of 8-14 mm in diameter through the incision. The size of a sphincterotomy opening should be tested by using a balloon before extraction of larger stones in the common bile duct is attempted. When endoscopic sphincterotomy is performed for papillary stenosis or sphincter of Oddi dysfunction, the sphincterotomy

Fig. 3.-Devices for extracting stones from common bile ducts include Dormia basket with a flexible wire tip (A), standard Dormia basket (B), pigtail end of nasoblllary catheter (C), and balloon stone extractor(D).

246

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ET AL.

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1992

Fig. woman tectomy hepatic

4.-A, cholangiogram in an elderly with cystic duct remnant after cholecysand retained stone (arrow) in common duct. B, cholangiogram after sphlncterotomy shows balloon (arrow) removal of stone was completed successfully.

Fig. 5.-A, Cholangiogram shows a retained stone (6 x 9 mm) in lower end of common bile duct. B, cholangiogram shows sphincterotome in vicinity of stone (arrow) that was removed subsequently with a basket.

cholithiasis, especially when large stones are found in the common bile duct [21 -23]. Direct intraluminal lithotripsy is performed with mechanical, electrohydraulic, or laser techniques. Mechanical lithotripsy is done by entrapping a stone in a modified Dormia basket, amputating the control handle, sliding a flexible metal sheath over the basket sheath, and forcibly retracting the basket against the metal sheath. This technique has been highly successful [24]. Electrohydraulic lithotripsy can be performed endoscopically or percutaneously, but direct choledochoscopy is required. The basic principle of electrohydraulic lithotripsy is the discharge of brief sparks into a fluid medium, producing an

acoustic shock that will fracture crystalline structures. Saline perfusion is needed concomitantly, and flexible sheaths in various sizes deliver the sparks [25]. Laser fragmentation of ductal calculi has been developed more recently as a proposed method for reducing the size of stones. The neodymium-yttrium aluminum garnet laser can fragment stones effectively in vitro, but the risk of damage to the bile duct is substantial [26]. The flash-lamp excited dye laser is a new technology that is highly effective for fragmenting biliary stones with minimal injury to the wall of the bile duct. In one series, the flash-lamp dye laser was successful in fragmenting stones in 23 of 25 patients who did

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ENDOSCOPY

OF BILIARY

not respond to standard nonsurgical treatment [27]. No major complications occurred. Laser techniques appear promising and offer an alternative to surgery in patients with large stones in the bile duct that are difficult to manage with the usual methods. Experience with ESWL for large stones in the bile duct is extensive. A sphincterotomy and placement of a nasobiliary drain are required, and the highly specialized direct lithotripsy techniques often are not needed, if ESWL is available (Fig. 6). Studies from both Europe [28] and the United States [29] in which ESWL was used to treat choledocholithiasis have

Fig. 6-A, catheter before otripsy (ESWL)

of common

Cholanglogram via nasobillary extracorporeal shack-wave 11thshows large stone in lower end bile duct. Cystic duct remnant is

present. B, On day after ESWL, second nasobiliary cholanglogram shows muftiple smaller fragments. C, Endoscopic cholanglogram obtained 4 days after ESWL shows stone fragments that did

not pass spontaneously. D,

Endoscopic

cholanglogram shows fragwIth a 14-mm balloon.

mented stones extracted

AND

PANCREATIC

DUCTS

247

shown that the technique is highly successful with otherwise difficult, large stones in the bile duct. Biliary catheters with infusion of various types of materials also can be used to treat gallstones [1 1 21 ]. These dissolution techniques are done when large stones cannot be removed by the usual methods. After placement of a transhepatic or nasobiliary catheter (Fig. 3C), perfusion with monooctanoin, methyl tert-butyl ether (MTBE), or ethylenediaminetetraacetic acid (EDTA) has been used for dissolution of stones. Monooctanoin is a cholesterol solvent used for direct dissolution of radiolucent gallstones located in the biliary ,

248

OTT

tract; it has only about a 50% success rate, and in many patients, severe diarrhea develops [21 30]. MTBE can dissolve cholesterol stones quickly and can be used in the gallbladder or biliary tract, but has many undesirable properties, including handling of the ether, risk of hemolytic anemia, and irritation of the duodenum [31 32]. Success in dissolving biliary tract stones with MTBE is limited and varied, although in one small series, stone dissolution was achieved in four of six patients [31]. EDTA may be useful for dissolving calcium bilirubinate stones, but further studies are needed. Endoscopic stents and percutaneous biliary drains are used in palliation for malignant biliary obstruction [17, 18, 33] (Fig. ,

,

A

B

-..

C

Fig. 7.-Devices used the-wire dilating catheter dam-style stent wIth side assembly; metal rings on and double pig-tall billary

to treat malIgnant billary obstruction Include over(A), coaxIal stent placement assembly (Amsterflaps Is positioned over a guldewire/gulde-sheath guIde sheath are for measuring stent lngth; stent (C).

B),

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7). Development of therapeutic duodenoscopes with larger instrumentation channels has allowed passage of larger stents, generally 10-French or 11 .5-French in diameter (Figs. 8 and 9). Compared with endoscopic sphincterotomy endoscopic drainage is more difficult to accomplish, and considerable expertise is required. However, technical advances have been made, and endoscopic success rates have improved. After a flexible guidewire is inserted past the tumor, tapered dilating catheters are passed over the wire to dilate the obstruction. Sometimes, hydrostatic balloon dilators are needed. When an adequate lumen is achieved, a flexible sheath is passed over the guidewire. This is used as a coaxial system for placement of a stent, selected beforehand for a proper length. Stents of different calibers and lengths are available. The most popular is the Amsterdam-style straight stent with side flaps. Single or double pigtail stents can be used, alternatively. Ideally, the length of the stent is selected so that the top flap is above the stricture and the lower flap is just below the ampulla. Satisfactory achievement of internal biliary drainage can reduce the prevalence of cholangitis and improve the survival rate in patients with malignant strictures [34]. However, stent clogging is a major problem, with the occlusion occurring after a median time of 190-200 days [35]. This necessitates additional interventional procedures for stent changes, generally 3-4 months after initial placement. A new technique is emerging that involves percutaneous or endoscopic placement of metallic prostheses, which expand to a diameter of 1.0-1.2 cm [36, 37]. Compared with conventional endoprostheses, advantages of the metallic stents include small introducer

Fig. 8.-A, Benign billary stricture scopic cholanglogram In a 46-year-old B, cholanglogram shows strIcture with a 10-French, 9-cm stent.

on endowoman. bridged

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OF BILIARY

AND

PANCREATIC

DUCTS

249

Fig. 9.-A, Endoscopic cholangiogram shows a malignant stricture of common hepatic duct in a 73-year-old man. Note pancreas divisum. B, cholangiogram shows a 10-French, 12-cm stent placed across stricture.

system, larger diameter, and smaller surface area; however, disadvantages include more difficult removal, shortening, and expense [38]. Questions concerning which type of stent provides more comfort to the patient and fewer replacements and complications remain unanswered. Endoscopic placement of stents is achieved in 70-80% of attempts [39]. Endoscopic access to the biliary tract is preferable to the transhepatic route because of fewer complications [40]. Percutaneous drainage, however, may be required. Percutaneous placement of a small biliary catheter via a sheathed needle and passage of a guidewire that is then recovered endoscopically has improved success rates compared with those of endoscopic management alone [41]. Combining endoscopic and percutaneous techniques is useful after a failed attempt at sphincterotomy or endoscopic placement of a stent [31 42]. A variety of techniques have been described, which allow innovative ways to deal with technical failures of interventional endoscopy of the biliary ducts. Percutaneous assistance has broadened the horizons of therapeutic endoscopy by combining the best attributes of each approach [42]. In summary, rapid development and technical advances in the past decade have greatly expanded the use of interventional endoscopy of the biliary and pancreatic ducts. These advances have had a profound effect on the management of pancreaticobiliary disease. Although we have reviewed the current indications and techniques of biliary and pancreatic endoscopic intervention, developments in the next decade will most likely be as dramatic. Many of the techniques described are still evolving and new applications will emerge. Indications for interventional endoscopy need clarification, ,

such as the use of sphincterotomy in patients less than 50 years old and treatment of those with an intact gallbladder. Sphincter of Oddi dysfunction and the role of biliary manometry need further study. Endoscopic and surgical options for biliary decompression, especially in malignant disease, remain unclear. Endoscopic techniques for removal, fragmentation, and dissolution of biliary stones will be improved and indications better defined. Finally, cooperation between endoscopists and radiologists will most likely continue to increase, and guidelines for training and performance of the procedures will be developed.

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