Stones in the bile duct: Endoscopic and percutaneous approaches

Historical overview

In the 1970s and 1980s, endoscopic retrograde cholangiopancreatography (ERCP) transformed the diagnostic approach to suspected biliary disease and jaundice (see Chapters 20 and 30 ). Similarly, in the years since it was first performed in humans, ^, endoscopic sphincterotomy (ES) has had a dramatic impact on the management of biliary disease, specifically in the treatment of common bile duct (CBD) stones. The widespread availability of ES has made endoscopic stone extraction the primary modality for the management of choledocholithiasis. Interest in ERCP and endoscopic sphincterotomy as definitive therapy for CBD stones grew in the 1990s after the introduction of laparoscopic cholecystectomy (see Chapter 36 ). Patient-related factors, clinical judgment, availability of expertise, and current evidence from clinical trials must be combined to decide on an endoscopic, percutaneous, or surgical approach. Although ERCP as a diagnostic modality has been replaced by noninvasive imaging modalities such as magnetic resonance cholangiopancreatography (MRCP) (see Chapter 13 ), it remains the major nonoperative tool for the management of biliary diseases such as choledocholithiasis and obstructive jaundice.

Indications for endoscopic therapy

Patients with choledocholithiasis may present with asymptomatic stones on noninvasive imaging or direct cholangiography or with a variety of clinical symptoms (see Chapter 33 ), such as cholestasis, pain, cholangitis (see Chapter 43 ), and pancreatitis (see Chapter 55 ). In the early days of ES—at a time when few endoscopy centers could offer the technique and criticisms by surgical experts were common—it was considered justifiable only in elderly postcholecystectomy patients with recurrent or retained bile duct stones who were at high risk of serious complications from open surgical CBD exploration or reexploration. The impressive success of ES in this group, combined with expanded availability, a low rate of complications, and strong patient preference, has led to ERCP becoming the primary modality for the management of CBD stones.

The endoscopist now must consider several clearly defined conditions for which endoscopic management may be indicated in patients with definite or suspected bile duct stones ^, :

• 1.

  Acute cholangitis

• 2.

  Visualized CBD stone on abdominal ultrasound, endoscopic ultrasound (EUS), computed tomography (CT), MRCP, or intraoperative cholangiogram

• 3.

  High suspicion of CBD stones: cholelithiasis, dilated CBD, and abnormal liver biochemical tests

• 4.

  Worsening gallstone pancreatitis

• 5.

  Recurrent CBD stones or gallstone pancreatitis, nonsurgical candidate for cholecystectomy

Endoscopic techniques

An endoscopy service that treats CBD stones must have access to an appropriate endoscopy facility and high-quality fluoroscopy. The endoscopy team must be fully cognizant of all basic ERCP maneuvers, less frequently used techniques, and potential complications and their management. It is essential to explain the nature of the procedure to the patient and to outline the purpose, benefits, advantages, alternatives, and potential hazards (see Chapters 20 and 30 ).

On successful deep biliary cannulation with a sphinctertome, a cholangiogram is initially performed, which defines the ductal anatomy and the extent of the stone burden. ES is usually the first therapeutic step in stone extraction. Balloon dilation of the biliary sphincter is an alternative to ES, but this has fallen out of favor due to increased risks of severe post-ERCP pancreatitis. Standard pull-type sphincterotomes allow a vertical incision to be made from the papillary orifice in a cephalad direction along the intramural course of the CBD for a variable length (average, 10 to 15 mm), depending on local anatomy, the degree of CBD dilation, and the size of the stone to be removed ( Fig. 37C.1 ). The incision is produced by the controlled application of monopolar electrocautery delivered by a generator specifically designed for endoscopic use. It is fundamental to ES technique that complete control of wire tension and electrocautery be maintained at all times. “Smart” generators incorporate a pulsed generator (Erbe, Tubingen, Germany; ConMed Endoscopic Technologies, Billerica, MA) with feedback-controlled power output, thus avoiding a “zipper effect” and reducing pancreatitis and bleeding.

Occasionally, a precut sphincterotomy, also referred to as an access papillotomy, is needed to initiate ES when the standard instrument cannot be inserted deeply. This incision is often needed when cannulation has been prevented by an impacted stone. The needle-knife is more useful in this situation because the intramural CBD is usually grossly distended and easily incised, starting from the papilla and extending cephalad. Needle-knife fistulotomy is a variant of this technique; the incision is begun above the papilla to form a choledochoduodenal fistulotomy. This technique is similar in efficacy to precut sphincterotomy, but more often it requires mechanical lithotripsy (ML) and may have a lower rate of pancreatitis. Patients with Billroth II partial gastrectomy ( Fig. 37C.2 ) and Roux-en-Y bypass operations present special problems to the endoscopist, and numerous methods have been described to obtain successful cannulation ^, and removal of CBD stones (see Chapter 37B ).

It is standard practice to attempt stone extraction from the CBD immediately after ES. The two accessory instruments used most commonly for this are the Dormia-type basket ( Fig. 37C.3 ) and the Fogarty-type balloon ( Figs. 37C.4 and 37C.5 ), which are greater than 90% successful in clearing the CBD. Occlusion cholangiography is performed after stone extraction to confirm complete ductal clearance.

Difficult stones

Difficulties in extraction of CBD stones are either related to anatomic factors affecting the ability to perform an adequate ES or related to complex morphology of the stones themselves (see Chapters 30 and 37B ). An inaccessible papilla may be related to aberrant anatomy or unfavorable duodenal or papillary structures, such as a periampullary diverticulum, or prior surgery, such as Billroth II or Roux-en-Y reconstruction. Techniques have been described for the unique challenge of selective bile duct cannulation in a patient with a Billroth II partial gastrectomy. The performance of ES in Billroth II or Roux-en-Y anatomy is also a challenge because the visualized anatomy is inverted. In especially difficult cases, needle-knife sphincterotomy with a stentor guidewire used as a guide may be an option, or specially designed reverse-direction accessories. Roux-en-Y gastric bypass patients pose an extra challenge for the endoscopist due to the long pancreaticobiliary limb. ERCP using overtube-assisted enteroscopy has been performed successfully in patients with Roux-en-Y gastric bypass, with a recent meta-analysis demonstrating a 75% technical success rate and an 8% adverse event rate.

When ES has been successfully performed, extraction may be hindered by a variety of stone factors, including size, number, consistency, shape, and location of stones, as well as ductal factors such as contour and diameter at the level of and distal to the stones, and the presence of coexisting pathology (e.g., stricture or tumor). Stones that are likely to be more difficult to extract and may require adjuvant techniques to remove them are those that appear larger than the endoscope on radiographic imaging (usually >15 mm); stones that are numerous or hard in consistency; stones that are square, piston shaped, or faceted that tightly fit the bile duct or that are packed against each other; intrahepatic stones; or stones located proximal to a stricture or narrowed distal bile duct or in a sigmoid-shaped duct.

Methods that have been developed to dilate the papillary orifice, reduce stone size, and facilitate endoscopic removal include endoscopic papillary large balloon dilation (EPLBD), ML, intracorporeal lithotripsy with laser or electrohydraulic probes, extracorporeal shockwave lithotripsy (ESWL), and chemical contact dissolution therapy. Treatment options must be discussed jointly by the endoscopist, surgeon, and interventional radiologist when difficulties are encountered ( Fig. 37C.6 ).

Extracorporeal shockwave lithotripsy

ESWL with a variety of lithotripsy machines is now an alternative to endoscopic management of difficult bile duct stones. In contrast to intracorporeal techniques, direct contact with the stone is unnecessary. Most centers localize stones with fluoroscopic focusing during contrast perfusion of the bile duct through an endoscopically placed nasobiliary catheter or percutaneous drain. ^, Ponchon et al. reported ESWL success with an ultrasound localization system, although it was less effective when multiple stones were present. Several large series indicated success rates for ESWL stone fragmentation of 53% to 91% and duct clearance in 58% to 90%. Minor complications are common and include biliary pain, hemobilia, transient liver function test elevations, and cutaneous petechiae. Overall, with the use of endoscopic techniques such as ML, EHL, laser lithotripsy, and ESWL, one report showed successful stone removal in 98% of 217 patients, with only 5 patients requiring surgery. However, given the high efficacy of newer endoscopic techniques, ESWL is currently rarely used for bile duct stones.

Mechanical lithotripsy

Removal of large CBD stones is a challenge for the most skilled endoscopists (see Chapter 30 ). ^, ML remains an excellent option for stones that cannot be removed by conventional techniques because it can be used safely and effectively during the initial endoscopic procedure. Mechanical lithotripters are modifications of standard Dormia baskets and possess great tensile strength ( Fig. 37C.7 ). The reinforced basket is opened in the CBD, and the stone is entrapped within the braided wires. This procedure can be performed through the endoscope instrumentation channel, or it can be done after the endoscope has been removed from the patient and a metal sheath has been extended over the inner Teflon catheter. The end of the metal sheath is attached to a winding mechanism, which retracts the basket when cranked and impales the stone against the rigid distal end of the metal sheath leading to stone fracturing. The stone fragments can be removed with the same basket or a standard retrieval basket or balloon. In experienced centers, this technique allows removal of more than 90% of difficult bile stones that are refractory to standard extraction techniques, but multiple procedures may be required to achieve complete ductal clearance.