INTRODUCTION — Choledocholithiasis (a gallstone in the common bile duct) occurs in 15 to 20 percent of patients with cholelithiasis. The majority of gallstones form in the gallbladder and then pass into the common bile duct via the cystic duct. Common bile duct stones can also develop in patients who have an apparently normal gallbladder; such patients represent about 10 percent of those with choledocholithiasis. In addition, approximately 5 percent of patients who have undergone a cholecystectomy have a retained or recurrent stone [1].

The introduction of endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic sphincterotomy in the late 1970s has virtually supplanted surgery for the treatment of this condition [2,3]. This topic will review the most frequently used endoscopic techniques for common bile duct stone clearance (including sphincterotomy and/or balloon dilation of the ampulla followed by stone extraction using baskets and extraction balloons) and mechanical lithotripsy. Other issues related to gallstones and their complications are presented separately. (See "Choledocholithiasis: Clinical manifestations, diagnosis, and management" and "Endoscopic ultrasound in patients with suspected choledocholithiasis" and "Overview of endoscopic retrograde cholangiopancreatography (ERCP) in adults" and "Endoscopic balloon dilatation for removal of bile duct stones" and "Surgical common bile duct exploration".)

SPHINCTEROTOMY — The term sphincterotomy refers to severing of the deep muscle layers of the sphincter of Oddi. In contrast, papillotomy suggests cutting of the superficial papillary sphincter of the main duodenal papilla. However, in practice, these terms are used interchangeably.

Sphincterotomy is the most commonly used therapy for treatment of choledocholithiasis. The goal of the sphincterotomy is to cut the biliary sphincter (figure 1), thereby eliminating the principal anatomic barrier impeding stone passage and facilitating stone extraction.

Technique — Standard sphincterotomy involves the application of electrocautery to create an incision through the musculature of the biliary portion of the sphincter of Oddi. A number of different devices are available with that vary in design to facilitate the procedure depending upon specific anatomic considerations. In expert hands, a sphincterotomy is possible in 95 to 100 percent of patients. (See "Endoscopic biliary sphincterotomy".)

The length of the sphincterotomy should be tailored to the size of the stone and papilla. We prefer to create a sphincterotomy that completely unroofs the papilla, since this maximizes access to the common bile duct and decreases the risk of developing papillary stenosis (see "Clinical manifestations and diagnosis of sphincter of Oddi dysfunction"). We use a standard Valleylab electrocautery unit in a 2:1 cut:coagulation ratio. Typical power settings are 40 watts in cut and 20 watts in coagulation with a blend setting of 1 or 2. When using the ERBE apparatus, the machine provides automatic settings of 150 watts in cut, and 25 to 35 watts in coagulation.

Sphincterotomy is usually performed after deep cannulation of the bile duct has been accomplished. However, in some circumstances, this may not be possible. As an example, impaction of a stone within the papillary sphincter may prohibit advancement of a papillotome or guidewire. In these patients, sphincterotomy can still be accomplished using a needle knife papillotome, a technique known as "precutting". (See "Precut (access) papillotomy".)

Safety — The most common complication associated with endoscopic sphincterotomy is pancreatitis, which can also occur during ERCP without sphincterotomy. Other risks of sphincterotomy include those related to the endoscopy (such as complications of conscious sedation and esophageal perforation), perforation of the duodenum or bile duct, bleeding, and infection. The safety of endoscopic sphincterotomy depends upon a number of variables including coexisting medical illnesses, the indications for the sphincterotomy, and the endoscopist's experience. (See "Overview of endoscopic retrograde cholangiopancreatography (ERCP) in adults".)

Short-term complications — Short-term complications related to biliary sphincterotomy (ie, immediately after or within 30 days of the procedure) occur in fewer than 10 percent of patients, as illustrated by the following studies:

●In one report, complications were observed in 112 of 1921 (6 percent) of patients at seven academic medical centers [4]. Two-thirds of the complications were considered to be mild (ie, requiring less than three days in the hospital).

●A slightly higher complication rate (10 percent) was observed in a multicenter study involving 2347 patients undergoing biliary sphincterotomy at 17 institutions in the United States and Canada [5]. The most frequent complications included pancreatitis (5 percent) and bleeding (2 percent).

Multivariate analysis identified two patient-related characteristics (suspected sphincter of Oddi dysfunction and the presence of cirrhosis) and three procedure-related characteristics (difficulty cannulating the bile duct, use of a precut sphincterotomy, and use of a combined percutaneous-endoscopic procedure) as independent risk factors for complications. Furthermore, endoscopists who performed more than one sphincterotomy per week had a significantly lower complication rate compared with endoscopists with less regular experience (8 versus 11 percent) and a lower rate of severe complications (0.9 versus 2.3 percent).

Pancreatitis — While initial studies suggested that precut sphincterotomy increases the risk for pancreatitis, a meta-analysis of five randomized trials with 523 patients found that if precut sphincterotomy was used early, the risk of post-ERCP pancreatitis was not increased [6].

An alternative to a full precut sphincterotomy, "shallow" needle-knife papillotomy, has been reported as an effective and safe method for gaining access to the bile duct [7].

In addition to the above risk factors for complications, other mostly anecdotal experience suggests that the risk of pancreatitis is increased in young women who have a non-dilated common bile duct (<6 mm) and after multiple injections of the pancreatic duct or pancreatic duct acinarization (ie, injection of contrast sufficient to cause opacification of the terminal branches of the pancreatic ducts) [8]. On the other hand, the risk of pancreatitis may be decreased in patients with a dilated common bile duct due to gallstones and in those with a history of chronic pancreatitis.

The American Society for Gastrointestinal Endoscopy and the European Society of Gastrointestinal Endoscopy recommend administration of rectal nonsteroidal anti-inflammatory drugs (NSAIDS) to reduce the incidence and severity of post-ERCP pancreatitis (eg, 100 mg of indomethacin or diclofenac rectally immediately before or after ERCP) [9,10], and this is discussed in further detail separately. (See "Post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis", section on 'Rectal NSAIDs' and "Society guideline links: Acute pancreatitis".)

In addition, the prophylactic placement of a pancreatic stent may decrease the risk of pancreatitis. (See "Prophylactic pancreatic stents to prevent ERCP-induced pancreatitis: When do you use them?", section on 'Prophylactic stenting'.)

A prior history of pancreatitis due to ERCP or other causes does not appear independently to increase the risk of complications. The management of pancreatitis is discussed separately. (See "Management of acute pancreatitis".)

Bleeding — Most studies have found that the risk of bleeding after sphincterotomy is increased in patients who have a bleeding diathesis (including those on hemodialysis) [11-13]. In addition, the risk of bleeding is probably related to the size of the sphincterotomy, and may be increased after repeated procedures, extension of a previous sphincterotomy, and in patients with gallstones impacted in the ampulla [12,13]. Furthermore, in approximately 4 percent of patients, the retroduodenal artery courses through the region of the sphincterotomy, predisposing to severe hemorrhage.

Long-term complications — Long-term complications following endoscopic sphincterotomy include stone recurrence, papillary stenosis, and cholangitis, which occur in approximately 6 to 24 percent of patients [14,15]. Many endoscopists are particularly concerned about these complications in younger patients who will live for many years following sphincterotomy.

This issue was evaluated in a review that included 94 patients younger than age 60 who were followed for a median of 15 years following biliary sphincterotomy [16]. Early complications occurred in 14 patients (15 percent), including one death due to retroperitoneal perforation. A total of 36 late complications were observed in 22 patients (24 percent), which included recurrent common bile duct stones in 13, combined with papillary stenosis in nine. Most complications were managed endoscopically or conservatively. One patient required surgery after failed endoscopic treatment, and one patient died of cholangitis before she could undergo ERCP.

Another report addressing the same issues included 156 patients in whom long-term follow-up (average 10 years) was available [17]. The majority of patients (88 percent) had no further biliary symptoms. However, recurrent biliary symptoms developed in 16 patients (10 percent); in nine of those cases, symptoms were potentially related to endoscopic sphincterotomy.

In most reports, recurrent common bile duct stones occur most frequently in patients with concurrent choledocholithiasis and cholecystolithiasis [14]. As a result, it is preferable to perform a cholecystectomy following biliary sphincterotomy since the majority of stones form in the gallbladder.

There has been a concern that sphincterotomy might increase the risk of biliary tract cancer by exposing the biliary tree to bacteria and other duodenal contents. A large registry study found an increased risk of malignancy in the bile ducts, liver, or pancreas in patients who underwent ERCP for apparent benign disease [18]. However, the risk was not increased by sphincterotomy.

High-risk patients — In addition to the risk factors for complications discussed above, patients with comorbid illness are at greater risk for complications. Two relatively common settings are patients who have had a recent myocardial infarction and patients with cirrhosis (in whom the prevalence of gallstones is increased relative to the general population). (See "Gallstones: Epidemiology, risk factors and prevention".)

●Although the risk is increased, ERCP with sphincterotomy has been safely performed within several weeks after an acute myocardial infarction [19]. Stratification of risk depends upon a number of clinical factors that are discussed in detail separately. (See "Evaluation of cardiac risk prior to noncardiac surgery".)

●The risk of biliary sphincterotomy in patients with cirrhosis was evaluated in a study that compared endoscopic therapy with surgery in 362 patients with choledocholithiasis complicated by acute obstructive suppurative cholangitis (group 1, 27 patients), cirrhosis (group 2, 12 patients), and patients who had neither disorder (group 3, 323 patients) [20]. In group 1, 3 of 17 patients treated emergently died (two had been treated surgically and one had been treated endoscopically). In group 2, two patients with Child class C cirrhosis died after elective sphincterotomy. Mortality was significantly higher in groups 1 and 2 compared with group 3 (11 and 17 versus 0.3 percent, respectively). Although not statistically significant, endoscopic treatment had a lower morbidity rate compared with surgery in group 1 (24 versus 67 percent) and group 2 (22 versus 67 percent). It is our opinion that these high-risk patients should be treated endoscopically.

Safety of outpatient sphincterotomy — Patients undergoing sphincterotomy traditionally were admitted to the hospital for overnight observation. However, increasing experience has demonstrated that the procedure can be safely performed in outpatients [21-23]. One study, for example, included 614 patients at 17 medical centers who were discharged on the same day following biliary sphincterotomy. Readmission to the hospital occurred in 35 patients (5.7 percent), the majority of whom had developed pancreatitis [22]. Readmission was more likely in patients who had one or more risk factors that were identified in multivariate analysis (suspected sphincter of Oddi dysfunction, cirrhosis, difficult bile duct cannulation, precut sphincterotomy, or combined percutaneous-endoscopic procedure) compared with those without these risk factors (12 versus 4 percent). The majority of complications requiring readmission occurred within six hours of the procedure.

The current standard of care for outpatients with choledocholithiasis is to discharge them from the endoscopy unit after one hour of observation. In our experience, the overwhelming majority do not require readmission. However, in patients at increased risk for complications (see 'High-risk patients' above), especially patients with cirrhosis or those in whom cannulation was difficult, we observe for longer or admit them to the hospital. For patients traveling a distance, we recommend an overnight stay in the city close to the hospital in the event that further intervention is necessary.

Cholecystectomy following sphincterotomy — Sphincterotomy is followed by cholecystectomy in most patients with symptomatic choledocholithiasis to eliminate the source of the majority of recurrent gallstones. However, in some clinical settings (such as in patients who are poor operative candidates), cholecystectomy may be undesirable.

Studies evaluating the natural history of gallstone disease in patients who underwent sphincterotomy or endoscopic papillary balloon dilation without subsequent cholecystectomy suggest that recurrent gallstone-related disease occurs in 10 to 50 percent of patients [24-27].

Data suggest that prophylactic cholecystectomy should generally be offered to patients whose gallbladders remain in-situ after endoscopic sphincterotomy and clearance of common bile ducts stones. However, expectant management after biliary sphincterotomy in patients with the gallbladder in-situ may be appropriate for those at high risk for surgery from associated comorbidities, those unsuitable for surgery, or for older patients.

A meta-analysis of five randomized trials (with a total of 662 patients) found that patients managed without cholecystectomy had significantly higher rates of recurrent biliary pain (RR 14.6, 95% CI 4.5-43), jaundice or cholangitis (RR 2.5, 95% CI 1.1-5.9), and need for repeat ERCP or other forms of cholangiography (RR 2.4, 95% CI 1.3-4.3) [28]. Cholecystectomy was eventually required in 35 percent of patients.

Individual studies have shown the following:

●One of the largest studies to examine this issue included 371 patients with symptomatic choledocholithiasis and cholecystolithiasis in whom the bile duct was clear following ERCP with sphincterotomy, but who did not undergo subsequent cholecystectomy [24]. During a mean follow-up of 7.7 years, cholecystitis and recurrence of choledocholithiasis were observed in 6 and 10 percent of patients, respectively. Recurrent choledocholithiasis was successfully treated endoscopically in all but one patient. The presence of pneumobilia and the need for lithotripsy were significantly associated with the recurrence of choledocholithiasis.

●Another study included a total of 178 patients (age >60 years) who underwent sphincterotomy and were randomly assigned to immediate laparoscopic cholecystectomy or expectant management [25]. Median follow-up was approximately five years, during which time recurrent biliary events were significantly more likely in the expectant management group (24 versus 7 percent). Biliary events in the cholecystectomy group included cholangitis and biliary pain, while in the expectant management group included cholangitis, acute cholecystitis, biliary pain and jaundice.

●Another trial included 120 patients who had undergone sphincterotomy for common duct stones and were then randomly assigned to laparoscopic cholecystectomy or to watchful waiting [26]. During two-years of follow-up, recurrent biliary events were observed significantly more often in the group randomized to watchful waiting (47 versus 2 percent). At the end of the study, 37 percent of those originally assigned to watchful waiting had required cholecystectomy.

The timing of cholecystectomy may also be important. Retrospective studies suggest that patients who undergo delayed cholecystectomy (more than two weeks after sphincterotomy) have higher conversion rates of laparoscopic procedures to open procedures compared with patients who undergo early cholecystectomy [29]. Patients undergoing delayed cholecystectomy also appear to be at high risk of recurrent biliary events during the waiting period (20 percent in one series) [30]. Other factors that appear to increase the risk of converting from a laparoscopic cholecystectomy to an open procedure include the presence of two or more bile duct stones, the use of mechanical lithotripsy, and the presence of cholecystitis, especially within two weeks of the endoscopic procedure. In one study, the presence of one of these factors was associated with a 16 percent rate of conversion from laparoscopic to open cholecystectomy [31].

In a randomized controlled trial, 94 patients were assigned either to early laparoscopic cholecystectomy (within 72 hours of sphincterotomy) or delayed laparoscopic cholecystectomy (six to eight weeks after sphincterotomy) [32]. Patients who underwent early cholecystectomy had a lower rate of recurrent biliary events compared with those in the delayed cholecystectomy group (2 percent versus 36 percent). There were no differences between the groups with regard to conversion rates to open cholecystectomy (4 percent in the early group and 9 percent in the delayed group), operating times, difficulty of surgery, or length of hospital stay.

Other nonsurgical options for treatment of gallstone-related disease are discussed separately. (See "Overview of nonsurgical management of gallbladder stones".)

PAPILLARY BALLOON DILATION — Because of concern regarding long-term complications related to biliary sphincterotomy (particularly in young patients), extraction of common bile duct stones while preserving the biliary sphincter has been attempted. One technique involves dilation of the ampulla with a balloon followed by stone extraction. Endoscopic balloon dilation has been evaluated in a number of studies. However, its safety has been questioned. Until more data are available, endoscopic sphincterotomy is the method of choice for the treatment of choledocholithiasis. However, combining large balloon dilation with small sphincterotomy appears to be safe and permits stone extraction while avoiding the need for mechanical lithotripsy [33-35]. In Asia, papillary balloon dilation, with or without sphincterotomy, is often used as first-line treatment for the removal of bile duct stones [36,37]. It is common practice to perform balloon dilation of the papilla in patients with large stones, multiple stones, or suprapapillary stenosis. In most instances, the size of the dilating balloon is selected to correspond to the diameter of the distal bile duct, but not less than 10 mm.

In a randomized trial with 156 patients, those who underwent balloon dilation following a limited sphincterotomy had similar stone clearance rates as those who underwent standard endoscopic sphincterotomy (89 percent for both groups) and similar complication rates (7 versus 10 percent) [35]. However, patients in the limited sphincterotomy with balloon dilation group had lower rates of mechanical lithotripsy (29 versus 46 percent) and lower hospital costs ($5025 versus $6005). (See "Endoscopic balloon dilatation for removal of bile duct stones".)

The approach of combining balloon dilation with sphincterotomy (can be a small or large sphincterotomy) is being used more often, particularly for patients with a dilated bile duct in whom a suprapapillary stricture is suspected. In our practice, we frequently use combination therapy in such patients and in cases where sphincterotomy alone to reach a deep area is likely to be associated with a high risk of complications.

Based on the available data, balloon dilation without sphincterotomy should be reserved for patients with increased risk for bleeding. Small sphincterotomy and balloon dilation should be performed when a larger sphincterotomy is not possible due to anatomic constraints. Balloon dilation for the purpose of sphincteroplasty should be performed for at least one minute to decrease potential complications and improve efficacy.

Available studies have shown the following:

●In a study of 70 patients undergoing an endoscopic removal of bile duct stones using balloons, patients were assigned to 60 seconds (conventional) or 20 seconds (short) of balloon inflation [38]. The conventional and short groups did not differ with regard to clearance rate (94 versus 97 percent) or in their requirement for mechanical lithotripsy (97 versus 100 percent).

●A randomized trial examined 170 patients undergoing endoscopic removal of bile duct stones using balloon sphincteroplasty [39]. Patients were assigned to one-minute balloon dilation or five-minute balloon dilation using a 10 mm balloon. Successful stone extraction was more common in the five-minute group than in the one-minute group (93 versus 80 percent). Pancreatitis was less common in the five-minute group than in the one-minute group (5 versus 15 percent). The authors postulated that the increased rate of pancreatitis in the one-minute group may be due to a compartment syndrome at the level of the ampulla that results in significant local edema and compression.

●A randomized trial compared sphincterotomy and balloon dilation in 282 patients with common bile duct stones [40]. The trial found that after a median of 6.7 years follow-up, patients who underwent sphincterotomy had more late biliary complications than patients who underwent balloon dilation (25 versus 10 percent). Complications included recurrent stones, cholangitis without stone recurrence, cholecystitis, and one case of gallbladder cancer. However, in an earlier report from the same trial, it was noted that patients who underwent balloon dilation had a significantly higher rate of post-procedure pancreatitis (11 versus 3 percent), though the overall rate of early complications was similar between those who were treated with balloon dilation and those treated with sphincterotomy (15 versus 12 percent) [41].

●Limited endoscopic sphincterotomy with large balloon dilation was compared with sphincterotomy in a randomized trial that included 156 patients [35]. Limited sphincterotomy was defined as up to half the sphincter. Balloon dilation was performed to 15 mm. Both arms had a similar stone clearance rate (89 percent), but fewer patients in the combined therapy group required mechanical lithotripsy (29 versus 46 percent) or had complications (7 versus 10 percent).

●A meta-analysis compared endoscopic sphincterotomy plus balloon dilation with endoscopic sphincterotomy for choledocholithiasis [42]. This meta-analysis included three randomized trials and found equal efficacy of stone removal as well as use of mechanical lithotripsy during the first session between those treated with combination therapy versus those treated with sphincterotomy. In addition, the complication rate was similar, but combination therapy was associated with a lower bleeding rate. Six cohort studies showed a higher success rate for stone removal, a similar complication rate, and better results for stones larger than 15 mm with combination therapy.

●The removal of bile duct stones with balloon sphincteroplasty without preceding sphincterotomy was examined in a study that compared two groups that were treated at different times (sphincterotomy and balloon dilation in 42 patients between March 2008 and February 2010, and balloon dilation alone in 28 patients between March 2010 and October 2011). The overall success rate in stone clearance was 98 percent, but only 79 percent with balloon dilation alone. Additional therapies, including mechanical and extracorporeal shock wave lithotripsy, were required in 20 percent of patients. The complication rate was the same in both groups.

●A meta-analysis of five randomized trials with 621 patients comparing papillary large balloon dilation versus sphincterotomy demonstrated a similar success rate in complete stone removal (94 versus 93 percent) and ductal clearance in one session (82 versus 78 percent). There was no significant difference in adverse events: pancreatitis (4 versus 5 percent), bleeding (1.7 versus 2.8 percent), perforation (0.3 versus 0.9 percent), and cholangitis (1.3 percent both) [43].

●In a study assessing biliary stone recurrence using small biliary sphincterotomy and balloon dilation versus standard biliary sphincterotomy, the short-term (<3 years) recurrence rate was equal in both groups. However, in the long-term (>3 years), the recurrence rate was higher in the biliary sphincterotomy alone group [44].

BASKETS AND EXTRACTING BALLOONS — Following endoscopic sphincterotomy or balloon dilation, devices may be needed to extract common bile duct stones. Most stones less than 1 cm (and some even larger) will pass spontaneously.

The most common tools used to extract stones are balloons and baskets. These devices are available in multiple shapes and sizes and have a variety of characteristics that may be preferentially suited to particular anatomic variations or stone characteristics.

●We usually choose a basket when the duct is dilated or multiple stones larger are present. A problem with using balloons in dilated ducts or when the stone is impacted is that the balloon may simply squeeze between the stone and the wall.

●We typically use a balloon the duct is not dilated or if there is a single free-floating stone. We choose a balloon that closely approximates or is larger than the diameter of the duct. Balloons are also useful when multiple small stones are present or when a larger stone has been crushed (image 1).

Once a stone has been grasped within a basket or a balloon has been advanced proximal to the stone, pulling the stone/balloon or stone/basket apparatus is often sufficient to extract the stone. However, in many instances, resistance is encountered when the stone reaches the ampulla, particularly if the sphincterotomy is smaller than the stone's diameter. Greater mechanical advantage can be obtained by turning the small wheel of the endoscope to the right and pushing the endoscope further in the stomach (ie, the long position), which straightens the bile duct axis. If more force is needed, the left hand can be flexed while grasping the endoscope and turning the body toward the right, which forces the endoscope into an even straighter position.

One risk of basket extraction is impaction of the basket within the bile duct. This results from imbedding of the basket's wires within the stone surface. As a result, the basket may not be removable from the stone, which anchors the basket within the bile duct. Furthermore, once the basket has become impacted, it may not be possible to regain access to the bile duct to perform additional therapeutic maneuvers. Mechanical lithotripsy is often helpful in these circumstances (see 'Mechanical lithotripsy' below). However, in extreme cases, surgery may be required to remove the basket.

The risk of impaction can be reduced by extraction of the most distal stone (ie, the one closest to the ampulla) first when multiple stones are present. Beginning with proximal stones risks creating a "traffic jam" as the captured stone is pulled through the remaining gallstones. The risk of impaction can also be reduced by gently pulling the basket and stone to the preampullary level without closing the basket tightly against the stone. Suction and steady force can then be applied to extract the stone using the methods to improve mechanical advantage discussed above. However, care should be taken to avoid perforation of the opposite duodenal wall by the endoscope (especially if a considerable amount of force is required), since the bend in the endoscope pushes against the duodenal wall during straightening.

Some authorities have used sublingual nitroglycerin [45] or an infusion of isosorbide [46] to relax the sphincter of Oddi and facilitate stone extraction. However, only a small number of patients have been studied, and the benefit of giving these medications is unclear.

MECHANICAL LITHOTRIPSY — Mechanical lithotripsy is most often used when the standard methods of stone extraction fail. Mechanical lithotriptors are devices that are designed to break stones that have been captured within a basket. Several lithotriptors are commercially available, including devices that can be passed through the endoscope, devices that can be used only after the endoscope has been removed from the patient, and hybrid-type devices that combine out-of-the-scope and inside-the-scope principles.

Most experience with through-the-endoscope lithotriptors has been with the Olympus lithotriptors BML-3Q and BML-4Q. These lithotriptors are reusable, but cumbersome to assemble and somewhat difficult to use. The larger model is stiffer, making ductal cannulation problematic. By comparison, many of the newer lithotriptors are disposable, more flexible, preassembled, and easier to use with better handles. These lithotriptors can be used with stones located anywhere in the biliary tree as long as the stone can be grasped.

The out-of-the-scope devices are used once a stone has been trapped within a standard basket. The outer sheath of the basket is either cut or disassembled, and the basket wire is then introduced through the metallic sheath of the lithotriptor. Cranking of the lithotriptor forces the metallic sheath to move forward until it reaches the stone causing tightening; the resulting pressure fragments the stone (picture 1).

The out-of-the-scope lithotriptors require the stone to be at the ampullary level and their use is contraindicated for more proximal stones (unless they can be dragged to an ampullary location) since ductal rupture can occur. In addition, it is very important that after the bare basket is wound in the handle, a loop inside the stomach be formed with the metallic sheath to permit straightening of the lithotriptor cable upon stone fragmentation. Failure to do this can lead to gastric lacerations. Once the stone is fragmented, the basket is removed and the smaller stones are extracted using standard techniques. A small mucosal laceration at the roof of the papilla or at the papillotomy site may be noted but is of uncertain clinical significance.

The overall success rate for ductal clearance with mechanical lithotripsy is 80 to 90 percent, although 20 to 30 percent of patients require more than one session [47-56]. Failure is most often due to impaction of the stone in the bile duct [55]. Complications directly related to the lithotripsy are uncommon. A large series from expert centers in the United States with over 600 cases reported that only 3.5 percent of biliary cases experienced complications, mainly from broken or trapped baskets. Most could be resolved without surgery by extending the sphincterotomy or using electrohydraulic lithotripsy [57].

The through-the-scope lithotriptor overcomes some of the disadvantages of out-of-scope lithotriptors discussed above. Experience with one of these devices (Monolith lithotriptor) was illustrated in a series of 20 patients who had gallstones ranging in size from 10 to 30 mm; 16 of the patients had multiple stones (median of five) [52]. Cannulation with the lithotriptor was successful in all patients, although some patients required multiple attempts to intubate the bile duct. The overall success rate to capture, fragment, and completely clear the bile duct was 80 percent. The basket was misshapen in 14 patients (although some stones could still be crushed) and deployment failed in one due to a large stone. Compared with the out-of-scope lithotriptors, the through-the-scope lithotriptors are better suited for stones that are impacted above the level of the ampulla.

Another series described experience with a different through-the-scope lithotripter (Olympus BML-4Q) in 304 patients with difficult bile duct stones [56]. Successful stone clearance was accomplished in 90 percent of patients. Most patients required only one session for stone clearance. Surgery was required in 32 patients in whom lithotripsy was unsuccessful. Complications included cholangitis in eight, pancreatitis in 21, and bleeding in 10. There was no mortality. The complication rate was greater in patients who required multiple sessions for stone clearance.

In a randomized trial of 90 patients with large bile duct stones, large balloon dilation was compared with mechanical lithotripsy [58]. A large bile duct stone was defined as any stone larger than 12 mm. Complete stone removal was possible in 98 percent of patients undergoing balloon dilation compared with 91 percent of those treated with mechanical lithotripsy, but the difference was not statistically significant. Post-procedure cholangitis was more common in the patients treated with mechanical lithotripsy compared with those treated with balloon dilation (13 versus 0 percent). Post-procedure pancreatitis and bleeding each occurred in 2 percent of the patients, with equal distribution between the groups.

EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY — Extracorporeal shock wave lithotripsy (ESWL) has been used for the treatment of pancreatic stones, gallstones within the gallbladder, and common bile duct stones that cannot be removed by the endoscopic methods described above [59-63]. However, it is now rarely used for the treatment of gallstones. (See "Extracorporeal shock wave lithotripsy for pancreatic stones".)

ELECTROHYDRAULIC LITHOTRIPSY — Electrohydraulic lithotripsy can be performed in conjunction with peroral, percutaneous, or intraoperative choledochoscopy. (See "Electrohydraulic lithotripsy in the treatment of bile and pancreatic duct stones" and "Cholangioscopy and pancreatoscopy" and "Percutaneous transhepatic cholangioscopy" and "Surgical common bile duct exploration".)

LASER LITHOTRIPSY — Lithotripsy can also be accomplished using laser light. This topic is discussed in detail elsewhere. (See "Laser lithotripsy for the treatment of bile duct stones".)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Biliary infection and obstruction".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topics (see "Patient education: Gallstones (The Basics)" and "Patient education: Gallbladder removal (cholecystectomy) (The Basics)")

●Beyond the Basics topics (see "Patient education: Gallstones (Beyond the Basics)")

SUMMARY AND RECOMMENDATIONS — Endoscopic techniques for common bile duct stone clearance include sphincterotomy and/or balloon dilation of the ampulla followed by stone extraction using baskets and extraction balloons as well as mechanical lithotripsy.

●Sphincterotomy is the most commonly used therapy for treatment of choledocholithiasis. The goal of the sphincterotomy is to cut the biliary sphincter (figure 1), thereby eliminating the principal anatomic barrier impeding stone passage and facilitating stone extraction. Standard sphincterotomy involves the application of electrocautery to create an incision through the musculature of the biliary portion of the sphincter of Oddi. (See 'Sphincterotomy' above.)

●The most common complication associated with endoscopic sphincterotomy is pancreatitis. Other risks of sphincterotomy include those related to the endoscopy (such as complications of conscious sedation and esophageal perforation), perforation of the duodenum or bile duct, bleeding, and infection. (See 'Safety' above.)

●Because of concern regarding long-term complications related to biliary sphincterotomy, extraction of common bile duct stones while preserving the biliary sphincter has been attempted. One technique involves dilation of the ampulla with a balloon followed by stone extraction. (See 'Papillary balloon dilation' above.)

●Following endoscopic sphincterotomy or balloon dilation, devices may be needed to extract common bile duct stones. The most common tools used to extract stones are balloons and baskets. These devices are available in multiple shapes and sizes and have a variety of characteristics that may be preferentially suited to particular anatomic variations or stone characteristics. (See 'Baskets and extracting balloons' above.)

●Mechanical lithotripsy is most often used when the standard methods of stone extraction fail. Mechanical lithotriptors are designed to break stones that have been captured within a basket. Several lithotriptors are commercially available, including devices that can be passed through the endoscope, devices that can be used only after the endoscope has been removed from the patient, and hybrid-type devices that combine out-of-the-scope and inside-the-scope principles. (See 'Mechanical lithotripsy' above.)

●The combination of biliary sphincterotomy and balloon dilation is a good therapeutic option, especially for larger stones and in patients with an associated suprapapillary stricture.

●Alternative methods for the removal of common bile duct stones are discussed elsewhere. (See "Electrohydraulic lithotripsy in the treatment of bile and pancreatic duct stones" and "Surgical common bile duct exploration".)