Bile Duct Stones

Abstract

Common bile duct stones (CBDS) incidence is about 10–15%. Clinical signs and symptoms are nonspecific but when associated with biochemical tests and abdominal ultrasound, patients can be categorized into low, intermediate, and high risk of choledocholithiasis. These clinical, biochemical, and radiological predictors will direct the diagnostic approach through cholangio magnetic resonance, endoscopic ultrasound, laparoscopic ultrasound, or intraoperative cholangiography. Treatment options must consider technological availability, technical skills, stone size, and bile duct diameter. In general, it involves endoscopic retrograde cholangiopancreatography or surgery for CBDS clearance. For difficult stones, endoscopic sphincterotomy followed by large balloon dilation, mechanical lithotripsy, cholangioscopy-guided lithotripsy, and extracorporeal shock wave lithotripsy are described, mainly as a bridge procedure.

1. Introduction

Gallbladder stone disease has an overall prevalence of approximately 15%. Choledocholithiasis is present in about 10–20% of patients with symptomatic cholelithiasis [1, 2, 3, 4, 5]. Secondary choledocholithiasis remains the leading cause of common bile duct stones (CBDS), originating from migration of gallbladder stones into hepatocholedochal duct, while primary choledocholithiasis is a rare cause, mainly affecting the eastern population [4, 6].

The pathophysiology of secondary CBDS is the same as for gallbladder stones. Most gallstones are composed of cholesterol, due to the supersaturation of the bile, leading microcrystals formation. These cholesterol crystals, incorporated into vesicular mucin and associated with bile stasis, form gallstones. While 80–90% are cholesterol gallstones, primary choledocholitiasis is related to brown stones, whose formation occurs directly in the common bile duct (CBD), resulting from mechanical obstruction of bile flow, leading to stasis with subsequent bacterial colonization. However, sometimes there is no obstructive factor, such as bile duct stricture or papillary stenosis. Therefore, dilated CBD, especially after cholecystectomy, is an important factor for primary CBDS [7, 8, 9].

Due to the multifactorial etiology of gallbladder stones, CBDS predominates in female gender aged over 55 years, with dietary, genetic, and hormonal associated factors, as metabolic syndrome, obesity, rapid weight loss, family history, pregnancy, multiparity, and oral contraceptives [4, 7, 8].

Symptomatology is quite varied, ranging from completely asymptomatic patients to classic clinical manifestations of biliary lithiasis, such as epigastric or right upper abdominal pain, nausea and vomiting, to obstructive symptoms as fluctuant jaundice, choluria, and acholia. Eventually, patients may present with other complications of choledocholithiasis, for example, acute pancreatitis or cholangitis [6, 10].

Recurrent primary choledocholithiasis is a chronic pathology conceptually characterized by recurrence of common bile duct stones after, at least, 6 months of cholecystectomy. Some risk factors are bile duct greater than 13–15 mm in diameter and with angle smaller than 145°, presence of periampullary diverticulum, biliary stricture or papilla stenosis, and identification of two or more stones in bile duct [3, 11, 12, 13].

There are specific predictors of choledocholithiasis, which include clinical findings (obstructive jaundice, acute pancreatitis, or cholangitis), abnormal hepatogram, and presence of a choledochal stone or bile duct dilatation >8 mm [3, 4]. Based on this, patients are stratified in low, intermediate, or high risk of choledocholithiasis which will guide all diagnostic effort and, therefore, treatment approach [1, 2, 6, 14].

2. Diagnosis

Clinical manifestations of choledocholithiasis are nonspecific such as epigastric or upper abdominal pain, nausea, vomiting, and fluctuating jaundice. History of acute pancreatitis, cholangitis, and jaundice are suggestive of choledocholithiasis, since nearly 50% of acute biliary pancreatitis and most cholangitis are caused by stones in the common bile duct (CBD) [6, 15].

Screening for choledocholithiasis includes clinical, biochemical (gamma-glutamyl transpeptidase (GGT), alkaline phosphatase (AF), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and bilirubin) and ultrasound showing CBD greater than 6 mm. These predictors, when normal, have high power to rule out the presence of choledocholithiasis, considering their negative predictive value is greater than 97% [5].

The initial evaluation with predictive factors allows us to stratify patients into high, intermediate, and low probability of choledocholithiasis. These factors are clinical evidence of acute cholangitis, bilirubin greater than 1.7 mg/dL, visualization of common bile duct stone, and dilated CBD on abdominal ultrasound. When two of these factors are present, the probability of choledocholithiasis is high, whereas with normal common bile duct diameter without cholangitis, the probability is low. Patients between these two spectra are stratified as having intermediate probability for diagnosis [3].

Based on the initial screening assessment, when the suspicion of choledocholithiasis is low, laparoscopic cholecystectomy (LC) is recommended. If it is intermediate, the options are endoscopic ultrasound (EUS), magnetic resonance cholangiopancreatography, or even computed tomography (CT scan) in the preoperative period, according to local availability. During intraoperative suspect, laparoscopic ultrasound (LUS) or intraoperative cholangiography (IOC) is indicated [3, 11].

2.1 Abdominal ultrasound

Ultrasound consists of an inexpensive, noninvasive, and widely available method; however, it is operator-dependent with limitations in obese patients in the investigation of choledocholithiasis. The most important contribution is to demonstrate dilation of the CBD above 6 mm at the time of initial screening, although its normality does not exclude the diagnosis [3, 6, 11, 16]. The sensitivity is 73% and specificity is 91% [11]. As we can see in Figure 1, the common bile duct is located over the portal vein and the common bile duct stone typically produces posterior acoustic shadow.

Figure 1.

Ultrasound showing common bile duct dilated (2.28×4.19 cm) with a 2.2 cm stone.

2.2 Magnetic resonance cholangiopancreatography

It is recommended in cases of intermediate suspicion of choledocholithiasis, that is, patients with altered biochemical tests, aged >55 years and dilatation of the common bile duct on ultrasound [4], consisting of a noninvasive option, with sensitivity >90% and specificity close to 100%. This accuracy is reduced for stones smaller than 3 mm. It is normally required for the diagnosis of choledocholithiasis before endoscopic intervention or surgical exploration [2].

It suggests choledocholithiasis on T2 when evidence of fluid (bile) as a bright, high-intensity signal on images. Solid material may be suggested by the filling failure—hypointense and well delimited—within the common bile duct, as we see in Figure 2 [6].

Figure 2.

MRCP showing common bile duct dilated (1.3 cm in diameter) with 0.6 cm stone at distal portion (circle).

It is contraindicated in patients with claustrophobia, obesity, cardiac pacemakers, or metal clips [3, 4].

2.3 Endoscopic and laparoscopic ultrasound

Endoscopic ultrasound (EUS) is a diagnostic method based on the introduction of an endoscope with an ultrasound transducer into the duodenal bulb, with specificity about 90% and sensitivity of 97% for CBD stones detection [4]. It is indicated mainly for patients who cannot perform magnetic resonance cholangiopancreatography (MRCP), that is, those who have intracranial metallic clips, pacemakers, mechanical heart valves, claustrophobia, and morbid obesity. Its main disadvantage is related to invasiveness, need for anesthetic sedation, and reduced availability. In addition, EUS is operator-dependent, which also makes it more expensive. Patients with gastric bypass present an important limitation of this method [4, 11].

Laparoscopic ultrasound consists in a specific laparoscopic probe used directly over the common bile duct and is indicated for patients with intermediate risk during intraoperative period which has not been detected by initial investigation by MRCP or EUS [3, 6]. With sensibility estimated in 95% and specificity near 100% [17], its main limitation is proximal biliary tree stone evaluation [18].

The stones are suggested by hyperechoic foci with posterior acoustic shadowing [6].

2.4 Endoscopic retrograde cholangiopancreatography (ERCP)

Method performed by combining upper digestive endoscopy and fluoroscopy presents sensitivity around 82% and specificity near 90% for the CBDS diagnosis. Main disadvantages of this method are invasiveness and risk of pancreatitis in 5–10% of patients. Currently, endoscopic retrograde cholangiopancreatography (ERCP) has been reserved for therapeutic purposes for patients diagnosed with choledocholithiasis by MRCP, endoscopic ultrasound, or even computed tomography [3, 6].

2.5 Computed tomography (CT scan)

Although not routinely used, this method is indicated when the hypotheses of common bile duct stones and a tendency to malignancy coexist or in absence of ERCP or MRCP. Its sensitivity is 78% and specificity is 96%, with reduced accuracy if CBDS <5 mm or bile-like density [6, 11].

There is an option for diagnosing choledocholithiasis with contrast-enhanced CT cholangiography, but contrast is poorly available [6].

As a disadvantage, contrast injection and exposure to ionizing radiation are described [6]. In Figure 3, we can see the stone in a patient with right upper abdominal pain and fluctuant jaundice.

Figure 3.

CT scan showing distal bile duct stone (white circle).

2.6 Intraoperative cholangiography (IOC)

It consists in a useful method to delineate the anatomy of the biliary tree and to demonstrate the presence of intraoperative common bile duct stones. It exhibits sensitivity of 75–99% and specificity around 90–100% for the diagnosis of choledocholithiasis, especially when correlated with clinical, biochemical, and ultrasound findings [2, 5].

IOC can be selectively indicated in patients at high risk of choledocholithiasis undergoing cholecystectomy (history of jaundice, cholangitis or pancreatitis, abnormal biochemical tests, and a CBD > 8 mm in the US) or routinely in all consecutive patients candidates to cholecystectomy, irrespective the risk of CBDS. However, the selective or routine indication remains controversial in the literature. Currently, as we can see in Figure 4, IOC is still considered the gold standard for intraoperative biliary anatomy evaluation [4, 5, 19].

Figure 4.

Intraoperative cholangiography showing intra and extrahepatic bile duct dilation.

3. Treatment

The management of choledocholithiasis is based on bile duct clearance and cholecystectomy, as most ductal stones migrate from gallbladder. Therefore, all patients with common bile duct stones, symptomatic or not, should be managed with gallbladder removal to treat the cause and to avoid recurrence of this chronic hepatobiliary pathology [1, 3, 6].

The approach of the CBDS depends on local technological resources availability, technical skills, moment of diagnosis, stone size, and common bile duct diameter [2, 3].

The treatment of choledocholithiasis involves, in general aspects, ERCP or surgical exploration of the common bile duct, laparoscopic, or open [1, 6]. Therefore, in non-cholecystectomy patients with choledocholithiasis, CBDS smaller than 1 cm and bile duct with diameter until 1.5 cm, preoperative ERCP followed by laparoscopic cholecystectomy is preferred. In case of unavailable ERCP, the option is to proceed with intraoperative cholangiography, bile duct exploration, and cholecystectomy in a unique procedure, laparoscopic, or open approach. When diagnosis is confirmed intraoperatively by cholangiography or LUS, it is possible to proceed with intraoperative ERCP or surgical exploration in the same surgical act, depending on the surgeon’s experience, biliary anatomy, and available resources. Another possibility is to proceed with postoperative ERCP [3]. Finally, in cholecystectomy patients, postoperative ERCP is the gold standard therapy [1, 3, 6]. We emphasize that stone size greater than 1.5 cm and CBD diameter greater than 1.5 cm, if considered isolated or together, are predictors of higher rates of success by surgical exploration than ERCP.

There are no differences in the success rates of gallstone removal regarding pre-, intra-, or postoperative ERCP, which is estimated around 80–90%. However, intraoperative ERCP has lower complication rates and faster hospital discharge. Ideally, as it is performed in a unique time, intraoperative approach is quite advantageous, but the dynamics, resources, and necessary structure are major disadvantages of this strategy [1]. Despite the high success rates in clearance of choledocholithiasis, ERCP presents risks and complications, especially post-ERCP pancreatitis, followed by infection, bleeding, and perforation of the bile ducts. Although there is no definitive consensus, there is a general preference for preoperative ERCP, due to the assurance that there is no more distal obstruction, reducing the need for another intervention [2]. Besides, an interval of up to 2 weeks after ERCP is recommended to proceed with LC [1, 11].

In stones larger than 1.5 cm, endoscopic sphincterotomy followed by large balloon dilation (12–20 mm), mechanical lithotripsy, cholangioscopy-guided lithotripsy, and extracorporeal shock wave lithotripsy are described, mainly as a bridge procedure to definitive ERCP or surgical approach. However, it must be emphasized that this size of stone is normally followed by bile duct dilation, which needs necessarily be considered when one chooses the treatment options [1, 4, 6, 11].

Therefore, stones larger than 1.5 cm, multiple bile duct stones (>15), tortuous biliary anatomy, and a CBD diameter > 2 cm present difficulty of endoscopic and laparoscopic removal, being predictors of open procedure, which will probably evolve associated biliodigestive derivation, preferably choledochojejunostomy Roux-en-Y derivation, to avoid biliary stasis and consequently recurrent choledocholithiasis. Choledochojejunostomy is preferred over choledochoduodenostomy due to lower rates of stone recurrence and complications such as sump syndrome Figure 5 [1, 2, 3, 4, 6, 11, 20, 21, 22, 23, 24].

Figure 5.

Diagnosis approach of common bile duct stones flowchart. US: ultrasound, CBD: common bile duct, LFT: liver function tests, EUS: endoscopic ultrasound, MRCP: magnetic resonance cholangiopancreatography, CT Scan: computed tomography, IOC: intraoperative cholangiography, ERCP: endoscopic retrograde cholangiopancreatography.

The main complications of surgical treatment are biliary leak at choledochotomy suture or at bile duct-enteric anastomosis, biloma, common bile duct stenosis which may cause also recurrent choledocholithiasis, pancreatic or bile duct injury due to instrumentation, and recurrent ascendent cholangitis mainly with choledochoduodenostomy technique [21, 23, 24, 25].

Bile leaks are prevented following general principles of anastomosis as tension-free and well-perfused anastomotic stumps, biliary, and enteric. It is also the crucial anatomical knowledge of common bile duct axial vascularization when performing choledochotomy, which must be longitudinal to avoid vascular section, for bile duct exploration and stones removal. Additionally, one must be certified of the absence of distal bile duct obstruction before proceeding with choledochotomy suture. The occurrence of biliary leak, despite all these precautions, has benign behavior and closes spontaneously in most cases when drain-oriented placed intraoperatively or after biloma percutaneous drainage [26, 27].

Biliary strictures are preferably managed through ERCP or transhepatic dilation, depending on the height of bile duct stricture and the magnitude of stenosis. Surgical management with redo anastomosis, a difficult procedure considering previous manipulation, is reserved when endoscopic or percutaneous approach fails [26, 27, 28, 29].

The preference for hepatic or choledochojejunostomy is recommended to avoid recurrent ascendent cholangitis also known as sump syndrome [24, 27].

New perspectives, mainly minimally invasive, for bile duct stones treatment include cholangioscopy-guided lithotripsy, extracorporeal shock wave lithotripsy, and laser lithotripsy under direct visualization through ureteroscopes or choledochoscopes employment [30]. SpyGlass™ system is a new device for high-resolution cholangioscopy which may be combined with electrohydraulic lithotripsy during ERCP or with laser lithotripsy, specially applied for difficult bile duct stones [31].

Although not yet widely available and clearly established by the guidelines, all these techniques could be used as adjunct to ERCP or laparoscopic bile duct exploration in order to improve one-step resolution rates in case of simultaneous gallbladder stones or common bile duct clearance if residual choledocholithiasis, according to technical skills development [3, 4, 11, 30, 31].

The summary of management is summarized in Figure 6.

Figure 6.

Management of common bile duct stones flowchart. ERCP: endoscopic retrograde cholangiopancreatography, LC: laparoscopic cholecystectomy, IOC: intraoperative cholangiography, LUS: laparoscopic ultrasound, EHL: cholangioscopy-guided electrohydraulic lithotripsy, LL: laser lithotripsy.

4. Conclusions

Bile duct stones is relatively prevalent condition. In patients with gallbladder, the diagnostic effort must include both silent and suspected stone based on clinical, biochemical, and radiological predictors of choledocholithiasis, in the cholecystectomy preoperative period. Once stratified as intermediate or high risk, the investigation will proceed according to local resources availability, preferably with MRCP and ERCP, respectively. The treatment will depend on several factors to be considered, such as the moment of diagnosis, stone size and number, bile duct diameter, ERCP availability, and technical skills. Considering all these factors, the surgeon must propose the best available approach to your patient.

Acknowledgments

We wish to express our gratitude to Santa Casa de Caridade de Uruguaiana, Brazil, where our medical care develops.

We would like to thank Universidade Federal do Pampa, Uruguaiana, Brazil, where our research, teaching, and learning activities develop.

Conflict of interest

The authors declare no conflict of interest.

Abbreviations

AF	alkaline phosphatase
ALT	alanine aminotransferase
AST	aspartate aminotransferase
CBD	common bile duct
CBDS	common bile duct stones
CT	computed tomography
ERCP	endoscopic retrograde cholangiopancreatography
EUS	endoscopic ultrasonography
LUS	laparoscopic ultrasonography
GGT	gamma-glutamyl transpeptidase
IOC	intraoperative cholangiography
LC	laparoscopic cholecystectomy
MRCP	magnetic resonance cholangiopancreatography