Factors related to the spontaneous passage of common bile duct stones through the papilla: a single-center retrospective cohort study
Shulan (Hangzhou) Hospital Affiliated to Zhejiang Shuren University, Zhejiang Shuren University, Shulan International Medical College, Hangzhou, Zhejiang, P.R. China
Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
Abstract
Objective
Common bile duct (CBD) stones can spontaneously pass through the papilla. This study explored factors associated with stone passage by comparing differences in the clinical features of stones retained in the CBD and excreted stones.
Methods
Data were retrospectively collected for all patients who were hospitalized in our center between March 2016 and May 2021 with clinical, laboratory, or imaging evidence of CBD stones. All patients underwent endoscopic retrograde cholangiopancreatography (ERCP) and were classified into two groups: group A (stones extracted by ERCP, n = 86) and group B (stones discharged before ERCP, n = 15). Demographic data, biochemical and radiological findings were compared between the groups.
Results
Stone size (0.82 vs. 0.33 cm), and levels of total bilirubin (58.2 vs. 28.8 μmol/L), gamma-glutamyl transpeptidase (416.7 vs. 193.9 U/L), alkaline phosphatase (191.9 vs. 123.1 U/L), carbohydrate antigen 19-9 (603.7 vs. 37.2 U/mL), and α-L-fucosidase (37.4 vs. 22.6 U/L) were significantly higher in group A than in group B. Logistic regression analyses showed that stone size was the only factor significantly associated with spontaneous passage of CBD stones.
Conclusions
CBD stones less than 0.33 cm in size may be self-expelled through the papilla.
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Keywords: Common bile duct stone, endoscopic retrograde cholangiopancreatography, gamma-glutamyl transpeptidase, alkaline phosphatase, carbohydrate antigen 19-9, α-L-fucosidase, retrospective analysis
Article notes
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Received 2021 Jul 18; Accepted 2021 Oct 14; Collection date 2021 Nov.
Introduction
The presence of common bile duct (CBD) stones, the most common cause of biliary obstruction worldwide, is a prevalent digestive disorder that can cause serious complications associated with considerable mortality, such as obstructive suppurative cholangitis, gallstone pancreatitis, and liver parenchyma inflammation.1–3 Until recently, the advice was to endoscopically or surgically remove CBD stones once a diagnosis was established. 4 Endoscopic retrograde cholangiopancreatography (ERCP) is the most common approach for CBD stones. 5 However, ERCP is an invasive procedure that is associated with several complications, including post-ERCP pancreatitis, retroperitoneal perforation, and post-sphincterotomy bleeding.6,7 Moreover, some CBD stones can spontaneously pass through the papilla. Previous studies have shown that stones with diameters <5 mm were more likely to spontaneously pass.8,9 Therefore, it is imperative to confirm whether stones still exist in the CBD before ERCP.
The American Society for Gastrointestinal Endoscopy (ASGE) guidelines suggest performing magnetic resonance cholangiopancreatography (MRCP) or endoscopic ultrasound (EUS) prior to ERCP. 10 MRCP has 77% to 100% sensitivity and 73% to 99% specificity for detecting CBD stones. 11 EUS has a reported sensitivity of 75% to 100% and a specificity of 85% to 100%. 11 However, EUS and MRCP do not have perfect negative predictive ability. EUS has higher technical requirements, which limits its clinical applicability. Interestingly, it has been reported that computed tomography (CT) scans have a sensitivity of 65% to 88% for detecting CBD stones. 12 Meanwhile, the revised ASGE guidelines in 2019 recommend CT for the risk stratification of patients suspected to have CBD stones. 13 Therefore, in our center, MRCP and CT are combined to confirm that stones still exist in the CBD before ERCP.
This study enrolled 101 cases of suspected choledocholithiasis treated with ERCP, and the patients were divided into two groups: group A (stones extracted by ERCP, n = 86) and group B (stones discharged before ERCP, n = 15). Clinical data were compared between groups A and B in detail to further explore the factors related to CBD stones that spontaneously discharged.
Materials and methods
Patients
Shulan (Hangzhou) Hospital, in affiliation with the Shulan International Medical College Review Board, approved this study. All patients signed informed consent before ERCP. We retrospectively reviewed electronic clinical medical records for all patients who underwent ERCP with suspected choledocholithiasis by imaging examinations (MRCP/CT) between 1 March 2016 and 1 May 2021. We excluded patients <18-years-old, those with a history of gastric, liver, or biliary surgery (partial hepatectomy, Roux-en-Y gastric bypass, Billroth I or II, choledocholithotomy, choledochojejunostomy, or hepaticojejunostomy), abdominal organ transplantation such as liver or kidney transplantation, prior ERCP, a history of malignancy including hepatobiliary and pancreatic malignancies, colorectal cancer, gastric cancer, lung cancer, or hematological malignancies, intraductal papillary mucinous tumors of the pancreas, serous or mucinous cystadenoma in the head of the pancreas, or benign diseases of the primary liver or bile duct or pancreas (including liver cirrhosis of various causes, primary sclerosing cholangitis, alcoholic liver disease, viral hepatitis including inactive hepatitis B virus carriers, autoimmune liver disease, autoimmune pancreatitis, chronic pancreatitis, pancreas divisum, and annular pancreas). We reviewed demographic data (age, sex, and body mass index [BMI]), liver function test results (alanine transaminase [ALT], aspartate aminotransferase [AST], total bile acids [TBA], gamma-glutamyl transpeptidase [γ-GGT], alkaline phosphatase [ALP], total bilirubin [TB], direct bilirubin [DB], indirect bilirubin [IB], cholinesterase [CHE], glycine proline dipeptidyl aminopeptidase [GPDA], α-L-fucosidase [AFU], total cholesterol [TC], triglycerides, high-density lipoprotein cholesterol [HDLC], low-density lipoprotein cholesterol [LDLC], and adenosine deaminase [ADA]), imaging findings (CBD diameter and stone diameter), time from admission to ERCP, pre-ERCP temperature, neutrophil ratio, and levels of white blood cells (WBCs), C-reactive protein (CRP), and carbohydrate antigen 19-9 (CA 19-9). Measurements of the CBD diameter and stone size were obtained by imaging examinations (MRCP/CT) before ERCP. A true positive CBD stone was defined as the visualization of a stone or stone fragments that were later removed on ERCP.
ERCP procedure
ERCP was performed with standard side-view duodenoscopes (Olympus TJF 260/JF 240, Olympus Optical Corporation, Tokyo, Japan). After successful intubation of the duodenal papilla, a contrast agent was injected into the CBD. An appropriate contrast medium was selected, i.e., one that clearly showed the filling defect (without splintering or obvious shape change) and the diameter of the CBD (especially the diameter of the CBD at the distal end of a stone). We usually used a spiral net basket (MWB-2X4/3X6, Wilson-Cook Medical Incorporated, Winston-Salem, NC, USA), but we also used a retrieval balloon catheter (FS-QEB-XL-A, Wilson-Cook Medical Incorporated; or M00547110, Boston Scientific Corporation, Marlborough, MA, USA) or both. When the stones were larger than 1.2 cm, we usually used a mechanical lithotripsy basket (FS-LXB-3X6, Wilson-Cook Medical Incorporated). Endoscopic nasobiliary drainage (ENBD) was a routine procedure after stone extraction to prevent cholangitis. In group B patients, an ENBD was also advised to be placed unless they refused. The nasobiliary ducts were usually placed for 3 to 5 days and would be removed when the patients were discharged. All ERCP findings, extraction models, and complications were recorded.
Statistical analysis
Data are presented as mean ± SD or median (interquartile range [IQR]) for normally or nonnormally distributed variables, respectively. Numerical data were compared using the independent Student’s t test and Mann–Whitney U test. Categorical variables were compared using the χ2 test or Fisher’s exact test. A p-value <0.05 was used to indicate statistical significance. Multivariate regression analyses were used to determine significantly associated risk factors. All statistical analyses were performed using IBM SPSS for Windows version 19.0 (IBM Corp., Armonk, NY, USA).
Results
This study included 101 patients with clinical, biochemical, or radiological suspicion of CBD stones. Their ages ranged from 19 to 90 years, with a mean age of 58.1 years. Among the 101 patients, 47 (46.5%) were male and 54 (53.5%) were female. The most common presenting complaint was upper abdominal pain. The proportion of patients with upper abdominal pain was 81.4% (70/86) in group A and 80.0% (12/15) in group B. Fifteen patients presented with complaints of nausea and vomiting (all in group A). Fever with or without chills was present in 10 patients (all in group A).
There were significant differences between groups A and group B in stone size (0.82 vs. 0.33 cm) and levels of TB (58.2 vs. 28.8 μmol/L), ALP (191.9 vs. 123.1 U/L), CA 19-9 (603.7 vs. 37.2 U/mL), γ-GGT (416.7 vs. 193.9 U/L), and AFU (37.4 vs. 22.6 U/L) (Figure 1, all P < 0.05). However, there were no significant differences between group A and group B in age, BMI, or levels of ALT, AST, DB, WBC, and CRP (Table 1). The proportion of male patients and those with a CBD diameter greater than 1 cm were not significantly higher in group A than in group B (Table 2). Comparing group A with group B by univariate analyses showed that larger stone size, and higher levels of γ-GGT and AFU were not conducive to the spontaneous discharge of stones into the intestinal tract (Table 3, P < 0.05). However, multivariate analyses showed that stone size was the only relevant factor (hazard ratio: 0.001, 95% confidence interval: 0.001–0.057, P = 0.017).
| Age | Alanine aminotransferase | Aspartate aminotransferase | Total bilirubin | Direct bilirubin | Indirect bilirubin | |
|---|---|---|---|---|---|---|
| Total patients | 58.1 ± 17.5 | 144.0 [272.8] | 83.5 [141.5] | 26.5 [48.8] | 13.5 [38.5] | 10.0 [13.0] |
| Group A | 59.0 ± 17.6 | 134.0 [277.5] | 82.0 [140.0] | 29.0 [52.0] | 17.0 [41.0] | 11.0 [13.0] |
| Group B | 52.6 ± 16.6 | 151.0 [228.0] | 114.0 [210.0] | 16.0 [20.0] | 7.0 [12.0] | 9.0 [9.0] |
| γ-glutamyl transpeptidase | Alkaline phosphatase | Cholinesterase | Total bile acids | Glycine proline dipeptidyl aminopeptidase | α-L-fucosidase | |
| Total patients | 294.5 [433.8] | 147.5 [133.0] | 7046.8 ± 1989.5 | 14.3 [120.8] | 136.6 ± 60.0 | 35.8 ± 17.5 |
| Group A | 320.0 [440.5] | 156.0 [144.5] | 7043.8 ± 2064.9 | 14.6 [139.9] | 138.7 ± 60.6 | 37.4 ± 17.8 |
| Group B | 118.0 [238.0] | 98.0 [90.0] | 7072.8 ± 1246.1 | 9.7 [68.9] | 119.0 ± 55.8 | 22.6 ± 7.4 |
| Totalcholesterol | Triglyceride | High density lipoprotein cholesterol | Low density lipoprotein cholesterol | Adenosine deaminase | Temperature | |
| Total patients | 4.7 ± 1.2 | 1.5 ± 0.9 | 1.2 ± 0.5 | 2.6 ± 0.9 | 11.0 [5.0] | 36.9 ± 0.5 |
| Group A | 4.7 ± 1.2 | 1.5 ± 0.9 | 1.2 ± 0.5 | 2.6 ± 0.9 | 11.0 [5.0] | 36.9 ± 0.5 |
| Group B | 4.4 ± 0.9 | 1.2 ± 0.5 | 1.3 ± 0.6 | 2.3 ± 0.5 | 9.0 [3.3] | 36.7 ± 0.2 |
| White blood cell count | Neutrophil ratio | C-reactive protein | Carbohydrate antigen-199 | Time from admission to ERCP | Body mass index | |
| Total patients | 6.2 [3.4] | 67.5 ± 13.8 | 5.3 [22.6] | 13.0 [56.7] | 3.0 [4.0] | 23.6 ± 3.3 |
| Group A | 6.1 [3.3] | 67.5 ± 14.0 | 6.0 [23.6] | 17.6 [64.7] | 3.0 [3.0] | 23.6 ± 3.2 |
| Group B | 6.2 [3.4] | 67.3 ± 13.4 | 5.0 [3.5] | 5.4 [14.2] | 4.0 [5.0] | 23.6 ± 3.8 |
| Male (%) | Abdominal pain (%) | Cholecystolithiasis (%) | CBD diameter>1 cm (%) | |
|---|---|---|---|---|
| Total patients | 46.5 | 81.2 | 60.4 | 60.4 |
| Group A | 50.0 | 81.4 | 61.6 | 64.0 |
| Group B | 26.7 | 80.0 | 53.3 | 40.0 |
| Stone extraction methods (1/2/3, %) | CBD stone >0.5 cm (%) | Amylase upregulation pre-ERCP (%) | Amylase upregulation post-ERCP (%) | |
| Total patients | 57.4 /13.9 /27.7 | 49.5 | 9.9 | 22.0 |
| Group A | 60.4/10.5/27.9 | 57.0 | 9.3 | 32.6 |
| Group B | 40.0/33.3/26.7 | 0.0 | 13.3 | 53.3 |
| Total bilirubin upregulation pre-ERCP (%) | Alanine aminotransferase upregulation pre-ERCP (%) | Balloon dilatation (%) | ENBD (%) | |
| Total patients | 55.4 | 75.2 | 27.7 | 98.0 |
| Group A | 59.3 | 75.6 | 32.6 | 98.9 |
| Group B | 33.3 | 73.3 | 0.0 | 93.3 |
| Univariate | Multivariate | |||||
|---|---|---|---|---|---|---|
| Variables | P value | HR | 95% CI | P value | HR | 95% CI |
| Age | >0.05 | / | / | >0.05 | / | / |
| Sex | >0.05 | / | / | >0.05 | / | / |
| Cholecystolithiasis | >0.05 | / | / | >0.05 | / | / |
| Alanine aminotransferase pre-ERCP | >0.05 | / | / | >0.05 | / | / |
| Aspartate aminotransferase pre-ERCP | >0.05 | / | / | >0.05 | / | / |
| Total bilirubin pre-ERCP | >0.05 | / | / | >0.05 | / | / |
| Direct bilirubin pre-ERCP | >0.05 | / | / | >0.05 | / | / |
| Indirect bilirubin pre-ERCP | >0.05 | / | / | >0.05 | / | / |
| γ-glutamyl transpeptidase pre-ERCP | 0.018 | 0.996 | 0.994-0.999 | >0.05 | / | / |
| Alkaline phosphatase pre-ERCP | >0.05 | / | / | >0.05 | / | / |
| Cholinesterase pre-ERCP | >0.05 | / | / | >0.05 | / | / |
| Total bile acids pre-ERCP | >0.05 | / | / | >0.05 | / | / |
| Glycine proline dipeptidyl aminopeptidase pre-ERCP | >0.05 | / | / | >0.05 | / | / |
| α-L-fucosidase pre-ERCP | 0.023 | 0.885 | 0.796-0.983 | >0.05 | / | / |
| Total cholesterol pre-ERCP | >0.05 | / | / | >0.05 | / | / |
| Triglyceride pre-ERCP | >0.05 | / | / | >0.05 | / | / |
| High density lipoprotein cholesterol pre-ERCP | >0.05 | / | / | >0.05 | / | / |
| Low density lipoprotein cholesterol pre-ERCP | >0.05 | / | / | >0.05 | / | / |
| Adenosine deaminase pre-ERCP | >0.05 | / | / | >0.05 | / | / |
| Temperature pre-ERCP | >0.05 | / | / | >0.05 | / | / |
| White blood cells pre-ERCP | >0.05 | / | / | >0.05 | / | / |
| Percentage of neutrophils pre-ERCP | >0.05 | / | / | >0.05 | / | / |
| C-reactive protein pre-ERCP | >0.05 | / | / | >0.05 | / | / |
| Common bile duct diameter >1 cm | >0.05 | / | / | >0.05 | / | / |
| Carbohydrate antigen 19-9 pre-ERCP | >0.05 | / | / | >0.05 | / | / |
| Time from admission to ERCP | >0.05 | / | / | >0.05 | / | / |
| Stone size | 0.001 | 0.001 | 0.001–0.008 | 0.017 | 0.001 | 0.001–0.057 |
After ERCP, 44 patients in group A underwent ENBD and 40 underwent ENBD and cholecystectomy. One patient’s CBD stone failed to be completely removed by ERCP because the diameter of the stone was nearly 6 cm. This patient underwent ENBD after ERCP and was followed up with choledocholithotomy. In another patient, titanium clips were used to close the perforation because of type II gastrointestinal perforation, and plastic stents were placed in the biliary and pancreatic ducts. In group B, after ERCP, seven patients underwent ENBD, seven received ENBD and cholecystectomy, and one patient underwent small duodenal papillotomy and balloon sweeping, without indwelling nasobiliary duct.
Discussion
As early as 1983, Levine et al. pointed out that 90% of CBD calculi could pass spontaneously. 14 Since then, increasing attention has been paid to the spontaneous discharge of CBD stones. In 2004, Collins et al. found that more than one third of choledocholithiasis could pass spontaneously within 6 weeks of laparoscopic cholecystectomy. 15 In 2011, Lefemine et al. presented data showing that more than half of patients with obstructive jaundice experienced spontaneous passage of gallstones from the CBD. 16 These findings suggested that CBD stones could often spontaneously pass without the need for endoscopic or surgical drainage procedures. 8 Thus, it is imperative to identify specific predictors of CBD stones that will spontaneously pass.
In 1985, a study reported that serum bilirubin >25 μmol/L, serum ALP >250 U/L, and a CBD width >10 mm were associated with an increased probability of CBD stones being present. 17 In 1994, a study by Barkun et al. showed that ALP >300 U/L and AST >120 U/L had sensitivities of 79% and 81%, respectively, for predicting the presence of CBD stones. 18 Later, Pereira-Lima et al. reported that γ-GGT, ALP, and TB were sensitive indicators of CBD stones. 19 Recently, several studies have concluded that γ-GGT is the most sensitive marker for predicting the presence of CBD stones, and it is also associated with the highest predictive value and diagnostic accuracy.19,20 In this study, we found that levels of TB, ALP, and γ-GGT were significantly higher in group A than in group B (P < 0.05). Univariate analyses showed that higher γ-GGT levels were not conducive to the spontaneous discharge of stones into the intestinal tract (P < 0.05). However, multivariate regression analyses showed that γ-GGT was not associated with spontaneous CBD stone passage. In accordance, other previous studies have also concluded that there is no significant correlation between abnormal liver function and spontaneous discharge of stones.6,21 Perhaps we lacked a dynamic observation process. Khoury et al. showed that improved γ-GGT levels predicted spontaneous CBD stone passage. 8
Increased CA 19-9 is associated with not only bile duct carcinoma but also acute cholangitis. 22 Mei et al. showed that elevated serum CA 19-9 levels were an important diagnostic indicator of acute cholangitis, secondary to CBD stones. 23 In this study, we found that CA 19-9 levels were significantly higher in group A than in group B (P < 0.05). However, CA 19-9 was not associated with stone retention or spontaneous passage. It has been reported that the properties of AFU in primary hepatocarcinoma are different from those in other human organs, 24 and AFU has been shown to be relevant in the diagnosis of hepatocellular carcinoma. 25 However, there are no reports showing a direct relationship between AFU and cholangitis or CBD stones. Patients with previous or current malignancies were excluded from this study. Unexpectedly, we found that AFU was significantly higher in group A than that in group B (P < 0.05). However, regression analyses showed that pre-ERCP AFU level was not an independently correlated factor for the spontaneous excretion of CBD stones.
A previous study concluded that CBD stones <3.5 mm in size were associated with a significantly increased likelihood of spontaneous passage, with an acceptable sensitivity of 71% and specificity of 69%. 8 Meanwhile, our study also concluded that a stone diameter of <0.33 cm was conducive to spontaneous discharge into the intestinal tract (hazard ratio: 0.001, 95% confidence interval: 0.001–0.057, P = 0.017).
A delay in the time between a patient’s admission and them undergoing ERCP could theoretically increase the possibility of CBD stones being spontaneously passed. 26 The mean time from admission to ERCP was relatively longer in group B than in group A (5.3 vs. 3.2 days), but the difference was not significant. Logistic regression analysis showed that time was not an independent factor for stone passage. Additionally, a previous study showed that advanced age and male sex were associated with the failure of spontaneously passing CBD stones. 8 The revised ASGE guidelines (2019) also deem age >55-years-old to be a moderate risk factor for CBD stones. 13 However, in this study, logistic regression analysis did not show that advanced age or male sex were risk factors for failing to spontaneously pass CBD stones.
The role of imaging in examining for CBD stones was also a focus of this study. Transabdominal US is not a sensitive enough tool for detecting CBD stones, with its sensitivity reported to range from 20% to 80%. 1 Both MRCP and EUS have high diagnostic accuracy for detecting CBD stones. 11 Intraoperative cholangiography is also a common method of evaluating for the presence of CBD stones, with a reported sensitivity of 59% to 100% and specificity of 93% to 100%. 10 It was reported that at least 3% to 10% of patients who underwent cholecystectomy might be complicated with CBD stones. 27 In this condition, there were two main approaches: the single-stage “laparoscopy-first” approach, which relied on intraoperative cholangiography for diagnosis and laparoscopic common bile duct exploration for treatment, and the two-stage “endoscopy-first” approach, which relied on MRCP or EUS for diagnosis and pre- or post-cholecystectomy ERCP for management. 28 There were no significant differences in the mortality, morbidity, or failure rates between laparoscopic CBD clearance and endoscopic bile duct management. 29
Our study had several limitations. First, it was a retrospective study that was performed in a single medical center. Second, the sample size was not large enough, and the study groups were not similar in the number of patients included.
In conclusion, the spontaneous passage of CBD stones is a common phenomenon. Stone size <0.33 cm is conducive to the spontaneous discharge of CBD stones into the intestinal tract. The observation of dynamic changes in liver function may be a better method for tracking spontaneous stone discharge. The relationship between AFU and choledocholithiasis deserves further study. Finally, we suggest performing EUS prior to ERCP during the two-stage “endoscopy-first” procedure.
Acknowledgement
We thank Ms. Biyao for assisting with the statistical analysis.
Footnotes
Footnote Group
References
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References
- 1.Magalhães J Rosa B andCotter J.. Endoscopic retrograde cholangiopancreatography for suspected choledocholithiasis: From guidelines to clinical practice. World J Gastrointest Endosc 2015; 7: 128–134.
- 2.Chiang PH, Lai KH, Tsai TJ, et al. Is endoscopic treatment beneficial in patients with clinically suspicious of common bile duct stones but no obvious filling defects during the ERCP examination? BMC Gastroenterol 2016. doi: 10.1186/s12876-016-0524-2.
- 3.Horwood J, Akbar F, Davis K, et al. Prospective evaluation of a selective approach to cholangiography for suspected common bile duct stones. Ann R Coll Surg Engl 2010; 92: 206–210.
- 4.Manes G, Paspatis G, Aabakken L, et al. Endoscopic management of common bile duct stones: European Society of Gastrointestinal Endoscopy (ESGE) guideline. Endoscopy 2019; 51: 472–491.
- 5.Andriulli A, Loperfido S, Napolitano G, et al. Incidence rates of post-ERCP complications: a systematic survey of prospective studies. Am J Gastroenterol 2007; 102: 1781–1788.
- 6.Bill JG, Kushnir VM, Mullady DK, et al. Evaluation of patients with abnormalities on intraoperative cholangiogram: time to abandon endoscopic retrograde cholangiopancreatography as the initial follow-up study. Frontline Gastroenterol 2016; 7: 105–109.
- 7.Anderson MA, Fisher L, Jain R, et al. Complications of ERCP. Gastrointest Endosc 2012; 75: 467–473.
- 8.Khoury T, Adileh M, Imam A, et al. Parameters Suggesting Spontaneous Passage of Stones from Common Bile Duct: A Retrospective Study. Can J Gastroenterol Hepatol 2019. doi: 10.1155/2019/5382708.
- 9.Gao J, Ding XM, Ke S, et al. Anisodamine accelerates spontaneous passage of single symptomatic bile duct stones ≤10 mm. World J Gastroenterol 2013; 19: 6618–6624.
- 10.Maple JT, Ben-Menachem T, Anderson MA, et al. The role of endoscopy in the evaluation of suspected choledocholithiasis. Gastrointest Endosc 2010; 71: 1–9.
- 11.Giljaca V, Gurusamy KS, Takwoingi Y, et al . Endoscopic ultrasound versus magnetic resonance cholangiopancreatography for common bile duct stones. Cochrane Database Syst Rev 2015. doi: 10.1002/14651858.CD011549.
- 12.Bang BW, Hong JT, Choi YC, et al. Is endoscopic ultrasound needed as an add-on test for gallstone diseases without choledocholithiasis on multidetector computed tomography? Dig Dis Sci 2012; 57: 3246–3251.
- 13.Buxbaum JL, Abbas Fehmi SM, Sultan S, et al. ASGE guideline on the role of endoscopy in the evaluation and management of choledocholithiasis. Gastrointest Endosc 2019; 89: 1075–1105.
- 14.Levine SB, Lerner HJ, Leifer ED, et al. Intraoperative cholangiography. A review of indications and analysis of age-sex groups. Ann Surg 1983; 198: 692–697.
- 15.Collins C, Maguire D, Ireland A, et al. A prospective study of common bile duct calculi in patients undergoing laparoscopic cholecystectomy: natural history of choledocholithiasis revisited. Ann Surg 2004; 239: 28–33.
- 16.Lefemine V andMorgan RJ.. Spontaneous passage of common bile duct stones in jaundiced patients. Hepatobiliary Pancreat Dis Int 2011; 10: 209–213.
- 17.Hauer-Jensen M, Kåresen R, Nygaard K, et al. Predictive ability of choledocholithiasis indicators. A prospective evaluation. Ann Surg 1985; 202: 64–68.
- 18.Barkun AN, Barkun JS, Fried GM, et al. Useful predictors of bile duct stones in patients undergoing laparoscopic cholecystectomy. McGill Gallstone Treatment Group. Ann Surg 1994; 220: 32–39.
- 19.Pereira-Limâ JCJakobs R Busnello JV, et al. The role of serum liver enzymes in the diagnosis of choledocholithiasis. Hepatogastroenterology 2000; 47: 1522–1525.
- 20.An MR, Lohse I, Tan ZJ, et al. Quantitative proteomic analysis of serum exosomes from patients with locally advanced pancreatic cancer undergoing chemoradiotherapy. J Proteome Res 2017; 16: 1763–1772.
- 21.Spinn MP, Wolf DS, Verma D, et al. Prediction of which patients with an abnormal intraoperative cholangiogram will have a confirmed stone at ERCP. Dig Dis Sci 2010; 55: 1479–1484.
- 22.Ker CG, Chen JS, Lee KT, et al. Assessment of serum and bile levels of CA19-9 and CA125 in cholangitis and bile duct carcinoma. J Gastroenterol Hepatol 1991; 6: 505–508.
- 23.Mei Y, Chen L, Peng CJ, et al. Diagnostic value of elevated serum carbohydrate antigen 199 level in acute cholangitis secondary to choledocholithiasis. World J Clin Cases 2018; 6: 441–446.
- 24.Li C Qian J, andLin JS.. Purification and characterization of alpha-L-fucosidase from human primary hepatocarcinoma tissue. World J Gastroenterol 2006; 12: 3770–3775.
- 25.Waidely E, Al-Youbi AO, Bashammakh AS, et al. Alpha-l-Fucosidase Immunoassay for Early Detection of Hepatocellular Carcinoma. Anal Chem 2017; 89: 9459–9466.
- 26.Al-Jiffry BO, Khayat S, Abdeen E, et al. A scoring system for the prediction of choledocholithiasis: a prospective cohort study. Ann Saudi Med 2016; 36: 57–63.
- 27.Freitas M Bell RL, andDuffy AJ.. Choledocholithiasis: evolving standards for diagnosis and management. World J Gastroenterol 2006; 12: 3162–3167.
- 28.Costi R, Gnocchi A, Mario FD, et al. Diagnosis and management of choledocholithiasis in the golden age of imaging, endoscopy and laparoscopy. World J Gastroenterol 2014; 20: 13382–13401.
- 29.Dasari BVTan CJ Gurusamy KS, et al . Surgical versus endoscopic treatment of bile duct stones. Cochrane Database Syst Rev 2013. doi: 10.1002/14651858.CD003327.pub4.