Clin Endosc > Volume 52(6); 2019 > Article
Parsa and Khashab: The Role of Peroral Cholangioscopy in Evaluating Indeterminate Biliary Strictures


Biliary strictures are considered indeterminate when the initial radiologic evaluation and endoscopic retrograde cholangiopancreatography with brush cytology and/or forceps biopsy do not reveal diagnostic findings. Evaluation of these strictures is challenging and often requires a multidisciplinary approach and multiple procedures. Peroral cholangioscopy allows direct visualization of these lesions and targeted tissue acquisition using miniature biopsy forceps. In the past decade, there have been significant improvements in the field of cholangioscopy. These advances have allowed higher-quality image acquisition, easy setup, operation by a single operator, easy maneuverability, and excellent targeted tissue sampling performance. However, the interpretation of cholangioscopic visual findings remains challenging. In this review, we discuss the role of peroral cholangioscopy in the evaluation of indeterminate biliary strictures.


Endoscopic retrograde cholangiopancreatography (ERCP) with standard brush cytology and/or forceps biopsy was one of the first approaches in the evaluation of obstructive biliary and pancreatic duct diseases. However, ERCP does not provide an intraluminal view of the pancreaticobiliary pathology. Cholangiopancreatoscopy overcomes this limitation by allowing direct visualization of the biliary and pancreatic ducts. The first cholangioscope was described in 1941, and the peroral approach was subsequently introduced in the early 1970s [1,2]. The early cholangioscopy system, known as the mother-daughter system, consisted of a mother duodenoscope and a daughter cholangiopancreatoscope. The limitations of this system were the need for two operators, scope fragility, and poor image quality. Over the past decade, there have been significant improvements in cholangioscopy technology. These include improved image quality, easy setup, need for only one operator, and ability to perform targeted biopsies and therapeutic procedures, such as lithotripsy. One of the main indications for cholangioscopy is the evaluation of biliary strictures when imaging, and ERCP with brush cytology and/or biopsy does not yield a definitive diagnosis. These indeterminate biliary strictures present a diagnostic challenge for endoscopists as both malignant and benign etiologies should be considered. Cholangioscopy offers the advantage of direct visualization of the biliary epithelium to assess malignant features and targeted biopsy results of suspected lesions. This review summarizes the role of peroral cholangioscopy in the evaluation of indeterminate biliary strictures.


Cholangioscopy can be performed perorally or percutaneously. The peroral approach can be performed using an ultraslim endoscope (direct peroral cholangioscopy system [DPCS], GIF-XP; Olympus Co., Tokyo, Japan) or a catheter-based system with a single-operator cholangiopancreatoscope (SOCP, SpyGlass Direct Visualization System; Boston Scientific Endoscopy, Marlboro, MA, USA). Table 1 summarizes the features, advantages, and disadvantages of the different cholangioscopy systems.
In the DPCS, an ultraslim gastroscope is advanced in a monorail fashion over a guidewire or with balloon assistance into the biliary tree. This approach requires sphincterotomy or distal duct dilation for advancement of the cholangioscope through the biliary sphincter. The DPCS allows targeted biopsy of mucosal abnormalities or direct treatment of stone diseases. This system has a high-definition video technology with a superior image quality compared with the SOCP. Additional complementary imaging modalities, such as narrow band imaging (NBI) and probe-based confocal laser endomicroscopy (pCLE), can be used to improve the diagnostic yield further. NBI allows enhanced visualization of superficial mucosal capillary and pit patterns and thicker capillaries of the deeper tissues by restricting light to two waveforms (i.e., 415 and 540 nm). pCLE provides histologic-level images by passing a laser light through a confocal aperture. Owing to the required expertise and high cost, the use of this technique is currently only limited to select centers.
In 2007, the first-generation SOCP was introduced to clinical practice. This device was a single-use fibro-optic-based device (fibro-optic SOCP [FSOCP]) that allowed a single operator to complete the procedure. A new digital version of the SOCP (SpyGlass DS, SPY DS; digital SOCP [DSOCP]) has several advantages compared with the fibro-optic-based device. The new system consists of a sterile, single-use SpyScope access and delivery catheter, SpyGlass digital controller, and SpyBite, which is a biliary biopsy forcep. This system utilizes two light-emitting diodes that improve the image quality and provides a wider endoscopic field of view. Further, there is a dedicated aspiration and irrigation channel, and the tapered tip enables a less traumatic advancement across the papilla and strictures.


Peroral cholangioscopy can be utilized for both diagnostic indications and therapeutic applications. Table 2 summarizes the key clinical indications and contraindications for performing cholangioscopy. The two most common indications for peroral cholangioscopy are management of complex bile duct stones and assessment of indeterminate biliary strictures [3,4].


Biliary strictures are considered indeterminate when the initial radiologic evaluation and ERCP with standard brush cytology and/or forceps biopsy do not yield a definitive diagnosis. These strictures can be benign or malignant and can originate from the intra- or extrahepatic biliary tree, pancreas, liver, gallbladder, ampulla, regional lymph nodes, or invasion from other gastrointestinal malignancies and metastases. Evaluation of these strictures is of paramount importance, as early diagnosis avoids unnecessary surgical procedures and yields optimal patient outcomes. Table 3 summarizes the differential diagnosis for benign and malignant biliary strictures. The leading causes of malignant biliary strictures are cholangiocarcinoma and pancreatic cancer [5].
The diagnosis of malignant biliary strictures can be predicted on the basis of cholangioscopic visual characteristics. However, tissue acquisition is required for the final diagnosis and can be performed via ERCP with standard brush cytology and/or forceps biopsy, endoscopic ultrasound-guided fine needle aspiration (EUS-FNA), and cholangioscopy-guided forceps biopsy. ERCP with standard brush cytology and/or forceps biopsy is often the first diagnostic approach employed. However, this is limited by its low sensitivity and high rates of false-negative results. In a systematic review and meta-analysis (nine studies; 730 patients) on the effectiveness of ERCP for detecting malignant biliary strictures, the pooled sensitivities of brushing cytology and forceps biopsy were 45% and 48.1%, respectively. The combination of the two methods increased the sensitivity only to 59.4% [6]. In patients with biliary strictures due to extrinsic compression (e.g., pancreatic tumors or regional lymph nodes), EUS-FNA has a high diagnostic value and should be considered the standard of care [7]. A recent meta-analysis on the diagnostic yield of EUS-FNA (41 studies; 4,766 patients) reported a pooled sensitivity and specificity of 86.8% and 95.8%, respectively, for diagnosing solid pancreatic masses [8]. The limitations of EUS are challenges in accessing proximal biliary strictures and concerns on seeding malignancy along the FNA tract [9,10].


Table 4 summarizes the biliary epithelial visual findings during cholangioscopy. Seo et al. and Fukuda et al. were the first to illustrate these findings and described malignant strictures as lesions with irregularly dilated and tortuous vessels (tumor vessels), nodularity, papillary characteristics, neovascularization, easy oozing, and irregular surface [11,12]. Conversely, benign strictures have smooth mucosa, borders without neovascularization, and papillo-granular mucosa with no obvious mass [11,12]. The strongest feature suggestive of malignancy is the presence of dilated and tortuous vessels, with a reported positive predictive value of up to 100% [13].
Table 5 summarizes the performance of the DPCS in the diagnosis of malignant biliary strictures. The reported sensitivity and specificity of DPCS visual impression for the diagnosis of malignancy are 83%–92% and 84%–92%, respectively [14-16]. In the first US report on the operating characteristics of the DPCS in 96 patients with indeterminate biliary strictures, the sensitivity and specificity were 85% and 84%, respectively [14]. In a feasibility study on the DPCS with the addition of NBI compared with the use of high-definition white light, Itoi et al. reported an improved visualization of both the surface structures and vessels with the use of NBI [17]. They also reported the detection of four out of 21 lesions on NBI that were not seen with the use of high-definition white light [17].
Table 6 summarizes the data on the diagnostic yield of SOCP visual impression for indeterminate biliary strictures [18-34]. The reported sensitivity, specificity, and accuracy ranged from 78% to 100%, from 77% to 97.6%, and from 80% to 97%, respectively (Table 7) [6,9,14,35-37]. In the report by Chen at al. (226 patients from 15 centers), FSOCP visual impression was found to be more sensitive and specific than ERCP fluoroscopic impression for diagnosing malignant biliary strictures (sensitivity, 78% vs. 51%; specificity, 82% vs. 54%, respectively). This study also found a higher sensitivity for strictures caused by intrinsic lesions than for those caused by extrinsic lesions (84% vs. 61%, respectively) [19]. In a systematic review and meta-analysis on the diagnostic yield of the FSOCP based on visual impression (a total of six studies; 456 patients), the pooled sensitivity and specificity for diagnosing malignant biliary strictures were 84.5% and 82.6%, respectively [38].
The visual diagnostic yield of the second-generation DSOCP (SPY DS) is reported to be higher than that of the first-generation FSOCP. In a multicenter study (two centers; 44 patients), the sensitivity and specificity of DSOCP visual impression for the diagnosis of malignant biliary strictures were 90% and 95.8%, respectively [34]. In another similar study, the sensitivity and specificity of DSOCP visual impression were 95.5% and 94.5%, respectively [26]. Recently, Mizrahi et al. compared the diagnostic yield of visual impression between the FSOCP and DSOCP for malignant biliary strictures (324 patients; FSOCP, 198 and DSOCP, 126) and reported a higher diagnostic yield with the DSOCP than with the FSOCP (78% vs. 37%, respectively, p=0.004) [39].
To date, there is a lack of uniformity as well as a poor inter-observer agreement among experts for interpreting the visual impression of biliary strictures. Moreover, in some instances, such as benign extrinsic compression and irregular biliary mucosal pattern in primary sclerosing cholangitis, visual impression can be misleading and may result in false-positive malignant diagnoses [12,40].


Several studies have evaluated the diagnostic yield of DPCS-guided biopsy for indeterminate biliary strictures (Table 5) [14-17,41]. In the report by Mounzer et al. on the diagnostic yield of DPCS-guided biopsy for malignant biliary strictures (96 patients), the sensitivity and specificity were 43% and 97%, respectively [14]. Table 6 summarizes the performance of SOCP-guided biopsy in diagnosing malignant biliary strictures [18-34]. The reported sensitivity, specificity, and accuracy of this technique were 49% to 100%, 82% to 100% and 55% to 100%, respectively (Table 7) [6,9,14,35-37]. In a multicenter study (140 patients from 15 centers) on the diagnostic yield of FSOCP-guided biopsy, the sensitivity and specificity for diagnosing malignant biliary strictures were 49% and 98%, respectively. This study also reported a higher sensitivity for intrinsic lesions than for extrinsic lesions (66% vs. 8%, respectively). This difference highlights an important limitation of cholangioscopy biopsy forceps, i.e., inability to reach extrinsic lesions for tissue sampling in a significant number of patients [19]. In a systematic review on the diagnostic yield of FSOCP-guided biopsy for malignant biliary strictures, the pooled sensitivity and specificity were 60% and 98%, respectively [38].
The first study on the diagnostic yield of DSOCP-guided biopsy for malignant biliary strictures (two centers; 44 patients) reported a sensitivity and specificity of 85% and 100%, respectively [34]. Another similar study (six centers; 250 procedures) reported a sensitivity and specificity of 57% and 100%, respectively [26].
Limited data suggest that the diagnostic yield of cholangioscopy-guided biopsy may be improved by rapid on-site evaluation using a method of touch imprint cytology, with reported sensitivity and accuracy of 100% and 93.5%, respectively, for diagnosing malignant biliary strictures [35]. However, more studies are needed to illustrate the cost-effectiveness of this approach further.


Table 8 summarizes the available data on overall cholangioscopy-related adverse events (AEs) [14-16,18-27,29-34,42]. The overall AE rate of the SOCP for both diagnostic and therapeutic procedures was between 2% and 30%. The AEs included cholangitis, pancreatitis, hemobilia, bile leak, and rare and serious AEs, such as air embolization and bile duct perforation. Sethi et al. compared the AE rate between 402 patients who underwent ERCP with cholangioscopy and 3,475 patients who underwent ERCP only and reported a higher overall AE rate in the former group of patients (7% vs. 2.9%, respectively; odds ratio [OR], 2.5; 95% confidence interval [CI], 1.56–3.89) [43]. Their subgroup analysis also revealed a higher rate of cholangitis in the former group (1.0% vs. 0.2%, respectively, OR, 4.95; 95% CI, 1.06–19.67), with similar rates of pancreatitis and perforation [43]. In a systematic review including 49 studies on the SOCP and DPCS, the overall and severe AE rates were 7% and 1%, respectively, with cholangitis being the most common AE (4%) [44]. Turowski et al. reported an AE rate of 13.2% in 250 patients who underwent surgery using the DSOCP, with cholangitis being the most common AE (8%) [26]. Prophylactic pre-procedural antibiotics were administered in 40% (102) of the patients, which resulted in a significantly lower rate of cholangitis in comparison with those who did not receive antibiotic prophylaxis (n=148, 60%) (1% vs. 12.8%, p<0.01). Therefore, administration of peri-procedural antibiotics should be recommended in all patients undergoing cholangioscopy [26]. The recent retrospective multicenter study (three centers; 341 patients) by Bernica et al. compared cholangioscopy-related AEs among 209 patients divided into three different age groups (178 patients aged <65 years; 86 patients aged 65-75 years; and 77 patients aged >75 years) [45]. The overall AE rate was 7.3%, with no significant difference among the three age groups (7.30% for the patients aged <65 years, 6.98% for those aged 65–75 years, and 7.79% for those aged >75 years; p<0.17) [45].
Air embolism is a rare but serious AE of the DPCS and has been reported in 0%–2.3% of procedures. The use of water for better visualization and CO2 instead of air for insufflation is recommended to minimize this fatal AE [46].


There are limited data on the economic impact of the use of cholangioscopy compared with other conventional modalities. Recently, Deprez et al. compared the use of ERCP and the SOCP for the diagnosis of malignant biliary strictures and reported that the use of the SOCP reduces the number of needed procedures by 31% and saves approximately 5% of the allocated budget [47]. Further studies are needed to evaluate the cost-effectiveness of the SOCP in other clinical settings.


The evaluation of indeterminate biliary strictures presents a diagnostic challenge, and early precise diagnosis is important for achieving optimal patient outcomes and avoiding unnecessary surgical procedures. Radiologic evaluation is useful to detect and characterize strictures and select the best endoscopic diagnostic technique. In patients with biliary strictures due to extrinsic compression (e.g., pancreatic tumors or regional lymphadenopathy) and those with distal biliary lesions, EUS-FNA should be considered as the first endoscopic procedure. If EUS-FNA reveals no diagnostic findings, ERCP with cholangioscopy should be performed next and possibly during the same session. The new-generation DSOCP has improved the image quality and is safe even in the geriatric population. However, the interpretation of cholangioscopic visual findings remains challenging, and to date, there is a lack of uniformity and a poor inter-observer agreement among experts for the visual interpretation of indeterminate biliary strictures. Although miniature biopsy forceps are essential in the sampling of indeterminate strictures, the yield is suboptimal in certain patients. Studies focusing on the optimization of biopsy techniques and handling of procured specimens are needed.


Conflicts of Interest: Mouen A. Khashab is a consultant for Boston Scientific and Olympus America. The Other author has no financial conflicts of interest.

Table 1.
Comparison between the Two Cholangioscopy Systems
Cholangioscopy system SpyGlass DS Ultraslim endoscope
Technology LED light source/120 degrees of digital field of view High-resolution video-scope
Outer diameter (mm) 3.5 4.9–5.9
Channel diameter (mm) 1.2 2.0
Working length (cm) 214 110–130
Accessories -SpyBite biopsy forceps -5-French instruments
-Lithotripsy devices: electrohydraulic lithotripsy and laser lithotripsy -Larger biopsy forceps
-Argon plasma coagulation probes and lithotripsy fibers
Tip deflection Four ways: up-down, left-right Four ways: up-down, left-right
Image quality Excellent Greater than that in the DSOCP
Advantages -Easier access to the pancreatobiliary duct compared with the DPCS -Markedly greater image quality compared with that in the DSOCP
-Separate irrigation channel -Allows NBI and improves visualization of lesion margins and vessels
-Tip maneuverability -Larger working channel (enables several interventions with the use of 5-French diagnostic and therapeutic devices, such as photodynamic therapy and argon plasma coagulation)
-Redesigned working channel for passing accessories
-Fixed imager for consistent steering -Allows simultaneous irrigation and therapy
-Single-use digital scope
-Simplified 5-minute setup
Disadvantages -Expensive -Large outer diameter necessitates prior sphincterotomy
-Narrow working channel diameter -More challenging procedure, requires highly skilled endoscopists
-Difficult to perform biliary cannulation owing to easy loop formation during insertion and trouble fixing the scope inside the biliary tract
-Can only be performed in dilated bile ducts

DPCS, direct peroral cholangioscopy system; DSOCP, digital single-operator cholangiopancreatoscope; LED, light-emitting diode; NBI, narrow band imaging.

Table 2.
Cholangioscopy Indications and Contraindications
Diagnostic indications Therapeutic indications Contraindications
Direct visualization of the biliary epithelium Electrohydraulic/intra-ductal laser lithotripsy of complex stones General contraindications to ERCP, including acute cholangitis
Targeted biopsy of biliary strictures initially or after non-diagnostic ERCP Endoscopic tumor ablation therapy Small duct, <5 mm in diameter
Preoperative assessment of main-duct IPMNs and differentiation of chronic pancreatitis from main-duct IPMN in the appropriately dilated duct Removal of proximally migrated stents Uncorrected coagulopathy
Post-liver transplant biliary complications Guiding treatment margins for biliary radiofrequency ablation
Evaluation of hemobilia Assistance with selective guidewire placement
Assessment of strictures in patients with primary sclerosing cholangitis Alternative to surgery in patients with Mirizzi type 2
Characterization of intra-ductal filling defects found on MRCP and ERCP Stent placement in the cystic duct
Assessment of the etiology of recurrent unexplained choledocholithiasis Photodynamic therapy of cholangiocarcinoma
Photocoagulation with argon in cases of IPMN

ERCP, endoscopic retrograde cholangiopancreatography; IPMN, intraductal papillary mucinous neoplasm; MRCP, magnetic resonance cholangiopancreatography.

Table 3.
Differential Diagnosis for Indeterminate Biliary Strictures
Malignant causes Benign causes
Cholangiocarcinoma Chronic pancreatitis
Pancreatic adenocarcinoma Autoimmune diseases:
 - IgG4-associated cholangitis
 - Sarcoidosis
 - Mast cell cholangitis
Ampullary adenocarcinoma Cholelithiasis
Gallbladder cancer Iatrogenic injury to the bile duct:
 - Cholecystectomy
 - Liver transplantation
Hepatocellular carcinoma Infectious diseases:
 - HIV-associated disease
 - Parasitic cholangiopathy
 - Tuberculosis
Metastatic cancer Vascular-related diseases:
 - Ischemic cholangiopathy
 - Vasculitis
 - Intra-arterial chemotherapy
 - Portal hypertensive biliopathy
Table 4.
Cholangioscopy Visual Impression of Benign and Malignant Lesions
Malignant features Benign features
Tortuous dilated vessels (“tumor vessels”) Ulceration
Infiltrative stricture Atrophy
Polypoid mass Concentric stenosis
Vegetative mass Low-papillary mucosal lesion
Fish-egg lesion Band-like scarring
Finger-like villiform lesion Erythema
Irregularly papillary or granular lesions Pseudo-diverticulae
Nodular elevated lesions
Friability and easily bleeding
Table 5.
Studies on the Diagnostic Yield of Direct Peroral Cholangioscopy System-Guided Visual Impression and Biopsy
Study Study design Patients (n) Technical success (%) Visual sensitivity (%) Visual specificity (%) Visual accuracy (%) Biopsy sensitivity (%) Biopsy specificity (%) Biopsy accuracy (%)
Mounzer et al. (2017) [14]a) Single-center, prospective 96 NR 85 84 NR 43 97 NR
Meves et al. (2014) [15] Single-center, prospective 84 87 NR NR NR 89.5 NR NR
Farnik et al. (2014) [16] Multicenter, retrospective 89 88.5 NR NR NR NR NR NR

NR, not reported.

a) In this study, 14 out of 96 patients were examined for pancreatic disease.

Table 6.
Single-Operator Cholangiopancreatoscope Visual Impression and SpyBite Biopsy Diagnostic Yield for Indeterminate Biliary Strictures
Study Study design Cholangioscopy system Patients (n) Technical success (%) Visual sensitivity (%) Visual specificity (%) Visual accuracy (%) Biopsy sensitivity (%) Biopsy specificity (%) Biopsy accuracy (%)
Chen et al. (2007) [18] Multicenter, prospective FSOCP 22 91 100 77 85 71 100 90
Chen et al. (2011) [19] Multicenter, prospective FSOCP 226 93 and 86a) 78 82 80 49b) 98 75
Ramchandani et al. (2011) [27] Single-center, prospective FSOCP 36 100 95 79 89 82 82 82
Hartman et al. (2012) [28] Single-center, retrospective FSOCP 89 NR 88 86 87 57 100 78
Draganov et al. (2012) [29] Single-center, prospective FSOCP 44 97.7 NR NR NR 76 100 84
Manta et al. (2013) [30] Single-center, prospective FSOCP 52 100 NR NR NR 88 94 90
Woo et al. (2014) [31] Single-center, retrospective FSOCP 32 96 100 90 96 64 100 73
Tieu et al. (2015) [32] Single-center, retrospective FSOCP 39 92.3 NR NR 97 NR NR 72
Kurihara et al. (2016) [33] Multicenter, prospective FSOCP 89 95.5 94 92 94 65 89 70
Navaneethan et al. (2016) [34] Multicenter, prospective DSOCP 44 100 90 96 NR 85 100 NR
Laleman et al. (2017) [20] Single-center, prospective FSOCP 45 88.9 83 83 83 85 100 95
Ogura et al. (2017) [21] Single-center, prospective DSOCP 25 100 83 89 93 80 100 89
Imanishi et al. (2017) [22] Single-center, retrospective DSOCP 20 100 NR NR NR NR NR 100
Shah et al. (2017) [23] Multicenter, prospective DSOCP 58 100 97 93 94 86 100 91
Pereira et al. (2018) [24] Single-center, retrospective DSOCP 12 100 NR NR 87.5 NR NR 55
Lenze et al. (2018) [25] Single-center, retrospective DSOCP 41 98.5 88.9 97.6 NR 62.5 90 NR
Turowski et al. (2018) [26] Multicenter, retrospective DSOCP 99 NR 95.5 94.5 NR 57.7 100 NR

DSOCP, digital single-operator cholangiopancreatoscope; FSOCP, fibro-optic single-operator cholangiopancreatoscope; NR, not reported.

a) Diagnostic FSOCP was performed without biopsy in 86 cases and with biopsy in 140 cases. The respective procedure success rates in those two groups were 93% and 86%.

b) The authors suggested that this low number may have been attributed to the inclusion of strictures caused by extrinsic compression.

Table 7.
Diagnostic Yield of the Different Available Methods for Evaluating Biliary Strictures
Diagnostic method Sensitivity (%) Specificity (%) Accuracy (%)
ERCP with brushing cytology 23-62.5 26-100 31-81.3
ERCP with standard forceps biopsy 43-91 97-100 30-93
Combined ERCP with brush cytology and biopsy 60-70 100 50
ERCP plus FISH 30-79 91-100 72-80
EUS-FNA 43-86a) 97
SOCP visual impression 78-100 78-97.6 80-97
SOCP SpyBite biopsy 49-100 82-100 55-100
SpyGlass with ROSE 100 93
DPCS visual impression 83-92 84-92
DPCS biopsy 43-89.5 97
Combined DPCS visual impression plus biopsy 85 84

DPCS, direct peroral cholangiopancreatoscopy system; ERCP, endoscopic retrograde cholangiopancreatography; EUS-FNA, endoscopic ultrasound-guided fine needle aspiration; FISH, fluorescence in situ hybridization; ROSE, rapid on-site evaluation; SOCP, single-operator cholangiopancreatoscope.

a) Depending on the proximal or distal strictures.

Table 8.
Studies with Reported Adverse Events for the Different Cholangioscopy Systemsa)
Study Cholangioscopy system Sample size (n) Overall adverse events (%) Most common adverse event (%) Severe adverse events (%)
Mounzer et al. (2017) [14] DPCS 96 2 Bleeding (1) Perforation (1) - conservative management
Meves et al. (2014) [15] DPCS 84 12 NR 0
Farnik et al. (2014) [16] DPCS 89 7.7 Cholangitis (1.5) 0
Bleeding (1.5)
Chen et al. (2011) [19] FSOCP 297 7.5 Cholangitis (3.5) 0
Kurihara et al. (2016) [33] FSOCP 89 5.4 Cholangitis (2.7) 0
Laleman et al. (2017) [20] FSOCP 84 21.4 Mild pancreatitis (7.1) 0
Ogura et al. (2017) [21] DSOCP 55 6 Cholangitis (6) 0
Imanishi et al. (2017) [22] DSOCP 28 4 NR 0
Shah et al. (2017) [23] DSOCP 108 3 NR 0
Lenze et al. (2018) [25] DSOCP 67 25.4 Abdominal pain (23.8) 16.4b)
Pereira et al. (2018) [24] DSOCP 16 38 NR 0
Turowski et al. (2018) [26] DSOCP 250 13.2 Cholangitis, 1% with and 12.8% without antibiotics Perforation (0.4) - conservative management
Chen et al. (2007) [18] FSOCP 35 6 NR 0
Ramchandani et al. (2011) [27] FSOCP 36 8.3 Cholangitis (5.6) 0
Draganov et al. (2012) [29] FSOCP 26 7.7 NR 0
Manta et al. (2013) [30] FSOCP 52 3.8 NR 0
Woo et al. (2014) [31] FSOCP 32 9.4 NR 0
Tieu et al. (2015) [32]c) FSOCP 88 15.9 Abdominal pain (11.1) 1.1
Tanaka et al. (2016) [42] DSOCP 22 7.7 Cholangitis (3.8) 0
Pancreatitis (3.8)
Navaneethan et al. (2016) [34] DSOCP 105 2.9 Cholangitis (1.9) 0

DPCS, direct peroral cholangiopancreatoscopy system; DSOCP, digital single-operator cholangiopancreatoscope; FSOCP, fibro-optic single-operator cholangiopancreatoscope; NR, not reported.

a) Numbers represent the adverse event rate for both diagnostic and therapeutic procedures and includes procedures with both biliary and pancreatic accesses.

b) In this study, cholangitis (7.5) and pancreatitis (8.9) were considered as severe adverse events. The high rate of pancreatitis was attributed to the lack of administration of rectal indomethacin.

c) All cases received pre-procedural antibiotics.


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