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Cholangioscopy
27 Cholangioscopy Raj J. Shah and Takao Itoi
Historically, cholangioscopy was performed with a fiberoptic mother (large-caliber duodenoscope) and daughter (cholangioscope) system requiring two endoscopists, two light sources, and two video monitors, if the endoscopy unit was fortunate enough to have two video cameras to interface with the respective endoscopes.1 The development of a video mother endoscope made the endoscopy suite a bit less cluttered, although even after video daughter endoscopes were markedly improved and variably marketed, equipment expense, fragility, and maintenance costs limited their use. It took the introduction of disposable daughter endoscopes, initially fiberoptic and currently digital, to change endoscopic retrograde cholangiopancreatography (ERCP) from a procedure in which virtually all diagnostic and therapeutic procedures were facilitated by fluoroscopy to one in which the endoscopist can look directly into the pancreaticobiliary tree both to improve diagnosis and to facilitate therapy. In recognition of this technological dichotomy, the authors have tried, Solomon-like, to split this chapter into two parts. We will leave it to the individuals performing cholangioscopy to decide whether they adopt one, both, or neither of these technologies and instead rely on interventional radiologists to provide access to the biliary tree through a transhepatic percutaneous biliary drain (PTBD) using the subsequent track as the cholangioscope entry port.
Equipment
SINGLE-OPERATOR CHOLANGIOSCOPY
FSOC has a control section that houses three ports: irrigation that feeds into two 0.6-mm channels, a 0.77-mm optical probe, and a 1.2-mm accessory channel that permits passage of guidewires, intraductal lithotripsy fibers, and miniature biopsy forceps.4 The control section is secured with a Silastic belt just below the working channel of the duodenoscope. The disposable 3.4-mm insertion tube has four steering wires embedded in its length. The 6000-pixel optical probe is a collection of light fibers that surround optical fiber bundles and is incorporated into a polyimide sheath, providing approximately a 70-degree field of view. The connector section entails a camera processor with 1/4-inch charge-coupled device (CCD) chip, a light source, an optical coupler that interfaces the optical probe with the light source and video camera head, a medical-grade isolation transformer, and a travel cart with a three-joint arm for extension. An irrigation pump with foot pedal and monitor are available through separate vendors.6 The DSOC has a complementary metal-oxide semiconductor (CMOS) chip for higher resolution, magnification, and field of view (120 degrees). It has a thin copper cable for digital transmission and lacks a separate fiber optic probe that may contribute to improved catheter tip articulation. A separate suction connection with the working channel seems to permit improved irrigation capability. The processor is portable for simplified setup.5
Introduction
Technique
The advantages of single-operator cholangioscopy using the catheter-based fiberoptic SpyGlass system (FSOC; SpyGlass Direct Visualization System; Boston Scientific, Marlborough, MA) include the ability of a single endoscopist to perform cholangiopancreatoscopy and the use of a disposable 4-lumen 10-Fr catheter, reusable optical fiber, and four-way tip deflection (up–down and left–right) that is passed through the working channel (4.2 mm) of a standard therapeutic duodenoscope.2 The device is approved by the Food and Drug Administration (FDA) for both biliary and pancreatic applications. In February 2015, a fully disposable digital single-operator cholangioscope (DSOC) was introduced in the United States.3 In an ex vivo study with FSOC, Chen compared four-quadrant access, simulated biopsy, irrigation flow rates, and optical resolution between FSOC and an endoscope-based system (CHF BP-30; Olympus Medical Systems, Tokyo, Japan).4 The author reported that the ability to access four quadrants for visualization and biopsy with FSOC was better than with the two-way tip deflection of the endoscope-based system (odds ratio 1.7 to 2.94, p < 0.001). A preliminary ex vivo study that included five investigators compared optical quality and maneuverability between DSOC and FSOC.5 A biliary tract model contained fixed and variable color targets. Runs (passes of the scope) were randomized, and DSOC outperformed FSOC by a higher percentage of visualized targets (96% vs 66%), successful targeting per run, and faster run times (all comparisons p < 0.01). Further, subjective parameters of image quality and ease of use were superior (p < 0.001).
For FSOC, the optical probe is preloaded into the access/therapeutic catheter and advanced to within a few millimeters of the catheter’s bending portion to reduce the potential for damage during passage across the duodenoscope’s elevator and ductal strictures. The DSOC system has the optical bundle incorporated into the catheter. Advancement through the duodenoscope’s working channel is similar to the endoscope-based cholangioscope. Once the duct is entered with the access catheter, the optical probe is advanced gently beyond the catheter’s tip for intraductal inspection. If resistance is encountered, the control section knobs should be unlocked and fluoroscopy may be used to determine whether the catheter’s tip is straight. The endoscopist has control of the four-way steering dials and may periodically lock the dials to stabilize scope position at a target during tissue acquisition or intraductal lithotripsy. Irrigation is performed through two dedicated channels facilitated by a foot pedal. Irrigation rates should be kept as low as possible to reduce the risk of cholangitis.7
Clinical Use and Efficacy Intraductal Lithotripsy
Electrohydraulic lithotripsy (EHL) or laser lithotripsy (LL) can be used to treat both bile duct and pancreatic duct stones (Fig. 27.1, A–E, and Fig. 27.2, A–E). Cholangioscopic or pancreatoscopic visualization during intraductal lithotripsy helps to avoid duct injury. The 1.9-Fr nitinol EHL fiber contains two coaxially insulated electrodes ending at an open
249
250
SECTION II Techniques A
B
C
E
D FIG 27.1 A, Fluoroscopic view of a lateral wall of bile duct filling defect consistent with impacted stones. B, FSOC view of two large common bile duct stones. C, FSOC view of common bile duct stone fragments after electrohydraulic lithotripsy. D, Duodenal view of removed stone fragments. E, Balloon occlusion cholangiogram after common bile duct stone clearance. FSOC, Fiberoptic single-operator cholangioscope.
tip. Water or saline immersion is necessary and, as an advantage over endoscope-based cholangioscopes, the dedicated channels for irrigation provide a sufficient medium. During immersion, sparks are generated that produce high-amplitude hydraulic pressure waves for stone fragmentation.8 A generator produces a series of high-voltage electrical impulses at a frequency of 1 to 20 per second, with settings ranging from a power of 50 to 100. The tip of the EHL fiber should protrude no more than 2 to 3 mm from the scope and be positioned en face with the stone while the generator’s foot pedal is depressed to deliver energy.9 During LL, a laser beam is transmitted via a flexible quartz fiber through the working channel of the cholangiopancreatoscope. LL requires more precise localization of the stone, and though fragmentation is enhanced by direct contact, it can lead to a “drilling” effect. The application of repetitive pulses of laser energy to the stone leads to the formation of a gaseous collection of ions and free electrons of high kinetic energy. This plasma rapidly expands as it absorbs the laser energy and then collapses, inducing a spherical mechanical shockwave between the laser fiber and the stone, leading to stone fragmentation.10
Clearance of Difficult Biliary Stone Clearance Using FSOC A multicenter US experience using FSOC with LL included 69 patients, 89% of whom had extrahepatic or cystic duct stones and the remainder had intrahepatic stones.11 All patients had a minimum of one prior failed attempt at ERCP for stone extraction and required a mean of 1.2 LL sessions to achieve an impressive 97% complete clearance rate with a 4% adverse event rate. In a large, single-center FSOC series from India, holmium LL was used in 60 patients with previously failed attempts of mechanical lithotripsy (44%) or other factors such as Mirizzi’s syndrome or stone impaction that precluded attempts at basket capture or large-balloon sphincter dilation.12 The mean stone size was 23 mm (range 15 to 40 mm) and 100% complete clearance was reported after a mean of 1.2 LL sessions. Interestingly, 24 potentially eligible patients were excluded because of portal hypertension or extensive stone burden occupying most of the bile duct and mostly referred to surgery without attempt at FSOC. In a small but significant series of 13 patients with cystic duct stones (four with Mirizzi’s syndrome type 1), FSOC was used to achieve complete clearance of the cystic duct and bile duct in 10/13 (77%) patients during a total of 17 FSOC sessions.13
CHAPTER 27 Cholangioscopy A
251
B
C
E
D FIG 27.2 A, Pancreatogram with stones in the head and genu. B, FSOC view of impacted pancreatic duct stone in head. C, FSOC view of pancreatic duct stone fragments after electrohydraulic lithotripsy. D, Duodenal view of pancreatic stone fragment after endoscopic removal. E, Pancreatogram revealing clearance of stones from head and genu. FSOC, Fiberoptic singleoperator cholangioscope.
In a multicenter international prospective registry study using FSOC, 66 of 297 total cases were for the treatment of difficult biliary stones and included EHL (n = 50) and LL (n = 16).14 The median stone size was 19 mm and the duration of index intraductal lithotripsy was 38 minutes. Ductal clearance was achieved in 100%: 47/66 (71%) at index study single-operator cholangioscopy (SOC) and the remaining 29% after an average of one to two ERCPs. Overall, in the appropriately identified patient, the treatment of difficult biliary stones remains an indispensable indication for single-operator cholangioscopy-guided intraductal lithotripsy.
Pancreatic Stone Therapy Using FSOC A potential advantage of peroral pancreatoscopy (POP) over extracorporeal shock wave lithotripsy (ESWL) as a primary modality in the approach to patients with main pancreatic duct (MPD) stones is the ability to fragment and remove stones during the same procedure. In a single-center study of 46 patients undergoing either endoscope or FSOC pancreatoscopy
with EHL or LL for MPD stones, 14 underwent FSOC.15 Overall, complete or partial stone clearance was achieved in 91%, with complete clearance in 70%; complete or partial clearance was similar between those undergoing FSOC and those undergoing endoscope-based pancreatoscopy (p = 0.294), although the disposable system with four-way tip deflection seems particularly advantageous for treating pancreatic duct stones (personal observation). Mild POP-related adverse events occurred in 3/25 (12%) procedures in the FSOC group. Overall clinical success at a median follow-up of 15 months was 74% and similar between endoscopebased and FSOC groups (p = 0.149). From a multicenter LL working group, 28 patients were retrospectively identified who underwent FSOC for MPD stones.16 Before index FSOC with LL, 32% had undergone adjunctive ESWL and 25% had failed or incomplete stone fragmentation with FSOC ± EHL. Median stone size was 15 mm (4 to 32 mm) and located in the head or neck (n = 12 [42%]) or body/tail (n = 10 [36%]), or multiple sites (n = 6 [21%]). Overall, there was 90% per protocol technical success with complete
252
SECTION II Techniques
(22/28 [79%]) and partial (3/28 [11%]) clearance associated with clinical success in 89% of patients at a median 13-month follow-up based on a 50% reduction in pain, narcotic usage, or hospitalizations. Of note, a 29% rate of mild postprocedural adverse events occurred.
FSOC Evaluation of Indeterminate Biliary Strictures Although comparative series of endoscope-based cholangioscopes and FSOC have not been performed, cohort series of FSOC have shown encouraging findings in patients with indeterminate pancreaticobiliary pathology (Fig. 27.3, A–F). It is likely that the ability to navigate and sample different quadrants of a stricture may be enhanced with four-way tip deflection and a compressible catheter tip.4 Lesions suggestive of malignancy have been based primarily on studies using the endoscopebased cholangioscopes and include (1) exophytic lesions, (2) ulceration, (3) papillary mucosal projections, and (4) dilated tortuous vessels.2,17,18
For FSOC, interobserver agreement of video clips to distinguish malignant from benign lesions revealed only slight to fair agreement and may be only modestly improved with the DSOC system. Accuracy by the investigators to distinguish benign from malignant was 70% (20% higher than with FSOC) and there was moderate interobserver agreement specifically for papillary projections.18-20 Intraductal biopsy with the FSOC technique can be performed using two methods previously described for the endoscope-based cholangioscope.17 Cholangioscopy-directed biopsy is performed by passing a miniature cholangioscope biopsy forceps with a span of 4.1 mm (SpyBite; Boston Scientific) through the 1.2-mm working channel of the FSOC.3 Cholangioscopy-assisted biopsy is performed by localizing the target biopsy site using cholangioscopic visualization. For example, for distal biliary strictures in which passage of the miniature forceps may be technically difficult, obtain fluoroscopic spot films of the cholangioscope
A
C
B
D
E
F
FIG 27.3 A, Cholangiogram of main bile duct stricture in mid-duct. B, Fluoroscopy view of FSOC position at level of pathology. C, FSOC view of a malignant-appearing nodule. D, FSOC view of a suspected tumor vessel. E, FSOC alternative view of a malignant-appearing nodule. F, Fluoroscopic view of SOC-S with miniature forceps biopsy. Pathology revealed high-grade dysplasia. FSOC, Fiberoptic single-operator cholangioscope.
CHAPTER 27 Cholangioscopy tip positioned at the target lesion. After removing the cholangioscope, a conventional biliary biopsy forceps is then passed through the working channel of the duodenoscope to obtain tissue samples under fluoroscopic guidance.17 Clinical feasibility studies reveal adequate histologic specimens for the miniature forceps in 95% to 97% of samples when the target lesion is reached.2,17 In a prospective small series, 26 patients with indeterminate biliary strictures underwent, per protocol, single-operator cholangioscopy using catheter-based SpyGlass system (FSOC)–directed biopsy followed by brush cytology and fluoroscopy-guided biopsy.21 Most patients (85%) had previous nondiagnostic tissue sampling and 46% were hilar strictures. Sensitivity, specificity, and accuracy of cytology (6%, 100%, 39%), standard forceps biopsy (29%, 100%, 54%), and miniature-forceps biopsy (77%, 100%, 85%) were reported, with significant differences noted when comparing the miniature-forceps biopsy with the other methods for sensitivity and accuracy (p < 0.0001 and p = 0.0215 for cytology and standard forceps biopsy, respectively). Whether brush cytology and conventional biopsy were performed by referencing a spot film of the cholangioscope at the target area is unknown. Further, there is not a satisfactory explanation provided as to the extremely low sensitivity of brush cytology in this series. In a study from India, data from a 9-month prospective enrollment period were reported in which approximately 10% of patients (n = 36) with indeterminate biliary strictures underwent FSOC for further characterization.22 Overall, adequate histology was obtained in 82%. A high proportion of hilar strictures (21/36 [58%]) may partially explain the lower rates of adequate histology from the miniature forceps because of limited access. The accuracy of the visual impression of SOC-S using the malignancy criteria described above was 89% (95% sensitivity and 79% specificity) and for histology using the miniature forceps was 82% (82% sensitivity and specificity). Benign appearance was suggested by smooth surface mucosa without definite neovascularization and homogenous granular mucosa. The largest multicenter trial on cholangioscopy included 15 centers from Europe and the United States in which FSOC was prospectively used for indeterminate pancreaticobiliary pathology and difficult stone disease.14 Chen and coinvestigators evaluated 226 patients with indeterminate biliary pathology who underwent diagnostic SOC-S; 140 had directed miniature forceps biopsy (median of 4 bites, 20% hilar, and histologic adequacy of 88%). Complete ERCP, FSOC, and biopsy data were available for a subset of 95 patients. The sensitivities and specificities of cholangiographic impression, FSOC visualization, and FSOC-directed tissue biopsies for detecting malignancy were 51% and 54%, 78% and 82%, and 49% and 98%, respectively. In a meta-analysis of FSOC, eight studies that evaluated operating characteristics of visual impression and use of directed SpyBite sampling were reported.23 The authors noted the sensitivity and specificity of the FSOC visual impression to be 90% and 87%, respectively (area under the curve [AUC] 0.94). The use of SpyBite sampling had a 69% sensitivity and 98% specificity in detection of neoplasia (AUC 0.93). With the introduction of DSOC, the hope is that improved optics will enhance the ability to detect and exclude neoplasia (Figs. 27.4 and 27.5). The first preliminary US multicenter clinical series using DSOC was by Shah et al. and included 121 patients: 85 for stricture and ductal dilatation evaluation and 36 with difficult stones.24 The patients with stones (29 biliary, 7 pancreatic) achieved 100% clearance using intraductal lithotripsy techniques. Eight patients underwent DSOC to assess the extent of cholangiocarcinoma (CCA), and two were found to have unsuspected, multifocal intrahepatic CCA. Of the 77 with indeterminate stricture/dilatation, 40% had confirmed neoplasia, of which 81% were positive by SpyBite sampling. Overall, the use of DSOC in the detection of neoplasia in the indeterminate cohort was found to carry sensitivity,
253
FIG 27.4 Digital single-operator cholangioscope view of an infiltrative stricture with tumor vessels.
FIG 27.5 Digital single-operator cholangioscope view of a villous mass of a biliary intraductal papillary mucinous neoplasm.
specificity, PPV, and NPV of 97%, 96%, 94%, and 98%, respectively (all confidence intervals [CIs] ranged from 0.87 to 1.0). An additional smaller series included 105 patients, 73 of whom had the examination for diagnostic purposes.25 There was a relatively low (27%) prevalence of neoplasia, and diagnostic SOC without biopsy was noted in a high proportion of examinations (40%). Indications and findings included PSC, posttransplant stricture, benign strictures from stones, and normal examinations, which are low-yield indications for the use of cholangiopancreatoscopy. Overall, the authors found the sensitivity and specificity of DSOC clinical and visual impression for diagnosis of malignancy to be 90% and 96%, respectively, and those of DSOC-guided biopsies to be 85% and 100%, respectively. An on-site pathologist performed immediate wet-prep evaluation of the specimens, which may have helped to improve the diagnostic yield of sampling. Because tissue sampling remains the key to further triaging and managing of patients with suspected neoplasia, perhaps the optimal use of SOC may be in the identification of suspicious lesions, followed by directed tissue sampling by either cholangioscopy-directed or cholangioscopy-assisted methods, in conjunction with brush cytology, to provide the highest probability of obtaining tissue confirmation of suspected lesions. If tissue sampling is nondiagnostic but the visual impression is concerning for neoplasia, then a close surveillance interval and sampling are recommended. Although a fully disposable DSOC is
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SECTION II Techniques
now available and simpler to use, given the lack of pass-through code and limited reimbursement, it is wise to be more selective in the use of this costly technology. A good clinical impression and cholangiography technique may help to avoid the need for some cholangioscopy use described in published series. Lastly, with the anticipated introduction of competing disposable digital cholangioscopes, retail costs for the technology may decrease.
Reimbursement and Limitations As of 2009, a current procedural terminology add-on code with ERCP exists for cholangiopancreatoscopy. Despite the described advances, there remains a limited ability of the 10-Fr-diameter catheter to traverse tight strictures without preinspection dilation, which, when performed, may alter visual interpretation. Although four-quadrant inspection of mucosa may be achieved with four-way tip deflection and the application of torque on the duodenoscope, circumferential views and the ability to advance accessories through the working channel may be difficult, depending on duodenoscope angulations, downstream duct strictures, small duct diameter, and intraductal debris. Aspirating debris and fluid through a Y-adapter fixed to the working channel while simultaneously irrigating through the flushing port can improve the latter.6 Circumferential visualization may also be difficult in the presence of markedly dilated ducts. During inspection of strictures, stent-associated changes may alter the mucosal appearance to include papillary mucosal projections, making visual diagnosis of malignancy very difficult.26 If resistance is encountered during accessory passage, advancing the cholangioscope to the upstream duct or increasing the loop of the cholangioscope within the duodenum may allow passage of the device beyond the point of angulations. The EHL and LL fibers are fragile and sometimes require preloading through a straight cholangioscope to facilitate introduction.9,27 During intraductal lithotripsy, there can be recoil of the fiber into the working channel because of transmitted energy, contact with fragmented stones, or a deflected scope tip. As blood and stone debris may reduce visualization, careful and frequent confirmation that the tip of the fiber is in the appropriate position by endoscopic and fluoroscopic visualization is necessary to reduce duct injury or optical fiber damage. If passage of the biopsy forceps is unsuccessful, cholangioscopy-assisted fluoroscopy-guided biopsy can be performed.17 Although the optical probe in the FSOC is reprocessed, use may be limited to 10 cases, beyond which image quality may diminish because of broken fiber bundles. In the presence of a lithotripsy fiber or biopsy forceps within the working channel, the dedicated irrigation channel provides higher flow rates compared with reusable cholangioscopes.4 The access catheter lacks a conventional suction button, and intermittent manual aspiration using a syringe attached to a Y-port adapter and/or intermittent duodenoscope suctioning is required to reduce intraductal pressure and gastroduodenal fluid reflux.6 For DSOC, a suction apparatus connected to the working channel provides improved irrigation ability (i.e., the ability to flush and aspirate) to improve visualization.3
Adverse Events Although not specific to FSOC, a single-center series of ERCP alone compared with ERCP and cholangiopancreatoscopy found that cholangiopancreatoscopy may be associated with a significantly higher rate of procedure-related adverse events than ERCP alone.7 This increased risk was observed in overall adverse events (7.0% vs 2.9%), consensus adverse events (pancreatitis, perforation, cholangitis, or bleeding; 4.2% vs 2.2%), and specifically with postprocedural cholangitis (1.0% vs 0.2%). Studies specific to FSOC reveal adverse event rates ranging from 5% to 13% and include mostly cholangitis and pancreatitis.12,13,22,24
Prophylactic IV antibiotics are therefore recommended when performing intraductal cholangioscopy.
Summary Single-operator cholangioscopy using SpyGlass has been demonstrated to be an established modality in the treatment of difficult biliary stones. When used in the evaluation of indeterminate biliary strictures by endoscopists experienced in recognizing intraductal pathology, it increases the diagnostic yield of tissue sampling. Results remain limited and mostly preliminary in its use for pancreatic duct stones and in the evaluation of pancreatic neoplasia. The digital imaging system provides a simplified setup and improved optical resolution.
VIDEOCHOLANGIOSCOPY USING THE MOTHER– BABY SYSTEM A videocholangioscope can provide outstanding quality digital images compared with conventional fiberoptic cholangioscopy.28–36 Two videocholangioscopes have been used in the mother-baby cholangioscopy system (Table 27.1). At present, however, their use is limited to a few countries. Recently, newly designed digital cholangioscopy (SpyGlass DS, Boston Scientific), which is available as a single-operator system, has been developed.37,38 (See details in the previous section.)
Description of the Technique The therapeutic duodenoscope that is used as the mother scope has a 4.2-mm working channel that helps prevent kinking of the baby videocholangioscope. Endoscopic sphincterotomy is needed to facilitate scope passage across the papilla. Two videocholangioscopes (CHF-B260/ B160 and CHF-BP260, with outer diameters of 3.4 and 2.6 mm and working channel diameters of 1.2 and 0.5 mm, respectively; B260 and BP260 [Olympus Medical Systems, Tokyo, Japan] and B160 [Olympus America Inc., Center Valley, PA]) are available (Fig. 27.6). They are advanced through the 4.2-mm working channel of therapeutic duodenoscopes into the bile duct with or without a 0.035-inch/0.025-inch guidewire. Both have two-way tip angulation. The wire-guided insertion technique is used with the CHF-B260 but not with the CHF-BP260 because of the diameter of the working channel. Saline irrigation and CO2 insufflation are used during cholangioscopy because of reports of air embolism.34,35 Endoscopic observation is usually performed using white-light imaging. Observation using narrow-band imaging (NBI) is available with the NBI system (CV-260SL, CVL-260SL,
TABLE 27.1 Mother–Baby
Videocholangioscopy Angle of view, degrees Observed depth, mm Outer diameter, mm Distal end Insertion end Bending section, degrees Up/down Right/left Working length, mm Working channel diameter, mm Image-enhanced endoscopy
CHF-BP260*
CHF-B260/B160*
90 3 to 20
90 3 to 20
2.6 2.9
3.4 3.5
70/70 NA 2000 0.5 NBI
70/70 NA 2000 1.2 NBI
NA, Not available; NBI, narrow-band imaging. Olympus Medical Systems, Tokyo, Japan.
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CHAPTER 27 Cholangioscopy
FIG 27.7 Papillary lesions in the intrahepatic bile duct. FIG 27.6 Videocholangioscopy using the mother–baby system.
TABLE 27.2 Summary of Diagnostic Ability of Mother–Baby-Type Videocholangioscopy Author (Year) 33
Itoi (2010) Nishikawa (2013)40 Osanai (2013)39
n
Study
144 33 87
R P P
Sensitivity (%) 99 100 94
Specificity (%) 96 92 92
PPV (%)
NPV (%)
99 96 NA
99 96 NA
Accuracy (%) 98 97 93
NA, Not applicable; NPV, negative predictive value; P, prospective study; PPV, positive predictive value; R, retrospective study. All data including visual impression + biopsy.
CVL-290SL/CV-180, CLV-180, CLV-S190, light source; Olympus Medical Systems).
Technique: Diagnostic and Therapeutic Videocholangioscopy provides better-quality digital images and offers enhanced mucosal detail compared with conventional fiberoptic cholangioscopes (Fig. 27.7 and Video 27.1). Thus it can delineate fine mucosal structures like shallow pseudodiverticula, papillary or granular lesions, and fine vessel patterns, leading to differentiation between benign and malignant lesions to include the indeterminate filling defects and biliary strictures as noted on cholangiography. A recent retrospective study33 and prospective studies39,40 of the ability of videocholangioscopy to differentiate between indeterminate filling defects and biliary strictures revealed that videocholangioscopy provided high diagnostic ability (accuracy, 93% to 98%; sensitivity, 94% to 100%; specificity, 92% to 96%; positive predictive value, 96% to 99%; negative predictive value, 96% to 100%) (Table 27.2). However, videocholangioscopy cannot always differentiate benign from malignant lesions. For instance, in cases of IgG4-related cholangitis, cholangioscopic images are often similar to those visualized in cholangiocarcinoma, for example, presence of thick and tortuous vessels.41 Thus cholangioscopic imaging alone is limited and biopsy appears to be mandatory in such cases. Mucinous-producing neoplasms in the bile duct can produce a large amount of mucin, resulting in misdiagnosis of tumor location when only cholangiography is employed. Videocholangioscopy is very useful for accurate localization of the primary site of the tumor.36 Detailed observations make it possible to not only detect abnormal findings but also accurately target biopsy sites by direct inspection (Fig. 27.8).
Bile duct neoplasms, in particular papillary growth type or mucinousproducing neoplasms, often show a longitudinal tumor spreading from the primary bile duct lesions. Detailed visualization of enlarged images obtained by videocholangioscopy permits detection of tiny abnormalities, regardless of benign or malignant nature.32,36 Furthermore, videocholangioscopy biopsy using a directed 3-Fr biopsy forceps further improves diagnostic capability.33 When a biliary stricture is too tight to allow passage by a videocholangioscope, balloon dilation or temporary 10-Fr plastic stent placement can increase the luminal diameter to allow for subsequent cholangioscopy. Image-enhanced videocholangioscopy using NBI clearly displays fine biliary mucosal structures and capillary vessels (Fig. 27.9, A, B; Video 27.2) and helps to distinguish benign from malignant lesions.31,39,41,42 Primary sclerosing cholangitis increases the lifetime risk of cholangiocarcinoma. A recent study suggested that cholangioscopy allowed visualization of tumor margins in CCA compared with traditional fluoroscopy-based ERCP.43 Although therapeutic videocholangioscopy is limited because of its small working channel, 1.9-Fr to 3-Fr EHL and LL using holmium YAG and FREDDY have been performed under direct videocholangioscopic visualization (Fig. 27.10 and Video 27.3).
Adverse Events and Limitations Videocholangioscopy can cause procedure-related adverse events such as cholangitis and pancreatitis. There are several limitations of the mother–baby videocholangioscopy system because of endoscope fragility, expense of repair, and need for two skilled endoscopists. On NBI cholangioscopy, bile resembles blood, which can lead to poor images, and it is time-consuming to clean the bile duct without a dedicated irrigation channel.31
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FIG 27.8 Biopsy under direct inspection.
A
FIG 27.10 Baby cholangioscopy–assisted intraductal electrohydraulic lithotripsy for large bile duct stone.
B
FIG 27.9 Early bile duct cancer. A, White-light imaging. B, Narrow-band imaging.
VIDEOCHOLANGIOSCOPY BY THE DIRECT INSERTION SYSTEM Direct peroral fiberoptic cholangioscopy is performed by the direct insertion technique was first described by Urakami et al. 3 decades ago using a standard upper gastrointestinal (GI) endoscope.44 However, this method has not become common because of the technical difficulty of passing a large-diameter endoscope into the biliary tree. In 2006 the first case series using ultraslim upper GI videoendoscopes was reported by Larghi and Waxman.45 Since then, diagnostic and therapeutic direct peroral videocholangioscopy (DPVCS) have become increasingly performed.46–54
Description of the Technique DPVCS is usually performed using conventional ultraslim upper GI endoscopes (Table 27.3). However, because they have a 5-mm to 6-mm outer diameter, endoscopic sphincterotomy is mandatory. On occasion, papillary balloon dilation is added to facilitate endoscope passage across the papilla. These instruments have four-way tip angulation and a 2-mm working channel. At present, five approaches for direct bile duct access have been reported: (1) free-hand insertion without any assisting devices, (2) wire-guided insertion, (3) balloon overtube–assisted insertion, (4)
occluded duodenal balloon–assisted insertion, and (5) intraductal anchoring balloon–assisted insertion55 (Fig. 27.11). In general, free-hand scope insertion is usually difficult when using a conventional ultraslim upper GI videoendoscope, and therefore either wire-guided insertion or intraductal anchoring balloon-assisted insertion is most frequently used. Early studies showed that the success rate of intraductal balloon catheter–assisted insertion was higher (20/21 [95.2%]) than that of wire-guided insertion (5/11 [45.5%]) or balloon overtube–assisted insertion (10/12 [83.3%]).46,47 For wire-guided insertion, initially a 0.035-inch or stiff-type 0.025-inch guidewire is inserted into the bile duct through a standard duodenoscope, which is then removed, leaving the guidewire in place. An ultraslim endoscope is then advanced into the bile duct using an over-the-wire technique. It is relatively easy to advance the tip of the endoscope into the lower bile duct in either an angulated or straight position. A combination of pushing and pulling techniques is needed for scope insertion up to the hilum. When we use the 5-Fr anchoring balloon for scope insertion into the bile duct, the anchoring balloon is advanced into the right or left intrahepatic bile duct and inflated as an anchor. A 0.018-inch or 0.025-inch guidewire is used for placing the 5-Fr anchoring balloon. Then, an ultraslim endoscope is advanced to the hilum or intrahepatic bile ducts using the pushing and pulling techniques in combination
257
CHAPTER 27 Cholangioscopy TABLE 27.3 Direct Peroral Videocholangioscopy OLYMPUS MEDICAL SYSTEMS Angle of view, degrees Observed depth, mm Outer diameter, mm Distal end Insertion end Bending section, degrees Up/down Right/left Working length, mm Working channel diameter, mm Image-enhanced endoscopy
GIF-XP160
GIF-XP180N
GIF-XP260N
Fujinon EG-530NW/530N2
Pentax EG-1690K
120 3 to 100
120 3 to 100
120 3 to 100
140 4 to 100
120 4 to 100
5.9 5.9
5.5 5.5
5.0 5.5
5.9 5.9
5.4 5.3
180/90 100/100 1030 2 NBI
210/90 100/100 1100 2 NBI
210/90 100/100 1030 2 NBI
210/90 100/100 1100 2 FICE
210/120 120/120 1100 2 i-SCAN
FICE, Flexible spectral imaging color enhancement; NBI, narrow-band imaging.
A
FIG 27.11 Direct videocholangioscopy with anchoring balloon.
with the anchoring balloon. At this time, the shape of endoscope shows an α-loop or U-loop scope position. Saline irrigation and CO2 insufflation are used to facilitate endoscopic visualization in the bile duct. Recently a prototype dedicated DPVCS with a multibending tip has been developed.56 It has two bending sections: the proximal section can be deflected in a single plane (90° up or 90° down), and the distal section can also be deflected in a single plane (160° up or 100° down). The endoscope is forward-viewing, with a working length of 133 cm, a field of view of 90°, and an outer diameter of the distal end and the insertion tube of 5.2 and 7.0 mm, respectively. The ratios of the distal bending section and the distal plus proximal bending section compared with the GIF-XP180N (Olympus Medical Systems) are 0.6 and 2.2, respectively. The endoscope has two accessory channels of 2.2 and 0.85 mm diameter. It also has suction and insufflation capabilities. The latest generation of dedicated DPVCS has shown an extremely high success rate (97%) using only the free-hand technique.54 For successful free-hand insertion of the dedicated DPVCS, the tip of cholangioscope is inserted into the distal bile duct using up-angle and torque of the cholangioscope shaft. The manipulation is similar to that of a colonoscope inserted into the terminal ileum, or “blinded” terminal ileum insertion. Once the tip of the cholangioscope is inserted into the bile duct, it is easily advanced to the hilum using scope angulation and by direct advancement. In contrast to a conventional ultraslim upper GI endoscope, the dedicated DPVCS is stable in the bile duct during scope manipulation.
Technique: Diagnostic and Therapeutic After reaching the bile duct segment of interest, DPVCS enables several diagnostic and therapeutic procedures, including visualization alone,
B
FIG 27.12 Direct videocholangioscopy–assisted electrohydraulic lithotripsy for large bile duct stone. A, Radiographic finding. B, Endoscopic imaging.
biopsy for diagnosis, electrohydraulic or LL (Fig. 27.12, A and B) tumor ablation using argon plasma coagulation, and photodynamic therapy or passage of guidewires to facilitate biliary stenting using plastic or metallic stents through the 2-mm working channel. However, 2-mm accessories are not commonly available (Fig. 27.13).
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Success Rate of Direct Peroral Cholangioscopy Author (Year) Larghi (2007)45 Choi (2009)46 Moon (2009)47 Tsou (2010)48
FIG 27.13 5-Fr Accessories for direct cholangioscopy.
Pohl (2011)49 Mori (2012)50 Farnik (2014)51 Itoi (2014)52 Weigt (2015)53 Beyna (2016)54
n
Endoscope
15 12 11 21 14 25 40 40 7 34 42 67 74
UGI UGI UGI UGI UGI UGI UGI UGI DDPVCS DDPVCS UGI UGI DDPVCS
Assistant Devices GW Balloon overtube GW AB Balloon overtube AB Duodenal balloon AB Free-hand GW and/or AB AB AB Free-hand w/wo AB
Insertion Success (%) 78 83 46 95 93 72 93 98 0 94 90 88 90
Based on the high success rate of scope insertion (Table 27.4) and the durability of DPVCS, as well as cost benefit (no need for two light sources or two skilled endoscopists), DPVCS appears to be the first choice for cholangioscopy when ducts are dilated and the target lesion is in the proximal bile duct. Image-enhanced endoscopy, enabling delineation of fine mucosal structures and vessels, is possible using various processor systems as follows: (1) NBI (Olympus Medical Systems), (2) flexible spectral imaging color enhancement (FICE; Fujifilm, Tokyo, Japan), and (3) i-Scan (Pentax, Tokyo, Japan).
AB, Anchoring balloon; DDPVCS, dedicated diagnostic and therapeutic direct peroral videocholangioscopy; GW, guidewire; UGI, upper gastrointestinal endoscopy.
Adverse Events and Limitations
Acknowledgment
DPVCS also causes procedure-related adverse events. The most serious adverse event is cardiac or cerebral air embolism if the procedure is performed using air insufflation rather than saline irrigation or CO2 insufflation.57 Ultraslim endoscopes do not always match the size of the bile duct or papilla as frequently as the smaller-diameter dedicated cholangioscopes. Care should be taken, because this size mismatch may
We are indebted to Professor Edward Barroga, Department of International Medical Communications of Tokyo Medical University, for his editorial review of the English manuscript.
cause unexpected serious adverse events, including bleeding, pancreatitis, and perforation of the duodenum at the site of sphincterotomy.
The complete reference list for this chapter can be found online at www.expertconsult.com.
CHAPTER 27 Cholangioscopy
REFERENCES 1. Kozarek RA. Direct cholangioscopy and pancreatoscopy at time of ERCP. Am J Gastroenterol. 1988;83:55–57. 2. Chen YK, Pleskow DK. SpyGlass single-operator per oral cholangiopancreatoscopy system for the diagnosis and therapy of bile-duct disorders: a clinical feasibility study (with video). Gastrointest Endosc. 2007;65:832–841. 3. Shah RJ, Raijman I, Brauer BC, et al. Multi-center first human use experience using the fully disposable, digital single-operator cholangiopancreatoscope (DSOCP). Gastrointest Endosc. 2016;83:AB141. 4. Chen YK. Preclinical characterization of the Spyglass per oral cholangiopancreatoscopy system for direct access, visualization, and biopsy. Gastrointest Endosc. 2007;65:303–311. 5. Shah RJ, Neuhaus H, Reddy ND, et al. A randomized assessment of a semi-disposable, fiberoptic single-operator cholangioscope with a fully-disposable, digital single-operator cholangioscope in a bench model. Gastrointest Endosc. 2016;83:AB601. 6. ASGE Technology Committee, Shah RJ, Tierney WM, et al. Status evaluation report: cholangiopancreatoscopy. Gastrointest Endosc. 2008;68:411–421. 7. Sethi A, Chen YK, Austin GL, et al. ERCP with cholangiopancreatoscopy may be associated with higher rates of complications than ERCP alone: a single-center experience. Gastrointest Endosc. 2011;73:251. 8. Sievert CE, Silvis SE. Evaluation of electrohydraulic lithotripsy as a means of gallstone fragmentation in a canine model. Gastrointest Endosc. 1987;33:233–235. 9. Shah RJ, Chen YK. Techniques of peroral and percutaneous choledochoscopy for evaluation and treatment of biliary stones and strictures. Tech Gastrointest Endosc. 2007;9:161–168. 10. Hochberger J, Gruber E, Wirtz P, et al. Lithotripsy of gallstones by means of a quality-switched giant-pulse neodymium:yttrium-aluminum-garnet laser. Gastroenterology. 1991;101:1391–1398. 11. Patel SN, Rosenkranz L, Hooks B, et al. Holmium-yttrium aluminum garnet laser lithotripsy in the treatment of biliary calculi using singleoperator cholangioscopy: a multicenter experience (with video). Gastrointest Endosc. 2014;79:344–348. 12. Maydeo A, Kwek BE, Bhandari S, et al. Single-operator cholangioscopyguided laser lithotripsy in patients with difficult biliary and pancreatic duct stones (with videos). Gastrointest Endosc. 2011;74:1308–1314. 13. Sepe PS, Berzin TM, Sanaka S, et al. Single-operator cholangioscopy for the extraction of cystic duct stones (with video). Gastrointest Endosc. 2012;75:206–210. 14. Chen YK, Parsi MA, Binmoeller KF, et al. Single-operator cholangioscopy in patients requiring evaluation of bile duct disease or therapy of biliary stones (with videos). Gastrointest Endosc. 2011;74:805–814. 15. Attwell AR, Brauer BC, Chen YK, et al. Endoscopic retrograde cholangiopancreatography with per oral pancreatoscopy for calcific chronic pancreatitis using endoscope and catheter-based pancreatoscopes: a 10-year single-center experience. Pancreas. 2014;43:268–274. 16. Attwell AR, Patel S, Kahaleh M, et al. ERCP with per-oral pancreatoscopyguided laser lithotripsy for calcific chronic pancreatitis: a multicenter U.S. experience. Gastrointest Endosc. 2015;82:311–318. 17. Shah RJ, Langer DA, Antillon MR, et al. Cholangioscopy and cholangioscopic forceps biopsy in patients with indeterminate pancreaticobiliary pathology. Clin Gastroenterol Hepatol. 2006;4:219–225. 18. Fukuda Y, Tsuyuguchi T, Sakai Y, et al. Diagnostic utility of peroral cholangioscopy for various bile-duct lesions. Gastrointest Endosc. 2005;62:374–382. 19. Sethi A, Widmer J, Shah NL, et al. Interobserver agreement for evaluation of imaging with single operator choledochoscopy: what are we looking at? Dig Liver Dis. 2014;46:518–522. 20. Sethi A, Tyberg A, Slivka A, et al. Digital single-operator cholangioscopy improves interobserver agreement and accuracy for evaluation of indeterminate biliary strictures. Gastrointest Endosc. 2016;83:AB600. 21. Draganov PV, Chauhan S, Wagh MS, et al. Diagnostic accuracy of conventional and cholangioscopy-guided sampling of indeterminate
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biliary lesions at the time of ERCP: a prospective, long-term follow-up study. Gastrointest Endosc. 2012;75:347–353. 22. Ramchandani M, Reddy DN, Gupta R, et al. Role of single-operator peroral cholangioscopy in the diagnosis of indeterminate biliary lesions: a single-center, prospective study. Gastrointest Endosc. 2011;74:511–519. 23. Sun X, Zhou Z, Tian J, et al. Is single-operator peroral cholangioscopy a useful tool for the diagnosis of indeterminate biliary lesion? A systematic review and meta-analysis. Gastrointest Endosc. 2015;82:79–87. 24. Shah RJ, Raijman I, Hawes R, et al. Multi-center first human use experience using the fully, digital single-operator cholangiopancreatoscope (DSOCP). Gastrointest Endosc. 2016;83:AB141. 25. Navaneethan U, Hasan MK, Kommaraju K, et al. Digital, single-operator cholangiopancreatoscopy in the diagnosis and management of pancreatobiliary disorders: a multicenter clinical experience (with video). Gastrointest Endosc. 2016;84:649–655. 26. Mounzer R, Austin G, Fukami N, et al. Per oral video cholangiopancreatoscopy with narrow-band imaging for the evaluation of indeterminate pancreaticobiliary disease: a single-center US experience. Gastrointest Endosc. 2015;81:AB143. 27. Piraka C, Shah RJ, Awadallah NS, et al. Transpapillary cholangioscopydirected lithotripsy in patients with difficult bile duct stones. Clin Gastroenterol Hepatol. 2007;5:1333–1338. 28. Meenan J, Schoeman M, Rauws E, et al. A video baby cholangioscope. Gastrointest Endosc. 1995;42:584–585. 29. Lew RJ, Kochman ML. Video cholangioscopy with a new choledochoscope: a case report. Gastrointest Endosc. 2003;57:804–807. 30. Igarashi Y, Okano N, Sato D, et al. Peroral cholangioscopy using a new thinner videoscope (CHF-B260). Dig Endosc. 2005;17:S63–S66. 31. Itoi T, Sofuni A, Itokawa F, et al. Peroral cholangioscopic diagnosis of biliary tract diseases using narrow-band imaging. Gastrointest Endosc. 2007;66:730–736. 32. Kawakami H, Kuwatani M, Etoh K, et al. Endoscopic retrograde cholangiography versus peroral cholangioscopy to evaluate intraepithelial tumor spread in biliary cancer. Endoscopy. 2009;41:959–964. 33. Itoi T, Osanai M, Igarashi Y, et al. Diagnostic peroral video cholangioscopy is an accurate diagnostic tool for patients with bile-duct lesions. Clin Gastroenterol Hepatol. 2010;8:934–938. 34. Doi S, Yasuda I, Nakashima M, et al. Carbon dioxide insufflation versus conventional saline irrigation for peroral video cholangioscopy. Endoscopy. 2011;43:1082–1089. 35. Ueki T, Mizuno M, Ota S, et al. Carbon dioxide insufflation is useful for obtaining clear images of the bile duct during peroral cholangioscopy (with video). Gastrointest Endosc. 2010;71:1046–1051. 36. Itoi T, Sofuni A, Itokawa F, et al. Evaluation of peroral videocholangioscopy using narrow-band imaging for diagnosis of intraductal papillary neoplasms of the bile duct. Dig Endosc. 2009;21:S103–S107. 37. Tanaka R, Itoi T, Honjo M, et al. New digital cholangiopancreatoscopy for diagnosis and therapy of pancreaticobiliary diseases (with videos). J Hepatobiliary Pancreat Sci. 2016;23:220–226. 38. Navaneethan U, Hasan MK, Kommaraju K, et al. Digital, single-operator cholangiopancreatoscopy in the diagnosis and management of pancreatobiliary disorders: a multicenter clinical experience (with video). Gastrointest Endosc. 2016;84:649–655. 39. Osanai M, Itoi T, Igarashi Y, et al. Peroral video cholangioscopy to evaluate indeterminate bile duct lesions and preoperative mucosal cancerous extension: a prospective multicenter study. Endoscopy. 2013;45:635–642. 40. Nishikawa T, Tsuyuguchi T, Ishigami H, et al. Peroral cholangioscopyguided forceps biopsy to evaluate a cicatricial stricture of the biliary duct (with video). Gastrointest Endosc. 2015;81:1030–1031. 41. Itoi T, Kamisawa T, Igarashi Y, et al. The role of peroral video cholangioscopy in patients with IgG4-related sclerosing cholangitis. J Gastroenterol. 2013;48:504–514. 42. Itoi T, Neuhaus H, Chen YK. Diagnostic value of image-enhanced video cholangiopancreatoscopy. Gastrointest Endosc Clin N Am. 2009;19:557–566.
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43. Azeem N, Gostout CJ, Knipschield M, et al. Cholangioscopy with narrow-band imaging in patients with primary sclerosing cholangitis undergoing ERCP. Gastrointest Endosc. 2014;79:773–779. 44. Urakami Y, Seifert E, Butke H. Peraol direct cholangiopancreatoscopy (PDPS) using routine straight-view endoscope: first report. Endoscopy. 1977;9:27–30. 45. Larghi A, Waxman I. Endoscopic direct cholangioscopy by using an ultra-slim upper endoscope: a feasibility study. Gastrointest Endosc. 2006;63:853–857. 46. Choi HJ, Moon JH, Ko BM, et al. Overtube-balloon-assisted direct peroral cholangioscopy by using an ultra-slim upper endoscope (with videos). Gastrointest Endosc. 2009;69:935–940. 47. Moon JH, Ko BM, Choi HJ, et al. Intraductal balloon guided direct peroral cholagioscopy using an ultra-slim upper endoscope. Gastrointest Endosc. 2009;70:297–302. 48. Tsou YK, Lin CH, Tang JH, et al. Direct peroral cholangioscopy using an ultraslim endoscope and overtube balloon-assisted technique: a case series. Endoscopy. 2010;42:681–684. 49. Pohl J, Ell C. Direct transnasal cholangioscopy with ultraslim endoscopes: a one-step intraductal balloon-guided approach. Gastrointest Endosc. 2011;74:309–316. 50. Mori A, Ohashi N, Nozaki M, et al. Feasibility of duodenal balloonassisted direct cholangioscopy with an ultrathin upper endoscope. Endoscopy. 2012;44:1037–1044.
51. Farnik H, Weigt J, Malfertheiner P, et al. A multicenter study on the role of direct retrograde cholangioscopy in patients with inconclusive endoscopic retrograde cholangiography. Endoscopy. 2014;46:16–21. 52. Itoi T, Nageshwar Reddy D, Sofuni A, et al. Clinical evaluation of a prototype multi-bending peroral direct cholangioscope. Dig Endosc. 2014;26:100–107. 53. Weigt J, Kandulski A, Malfertheiner P. Technical improvement using ultra-slim gastroscopes for direct peroral cholangioscopy: analysis of the initial learning phase. J Hepatobiliary Pancreat Sci. 2015;22:74–78. 54. Beyna T, Farnik H, Sarrazin C, et al. Direct retrograde cholangioscopy with a new prototype double-bending cholangioscope in comparison to an ultra-slim standard endoscope. Endoscopy. 2016. 55. Itoi T, Moon JH, Waxman I. Current status of direct peroral cholangioscopy. Dig Endosc. 2011;23(suppl 1):154–157. 56. Itoi T, Sofuni A, Itokawa F, et al. Initial experience with a prototype peroral direct cholangioscope to perform intraductal lithotripsy (with video). Gastrointest Endosc. 2011;73:841–843. 57. Efthymiou M, Raftopoulos S, Antonio Chirinos J, et al. Air embolism complicated by left hemiparesis after direct cholangioscopy with an intraductal balloon anchoring system. Gastrointest Endosc. 2012;75:221–223.
Historically, cholangioscopy was performed with a fiberoptic mother (large-caliber duodenoscope) and daughter (cholangioscope) system requiring two endoscopists, two light sources, and two video monitors, if the endoscopy unit was fortunate enough to have two video cameras to interface with the respective endoscopes.1 The development of a video mother endoscope made the endoscopy suite a bit less cluttered, although even after video daughter endoscopes were markedly improved and variably marketed, equipment expense, fragility, and maintenance costs limited their use. It took the introduction of disposable daughter endoscopes, initially fiberoptic and currently digital, to change endoscopic retrograde cholangiopancreatography (ERCP) from a procedure in which virtually all diagnostic and therapeutic procedures were facilitated by fluoroscopy to one in which the endoscopist can look directly into the pancreaticobiliary tree both to improve diagnosis and to facilitate therapy. In recognition of this technological dichotomy, the authors have tried, Solomon-like, to split this chapter into two parts. We will leave it to the individuals performing cholangioscopy to decide whether they adopt one, both, or neither of these technologies and instead rely on interventional radiologists to provide access to the biliary tree through a transhepatic percutaneous biliary drain (PTBD) using the subsequent track as the cholangioscope entry port.
Equipment
SINGLE-OPERATOR CHOLANGIOSCOPY
FSOC has a control section that houses three ports: irrigation that feeds into two 0.6-mm channels, a 0.77-mm optical probe, and a 1.2-mm accessory channel that permits passage of guidewires, intraductal lithotripsy fibers, and miniature biopsy forceps.4 The control section is secured with a Silastic belt just below the working channel of the duodenoscope. The disposable 3.4-mm insertion tube has four steering wires embedded in its length. The 6000-pixel optical probe is a collection of light fibers that surround optical fiber bundles and is incorporated into a polyimide sheath, providing approximately a 70-degree field of view. The connector section entails a camera processor with 1/4-inch charge-coupled device (CCD) chip, a light source, an optical coupler that interfaces the optical probe with the light source and video camera head, a medical-grade isolation transformer, and a travel cart with a three-joint arm for extension. An irrigation pump with foot pedal and monitor are available through separate vendors.6 The DSOC has a complementary metal-oxide semiconductor (CMOS) chip for higher resolution, magnification, and field of view (120 degrees). It has a thin copper cable for digital transmission and lacks a separate fiber optic probe that may contribute to improved catheter tip articulation. A separate suction connection with the working channel seems to permit improved irrigation capability. The processor is portable for simplified setup.5
Introduction
Technique
The advantages of single-operator cholangioscopy using the catheter-based fiberoptic SpyGlass system (FSOC; SpyGlass Direct Visualization System; Boston Scientific, Marlborough, MA) include the ability of a single endoscopist to perform cholangiopancreatoscopy and the use of a disposable 4-lumen 10-Fr catheter, reusable optical fiber, and four-way tip deflection (up–down and left–right) that is passed through the working channel (4.2 mm) of a standard therapeutic duodenoscope.2 The device is approved by the Food and Drug Administration (FDA) for both biliary and pancreatic applications. In February 2015, a fully disposable digital single-operator cholangioscope (DSOC) was introduced in the United States.3 In an ex vivo study with FSOC, Chen compared four-quadrant access, simulated biopsy, irrigation flow rates, and optical resolution between FSOC and an endoscope-based system (CHF BP-30; Olympus Medical Systems, Tokyo, Japan).4 The author reported that the ability to access four quadrants for visualization and biopsy with FSOC was better than with the two-way tip deflection of the endoscope-based system (odds ratio 1.7 to 2.94, p < 0.001). A preliminary ex vivo study that included five investigators compared optical quality and maneuverability between DSOC and FSOC.5 A biliary tract model contained fixed and variable color targets. Runs (passes of the scope) were randomized, and DSOC outperformed FSOC by a higher percentage of visualized targets (96% vs 66%), successful targeting per run, and faster run times (all comparisons p < 0.01). Further, subjective parameters of image quality and ease of use were superior (p < 0.001).
For FSOC, the optical probe is preloaded into the access/therapeutic catheter and advanced to within a few millimeters of the catheter’s bending portion to reduce the potential for damage during passage across the duodenoscope’s elevator and ductal strictures. The DSOC system has the optical bundle incorporated into the catheter. Advancement through the duodenoscope’s working channel is similar to the endoscope-based cholangioscope. Once the duct is entered with the access catheter, the optical probe is advanced gently beyond the catheter’s tip for intraductal inspection. If resistance is encountered, the control section knobs should be unlocked and fluoroscopy may be used to determine whether the catheter’s tip is straight. The endoscopist has control of the four-way steering dials and may periodically lock the dials to stabilize scope position at a target during tissue acquisition or intraductal lithotripsy. Irrigation is performed through two dedicated channels facilitated by a foot pedal. Irrigation rates should be kept as low as possible to reduce the risk of cholangitis.7
Clinical Use and Efficacy Intraductal Lithotripsy
Electrohydraulic lithotripsy (EHL) or laser lithotripsy (LL) can be used to treat both bile duct and pancreatic duct stones (Fig. 27.1, A–E, and Fig. 27.2, A–E). Cholangioscopic or pancreatoscopic visualization during intraductal lithotripsy helps to avoid duct injury. The 1.9-Fr nitinol EHL fiber contains two coaxially insulated electrodes ending at an open
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B
C
E
D FIG 27.1 A, Fluoroscopic view of a lateral wall of bile duct filling defect consistent with impacted stones. B, FSOC view of two large common bile duct stones. C, FSOC view of common bile duct stone fragments after electrohydraulic lithotripsy. D, Duodenal view of removed stone fragments. E, Balloon occlusion cholangiogram after common bile duct stone clearance. FSOC, Fiberoptic single-operator cholangioscope.
tip. Water or saline immersion is necessary and, as an advantage over endoscope-based cholangioscopes, the dedicated channels for irrigation provide a sufficient medium. During immersion, sparks are generated that produce high-amplitude hydraulic pressure waves for stone fragmentation.8 A generator produces a series of high-voltage electrical impulses at a frequency of 1 to 20 per second, with settings ranging from a power of 50 to 100. The tip of the EHL fiber should protrude no more than 2 to 3 mm from the scope and be positioned en face with the stone while the generator’s foot pedal is depressed to deliver energy.9 During LL, a laser beam is transmitted via a flexible quartz fiber through the working channel of the cholangiopancreatoscope. LL requires more precise localization of the stone, and though fragmentation is enhanced by direct contact, it can lead to a “drilling” effect. The application of repetitive pulses of laser energy to the stone leads to the formation of a gaseous collection of ions and free electrons of high kinetic energy. This plasma rapidly expands as it absorbs the laser energy and then collapses, inducing a spherical mechanical shockwave between the laser fiber and the stone, leading to stone fragmentation.10
Clearance of Difficult Biliary Stone Clearance Using FSOC A multicenter US experience using FSOC with LL included 69 patients, 89% of whom had extrahepatic or cystic duct stones and the remainder had intrahepatic stones.11 All patients had a minimum of one prior failed attempt at ERCP for stone extraction and required a mean of 1.2 LL sessions to achieve an impressive 97% complete clearance rate with a 4% adverse event rate. In a large, single-center FSOC series from India, holmium LL was used in 60 patients with previously failed attempts of mechanical lithotripsy (44%) or other factors such as Mirizzi’s syndrome or stone impaction that precluded attempts at basket capture or large-balloon sphincter dilation.12 The mean stone size was 23 mm (range 15 to 40 mm) and 100% complete clearance was reported after a mean of 1.2 LL sessions. Interestingly, 24 potentially eligible patients were excluded because of portal hypertension or extensive stone burden occupying most of the bile duct and mostly referred to surgery without attempt at FSOC. In a small but significant series of 13 patients with cystic duct stones (four with Mirizzi’s syndrome type 1), FSOC was used to achieve complete clearance of the cystic duct and bile duct in 10/13 (77%) patients during a total of 17 FSOC sessions.13
CHAPTER 27 Cholangioscopy A
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B
C
E
D FIG 27.2 A, Pancreatogram with stones in the head and genu. B, FSOC view of impacted pancreatic duct stone in head. C, FSOC view of pancreatic duct stone fragments after electrohydraulic lithotripsy. D, Duodenal view of pancreatic stone fragment after endoscopic removal. E, Pancreatogram revealing clearance of stones from head and genu. FSOC, Fiberoptic singleoperator cholangioscope.
In a multicenter international prospective registry study using FSOC, 66 of 297 total cases were for the treatment of difficult biliary stones and included EHL (n = 50) and LL (n = 16).14 The median stone size was 19 mm and the duration of index intraductal lithotripsy was 38 minutes. Ductal clearance was achieved in 100%: 47/66 (71%) at index study single-operator cholangioscopy (SOC) and the remaining 29% after an average of one to two ERCPs. Overall, in the appropriately identified patient, the treatment of difficult biliary stones remains an indispensable indication for single-operator cholangioscopy-guided intraductal lithotripsy.
Pancreatic Stone Therapy Using FSOC A potential advantage of peroral pancreatoscopy (POP) over extracorporeal shock wave lithotripsy (ESWL) as a primary modality in the approach to patients with main pancreatic duct (MPD) stones is the ability to fragment and remove stones during the same procedure. In a single-center study of 46 patients undergoing either endoscope or FSOC pancreatoscopy
with EHL or LL for MPD stones, 14 underwent FSOC.15 Overall, complete or partial stone clearance was achieved in 91%, with complete clearance in 70%; complete or partial clearance was similar between those undergoing FSOC and those undergoing endoscope-based pancreatoscopy (p = 0.294), although the disposable system with four-way tip deflection seems particularly advantageous for treating pancreatic duct stones (personal observation). Mild POP-related adverse events occurred in 3/25 (12%) procedures in the FSOC group. Overall clinical success at a median follow-up of 15 months was 74% and similar between endoscopebased and FSOC groups (p = 0.149). From a multicenter LL working group, 28 patients were retrospectively identified who underwent FSOC for MPD stones.16 Before index FSOC with LL, 32% had undergone adjunctive ESWL and 25% had failed or incomplete stone fragmentation with FSOC ± EHL. Median stone size was 15 mm (4 to 32 mm) and located in the head or neck (n = 12 [42%]) or body/tail (n = 10 [36%]), or multiple sites (n = 6 [21%]). Overall, there was 90% per protocol technical success with complete
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(22/28 [79%]) and partial (3/28 [11%]) clearance associated with clinical success in 89% of patients at a median 13-month follow-up based on a 50% reduction in pain, narcotic usage, or hospitalizations. Of note, a 29% rate of mild postprocedural adverse events occurred.
FSOC Evaluation of Indeterminate Biliary Strictures Although comparative series of endoscope-based cholangioscopes and FSOC have not been performed, cohort series of FSOC have shown encouraging findings in patients with indeterminate pancreaticobiliary pathology (Fig. 27.3, A–F). It is likely that the ability to navigate and sample different quadrants of a stricture may be enhanced with four-way tip deflection and a compressible catheter tip.4 Lesions suggestive of malignancy have been based primarily on studies using the endoscopebased cholangioscopes and include (1) exophytic lesions, (2) ulceration, (3) papillary mucosal projections, and (4) dilated tortuous vessels.2,17,18
For FSOC, interobserver agreement of video clips to distinguish malignant from benign lesions revealed only slight to fair agreement and may be only modestly improved with the DSOC system. Accuracy by the investigators to distinguish benign from malignant was 70% (20% higher than with FSOC) and there was moderate interobserver agreement specifically for papillary projections.18-20 Intraductal biopsy with the FSOC technique can be performed using two methods previously described for the endoscope-based cholangioscope.17 Cholangioscopy-directed biopsy is performed by passing a miniature cholangioscope biopsy forceps with a span of 4.1 mm (SpyBite; Boston Scientific) through the 1.2-mm working channel of the FSOC.3 Cholangioscopy-assisted biopsy is performed by localizing the target biopsy site using cholangioscopic visualization. For example, for distal biliary strictures in which passage of the miniature forceps may be technically difficult, obtain fluoroscopic spot films of the cholangioscope
A
C
B
D
E
F
FIG 27.3 A, Cholangiogram of main bile duct stricture in mid-duct. B, Fluoroscopy view of FSOC position at level of pathology. C, FSOC view of a malignant-appearing nodule. D, FSOC view of a suspected tumor vessel. E, FSOC alternative view of a malignant-appearing nodule. F, Fluoroscopic view of SOC-S with miniature forceps biopsy. Pathology revealed high-grade dysplasia. FSOC, Fiberoptic single-operator cholangioscope.
CHAPTER 27 Cholangioscopy tip positioned at the target lesion. After removing the cholangioscope, a conventional biliary biopsy forceps is then passed through the working channel of the duodenoscope to obtain tissue samples under fluoroscopic guidance.17 Clinical feasibility studies reveal adequate histologic specimens for the miniature forceps in 95% to 97% of samples when the target lesion is reached.2,17 In a prospective small series, 26 patients with indeterminate biliary strictures underwent, per protocol, single-operator cholangioscopy using catheter-based SpyGlass system (FSOC)–directed biopsy followed by brush cytology and fluoroscopy-guided biopsy.21 Most patients (85%) had previous nondiagnostic tissue sampling and 46% were hilar strictures. Sensitivity, specificity, and accuracy of cytology (6%, 100%, 39%), standard forceps biopsy (29%, 100%, 54%), and miniature-forceps biopsy (77%, 100%, 85%) were reported, with significant differences noted when comparing the miniature-forceps biopsy with the other methods for sensitivity and accuracy (p < 0.0001 and p = 0.0215 for cytology and standard forceps biopsy, respectively). Whether brush cytology and conventional biopsy were performed by referencing a spot film of the cholangioscope at the target area is unknown. Further, there is not a satisfactory explanation provided as to the extremely low sensitivity of brush cytology in this series. In a study from India, data from a 9-month prospective enrollment period were reported in which approximately 10% of patients (n = 36) with indeterminate biliary strictures underwent FSOC for further characterization.22 Overall, adequate histology was obtained in 82%. A high proportion of hilar strictures (21/36 [58%]) may partially explain the lower rates of adequate histology from the miniature forceps because of limited access. The accuracy of the visual impression of SOC-S using the malignancy criteria described above was 89% (95% sensitivity and 79% specificity) and for histology using the miniature forceps was 82% (82% sensitivity and specificity). Benign appearance was suggested by smooth surface mucosa without definite neovascularization and homogenous granular mucosa. The largest multicenter trial on cholangioscopy included 15 centers from Europe and the United States in which FSOC was prospectively used for indeterminate pancreaticobiliary pathology and difficult stone disease.14 Chen and coinvestigators evaluated 226 patients with indeterminate biliary pathology who underwent diagnostic SOC-S; 140 had directed miniature forceps biopsy (median of 4 bites, 20% hilar, and histologic adequacy of 88%). Complete ERCP, FSOC, and biopsy data were available for a subset of 95 patients. The sensitivities and specificities of cholangiographic impression, FSOC visualization, and FSOC-directed tissue biopsies for detecting malignancy were 51% and 54%, 78% and 82%, and 49% and 98%, respectively. In a meta-analysis of FSOC, eight studies that evaluated operating characteristics of visual impression and use of directed SpyBite sampling were reported.23 The authors noted the sensitivity and specificity of the FSOC visual impression to be 90% and 87%, respectively (area under the curve [AUC] 0.94). The use of SpyBite sampling had a 69% sensitivity and 98% specificity in detection of neoplasia (AUC 0.93). With the introduction of DSOC, the hope is that improved optics will enhance the ability to detect and exclude neoplasia (Figs. 27.4 and 27.5). The first preliminary US multicenter clinical series using DSOC was by Shah et al. and included 121 patients: 85 for stricture and ductal dilatation evaluation and 36 with difficult stones.24 The patients with stones (29 biliary, 7 pancreatic) achieved 100% clearance using intraductal lithotripsy techniques. Eight patients underwent DSOC to assess the extent of cholangiocarcinoma (CCA), and two were found to have unsuspected, multifocal intrahepatic CCA. Of the 77 with indeterminate stricture/dilatation, 40% had confirmed neoplasia, of which 81% were positive by SpyBite sampling. Overall, the use of DSOC in the detection of neoplasia in the indeterminate cohort was found to carry sensitivity,
253
FIG 27.4 Digital single-operator cholangioscope view of an infiltrative stricture with tumor vessels.
FIG 27.5 Digital single-operator cholangioscope view of a villous mass of a biliary intraductal papillary mucinous neoplasm.
specificity, PPV, and NPV of 97%, 96%, 94%, and 98%, respectively (all confidence intervals [CIs] ranged from 0.87 to 1.0). An additional smaller series included 105 patients, 73 of whom had the examination for diagnostic purposes.25 There was a relatively low (27%) prevalence of neoplasia, and diagnostic SOC without biopsy was noted in a high proportion of examinations (40%). Indications and findings included PSC, posttransplant stricture, benign strictures from stones, and normal examinations, which are low-yield indications for the use of cholangiopancreatoscopy. Overall, the authors found the sensitivity and specificity of DSOC clinical and visual impression for diagnosis of malignancy to be 90% and 96%, respectively, and those of DSOC-guided biopsies to be 85% and 100%, respectively. An on-site pathologist performed immediate wet-prep evaluation of the specimens, which may have helped to improve the diagnostic yield of sampling. Because tissue sampling remains the key to further triaging and managing of patients with suspected neoplasia, perhaps the optimal use of SOC may be in the identification of suspicious lesions, followed by directed tissue sampling by either cholangioscopy-directed or cholangioscopy-assisted methods, in conjunction with brush cytology, to provide the highest probability of obtaining tissue confirmation of suspected lesions. If tissue sampling is nondiagnostic but the visual impression is concerning for neoplasia, then a close surveillance interval and sampling are recommended. Although a fully disposable DSOC is
254
SECTION II Techniques
now available and simpler to use, given the lack of pass-through code and limited reimbursement, it is wise to be more selective in the use of this costly technology. A good clinical impression and cholangiography technique may help to avoid the need for some cholangioscopy use described in published series. Lastly, with the anticipated introduction of competing disposable digital cholangioscopes, retail costs for the technology may decrease.
Reimbursement and Limitations As of 2009, a current procedural terminology add-on code with ERCP exists for cholangiopancreatoscopy. Despite the described advances, there remains a limited ability of the 10-Fr-diameter catheter to traverse tight strictures without preinspection dilation, which, when performed, may alter visual interpretation. Although four-quadrant inspection of mucosa may be achieved with four-way tip deflection and the application of torque on the duodenoscope, circumferential views and the ability to advance accessories through the working channel may be difficult, depending on duodenoscope angulations, downstream duct strictures, small duct diameter, and intraductal debris. Aspirating debris and fluid through a Y-adapter fixed to the working channel while simultaneously irrigating through the flushing port can improve the latter.6 Circumferential visualization may also be difficult in the presence of markedly dilated ducts. During inspection of strictures, stent-associated changes may alter the mucosal appearance to include papillary mucosal projections, making visual diagnosis of malignancy very difficult.26 If resistance is encountered during accessory passage, advancing the cholangioscope to the upstream duct or increasing the loop of the cholangioscope within the duodenum may allow passage of the device beyond the point of angulations. The EHL and LL fibers are fragile and sometimes require preloading through a straight cholangioscope to facilitate introduction.9,27 During intraductal lithotripsy, there can be recoil of the fiber into the working channel because of transmitted energy, contact with fragmented stones, or a deflected scope tip. As blood and stone debris may reduce visualization, careful and frequent confirmation that the tip of the fiber is in the appropriate position by endoscopic and fluoroscopic visualization is necessary to reduce duct injury or optical fiber damage. If passage of the biopsy forceps is unsuccessful, cholangioscopy-assisted fluoroscopy-guided biopsy can be performed.17 Although the optical probe in the FSOC is reprocessed, use may be limited to 10 cases, beyond which image quality may diminish because of broken fiber bundles. In the presence of a lithotripsy fiber or biopsy forceps within the working channel, the dedicated irrigation channel provides higher flow rates compared with reusable cholangioscopes.4 The access catheter lacks a conventional suction button, and intermittent manual aspiration using a syringe attached to a Y-port adapter and/or intermittent duodenoscope suctioning is required to reduce intraductal pressure and gastroduodenal fluid reflux.6 For DSOC, a suction apparatus connected to the working channel provides improved irrigation ability (i.e., the ability to flush and aspirate) to improve visualization.3
Adverse Events Although not specific to FSOC, a single-center series of ERCP alone compared with ERCP and cholangiopancreatoscopy found that cholangiopancreatoscopy may be associated with a significantly higher rate of procedure-related adverse events than ERCP alone.7 This increased risk was observed in overall adverse events (7.0% vs 2.9%), consensus adverse events (pancreatitis, perforation, cholangitis, or bleeding; 4.2% vs 2.2%), and specifically with postprocedural cholangitis (1.0% vs 0.2%). Studies specific to FSOC reveal adverse event rates ranging from 5% to 13% and include mostly cholangitis and pancreatitis.12,13,22,24
Prophylactic IV antibiotics are therefore recommended when performing intraductal cholangioscopy.
Summary Single-operator cholangioscopy using SpyGlass has been demonstrated to be an established modality in the treatment of difficult biliary stones. When used in the evaluation of indeterminate biliary strictures by endoscopists experienced in recognizing intraductal pathology, it increases the diagnostic yield of tissue sampling. Results remain limited and mostly preliminary in its use for pancreatic duct stones and in the evaluation of pancreatic neoplasia. The digital imaging system provides a simplified setup and improved optical resolution.
VIDEOCHOLANGIOSCOPY USING THE MOTHER– BABY SYSTEM A videocholangioscope can provide outstanding quality digital images compared with conventional fiberoptic cholangioscopy.28–36 Two videocholangioscopes have been used in the mother-baby cholangioscopy system (Table 27.1). At present, however, their use is limited to a few countries. Recently, newly designed digital cholangioscopy (SpyGlass DS, Boston Scientific), which is available as a single-operator system, has been developed.37,38 (See details in the previous section.)
Description of the Technique The therapeutic duodenoscope that is used as the mother scope has a 4.2-mm working channel that helps prevent kinking of the baby videocholangioscope. Endoscopic sphincterotomy is needed to facilitate scope passage across the papilla. Two videocholangioscopes (CHF-B260/ B160 and CHF-BP260, with outer diameters of 3.4 and 2.6 mm and working channel diameters of 1.2 and 0.5 mm, respectively; B260 and BP260 [Olympus Medical Systems, Tokyo, Japan] and B160 [Olympus America Inc., Center Valley, PA]) are available (Fig. 27.6). They are advanced through the 4.2-mm working channel of therapeutic duodenoscopes into the bile duct with or without a 0.035-inch/0.025-inch guidewire. Both have two-way tip angulation. The wire-guided insertion technique is used with the CHF-B260 but not with the CHF-BP260 because of the diameter of the working channel. Saline irrigation and CO2 insufflation are used during cholangioscopy because of reports of air embolism.34,35 Endoscopic observation is usually performed using white-light imaging. Observation using narrow-band imaging (NBI) is available with the NBI system (CV-260SL, CVL-260SL,
TABLE 27.1 Mother–Baby
Videocholangioscopy Angle of view, degrees Observed depth, mm Outer diameter, mm Distal end Insertion end Bending section, degrees Up/down Right/left Working length, mm Working channel diameter, mm Image-enhanced endoscopy
CHF-BP260*
CHF-B260/B160*
90 3 to 20
90 3 to 20
2.6 2.9
3.4 3.5
70/70 NA 2000 0.5 NBI
70/70 NA 2000 1.2 NBI
NA, Not available; NBI, narrow-band imaging. Olympus Medical Systems, Tokyo, Japan.
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CHAPTER 27 Cholangioscopy
FIG 27.7 Papillary lesions in the intrahepatic bile duct. FIG 27.6 Videocholangioscopy using the mother–baby system.
TABLE 27.2 Summary of Diagnostic Ability of Mother–Baby-Type Videocholangioscopy Author (Year) 33
Itoi (2010) Nishikawa (2013)40 Osanai (2013)39
n
Study
144 33 87
R P P
Sensitivity (%) 99 100 94
Specificity (%) 96 92 92
PPV (%)
NPV (%)
99 96 NA
99 96 NA
Accuracy (%) 98 97 93
NA, Not applicable; NPV, negative predictive value; P, prospective study; PPV, positive predictive value; R, retrospective study. All data including visual impression + biopsy.
CVL-290SL/CV-180, CLV-180, CLV-S190, light source; Olympus Medical Systems).
Technique: Diagnostic and Therapeutic Videocholangioscopy provides better-quality digital images and offers enhanced mucosal detail compared with conventional fiberoptic cholangioscopes (Fig. 27.7 and Video 27.1). Thus it can delineate fine mucosal structures like shallow pseudodiverticula, papillary or granular lesions, and fine vessel patterns, leading to differentiation between benign and malignant lesions to include the indeterminate filling defects and biliary strictures as noted on cholangiography. A recent retrospective study33 and prospective studies39,40 of the ability of videocholangioscopy to differentiate between indeterminate filling defects and biliary strictures revealed that videocholangioscopy provided high diagnostic ability (accuracy, 93% to 98%; sensitivity, 94% to 100%; specificity, 92% to 96%; positive predictive value, 96% to 99%; negative predictive value, 96% to 100%) (Table 27.2). However, videocholangioscopy cannot always differentiate benign from malignant lesions. For instance, in cases of IgG4-related cholangitis, cholangioscopic images are often similar to those visualized in cholangiocarcinoma, for example, presence of thick and tortuous vessels.41 Thus cholangioscopic imaging alone is limited and biopsy appears to be mandatory in such cases. Mucinous-producing neoplasms in the bile duct can produce a large amount of mucin, resulting in misdiagnosis of tumor location when only cholangiography is employed. Videocholangioscopy is very useful for accurate localization of the primary site of the tumor.36 Detailed observations make it possible to not only detect abnormal findings but also accurately target biopsy sites by direct inspection (Fig. 27.8).
Bile duct neoplasms, in particular papillary growth type or mucinousproducing neoplasms, often show a longitudinal tumor spreading from the primary bile duct lesions. Detailed visualization of enlarged images obtained by videocholangioscopy permits detection of tiny abnormalities, regardless of benign or malignant nature.32,36 Furthermore, videocholangioscopy biopsy using a directed 3-Fr biopsy forceps further improves diagnostic capability.33 When a biliary stricture is too tight to allow passage by a videocholangioscope, balloon dilation or temporary 10-Fr plastic stent placement can increase the luminal diameter to allow for subsequent cholangioscopy. Image-enhanced videocholangioscopy using NBI clearly displays fine biliary mucosal structures and capillary vessels (Fig. 27.9, A, B; Video 27.2) and helps to distinguish benign from malignant lesions.31,39,41,42 Primary sclerosing cholangitis increases the lifetime risk of cholangiocarcinoma. A recent study suggested that cholangioscopy allowed visualization of tumor margins in CCA compared with traditional fluoroscopy-based ERCP.43 Although therapeutic videocholangioscopy is limited because of its small working channel, 1.9-Fr to 3-Fr EHL and LL using holmium YAG and FREDDY have been performed under direct videocholangioscopic visualization (Fig. 27.10 and Video 27.3).
Adverse Events and Limitations Videocholangioscopy can cause procedure-related adverse events such as cholangitis and pancreatitis. There are several limitations of the mother–baby videocholangioscopy system because of endoscope fragility, expense of repair, and need for two skilled endoscopists. On NBI cholangioscopy, bile resembles blood, which can lead to poor images, and it is time-consuming to clean the bile duct without a dedicated irrigation channel.31
256
SECTION II Techniques
FIG 27.8 Biopsy under direct inspection.
A
FIG 27.10 Baby cholangioscopy–assisted intraductal electrohydraulic lithotripsy for large bile duct stone.
B
FIG 27.9 Early bile duct cancer. A, White-light imaging. B, Narrow-band imaging.
VIDEOCHOLANGIOSCOPY BY THE DIRECT INSERTION SYSTEM Direct peroral fiberoptic cholangioscopy is performed by the direct insertion technique was first described by Urakami et al. 3 decades ago using a standard upper gastrointestinal (GI) endoscope.44 However, this method has not become common because of the technical difficulty of passing a large-diameter endoscope into the biliary tree. In 2006 the first case series using ultraslim upper GI videoendoscopes was reported by Larghi and Waxman.45 Since then, diagnostic and therapeutic direct peroral videocholangioscopy (DPVCS) have become increasingly performed.46–54
Description of the Technique DPVCS is usually performed using conventional ultraslim upper GI endoscopes (Table 27.3). However, because they have a 5-mm to 6-mm outer diameter, endoscopic sphincterotomy is mandatory. On occasion, papillary balloon dilation is added to facilitate endoscope passage across the papilla. These instruments have four-way tip angulation and a 2-mm working channel. At present, five approaches for direct bile duct access have been reported: (1) free-hand insertion without any assisting devices, (2) wire-guided insertion, (3) balloon overtube–assisted insertion, (4)
occluded duodenal balloon–assisted insertion, and (5) intraductal anchoring balloon–assisted insertion55 (Fig. 27.11). In general, free-hand scope insertion is usually difficult when using a conventional ultraslim upper GI videoendoscope, and therefore either wire-guided insertion or intraductal anchoring balloon-assisted insertion is most frequently used. Early studies showed that the success rate of intraductal balloon catheter–assisted insertion was higher (20/21 [95.2%]) than that of wire-guided insertion (5/11 [45.5%]) or balloon overtube–assisted insertion (10/12 [83.3%]).46,47 For wire-guided insertion, initially a 0.035-inch or stiff-type 0.025-inch guidewire is inserted into the bile duct through a standard duodenoscope, which is then removed, leaving the guidewire in place. An ultraslim endoscope is then advanced into the bile duct using an over-the-wire technique. It is relatively easy to advance the tip of the endoscope into the lower bile duct in either an angulated or straight position. A combination of pushing and pulling techniques is needed for scope insertion up to the hilum. When we use the 5-Fr anchoring balloon for scope insertion into the bile duct, the anchoring balloon is advanced into the right or left intrahepatic bile duct and inflated as an anchor. A 0.018-inch or 0.025-inch guidewire is used for placing the 5-Fr anchoring balloon. Then, an ultraslim endoscope is advanced to the hilum or intrahepatic bile ducts using the pushing and pulling techniques in combination
257
CHAPTER 27 Cholangioscopy TABLE 27.3 Direct Peroral Videocholangioscopy OLYMPUS MEDICAL SYSTEMS Angle of view, degrees Observed depth, mm Outer diameter, mm Distal end Insertion end Bending section, degrees Up/down Right/left Working length, mm Working channel diameter, mm Image-enhanced endoscopy
GIF-XP160
GIF-XP180N
GIF-XP260N
Fujinon EG-530NW/530N2
Pentax EG-1690K
120 3 to 100
120 3 to 100
120 3 to 100
140 4 to 100
120 4 to 100
5.9 5.9
5.5 5.5
5.0 5.5
5.9 5.9
5.4 5.3
180/90 100/100 1030 2 NBI
210/90 100/100 1100 2 NBI
210/90 100/100 1030 2 NBI
210/90 100/100 1100 2 FICE
210/120 120/120 1100 2 i-SCAN
FICE, Flexible spectral imaging color enhancement; NBI, narrow-band imaging.
A
FIG 27.11 Direct videocholangioscopy with anchoring balloon.
with the anchoring balloon. At this time, the shape of endoscope shows an α-loop or U-loop scope position. Saline irrigation and CO2 insufflation are used to facilitate endoscopic visualization in the bile duct. Recently a prototype dedicated DPVCS with a multibending tip has been developed.56 It has two bending sections: the proximal section can be deflected in a single plane (90° up or 90° down), and the distal section can also be deflected in a single plane (160° up or 100° down). The endoscope is forward-viewing, with a working length of 133 cm, a field of view of 90°, and an outer diameter of the distal end and the insertion tube of 5.2 and 7.0 mm, respectively. The ratios of the distal bending section and the distal plus proximal bending section compared with the GIF-XP180N (Olympus Medical Systems) are 0.6 and 2.2, respectively. The endoscope has two accessory channels of 2.2 and 0.85 mm diameter. It also has suction and insufflation capabilities. The latest generation of dedicated DPVCS has shown an extremely high success rate (97%) using only the free-hand technique.54 For successful free-hand insertion of the dedicated DPVCS, the tip of cholangioscope is inserted into the distal bile duct using up-angle and torque of the cholangioscope shaft. The manipulation is similar to that of a colonoscope inserted into the terminal ileum, or “blinded” terminal ileum insertion. Once the tip of the cholangioscope is inserted into the bile duct, it is easily advanced to the hilum using scope angulation and by direct advancement. In contrast to a conventional ultraslim upper GI endoscope, the dedicated DPVCS is stable in the bile duct during scope manipulation.
Technique: Diagnostic and Therapeutic After reaching the bile duct segment of interest, DPVCS enables several diagnostic and therapeutic procedures, including visualization alone,
B
FIG 27.12 Direct videocholangioscopy–assisted electrohydraulic lithotripsy for large bile duct stone. A, Radiographic finding. B, Endoscopic imaging.
biopsy for diagnosis, electrohydraulic or LL (Fig. 27.12, A and B) tumor ablation using argon plasma coagulation, and photodynamic therapy or passage of guidewires to facilitate biliary stenting using plastic or metallic stents through the 2-mm working channel. However, 2-mm accessories are not commonly available (Fig. 27.13).
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SECTION II Techniques TABLE 27.4 Summary of Insertion
Success Rate of Direct Peroral Cholangioscopy Author (Year) Larghi (2007)45 Choi (2009)46 Moon (2009)47 Tsou (2010)48
FIG 27.13 5-Fr Accessories for direct cholangioscopy.
Pohl (2011)49 Mori (2012)50 Farnik (2014)51 Itoi (2014)52 Weigt (2015)53 Beyna (2016)54
n
Endoscope
15 12 11 21 14 25 40 40 7 34 42 67 74
UGI UGI UGI UGI UGI UGI UGI UGI DDPVCS DDPVCS UGI UGI DDPVCS
Assistant Devices GW Balloon overtube GW AB Balloon overtube AB Duodenal balloon AB Free-hand GW and/or AB AB AB Free-hand w/wo AB
Insertion Success (%) 78 83 46 95 93 72 93 98 0 94 90 88 90
Based on the high success rate of scope insertion (Table 27.4) and the durability of DPVCS, as well as cost benefit (no need for two light sources or two skilled endoscopists), DPVCS appears to be the first choice for cholangioscopy when ducts are dilated and the target lesion is in the proximal bile duct. Image-enhanced endoscopy, enabling delineation of fine mucosal structures and vessels, is possible using various processor systems as follows: (1) NBI (Olympus Medical Systems), (2) flexible spectral imaging color enhancement (FICE; Fujifilm, Tokyo, Japan), and (3) i-Scan (Pentax, Tokyo, Japan).
AB, Anchoring balloon; DDPVCS, dedicated diagnostic and therapeutic direct peroral videocholangioscopy; GW, guidewire; UGI, upper gastrointestinal endoscopy.
Adverse Events and Limitations
Acknowledgment
DPVCS also causes procedure-related adverse events. The most serious adverse event is cardiac or cerebral air embolism if the procedure is performed using air insufflation rather than saline irrigation or CO2 insufflation.57 Ultraslim endoscopes do not always match the size of the bile duct or papilla as frequently as the smaller-diameter dedicated cholangioscopes. Care should be taken, because this size mismatch may
We are indebted to Professor Edward Barroga, Department of International Medical Communications of Tokyo Medical University, for his editorial review of the English manuscript.
cause unexpected serious adverse events, including bleeding, pancreatitis, and perforation of the duodenum at the site of sphincterotomy.
The complete reference list for this chapter can be found online at www.expertconsult.com.
CHAPTER 27 Cholangioscopy
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