Chapter 26 Cholangioscopy

Introduction

Advances in cholangiopancreatoscopy continue to broaden the interventionalist’s scope of effectiveness in the diagnosis and management of biliary and pancreatic disease. Continued design evolution has moved this technology from academic research centers to the hands of the practicing community. The nomenclature has likewise evolved through a spectrum of descriptive terms including cholangioscopy, choledochoscopy, duodenoscope-assisted cholangiopancreatoscopy, and peroral cholangioscopy, among others. The duct can be accessed through a variety of approaches: through the native papilla of Vater via a duodenoscope, percutaneously through a transhepatic route, or intraoperatively through a choledochotomy or cystic duct exploration. This chapter is divided into three parts. Part B focuses on the developing field of videocholangioscopy and the enhancements that can be expected as that technology becomes more available. Part C, on the Spyglass system, emphasizes the single-operator approach that has greatly simplified cholangioscopy, allowing for its expanded use.

If cholangioscopy is to become a truly meaningful adjunct for the interventionalist, the equipment needs to be readily available as indications arise. Management of large and recalcitrant common duct stones and more accurate evaluation of suspicious biliary strictures are among the two most common indications for biliary endoscopy. For its practical use, the equipment needs to be on hand and the support staff well instructed on its setup and maintenance.

Video for this chapter can be found online at www.expertconsult.com.

Cholangioscopes first appeared in research academic settings over 25 years ago and since then have slowly undergone a series of iterations. Currently, in the United States, there is a limited assortment of fiberoptic cholangioscopes available for purchase (Table 26.1). In general, the smaller the outer diameter of the cholangioscope, the greater its maneuverability within the bile duct. The trade-off, however, is that these smaller scopes may have a smaller working channel or fewer internal cables for tip deflection. The ultraslim scopes are of sufficiently small caliber that they can be introduced into either the biliary or the pancreatic ducts through standard catheters and deliver good visualization of small secondary ductal branches. Their lack of a working channel or flushing mechanism, however, is a disadvantage compared with the larger therapeutic cholangioscopes.

Table 26.1 Cholangioscopes Available in the United States

The optimal endoscopic retrograde cholangiopancreatography (ERCP) suite design places the cholangioscope, its power supply, and accessories in close proximity to the endoscopist. Because of the intimate spatial working relationships between the mother and baby scope, the cholangioscope components are set up on or adjacent to the ERCP processor cart. These components include the light generator and image processor as well as the flushing and suctioning equipment. Depending on the manufacturer and the model, the light source, image processing hardware, and air and fluid pump are available either as individual components or combined in a single unit. The Spyglass system, as discussed in Part C, combines all of these units on one cart.

Strategic placement of the monitors is critical to permit simultaneous viewing of the video images from the mother scope, the baby scope, and the fluoroscopic unit during cholangioscopy. Ideally, the three monitors are clustered and mounted at eye level in front of the endoscopist. In new unit designs, these three monitors are mounted on articulating arms to maximize the operator’s comfort and ergonomics. Toggle switches or foot pedals permit easy switching between other video output sources such as endoscopic ultrasound (EUS) or microscopy. Extra monitors are positioned for the assisting staff. Digital recording of the cholangioscopic exam provides a permanent record of the exam and most importantly permits postprocedure review of the findings.

A variety of accessories are used during routine cholangioscopy. Special adapters attached to the opening of the mother scope’s instrument channel prevent crimping of the baby scope as it is maneuvered during the procedure. As copious flushing and suctioning is routine during cholangioscopy, saline irrigant, connector tubing, stopcocks, and syringes need to be available. Some processors are equipped with irrigation and suctioning components. Finally, there are a variety of accessories specific to cholangioscopy such as cytology brushes, biopsy forceps, snares, and electrohydraulic lithotripsy probes that need to be organized and readily available.

To show how far we have come from the time when I first converted a two-person procedure to one that could be performed solo, refer to Fig. 26.1.

Fig. 26.1 The baby scope secured to the endoscopist by a breastplate.

Videocholangioscopy

Takao Itoi

Videocholangioscopy Using the Mother-Baby System

A videocholangioscope can provide outstanding quality digital images compared to conventional fiberoptic cholangioscopy.¹^–⁹ Two videocholangioscopes are used in the mother-baby cholangioscopy system (Table 26.2). At the present time, however, their use is limited to a few countries.

Table 26.2 Mother-Baby Videocholangioscopy

NA, Not available; NBI, narrow band imaging.

Description of the Technique

The therapeutic duodenoscope that is used as the mother scope has a 4.2-mm working channel, which 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 2.8 mm and working channel diameters of 1–2 and 0.8 mm, respectively; B260 and BP260, Olympus Medical Systems, Tokyo; B160, Olympus America Inc., Center Valley, Pa.) (Fig. 26.2) are advanced through the 4.2-mm working channel of the therapeutic duodenoscope into the bile duct with or without a 0.035-in guidewire. They 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 carbon dioxide (CO₂) insufflation are used for observation in the bile duct.^7,⁸ 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/CV-180, CLV-180, light source, Olympus).

Fig. 26.2 Videocholangioscopy using the mother-baby system.

Technique: Diagnostic and Therapeutic

Videocholangioscopy provides better-quality digital images and offers enhanced mucosal detail compared with conventional fiberoptic cholangioscopes (Fig. 26.3; Video 26.1). Thus it can delineate fine mucosal structures like shallow pseudodiverticular, bumpy surface, papillary, or granular lesions and fine vessel patterns, leading to differentiation between benign and malignant lesions on the basis of the indeterminate filling defects and biliary strictures as described by cholangiography. A recent study of the ability of videocholangioscopy to differentiate between indeterminate filling defects and biliary strictures revealed that ERCP/tissue sampling and videocholangioscopy provide high diagnostic ability (accuracy 98.3%, sensitivity 99.0%, specificity 95.8%, positive predictive value 99.0%, negative predictive value 95.8%) compared with ERCP/tissue sampling alone (accuracy 85.0%, sensitivity 86.5%, specificity 79.2%, positive predictive value 94.3%, negative predictive value 59.4%).⁶ Mucin-producing neoplasms in the bile duct can produce a large amount of mucin, resulting in misdiagnosis of tumor location if only cholangiography is employed. Videocholangioscopy is very useful for accurate detection of the primary site of the tumor.⁹ Detailed observations make it possible not only to detect abnormal findings but also to accurately target biopsy sites by direct inspection (Fig. 26.4).

Fig. 26.3 Papillary lesions in the intrahepatic bile duct.

Fig. 26.4 Biopsy under direct inspection.

Bile duct neoplasms, in particular papillary growth type or mucin-producing neoplasms, often show a longitudinal tumor spreading from the primary bile duct lesions. Detailed imaging on enlarged images obtained by videocholangioscopy permits detection of tiny abnormal findings, regardless of benign or malignant nature.^5,⁹ Furthermore, biopsy view videocholangioscopy using 3 Fr biopsy forceps provides good diagnostic ability.⁶ When the biliary stricture is too inelastic to allow passage by a videocholangioscope, a biliary dilating balloon catheter or temporary 10 Fr plastic stent placement can be effective.

Image-enhanced videocholangioscopy using NBI clearly displays fine biliary mucosal structures and capillary vessels (Fig. 26.5; Video 26.2) contributing to accurate biopsy and diagnosis of biliary tract diseases.

Fig. 26.5 Early bile duct cancer. A, White light imaging. B, Narrow band imaging.

Although therapeutic videocholangioscopy is limited because of its small working channel, 1.9 to 3 Fr electrohydraulic lithotripsy (EHL) and laser lithotripsy using holmium YAG and FREDDY have been performed under direct videocholangioscopic visualization (Fig. 26.6; Video 26.3).

Fig. 26.6 Baby cholangioscopy-assisted intraductal electrohydraulic lithotripsy for large bile duct stone.

Adverse Events and Limitations

Videocholangioscopy, like fiberoptic cholangioscopy, can cause procedure-related adverse events such as cholangitis and pancreatitis. There are several limitations of the mother-baby videocholangioscopy system because of the 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.⁴

Videocholangioscopy by the Direct Insertion System

Direct peroral fiberoptic cholangioscopy performed by the direct insertion technique was described by Urakami et al.¹¹ 3 decades ago using a standard upper gastrointestinal (GI) endoscope. However, this method has not become common because of the difficulty of direct insertion using a standard upper GI endoscope. In 2006 the first case series using ultraslim upper GI videoendoscopes was reported by Larghi and Waxman.¹² Since then diagnostic and therapeutic direct peroral videocholangioscopy (DPVCS) have become increasingly common.¹³^–²³

Description of the Technique

DPVCS is usually performed using conventional ultraslim upper GI endoscopes (Table 26.3). However, since they have a 5- to 6-mm outer diameter, endoscopic sphincterotomy is mandatory. On occasion papillary dilation is added to facilitate scope passage across the papilla. It has four-way tip angulation and a 2-mm working channel.

Table 26.3 Direct Peroral Videocholangioscopy