Full-depth evaluation of the bile duct with a 7F cholangioscope and its possibility for guiding therapeutics

Abstract

Background and Aims

Digital single-operator cholangioscopy (DSOC) plays a critical role in directly visualizing and treating the bile duct system. Although various cholangioscopes with different external diameters are available for DSOC, certain challenging scenarios persist in which existing scopes fail to complete a thorough evaluation of the bile ducts. To overcome these limitations, we aimed to introduce and highlight the application of a novel 7F cholangioscope.

Methods

In this review article we describe the novel 7F cholangioscope, provide its assembly and setup, and review cases in which the 7F cholangioscope was used for diagnostic and therapeutic guidance.

Results

Four cases involving challenging biliary assessments were presented, all of which achieved technical and clinical success. No procedure-related adverse events were reported in any of these cases.

Conclusions

The 7F cholangioscope can provide additional information regarding the biliary tree and guidance for treatment, overcoming the challenging assessment of small pancreatobiliary ducts and its strictures. Its potential use in cases of severe bile duct stenosis is recommended. However, further studies evaluating safety and efficacy are needed.

Video

Video 1

Seven-French cholangioscopy bile duct evaluation.

Introduction

Digital single-operator cholangioscopy (DSOC) allows direct visualization of the bile duct system for both diagnosis and treatment.^1,2 Currently, DSOC has multiple diagnostic and therapeutic indications ranging from visualizing indeterminate strictures, mapping tumors, and addressing post–liver transplant duct disorders, to managing challenging biliary strictures by placing guidewires and performing ablative therapy.³ DSOC grants crucial insight regarding patients’ prognoses and changes their management.^4,5

Given the expanding range of indications for DSOC and the growing supportive data for its early use, new tools are in development.⁶ Although numerous accessories are now accessible, we focus this review on the newly introduced 7F cholangioscope. The aim of this article is to describe the 7F cholangioscope, compare it with existing cholangioscopes, and highlight cases in which its use was instrumental. In our cases, the use of a 7F cholangioscope allowed for a full-depth evaluation of the bile duct system up to the most proximal portions of the intrahepatic ducts (IHDs) and through anastomosis and strictures (Video 1, available online at www.videogie.org).

Current Limitations of Existing Cholangioscopes

Although direct visualization through a cholangioscope aids in identifying mucosal, surface, and vascular patterns, there are still several scenarios in which cholangioscopy encounters limitations. The current available cholangioscopes for DSOC, such as the eyeMAX (9.3F and 11.1F; Micro-Tech, Nanjing, China) and the SpyGlass DS Direct Visualization System (10.5F; Boston Scientific, Marlborough, Mass, USA), may present limitations when targeting very distal locations, areas with duct angulations, or even the proximal pancreatic ducts, thus making a comprehensive evaluation difficult.⁷ In such cases, the use of a cholangioscope with a smaller external diameter might be necessary. The characteristics of the currently available cholangioscopes along with the novel 7F cholangioscope are summarized in Table 1.

Table 1.

Characteristics of the currently available cholangioscopes and the novel 7F cholangioscope

External diameter	7F	9.3F	10.5F	11.1F
Trade name	eyeMAX	eyeMAX	SpyGlass DS Direct Visualization System	eyeMAX
Brand	Micro-Tech	Micro-Tech	Boston Scientific	Micro-Tech
Working channel diameter (mm)	0.8	1.2	1.2	2.0
Length (mm)	2200	2200	2300	2200
Insertion diameter (mm)	3.2	3.2	3.8	3.9
Field of view	120°	120°	120°	120°
Handle	Dial knob controls with locking mechanism 4-way steering

Novel 7F Cholangioscope

Components

The 7F cholangioscope consists of 3 primary components: (1) the scope, (2) an attachment strap, and (3) a Y-port adapter. The Y-port adapter serves as a working channel for a compatible guidewire (<0.025 inches) or as an irrigation and suction port during procedures. Moreover, the cholangioscope has a knob control that facilitates 4-way steering. The 7F cholangioscope works with the eyeMAX processor.

Characteristics

The cholangioscope has an external diameter of 7F and a length of 2200 mm. It has a working channel diameter of 0.8 mm, an insertion diameter of 3.2 mm, and a field view of 120 degrees. Notably, it includes dual-knob control with a locking mechanism and 4-way steering, enhancing its maneuverability and control during procedures.

Assembly and Setup

To assemble the cholangioscope, first attach the strap securing the cholangioscope to the duodenoscope shaft, followed by fixing the Y-port adapter. Next, connect the cholangioscope to the eyeMax processor and verify that its functionality precedes the display of the scope image on the monitor. Completing the assembly involves inserting the catheter cable fully into the duodenoscope’s working channel, navigating it through the bile ducts using the cholangioscope’s steering control. Validation of irrigation and suction ports ensures operational readiness.

Cases

Case 1

A 72-year-old man was diagnosed with an extrahepatic biliary mass and dilated IHDs. ERCP revealed proximal common bile duct (CBD) filiform stenosis, where a 0.035-mm guidewire–assisted biliary cannulation was performed (Fig. 1). After 2 failed cholangioscopic canalizations (9F and 11F), a 7F cholangioscope (eyeMax) allowed passage through the stricture and allowed for a full-depth biliary tract assessment and the length of the stricture evaluation, accurately identifying the lesion from the proximal CBD to both IHDs (Fig. 2), where a 8.5F $\times$ 12-cm stent and a 8.5F $\times$ 15-cm plastic stent were placed (Figs. 3 and 4).

Figure 1.

Fluoroscopic image of a 72-year-old man with filiform stenosis located at the proximal common bile duct.

Figure 2.

Stenosis of the proximal common bile duct was observed during digital single-operator cholangioscopy using a 7F cholangioscope.

Figure 3.

Fluoroscopic image in which the 7F cholangioscope can be observed in the left intrahepatic duct after passing through the filiform stenosis.

Figure 4.

Fluoroscopic image of the double-pigtail stents placed in both the left and right hepatic ducts.

Case 2

A 52-year-old man with an 18-month history of orthotopic liver transplantation presented with a proximal CBD stricture and IHD dilation diagnosed by the hybrid technique ERCP/EUS (Fig. 5). After left IHD puncture, cholangiogram revealed contrast filling only the dilated left IHD and the cystic duct remnant (Fig. 6). Complete 7F cholangioscope–guided bile duct assessment, including evaluation of the length of the stricture, was performed. At the stricture, a congestive, friable mucosa with hypoperfused areas suggestive of ischemia was identified. Biopsy confirmed bile duct necrosis.

Figure 5.

EUS revealing a proximal common bile duct stricture along with intrahepatic duct dilation.

Figure 6.

Cholangiogram revealing contrast filling the dilated left intrahepatic duct (A) and cystic duct remnant (B).

Case 3

A 50-year-old woman presented with stenosis of a hepatojejunal anastomosis. By EUS/fluoroscopic guidance, puncture of the left IHD with passage of a 0.035-mm guidewire through the stomach and stenosis up to the intestinal lumen was performed. With a 6F cystotome (EndoFlex; Medi-Globe, Rohrdorf, Germany), a hepatogastric fistula was created. Balloon dilation of the fistula allowed anastomotic communication and deployment of a 7F $\times$ 10-cm double pigtail for cholangitis prevention. Three months later, a 9F cholangioscope could not be passed through the fistula owing to angulation; a 7F cholangioscope allowed for a full-depth evaluation of the biliary tract and the length of the stricture extension assessment with passage of a 0.025-mm guidewire and a 12-mm dilation. A 7F $\times$ 10-cm double-pigtail stent was placed to maintain a gastro-hepatojejunal anastomosis (Fig. 7).

Figure 7.

Fluoroscopic image revealing a hepatic-jejunal-gastric anastomosis formed using a 7F $\times$ 10-cm double-pigtail stent.

Case 4

A 59-year-old man presented 6 days after a cholecystectomy with abdominal pain, vomiting, and jaundice. MRCP/EUS revealed a dilated IHD, common hepatic duct stenosis, and ascites. Under EUS/fluoroscopic guidance, the left IHD was punctured with a 19-gauge needle. A cholangiogram revealed postsurgical proximal CBD stenosis and contrast leakage (Fig. 8). A hepatogastric fistula was created with a 6F cystotome, and the 7F cholangioscope was inserted through the tract, revealing total proximal CBD stenosis, cautery ischemia, and a biliodigestive anastomosis insufficiency. With the same cholangioscope, a 0.025-mm guidewire was passed from the right to left IHD, and a 7F $\times$ 10-cm double pigtail was placed through the fistula, creating a hepatogastric anastomosis (Fig. 9). At the 2-month follow-up, granulation tissue at the CBD and no contrast leakage at the anastomosis were observed. A 7F $\times$ 10-cm double pigtail was placed.

Figure 8.

Fluoroscopic image showing bile duct stenosis and contrast leakage into the abdominal cavity.

Figure 9.

Fluoroscopic image of a hepatic-gastric anastomosis formed with a 7F $\times$ 10-cm double-pigtail stent.

Discussion

In the presented cases, during the biliary evaluation of indeterminate strictures, challenges arose with the 9.3F, 10.5F, and 11.1F cholangioscopes, especially in regions with pronounced angulation and obstruction. Fortunately, the 7F cholangioscope allowed us to assess these challenging areas, enabling comprehensive assessment of the biliary strictures and facilitation of precise mapping of their extent as well as offering crucial guidance for selecting suitable therapeutic interventions, whether surgical or endoscopic. Additionally, we achieved both technical and clinical success without any reported procedure-related adverse events.

Based on our initial experience, the following indications for the use of a 7F cholangioscope are proposed: (1) full-depth evaluation and therapeutic guidance in nondilated IHDs; (2) pediatric biliary tract evaluation; (3) complete evaluation of the main pancreatic duct with smaller diameters; (4) complete extension evaluation of tumors with stenosis in the biliopancreatic tract; and (5) direct-visualization therapeutic guidance and guidewire passage for stent placement.

Although the 7F cholangioscope proved valuable in navigating small ducts and areas with strictures, its limitations arose from its 0.8-mm working channel, restricting the insertion and guidance of wires greater than 0.025 inches. Consequently, its limitations confine its use primarily to diagnostic purposes.

In conclusion, a 7F cholangioscope can provide additional information regarding the biliary tree and guidance for treatment, overcoming the challenging assessment of small pancreatobiliary ducts and the strictures within them. Its use in cases of severe bile duct stenosis is suggested; further studies evaluating safety and efficacy are needed.

Disclosure

Dr Robles-Medranda is a consultant for Pentax Medical, Steris, Microtech, G-Tech Medical Supply, CREO Medical, EndoSound, and mdconsgroup. All other authors disclosed no financial relationships relevant to this publication.

Supplementary data

Video 1

Seven-French cholangioscopy bile duct evaluation.