Introduction
Peroral cholangioscopy (POC) enables not only endoscopic direct visualization of the
biliary system, but also interventions for diseases of the bile duct [1]. POC can be achieved using a conventional mother baby scope system, or the single
operator cholangioscopy system with the SpyGlass Direct Visualization system or direct
POC using an ultra-slim upper endoscope [1]. Selective guidewire access through complex strictures or stones, and subsequent
stent insertion under direct visualization, may increase the therapeutic utility of
POC. However, mother-baby endoscope system and the SpyGlass direct visualization system
have working channels of only 1.2 mm. Although selective guidewire advancement is
possible, direct biliary stent placement is impossible using endoscopes with such
small working channels. In contrast, direct POC using an ultra-slim upper endoscope
with an up to 2.2-mm working channel expands the therapeutic indications for direct
POC. We evaluated the feasibility of selective biliary drainage under direct POC.
Patients and methods
Patients and study design
This retrospective analysis of a prospectively maintained database study was performed
in a single tertiary referral center from April 2015 to March 2019. The inclusion
criteria were: (1) clinical symptoms of bile duct obstruction with jaundice; (2) diameter
of the distal common bile duct (CBD) of ≥ 8 mm; (3) endoscopic sphincteroplasty and/or
endoscopic papillary balloon dilation; and (4) need for direct POC. The exclusion
criteria were: (1) age < 18 years; (2) contradictions for endoscopic retrograde cholangiopancreatography
(ERCP); (3) bleeding tendency (platelet count of < 50,000/mm3 or prothrombin time [PT] international normalised ratio [INR] of > 1.5); and (4)
refusal to participate. Written informed consent for the endoscopic procedure was
obtained from all of the enrolled patients. The Institutional Review Board of Soonchunhyang
Medical Center approved the study protocol.
Instruments
The ultra-slim upper endoscopes were the GIF-XP260N, GIF-XP260NS, and GIF-XP290N instruments
(Olympus Medical Systems, Co., Ltd., Tokyo, Japan), which have distal tips 5.0 to
5.5 mm in diameter. All of these endoscopes are forward-viewing type, featuring a
2.0- to 2.2-mm-diameter working channel and four-way deflection steering of the tip. A
5-Fr balloon catheter (MTW Endoskopie, Wesel, Germany) was used to assist the cholangioscopy
[2]. For biliary drainage, 5-Fr plastic stents or nasobiliary drainage catheters were
used (Cook Endoscopy, Winston-Salem, North Carolina, United States).
Direct POC procedure
The patients were placed in the prone position under sedation with midazolam and/or
propofol and received prophylactic antibiotics. Endoscopic sphincterotomy and/or endoscopic
papillary balloon dilatation was performed before the introduction of an ultra-slim
endoscope for direct POC, which was performed using a previously described intraductal
balloon-guided method [2]
[3]. Irrigation with sterile 0.9 % NaCl and frequent suction were used to improve visualization
during direct POC. Minimal insufflation of CO2 (Colcosense CO-3000; Mirae Medics,
Co., Seoul, South Korea) was applied as needed, and room air insufflation was not
used.
Biliary drainage procedure
A guidewire with a diameter of 0.025 or 0.035 inches was inserted under direct visualization
through the stricture or stone. Biliary drainage was performed over the guidewire
through the working channel of the ultra-slim upper endoscope using 5-Fr double-pigtail
or straight plastic stent, and/or 5-Fr nasobiliary drainage catheters ([Fig. 1], [Video 1], [Video 2]).
Video 1 Endoscopic view of biliary drainage with a plastic stent for intrahepatic biliary
stricture under direct peroral cholangioscopy using an ultra-slim upper endoscope.
Video 2 Fluoroscopic view of biliary drainage with a plastic stent for intrahepatic biliary
stricture under direct peroral cholangioscopy using an ultra-slim upper endoscope.
Fig. 1 a Cholangiogram of difficult bile duct stones. b Direct peroral cholangioscopy-guided intraductal electrohydraulic lithotripsy. c A 5-Fr plastic stent was inserted under direct peroral cholangioscopy (POC). d and e Fluoroscopic findings showing endoscopic retrograde biliary drainage (ERBD) under
direct POC.
Definition of events and outcomes
Technical success was defined as successful endoscopic retrograde biliary drainage
(ERBD) and/or endoscopic nasobiliary drainage (ENBD) placement in the bile duct under
direct POC without exchange for a duodenoscope. Functional success was defined as
resolution of clinical symptoms, including jaundice, after biliary drainage without
any need for repeated drainage procedures. Adverse events (AEs) after ERCP were recorded
according to the guidelines of the American Society for Gastrointestinal Endoscopy
[4]. The primary outcome was the technical success rate. The secondary outcomes were
the functional success rate and incidence of procedure-related AEs.
Statistical analysis
Demographic and clinical characteristics are presented as means (standard deviation)
for continuous variables and frequencies (percentage) for categorical variables. Statistical
analysis was performed using R (version 3.3.3; R Foundation for Statistical Computing,
Vienna, Austria) or SPSS software (version 23.0; IBM Corp., Armonk, New York, United
States).
Results
Selective biliary drainage under direct POC using an ultra-slim upper endoscope was
attempted in 32 patients (16 males, 16 females; mean age, 71.2 years). The baseline
characteristics of the patients are listed in [Table 1]. The most common indication for direct POC was difficult bile duct stones (17 patients,
53.1 %). Difficult bile duct stones were defined as larger than 15 mm and/or more
than three stones that could not be removed despite an extended sphincterotomy and
recurrent ERCP procedures may be needed [5]
[6]. Biliary drainage was attempted after endoscopic intervention by direct POC guided
intraductal electrohydraulic lithotripsy (EHL) ([Fig. 1]), tumor ablation with photodynamic therapy (PDT) to check the exact extent and perform
the procedure ([Fig. 2]), and indeterminate biliary stricture in case of suspected malignant bile duct stricture,
but failed diagnosis through conventional ERCP-guided tissue sampling ([Fig. 3]).
Table 1
Baseline characteristics of the patients.
|
Characteristic
|
All patients (N = 32)
|
|
Mean age ± SD, years
|
71.2 ± 11.3
|
|
Sex – number (%)
|
|
|
16 (50)
|
|
|
16 (50)
|
|
Indications for direct POC – number (%)
|
|
|
17 (53.1)
|
|
|
12 (37.5)
|
|
|
3 (9.4)
|
SD, standard deviation; POC, peroral cholangioscopy; CBD, common bile duct; BD, bile
duct; PDT, photodynamic therapy.
Fig. 2 a Cholangiogram of a luminal-obstructing mass lesion. b Fluoroscopic view showing the advancement of an ultra-slim endoscope using intraductal
balloon-guided method. c Fluoroscopic view showing the advancement of a photodynamic therapy (PDT) catheter
using an ultra-slim endoscope into the bile duct. d A 5-Fr endoscopic nasobiliary drainage was inserted under direct peroral cholangioscopy
(POC). e Cholangioscopic view showing bile duct cancer. f Direct POC-guided PDT.
Fig. 3 a Cholangiogram of indeterminate biliary stricture. b Fluoroscopic view showing the advancement of an ultra-slim endoscope into the bile
duct and cannulation through the stricture. c Cholangioscopic view of intraductal mass. d A 5-Fr plastic stent was inserted under direct peroral cholangioscopy. e and f Fluoroscopic view showing selective cannulation and insertion of a 5-Fr plastic stent.
The technical success rate for selective biliary drainage under direct POC using an
ultra-slim upper endoscope was 100 %. Results of selective biliary drainage under
direct POC are listed in [Table 2]. Twenty-nine patients (91 %) underwent ERBD with 5-Fr plastic stents. One patient
(3 %) underwent only ENBD. ERBD and ENBD were performed simultaneously in two patients
(6 %). The functional success rate was 100 % (32/32 patients). Only one patient had
minor bleeding during the procedure after fragmentation of a stone by EHL.
Table 2
Summary of biliary drainage under direct POC.
|
Number (%) (N = 32)
|
|
Drainage under direct POC
|
|
|
29 (91)
|
|
|
2 (6)
|
|
|
1 (3)
|
|
Technical success
|
32 (100)
|
|
Functional success
|
32 (100)
|
|
Adverse events[1]
|
1 (3.1)
|
POC, peroral cholangioscopy; ERBD, endoscopic retrograde biliary drainage; ENBD, endoscopic
nasobiliary drainage.
1 Minor bleeding.
Discussion
A variety of clinical conditions accompanied by jaundice necessitate biliary drainage.
In cases of difficult guidewire placement, POC enables direct visualization of the
lesion [7]. There have been several case reports of successful guidewire placement using the
SpyGlass cholangioscope [8]
[9]
[10]. However, although SpyGlass cholangioscopy enables direct visualization of the bile
duct, its therapeutic utility is limited by the small working channel (1.2 mm). Thus,
the SpyGlass cholangioscope must be withdrawn before inserting the stent for drainage
[11].
Single-operator direct POC using an ultra-slim upper endoscope has been proposed.
Direct POC allows high-quality narrow-band imaging (NBI) and has a larger working
channel (up to 2.2 mm in diameter) for interventional procedures [1]
[2]. Thus, the limitations of cholangioscopy can be overcome by direct POC using a conventional
ultra-slim upper endoscope. The 2.0-mm working channel of an ultra-slim endoscope
enables direct placement of a 5 Fr diameter plastic stent or drainage tube, intraductal
lithotripsy, intraductal ablation therapy for bile duct tumors, and cholangioscopy-guided
direct biliary drainage [1]. Direct POC also facilitates identification of the stricture site and direct drainage
without changing the endoscope [7].
Our findings demonstrate the feasibility of selective biliary drainage under direct
POC using an ultra-slim upper endoscope. The technical and functional success rates
of biliary drainage were 100 % in patients with a variety of clinical conditions,
and minor bleeding after fragmentation of an intraductal stone by EHL was the only
procedure-related AE. This indicates the safety of selective biliary drainage under
direct POC using an ultra-slim upper endoscope, which also requires only minimal insufflation
with CO2 and administration of prophylactic antibiotics.
However, direct POC also has several limitations. First, direct POC can be performed
only in patients with a dilated CBD (> 8 mm). Major sphincterotomy and/or papillary
balloon dilation are needed for smooth insertion of the ultra-slim endoscope into
the biliary tree. Second, only 5 Fr plastic stents can be used due to the 2.0-mm working
channel of the ultra-slim endoscope; therefore, > 7-Fr conventional plastic stents
cannot be used. In this study, direct POC was performed for the purpose of directly
visualizing the extent of the lesion, biopsy, or PDT, especially in a malignant biliary
stricture. Selective biliary drainage in this study was for biliary drainage to prevent
development of cholangitis. Third, although intraductal balloon-guided direct POC
may be helpful, maintaining the position of the endoscope during the procedure is
problematic. Fourth, cholangitis, pancreatitis can be additional procedure-related
complications of direct POC. The most important procedure-related complication of
direct POC is possible of air embolism [12].
This study had several limitations. First, the retrospective cohort may have introduced
selection bias. Second, the number of patients was relatively small and there was
no control group, limiting the statistical power. Third, the two endoscopists who
performed direct POC were experienced in both that procedure and endoscopic retrograde
cholangiography. Thus, prospective studies involving operators with a standardized
level of skill in direct POC are required to validate our findings.
Conclusions
In conclusion, selective biliary drainage under direct POC using an ultra-slim upper
endoscope is feasible and safe for patients with a variety of clinical conditions.
Although we have shown that drainage is feasible, it can only be used as a temporary
measure to prevent the risk of cholangitis after direct POC. This is because only
5-Fr double-pigtail or straight plastic stent, and/or 5-Fr nasobiliary drainage catheters
can be inserted through the POC system. Continuing development of the endoscopes and
accessories is expected to facilitate the therapeutic application of direct POC.
Funding
This work was partly supported by SoonChunHyang University Research Fund.
