The most important among the steps of endoscopic ultrasound-guided biliary drainage
(EUS-BD) is the success of tract dilation. Electrocautery dilation can certainly dilate
the biliary or luminal wall. However, bleeding may occur around the dilation site
due to burning effects. Here, we describe some technical tips for tract dilation in
EUS-BD using a novel electrocautery device. We attempted EUS-BD using the novel electrocautery
dilator in 12 patients, among whom nine and three underwent EUS-guided hepaticogastrostomy
and EUS-guided gallbladder drainage, respectively. Severe adverse events were not
seen in any patients although abdominal pain, which might occur due to stent expansion,
was seen in one patient. The novel electrocautery dilator could be inserted into the
biliary tract and gallbladder after guidewire placement, and the stent delivery system
could also be inserted without additional dilation. Therefore, technical success was
achieved in all patients. The procedural durations were less than 20 minutes for each
technique. In conclusion, the novel electrocautery dilator might be useful as a tract
dilation device, although additional cases and prospective evaluation studies are
essential to confirm our results.
Introduction
Endoscopic ultrasound-guided biliary drainage (EUS-BD) has emerged as an alternative
drainage technique for endoscopic retrograde cholangiopancreatography (ERCP) [1]. EUS-BD can be divided into two main categories. The first category is the transduodenal
route, for example, EUS-guided choledochoduodenostomy (CDS). The second is transgastric,
for example, EUS-guided hepaticogastrostomy (HGS). In addition, EUS-guided gallbladder
drainage (GBD) can be performed from both routes. Among these procedures, technical
tips can be divided into four steps. The first category is puncturing the biliary
tract. The second is guidewire insertion, followed by tract dilation. The final step
is stent deployment. Successful tract dilation is the most important among these steps.
To date, various techniques have been reported for tract dilation including graded,
balloon, or electrocautery dilation [2]
[3]
[4]. To prevent bile leakage during EUS-BD, a simple dilation technique may be used.
The electrocautery dilation technique can certainly dilate the biliary or luminal
wall; however, bleeding may occur around the dilation site due to its burning effects.
To overcome this, we have developed a novel fine gauge electrocautery dilator device
[5]. An experimental study was performed before clinical use of this novel electrocautery
dilator.
In this technical view, we describe the results of our experimental study and some
technical tips for tract dilation in EUS-BD using this novel electrocautery dilator.
Patients and method
Novel fine gauge electrocautery dilator and experimental study
[Fig. 1] shows the novel electrocautery dilator (Fine 025, Medico’s Hirata Inc., Osaka, Japan)
([Fig. 1a]). In the experimental study of the burning effect, we compared a conventional electrocautery
dilator (6 Fr, Cysto-Gastro-Set; Endo-Flex GmbH, Voerde, Germany) with the novel electrocautery
dilator ([Table 1]), using resected fresh liver from adult pigs. Energy was delivered by an electronic
generator. The Erbe VIO300 D electrosurgical system (Erbe Elektromedizin GmbH, Tubingen,
Germany) was used for electrocautery with Auto-Cut mode; effect 1 to 4 (550 V) was
set, and electrocautery dilation was performed in around 2 seconds. The diameter of
the tract and the tract including the burning effect were measured, and the differences
in burning effect between the two devices were compared.
Fig. 1 a The novel fine gauge electrocautery dilator (Fine 025, Medico’s Hirata Inc., Japan,
Osaka). The distal end of the outer dilator contains a metal tip, and the top of this
metal tip is only 3 Fr. This electrocautery dilator is wire-guided, coaxial with the
0.025-inch guidewire. b Image of the tract and burning effect. Compared with a conventional electrocautery
dilator, the burning effect of the novel electrocautery dilator is smaller at each
effect setting.
Table 1
Results of the experimental study.
|
Effect
|
Tract, mm
|
Tract including burning effect, mm
|
|
Conventional ED
|
1
|
1.57
|
2.54
|
|
Novel ED
|
0.80
|
1.60
|
|
Conventional ED
|
2
|
1.68
|
2.66
|
|
Novel ED
|
1.14
|
1.76
|
|
Conventional ED
|
3
|
1.78
|
2.71
|
|
Novel ED
|
1.26
|
1.98
|
|
Conventional ED
|
4
|
1.81
|
2.98
|
|
Novel ED
|
1.37
|
1.95
|
ED, electrocautery dilator.
Patients
This retrospective study was carried out in Osaka Medical College between June 2018
and November 2018. The inclusion criteria comprised obstructive jaundice or acute
cholecystitis, having failed an ERCP, or inaccessible ampulla of Vater due to malignant
duodenal obstruction or surgically altered anatomy such as Rouen-Y anastomosis. The
exclusion criteria comprised being contraindicated for endoscopic biliary drainage
including ERCP and EUS guidance due to conditions such as massive ascites, or performance
status determined as Eastern Cooperative Oncology Group (ECOG) scores of 3 or 4, other
organ failure, or withholding consent.
Technical tips for EUS-BD using the novel electrocautery dilator
All procedures were implemented by endoscopists who were trained and experienced in
diagnostic and therapeutic procedures under ERCP guidance at the participating institutions.
Patients received antibiotics before undergoing all procedures under sedation.
[Fig. 2] shows the EUS-HGS procedure. A convex EUS (GF-UCT240 or 260; Olympus Optical, Tokyo,
Japan) connected to an ultrasound device (SSD5500; Aloka, Tokyo, Japan) was initially
advanced into the intestine to visualize the intrahepatic bile duct, which was then
punctured using a 19G needle (Sono Tip Pro Control, Medi-Globe GmbH, Germany) via
color Doppler ultrasonography to avoid intervening vessels. After aspirating the bile
juice, the contrast medium was injected ([Fig. 2a]). Then, a 0.025-inch guidewire (Olympus Medical Systems, Tokyo, Japan) was inserted
into the biliary tract ([Fig. 2b]). Next, the tract was dilated using the novel electrocautery dilator (effect 4)
([Fig. 2c]). Finally, an 8.5-Fr stent delivery system (Niti-S Biliary Covered Metal Stent;
TaeWoong Medical, Seoul, Korea) was inserted into the intrahepatic bile duct, and
stent deployment was performed ([Fig. 2d]). To prevent stent migration into the abdominal cavity in EUS-HGS, a 10 cm length
of the metal stent was used in all patients.
Fig. 2 a The contrast medium is injected after the intrahepatic bile duct is punctured using
a 19G needle. b The 0.025-inch guidewire is inserted into the biliary tract. c The bile duct wall is dilated using the novel electrocautery dilator. d Covered self-expandable metal stent deployment is performed from the intrahepatic
bile duct to the stomach.
[Video 1] shows the EUS-GBD procedure. The neck of the gallbladder was punctured using a 19G
FNA needle. After the bile juice had been aspirated, the 0.025-inch guidewire was
inserted into the gallbladder. Next, the novel electrocautery dilator was inserted,
and the duodenum and gallbladder wall were dilated. After this procedure, an 8-Fr
stent delivery system (BONA Biliary Covered Metal Stent; Standard Sci Inc., Seoul,
South Korea) was inserted into the gallbladder, and stent deployment was performed
from the gallbladder to the duodenum. In EUS-GBD, a 6 cm length of the metal stent
was used in all patients.
Finally, if these stent delivery systems could not be inserted during both procedures,
another dilation technique such as balloon dilation was used.
Video 1 Endoscopic ultrasound-guided gallbladder drainage. The gallbladder is punctured using
a 19G needle, and the contrast medium is injected. The 0.025-inch guidewire is inserted
into the gallbladder. Then, the duodenal and gallbladder walls are dilated using the
novel electrocautery dilator. Finally, stent deployment is successfully performed
from the gallbladder to the duodenum.
Definition
The primary end point of this study was focused on adverse events, and technical success
was evaluated secondarily. Technical success was defined as successful metal stent
deployment after tract dilation using only the novel electrocautery dilator. In addition,
clinical success of EUS-HGS was defined as a decrease in serum bilirubin to < 75 %
of pre-biliary drainage within 30 days. Clinical success of EUS-GBD was defined as
complete resolution of clinical symptoms, such as abdominal pain and fever, or decreased
inflammation on blood tests.
Adverse events including bleeding, perforation, and stent migration during the procedure
were evaluated. Bleeding was defined as that necessitating transfusion or requiring
hospitalization, upper endoscopy, or a procedure by interventional radiology. Adverse
events were graded according to the severity grading system of the American Society
for Gastrointestinal Endoscopy [6]. Adverse events occurring with 1 month after the procedure and possibly related
to it were described in accordance with this guideline. Procedure time was measured
from puncturing of the target lesion to stent deployment.
Results
Experimental study
Differences between the conventional and novel electrocautery dilator were examined.
As shown in [Fig. 1b], the burning effect of the novel electrocautery dilator was visibly smaller compared
with the conventional electrocautery dilator. Indeed, among effects 1 to 4, the diameter
of the tract including the burning effect was smaller with the novel electrocautery
dilator ([Table 1]).
Clinical study
EUS-BD was attempted in 12 patients using the novel electrocautery dilator ([Table 2]). Among the 12 patients, EUS-HGS was performed because of surgical anatomy (n = 10),
or duodenal obstruction (n = 2), and three patients underwent EUS-GBD as their condition
was either too poor to undergo surgical treatment (n = 2), or they had advanced cancer
(n = 1). An antithrombotic agent (warfarin potassium) was administered for one patient
who underwent EUS-HGS.
Table 2
Patient characteristics.
|
No.
|
Age/Sex
|
Disease
|
Procedure
|
Technical success
|
Adverse events
|
Procedure time, min
|
|
1
|
78/M
|
AC
|
GBD
|
Yes
|
None
|
12
|
|
2
|
81/F
|
PC
|
HGS
|
Yes
|
None
|
18
|
|
3
|
70/M
|
PC
|
HGS
|
Yes
|
None
|
16
|
|
4
|
70/F
|
PC
|
HGS
|
Yes
|
None
|
12
|
|
5
|
69/F
|
PC
|
HGS
|
Yes
|
Abdominal pain
|
11
|
|
6
|
73/M
|
AC
|
GBD
|
Yes
|
None
|
10
|
|
7
|
81/M
|
BC
|
HGS
|
Yes
|
None
|
13
|
|
8
|
78/M
|
AC
|
GBD
|
Yes
|
None
|
16
|
|
9
|
88/M
|
GC
|
HGS
|
Yes
|
None
|
22
|
|
10
|
81/M
|
GC
|
HGS
|
Yes
|
None
|
19
|
|
11
|
72/F
|
GC
|
HGS
|
Yes
|
None
|
20
|
|
12
|
77/M
|
PC
|
HGS
|
Yes
|
None
|
17
|
M, male; F, female; PC, pancreatic cancer; BC, bile duct cancer; AC, acute cholecystitis;
GC, gastric cancer; HGS, hepaticogastrostomy; GBD, gallbladder drainage.
For the EUS-HGS procedure, the diameter of the intrahepatic bile duct was around 4 mm,
and the puncture site was B3 in all patients. Severe adverse events including bile
peritonitis were not seen in any patient although abdominal pain, which might occur
due to the stent expanding, was seen in one patient. The novel electrocautery dilator
could be inserted into the biliary tract and gallbladder after guidewire placement,
and the stent delivery system could also be inserted without any dilation device apart
from the diathermic dilator. Therefore, technical and clinical success was achieved
in all patients. The procedure time was less than 22 minutes (range 11 to 22).
Among the three patients who underwent EUS-GBD, the etiology of acute cholecystitis
was gallbladder stones (n = 2), and cystic duct obstruction due to pancreatic cancer
(n = 1). All EUS-GBD procedures were performed from the duodenum. After tract dilation
using the novel electrocautery dilator, stent deployment was successfully performed
in all patients without an additional dilation technique. Clinical success was achieved
in all patients without any adverse events. The procedure time was within 16 minutes
(range 10 to 16).
Discussion
According to a recent review of EUS-BD which included 686 patients undergoing either
HGS or CDS, the overall technical and clinical success rates were, respectively 96 %
(95 %CI: 93 – 98) and 84 % (95 %CI: 80 – 88) for HGS, and, respectively 95 % (95 %CI:
91 – 97) and 87 % (95 %CI: 82 – 91) for CDS. However, the rate of adverse events such
as bleeding, hemobilia, peritonitis, and pneumoperitoneum was relatively high in 29 %
of patients undergoing HGS, and 20 % of patients undergoing CDS [7]. In a review of EUS-GBD [8], overall technical success was achieved in 83.7 % (185/221), and clinical success
in 92.3 % (204/221) of patients. Procedure-related adverse events were seen in 16
patients (7.2 %). Pneumoperitoneum was the most commonly seen adverse event (53 %,
n = 9). If EUS-GBD was performed using a lumen apposing metal stent, overall technical
success was achieved in 90.2 % (259/287), and clinical success in 93.0% (267/287)
of patients. Procedure-related adverse events were seen in 23 patients (8.0 %).
Almost all of these adverse events can be managed conservatively. However, EUS-BD
is sometimes attempted in patients with poor condition, therefore, these adverse events
may decrease the quality of life and may sometimes be fatal. In addition, in terms
of being able to undergo chemotherapy or recommencing solid food intake without a
delay, avoiding these adverse events can have a clinical impact.
Bile peritonitis may occur during the EUS-BD procedure, especially during device exchanging.
Therefore, a simplified technique may be preferred during EUS-BD procedures. Among
the steps in EUS-BD procedures, tract dilation should be simplified. Paik et al. reported
a simplified tract dilation technique for EUS-HGS [2]. They used a balloon catheter with a 4-Fr tip to dilate the tract. The technical
success rate was 96 % (27/28), and median procedure time was short (15.3 minutes);
however, one patient needed fistula dilation using a needle-knife. In addition, to
manipulate the guidewire in place in the desired intrahepatic bile duct, a 4-Fr cannula
was initially used in seven patients. We performed a prospective clinical study of
EUS-BD using a novel fine gauge balloon catheter [3]. In that study, technical success was defined as successful stent deployment after
tract dilation using only the balloon catheter (diameter of this balloon was 3 Fr).
As result, technical success was achieved in all patients including those undergoing
EUS-CDS and HGS. In addition, adverse events were seen in self-limited abdominal pain
(n = 2), and bile peritonitis (n = 1). Therefore, this device may have clinical benefit
as a simplified dilation technique; however, as shown [Fig. 3], the balloon catheter dilated not only the bile duct and luminal wall but also the
hepatic parenchyma, therefore, bile leakage can easily occur through this tract.
Fig. 3 a The intrahepatic bile duct is dilated using a balloon catheter. b The hole is made by balloon dilation. c The stomach wall is dilated using the balloon catheter. d Bile leakage is seen because the hepatic parenchyma is dilated by the balloon catheter.
On the other hand, the electrocautery dilation technique can certainly dilate only
the bile duct and transluminal wall, and compared with balloon dilation, the frequency
of bile leakage may be reduced; however, the electrocautery dilation technique also
has disadvantages such as the risk of bleeding due to the burning effect. Park et
al. [4] reported that, among 57 consecutive patients, post-procedural adverse events occurred
in 11 (bile peritonitis, n = 2; mild bleeding, n = 2; and self-limited pneumoperitoneum,
n = 7). In multivariate analysis, using a needle-knife was the only risk factor for
post-procedural adverse events in EUS-BD. They concluded that a needle-knife should
not be used as a dilation device if possible. Honjo et al. evaluated the ultra-tapered
mechanical dilator for EUS-HGS and EUS-guided pancreatic duct drainage compared with
the electrocautery dilator [9]. Among 64 patients, 49 underwent EUS-HGS and of these, 23 underwent EUS-HGS with
the conventional electrocautery dilator, and 26 patients with a mechanical dilator.
Although overall adverse events were also significantly different between the groups,
bleeding was frequently observed in the electrocautery dilator group (P = 0.04). In that retrospective study, the authors mentioned that the electrocautery
dilation technique can cause possible burning effects to the hepatic parenchyma and
vessels around the needle tract or the gastrointestinal lumen, causing unexpected
bleeding or inflammation. On the other hand, in our study, bleeding was not seen in
any patient. During the EUS-BD procedure, a pushing force is also important to insert
the various devices into the biliary tract. However, if the devices are difficult
to advance due to inflammations or wall thickness, electrocautery dilation may be
useful because the bile duct wall is certainly dilated, and the procedure time is
reduced. In our study, to reduce the cautery effect, the function of the electrocautery
dilator was only used when the bile duct and intestinal wall were dilated. In addition,
a fine gauge electrocautery dilator was used in EUS-BD procedures. Therefore, EUS-BD
using our device and technique may be technically feasible and safe, although there
are critical limitations such as the small number of patients in our study, its retrospective
nature, and the fact that it was a single-arm trial.
In our experience, the best indication of tract dilation using the novel electrocautery
dilator may be the intrahepatic bile duct access such as EUS-HGS or EUS-guided jejunostomy.
Regarding EUS-GBD, recently, the electrocautery-enhanced delivery system (hot AXIOS
stent, Boston Scientific, Marlborough, Massachusetts, United States) has become available
[10]. This stent is a through-the-scope LAMS mounted on a stent delivery system with
an electrocautery wire at the distal tip. The electrocautery tip allows passage of
the catheter into the gallbladder without the need for prior dilation of the tract
by application of a pure cutting current. This fact may have clinical benefits, such
as shortening of the procedure time, reduced bile leakage during fistula dilation,
and improved technical success rate due to its being a single-step procedure. Although
technical tips for EUS-GBD using this stent are simple, and may be easily compared
with a conventional stent, this stent is not available in all countries. Therefore,
our device may be useful for EUS-GBD using the conventional technique.
In conclusion, the novel electrocautery dilator may be useful as a tract dilation
device, but additional cases and a prospective evaluation study are essential to confirm
our results.
