Introduction
Endoscopic sphincterotomy (EST) is a well-established treatment for common bile duct
(CBD) stones and the procedure of choice for CBD stone removal [1]. However, the removal of large bile duct stones by conventional EST is difficult
and large incisions are frequently required. Although large incisions are effective
in terms of retrieving large biliary stones, they increase the risk of adverse events
such as hemorrhage and perforation [2]. Ersoz et al. first reported the usefulness of large balloon dilation (12 – 20 mm
in diameter) after EST for the removal of large bile duct stones and achieved stone
clearance rates of up to 95 % without the use of mechanical lithotripsy [1]. Many studies have since been conducted to verify the utility of endoscopic papillary
large balloon dilation (EPLBD), and have demonstrated the safety and feasibility of
this technique [3]
[4]
[5]. Other studies have shown that hemorrhage and perforation might be reduced by EPLBD
because dilation of the papilla is relatively slow [6], and that this technique may reduce the need for mechanical lithotripsy during the
retrieval of large bile duct stones by providing a large biliary opening [7].
EST is generally recommended before EPLBD because prior EST is believed to prevent
post-procedural pancreatitis by shifting the radial force generated by balloon dilation
along the EST cutting direction toward the bile duct rather than the pancreatic duct,
thus minimizing peripapillary edema after papilla dilation [5]
[8]. However, this hypothesis has not been sufficiently explored to determine the clinical
usefulness and benefits of EST before balloon dilation. Furthermore, some authors
have reported that EPLBD alone is effective for large bile duct stone removal and
has acceptable adverse event rates [9]
[10]. However, the majority of previous investigations that compared EPLBD alone vs.
EPLBD with EST were performed using small sample sizes [11]
[12], and thus, data available on the clinical aspects and the benefits of EST before
EPLBD are limited. Accordingly, the current randomized study was undertaken to evaluate
the efficacy and safety of EPLBD with EST vs. EPLBD alone for the removal of common
bile duct stones.
Methods
This prospective, randomized, comparative study was conducted at four tertiary referral
centers in South Korea by expert pancreaticobiliary endoscopists between November
2010 and October 2013. The study protocol was approved by the institutional review
board of Inha University Hospital (IUH-IRB 09-15), and all patients provided written
informed consent before participating in the study. All authors had access to study
data, and reviewed and approved the final manuscript. The study has been registered
as a clinical trial (Cris.nih.go.kr number, KCT0001564).
Patients
Consecutive patients with a large (≥ 10 mm) CBD stone were enrolled. CBD stones were
identified in all patients by imaging (abdominal ultrasonography, endoscopic ultrasonography,
computed tomography, or magnetic resonance cholangiopancreatography). The study inclusion
criteria were age ≥ 18 years, maximum stone size ≥ 10 mm, and distal CBD diameter
≥ 12 mm. The exclusion criteria were: previous history of EST or endoscopic papillary
balloon dilation; uncontrolled coagulopathy; acute pancreatitis; history of gastrointestinal
surgery; concomitant pancreatic or biliary malignancy; benign biliary stricture; pregnancy
or suspected pregnancy; the administration of specific medicines (protease inhibitor,
protamine sulfate, somatostatin, morphine-like analgesics) from 2 days before to 2
days after the procedure; failure of selective biliary cannulation; and refusal to
agree to the study protocol. Previously identified patient-related risk factors for
post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP), that
is, young age (< 60 years), female sex, and previous history of PEP, were also examined.
Endoscopic procedures
ERCP was performed using a side-viewing duodenoscope (TJF-240, TJF-260V; Olympus Co.,
Tokyo, Japan). Before ERCP, patients were sedated with 5 mg midazolam and 25 mg meperidine
hydrochloride (intravenously). Prophylactic antibiotics were routinely administered
before ERCP, but protease inhibitors, which might affect the occurrence of PEP, were
not administered either before or after ERCP. Selective CBD cannulation was achieved
using a 0.035-inch guidewire, and a diagnostic cholangiogram was obtained in all cases.
Randomization was performed after cholangiography confirmed the presence of a large
stone in a dilated CBD (diameter ≥ 12 mm). Patients were assigned randomly to an EPLBD
alone group or an EPLBD with EST group using opaque sealed envelopes prepared by a
third party. After achieving selective cannulation of the bile duct, a clinician opened
the patient’s envelope and performed the procedure indicated.
After sphincter dilation, stones were retrieved using a Dormia basket and/or an extraction
balloon catheter ([Fig. 1]). When stone extraction was impossible using a conventional method, a mechanical
lithotriptor (Lithotriptoren; MTW Endoskopie, Wesel, Germany) was used.
Fig. 1 Endoscopic stone removal by endoscopic papillary large balloon dilation without sphincterotomy.
a Fluoroscopic image. b – d Endoscopic images. b A guidewire positioned across the papilla. c A large balloon inflated across the papilla. d A large brown-pigmented stone extracted using a retrieval balloon catheter through
the dilated papilla.
An occlusion cholangiogram was obtained at the end of the procedure to confirm complete
CBD clearance. When a stone had not been completely removed, a nasobiliary drainage
catheter or plastic stents were inserted to ensure biliary drainage, and repeat ERCP
was performed every 2 or 3 days until complete stone removal had been achieved.
Endoscopic sphincterotomy
Limited sphincterotomy was performed before EPLBD using a 25-mm pull-type papillotome
(CleverCut 3V; KD-V411 M, Olympus) and extended to a third of the total ampulla length.
An electrosurgical unit (UES-30; Olympus) with a blended current was used at a power
setting of 40 W.
Endoscopic papillary large balloon dilation
EPLBD was performed using a 5-Fr hydrostatic balloon catheter (Microvasive; Boston
Scientific Corp., Marlborough, Massachusetts, USA), with a maximum balloon diameter
and length of 10 – 20 mm and 5.5 cm, respectively, over a 0.035-inch guidewire. After
centering the balloon at the sphincter, the balloon was inflated slowly and incrementally
up to ≥ 10 mm under low hydrostatic pressure using an inflation device (Indeflator;
Abbott, Santa Clara, California, USA) and diluted contrast under fluoroscopic examination.
EPLBD was terminated if “the waist sign” persisted in the inflated balloon when balloon
inflation pressure reached 75 % of the target pressure. After achieving the target
diameter, the balloon inflation pressure was maintained for 60 seconds and then the
balloon was deflated and removed. Balloon diameters were determined based on considerations
of stone size, but did not exceed distal CBD diameter in order to avoid bile duct
perforation.
Outcome measurements
The primary outcome measure was overall adverse event rate, such as bleeding, perforation,
asymptomatic hyperamylasemia, and pancreatitis. Secondary outcome measures were technical
success rate, initial success rate, overall success rate, procedure time, number of
ERCPs required for complete stone removal, and the need for mechanical lithotripsy.
Technical success was defined as the successful performance of EPLBD alone or EPLBD
with EST. Complete stone clearance was defined as the absence of any filling defect,
as determined by occlusion cholangiography conducted by an endoscopist after procedures.
Initial success rate was defined as the rate of complete CBD clearance at the first
ERCP session. Overall success rate was defined as the rate of complete CBD clearance
irrespective of the number of ERCP sessions. Procedure time was defined as time from
procedure start to endoscope removal.
Bleeding was defined as clinical evidence of bleeding, such as melena or hematemesis,
with an associated hemoglobin concentration fall of 2 g/dL. PEP was defined as upper
abdominal pain persisting for at least 24 hours and a serum amylase level the morning
after surgery exceeding three times the upper limit of normal, as determined by 1991
consensus guidelines.
Sample size calculation
The study was conducted to evaluate the hypothesis that the safety of EPLBD alone
is not inferior to that of EPLBD with EST. The study sample size was calculated as
follows: level of significance α = 0.05; power 1 – ß = 0.9; noninferiority margin,
δ = 11 % (based on an overall adverse event rate of 15 % in a previous representative
study on EPLBD with EST [1]); success rate P = 90 %; and a dropout rate of 5 %. Using these data, the required sample size was
calculated to be 97 patients per group.
Statistical analysis
Continuous variables are presented as medians and ranges. Categorical variables were
compared using the chi-squared test and Fisher’s exact test. Quantitative variables
were compared using the Mann-Whitney test, and P values of < 0.05 were considered to indicate significance. The analysis was conducted
using SPSS version 19.0 (IBM Corp., Armonk, New York, USA).
Results
Patient demographic details
During the study period, 209 patients were initially recruited. Five patients with
a previous history of EST and one patient with suspected pancreatic cancer were recruited
by mistake, and in three patients attempts to achieve selective biliary cannulation
failed. Thus, nine patients were excluded ( [Fig. 2]), and 200 patients with a CBD stone of ≥ 10 mm in maximum diameter were enrolled,
and randomly and equally allocated to the EPLBD alone group or the EPLBD with EST
group.
Fig. 2 Flow diagram of the study design, showing the number of patients at each step. CBD,
common bile duct; EPLBD, endoscopic papillary large balloon dilation; EST, endoscopic
sphincterotomy.
Baseline clinical characteristics are summarized in [Table 1]. Background demographic details were similar in the two groups. The median (range)
stone size was 15.2 mm (14.1 – 16.2 mm) in the EPLBD alone group and 14.6 mm (13.8 – 15.5 mm)
in the EPLBD with EST group (P = 0.38). The median number of stones was 2 (1 – 19) and 2 (1 – 28; P = 0.88), and the median CBD diameter was 17.8 mm (11.0 – 29.7 mm) and 18 mm (10.0 – 45.0 mm),
respectively (P = 0.38).
Table 1
Baseline clinical characteristics of the patients.
|
Variable
|
EPLBD alone
(n = 100)
|
EPLBD with EST
(n = 100)
|
P value
|
|
Age, median (range), years
|
74 (56 – 91)
|
73 (49 – 91)
|
0.42
|
|
Age < 60 years, n (%)
|
1 (1)
|
6 (6)
|
0.05
|
|
Sex, male/female, n
|
55/45
|
48/52
|
0.32
|
|
Previous history of PEP, n
|
0
|
0
|
|
|
Maximum transverse diameter of the largest CBD stone, median (range), mm
|
15.2 (14.1 – 16.2)
|
14.6 (13.8 – 15.5)
|
0.38
|
|
No. of CBD stones, median (range)
|
2 (1 – 19)
|
2 (1 – 28)
|
0.88
|
|
Maximum CBD diameter, median (range), mm
|
17.8 (11 – 29.7)
|
18 (10 – 45)
|
0.38
|
|
Hematologic results, median (range)
|
|
|
9535 (3330 – 145 540)
|
9465 (2310 – 49 120)
|
0.48
|
|
|
2.25 (0.2 – 12.3)
|
2.4 (2 – 20.4)
|
0.70
|
|
|
115 (15 – 1770)
|
72 (10 – 1807)
|
0.46
|
|
|
119.5 (7 – 940)
|
99.5 (8 – 1194)
|
0.80
|
|
|
422.5 (11 – 3226)
|
345.5 (5 – 2523)
|
0.11
|
EPLBD, endoscopic papillary large balloon dilation; EST, endoscopic sphincterotomy;
PEP, post-endoscopic retrograde cholangiopancreatography pancreatitis; CBD, common
bile duct.
Adverse events
Adverse events related to endoscopic procedures are summarized in [Table 2]. Overall adverse event rates were similar in the EPLBD alone and EPLBD with EST
groups (6 % and 4 %, respectively; P = 0.75). Three patients in the EPLBD alone group and one patient in the EPLBD with
EST group experienced post-procedural abdominal pain (P = 0.62). Pancreatitis occurred in one patient (1 %) in the EPLBD alone group and
in three patients (3 %) in the EPLBD with EST group (P = 0.62). In all cases, pancreatitis was of mild grade and all patients recovered
uneventfully with conservative treatment. No patient developed bleeding or perforation.
In the EPLBD alone group, two patients experienced asymptomatic hyperamylasemia compared
with none in the EPLBD with EST group.
Table 2
Adverse events of endoscopic papillary large balloon dilation with or without endoscopic
sphincterotomy.
|
Variable
|
EPLBD alone
(n = 100)
|
EPLBD with EST
(n = 100)
|
P value
|
|
Abdominal pain, n (%)
|
3 (3)
|
1 (1)
|
0.62
|
|
Pancreatitis, n (%)
|
1 (1)
|
3 (3)
|
0.62
|
|
Asymptomatic hyperamylasemia, n (%)
|
2 (0)
|
0 (0)
|
0.50
|
|
Perforation, n (%)
|
0 (0)
|
0 (0)
|
|
|
Bleeding, n (%)
|
0 (0)
|
0 (0)
|
|
|
Mortality, n (%)
|
0 (0)
|
0 (0)
|
|
EPLBD, endoscopic papillary large balloon dilation; EST, endoscopic sphincterotomy.
Clinical outcomes and endoscopic procedure
The technical success rate was 100 % in both groups. The median (range) balloon diameter
used was 13.5 mm (11 – 19 mm) for EPLBD alone and 13.5 mm (10 – 20 mm) for EPLBD with
EST (P = 0.24). CBD stones were extracted mainly using an extraction balloon catheter in
both groups (EPLBD alone 76.1 % and EPLBD with EST 72.7 %). A stone retrieval basket
was required for 22 patients in the EPLBD alone group and for 24 patients in the EPLBD
with EST group (P = 0.19). Complete stone removal rates were similar in the two groups ([Table 3]). Stones were cleared during the first ERCP session in 77 patients in the EPLBD
alone group and in 78 patients in the EBLBD with EST group (P = 0.28). Overall success rates in the EPLBD alone and EPLBD with EST groups were
92 % and 88 %, respectively (P = 0.35). Failure to achieve complete CBD clearance occurred in 20 patients (8 in
the EPLBD alone group and 12 in the EPLBD with EST group); causes of failure were
stone impaction and incomplete stone capture using the basket despite mechanical lithotripsy.
Stone removal in these 20 patients was achieved by percutaneous transhepatic cholangioscopy.
Median total procedure time tended to be greater in the EPLBD alone group (20.5 minutes)
than in the EPLBD with EST group (18 minutes; P = 0.08).
Table 3
Comparison of clinical outcomes and endoscopic procedure between endoscopic papillary
large balloon dilation with and without endoscopic sphincterotomy.
|
Variable
|
EPLBD alone
(n = 100)
|
EPLBD with EST
(n = 100)
|
P value
|
|
Technical success rate, n (%)
|
100 (100)
|
100 (100)
|
> 0.99
|
|
Initial success for complete stone removal, n (%)
|
77 (77)
|
78 (78)
|
0.28
|
|
Overall success for complete stone removal, n (%)
|
92 (92)
|
88 (88)
|
0.35
|
|
Balloon diameter, median (range), mm
|
13.5 (11 – 19)
|
13.5 (10 – 20)
|
0.24
|
|
Methods of stone extraction, n (%)
|
n = 92
|
n = 88
|
0.19
|
|
|
70 (76.1)
|
64 (72.7)
|
|
|
|
4 (4.3)
|
7 (8.0)
|
|
|
|
18 (19.6)
|
17 (19.3)
|
|
|
Mechanical lithotripsy, n/N (%)
|
6/92 (6.5)
|
8/88 (9.1)
|
0.39
|
|
Number of endoscopic sessions, n (%)
|
n = 92
|
n = 88
|
0.25
|
|
|
77 (83.7)
|
78 (88.6)
|
|
|
|
14 (15.2)
|
7 (8.0)
|
|
|
|
1 (1.1)
|
3 (3.4)
|
|
|
Total procedure time, median (range), minutes
|
20.5 (2.35 – 57.4)
|
18.0 (2.0 – 58.3)
|
0.08
|
EPLBD, Endoscopic papillary large balloon dilation; EST, Endoscopic sphincterotomy.
Discussion
The results of this study indicate that EPLBD alone is equivalent to EPLBD with EST
in terms of safety and efficacy for the treatment of patients with large CBD stones
(≥ 10 mm). EPLBD alone and EPLBD with EST both resulted in similarly high stone clearance
rates, and overall adverse event rates in both groups were low and comparable. Stone-to-balloon
ratio was found to independently predict the requirement for mechanical lithotripsy,
the use of which was significantly associated with the development of pancreatitis.
Procedural simplification and the maintenance of treatment efficacy are the developmental
principles of new endoscopic treatment strategies. In this respect, EPLBD alone is
a more attractive option than EPLBD with EST, because it is easier to perform, especially
in patients with an anatomy unsuitable for EST, such as those who have undergone Roux-en-Y
or Billroth II gastrectomy [12]. Furthermore, EPLBD alone is more suitable for patients with concomitant large stones
and a bleeding tendency.
In the current study, EPLBD alone produced satisfactory results with respect to stone
removal efficacy. The overall success rate of complete stone retrieval was 92 %, which
compares favorably with previously reported success rates of EPLBD with EST (74 % – 99 %)
[3]
[5]
[8], and was not significantly different from that observed for EPLBD with EST in the
current study (88 %; P = 0.35). Nearly 80 % of patients in both groups achieved complete ductal clearance
in one endoscopic session, which is similar to that previously reported for EPLBD
with EST [6]. In addition, no significant difference was observed in the need for mechanical
lithotripsy (EPLBD alone 6.5 % and EPLBD with EST 9.1 %). These findings suggest that
EPLBD alone provides sufficient orifice dilation for stone removal, and that it is
a reasonable alternative treatment for the removal of large CBD stones. These results
concur with those of a previous retrospective study, in which 131 patents with large
CBD stones were treated by EPLBD alone (n = 62) or by EPLBD with EST (n = 69), and
overall successful stone removal rates were not significantly different (96.8 % and
95.7 %, respectively) [11].
Theoretically, EPLBD alone is easier to perform than EPLBD with EST, and thus, would
be expected to shorten procedure times. In a retrospective comparative study, procedure
times from successful CBD cannulation to complete stone removal were found to be significantly
shorter for EPLBD alone than for EPLBD with EST (21.5 vs. 17.3 minutes; P = 0.04) [13]. However, in the current study, total procedure time was longer for EPLBD alone
(20.5 minutes) than for EPLBD with EST (18.0 minutes; P = 0.08), which probably reflects the number of endoscopic sessions required for complete
stone removal; 16.3 % of patients in the EPLBD group and 11.4 % of patients in the
EPLBD with EST group required multiple endoscopic sessions. These findings demonstrate
that EPLBD alone does not reduce total procedure time compared with EPLBD with EST.
Debate regarding the safety of EPLBD for the treatment of large CBD stones has continued
since the technique was introduced in 2003, especially with respect to PEP [14]. Although the mechanisms of pancreatitis after EPLBD are unclear, the risk of EPLBD-related
pancreatitis is believed to be related to pressure loading of the orifice of the main
pancreatic duct during balloon dilation and consequent pancreatic duct obstruction
[15]
[16]
[17]. Thus, performing EST prior to EPLBD might reduce the incidence of pancreatitis
because it separates pancreatic and biliary orifices and directs balloon dilation
forces away from the pancreatic duct [1]
[18]. However, the current study showed that PEP is rare after EPLBD regardless of EST,
and that the two techniques have similar PEP rates (EPLBD alone n = 1; EPLBD with
EST n = 3; P = 0.62). These results are supported by the findings of a previous comparative, retrospective
study on EPLBD alone vs. EPLBD with EST conducted by Hwang et al., in which the PEP
rates of EPLBD with EST and EPLBD alone were found to be similar (P = 0.59) [11]. Therefore, we suggest that performing EST before EPLBD will probably not reduce
the rate of pancreatitis substantially.
Most researchers in Eastern populations have reported no direct link between endoscopic
balloon dilation and pancreatitis risk, and our results concur. However, studies in
Western populations have reported significantly higher incidences of PEP after endoscopic
balloon dilation [19]. In our opinion, this phenomenon is probably due to racial differences rather than
to variabilities in the techniques used for balloon dilation of the biliary orifice
or stone extraction techniques. Sphincter of Oddi dysfunction (SOD) is a benign noncalculous
obstructive disorder encountered at the level of the Sphincter of Oddi that causes
pancreaticobiliary-type pain. Clinical suspicion of SOD before ERCP has been reported
to be a strong independent predictor of PEP (a PEP rate of 19.1 % was reported when
SOD was suspected) [20]. The pathogenesis of SOD in a background of developing pancreatitis is not well
understood, but it may be caused by poor outflow of pancreatic juice caused by post-procedural
spasm of the Sphincter of Oddi. No study has been conducted on the prevalence of SOD
in normal populations, and thus, it is not clear whether the prevalence of SOD is
race dependent. However, it is generally accepted that the prevalence of SOD in Western
countries is higher than in Asia. In a large single-center series (Indianapolis, USA)
involving 1241 patients with recurrent pancreatitis, SOD (40.3 %) was found to be
the most common etiology of recurrent pancreatitis [21]. Conversely, according to reports issued in Asian countries [22]
[23], biliary microlithiasis is the most common cause of recurrent pancreatitis and SOD
is unusual. Therefore, different prevalences of SOD in the West and East might underlie
different PEP incidences after balloon dilation.
Differences between the nature of the stones extracted in Asian and Western populations
might also affect the incidence of PEP. In the West, the majority of CBD stones are
cholesterol stones that originate from the gallbladder and fewer than 10 % of CBD
stones are formed de novo within the CBD. In contrast, in Asia, because of a higher
incidence of chronic biliary tree infection and infestation, pigment stones are much
more common [24]. Unlike cholesterol stones, pigment stones are often soft and easily broken [25], and thus, clearance is often achieved by retrieval balloon sweeping and using a
basket, even in cases of inadequate papilla dilation; whereas, for cholesterol stones,
especially large stones, complete clearance frequently requires mechanical lithotripsy
and multiple endoscopic sessions, which are potential risk factors for PEP.
In the current study, no clinically significant hemorrhage was encountered in either
group. Minor intraprocedural bleeding was noted in some cases during EPLBD but this
was controlled easily in all cases by spraying diluted epinephrine solution. Delayed
bleeding did not occur in any patient. In previous studies, bleeding rates during
EPLBD have been reported to vary between 0 % and 9 % [1]
[8]
[18]
[26], and bleeding rates have been reported to be significantly higher for EPLBD with
large EST (8.3 % – 9 %) than for EPLBD alone or EPLBD with minor EST [1]
[4]. In the current study, the extent of ampullary incision during prior EST was limited
to a third of the total ampulla length. We believe that both EPLBD with limited EST
and EPLBD alone are safe with respect to procedure-related bleeding.
Perforation is a rare but the most serious adverse event after EPLBD. Although almost
all patients who develop retroperitoneal perforation recover with medical treatment,
perforation often requires surgical treatment and is potentially life threatening
[27]. In the current study, perforation was not encountered in either group. To prevent
perforation, we used a cautious balloon inflation technique, whereby the balloon was
gradually inflated up to the target diameter, and if a balloon waist was observed
in the distal CBD during inflation, no further pressure was applied until the waist
disappeared. Generally, we find that the balloon waist disappears after waiting for
about 1 minute, but if the waist does not disappear, we suggest conversion to an alternative
stone retrieval method or repeat ERCP, because failure to disappear suggests the presence
of an invisible biliary stricture.
Having achieved good results of EPLBD for large CBD stone removal, some investigators
have tried to extend the indication of EPLBD to patients with large stones, a tapered
distal bile duct, or stricture of the distal bile duct [3]
[8]. However, perforation, which is the most serious adverse event of EPLBD, is more
likely to occur in patients with distal bile duct stricture. In a retrospective study
of 945 patients from South Korea who underwent large CBD stone removal by EPLBD, it
was reported that distal CBD stricture independently predicted perforation (odds ratio
17.08; P < 0.001) [28]. Therefore, we suggest that the presence of a distal CBD stricture should be considered
a relative contraindication to EPLBD. In addition, EPLBD alone would be more effective
in patients with a predicted dilated CBD diameter greater than that of the stone (due
to the risk of bile duct perforation). In cases with insufficient ampulla dilation,
mechanical lithotripsy or multiple endoscopic sessions would be required to achieve
complete CBD clearance. In the current study, mechanical lithotripsy was required
to remove stones in 14 patients, and stone diameter to CBD diameter ratios tended
to be larger in patients who required mechanical lithotripsy (median ratio 1.2, range
0.88 – 2.5) than in those who did not (median 1.0, range 0.4 – 2.0), although this
result was not statistically significant (P = 0.28). Therefore, we recommend that EPLBD alone is used in patients with a maximum
CBD diameter large enough to accommodate the largest stone.
The current study has several limitations that require consideration. First, intent-to-treat
analysis was not conducted, and thus, our results are subject to the effects of crossover
and dropout. However, the aim of this study was to compare the adverse event rates
and effectiveness of EPLBD with EST vs. EPLBD alone. Thus, the intent-to-treat approach
was not actually required because the study was designed to provide information about
the potential effects of treatment policy rather than on information on the potential
effects of specific treatments. Second, the presence of a tapered CBD can also cause
stone removal difficulties despite adequate balloon dilation [5], and we did not address this topic. Third, a large CBD stone was defined as a stone
diameter of ≥ 10 mm because many authors have defined CBD stones > 10 – 15 mm in diameter
as “large.” However, no consensus has been reached on the definition of a “large CBD
stone.” Based on clinical experience, a stone of 10 – 11 mm can be removed effectively
using conventional methods even if EPLBD is not used. In the current study, the median
largest CBD stone diameter was 13.6 mm, but 40 patients (20 %) had a largest stone
that was < 11 mm. Therefore, it is possible that the current study exaggerates the
efficacy of EPLBD regardless of EST. Finally, long-term outcomes of EPLBD with EST
and EPLBD alone were not evaluated.
In conclusion, the current study shows that procedural success and adverse event rates
of EPLBD without EST are comparable to those of EPLBD with EST, and thus, indicate
that EPLBD alone could be considered a useful alternative modality for the treatment
of large CBD stones.
