Introduction
Endoscopic retrograde cholangiopancreatography (ERCP) is one of the most technically
demanding and high-risk procedures in gastrointestinal endoscopy. Traditionally, trainees
have learned endoscopy by hands-on training in clinical setting on real patients under
the supervision of an experienced endoscopist. In recent decades, simulators have
assumed an important role in creating sufficient hands-on training without compromising
patient safety and creating a safe learning environment for trainees [1]. Despite the fact that ERCP seems to be an ideal platform for simulation-based training,
limited data are available on simulators in training ERCP. Recently, our study group
has validated a novel mechanical ERCP simulator, the Boškoski-Costamagna ERCP Trainer
[2]. This simulator allows novice trainees to practice cannulation, stent placement
in both common bile duct (CBD) and pancreatic duct (PD), and CBD stone extraction.
To date, this simulator has not been equipped with a papilla that could be used to
train endoscopic sphincterotomy.
Endoscopic sphincterotomy was first reported in 1974 and is one of the key therapeutic
interventions during ERCP [3]. At the same time, it is also considered one of the riskier parts of the procedure.
This is because of its technical difficulty and the associated risk of bleeding, perforation,
and post-ERCP pancreatitis [4]
[5]. These complications are most often a result of an incorrectly performed sphincterotomy
and frequently associated with trainees or inexperienced endoscopists [5]. First experience in sphincterotomy is usually acquired through practice during
live cases in an “on-the-job” setting. It goes without saying that, for both trainees
and trainers alike – let alone the patient – this is not the ideal situation in which
to do training on such a complex procedure. Ideally, such training requires a simulated
setting that resembles the real thing as close as possible without jeopardizing patient
safety and preferably with the ability to break down the procedure in steps that can
be repeated as many times as necessary in order to gain proficiency. Currently, only
a handful of training models are available for training ERCP and not every model is
equipped for using in training on sphincterotomy. Available training models include
in vivo and ex vivo training simulators, mechanical simulators, and virtual reality
simulators [6]
[7]
[8]
[9]
[10]
[11]
[12]. Each training model has its own prominent features, but all the devices have important
limitations, including ethical and practical concerns, differences in anatomy of the
papilla, and lack of realism and tactile feedback. Up until now, no optimal training
model for training sphincterotomy has been designed. A novel synthetic papilla has
recently been developed and produced by Cook Medical (Cook Medical, Limerick, Ireland)
for the Boškoski-Costamagna ERCP Trainer for use in training on sphincterotomy. This
is a single-use synthetic papilla that can be easily replaced for repeated attempts
at sphincterotomy. Validity assessment of a simulator can be performed on various
levels. One of the most commonly used forms of validation is face validity. Face validity
is evaluated by a defined group of subjects who are asked to judge the degree of resemblance
between a training model and the real activity. The aim of this study was to evaluate
the extent to which the novel papilla simulates real-life endoscopic biliary sphincterotomy,
and to assess the didactic value or potential of the papilla for sphincterotomy training.
Materials and methods
Synthetic papilla
The synthetic papilla is a newly developed insertable component in the previously
described mechanical ERCP simulator, the Boškoski-Costamagna ERCP Trainer (Cook Medical,
Limerick, Ireland) [2]. It can be used to perform sphincterotomy. This novel synthetic papilla is made
out of rubber and metal filaments and can be easily manually inserted into the Boškoski-Costamagna
ERCP Trainer ([Fig. 1] and [Fig. 2]). It is a single-use disposable papilla, with a specific alloy allowing for electrical
conduction and cutting of the material with all commercially available sphincterotomes
and needle knives.
Fig. 1 The synthetic papilla. a Front view of the papilla. b Close-up of the papilla, demonstrating the rubber with incorporated metal filaments.
Fig. 2 The Boškoski-Costamagna ERCP Trainer. (Source: Cook Medical, Bloomington, Indiana)
Participants
We included participants with broad experience in ERCP based on lifetime endoscopic
experience. Expressing experience levels in ERCP remains debatable, and currently
there is no consensus in the literature. In our previous study [2] we attempted to define four groups of participants according to the most reported
numbers in the literature [13]
[14]
[15]. We set the bar for defining an individual as an ERCP expert at 2500 ERCPs to ensure
that participants had an irrefutable reputation and broad experience in performing
sphincterotomy.
Sphincterotomy simulation setting
All participants performed a simulator session during the course of the UEG Week in
2016 in Vienna, Austria. Experts were asked to perform a single biliary sphincterotomy
and to fill out a questionnaire on demographics, medical experience, and endoscopy
experience, including the numbers of ERCP procedures performed annually and estimated
lifetime numbers. We asked participants to perform a sphincterotomy using a standard
sphincterotome (Omnitome, Cook Medical, Limerick, Ireland) ([Video 1]). Following this assignment, they were asked to rate their appreciation of the realism
of the cutting papilla. Appreciation was expressed on a 10-point Likert scale [16], varying from very unrealistic (1) to very realistic (10). Questions were asked
about the realism of performing sphincterotomy, anatomical representation, difficulty,
the actual cutting, and the achieved cutting result. Furthermore, experts were asked
to evaluate the didactic value of the cutting papilla on a 4-point Likert scale, varying
from strongly disagree (1) to strongly agree (4).
Video 1 Training sphincterotomy on the synthetic papilla.
Data analysis
Statistical analyses were performed using IMB SPSS Statistics, Version 24.0 (IBM Corporation,
Armonk, New York, United States). Descriptive statistics were used for all measures.
Data are presented as median and interquartile range. Inter-rater agreement and reliability
were evaluated by computing the intraclass correlation coefficient (ICC) in a two-way
mixed model.
Results
Participants
In total, 40 ERCP experts participated in this study originating from 16 different
countries worldwide. Of the participants, 37 were gastroenterologists and the remaining
three participants (7.5 %) were surgeons. All participants were male, with a mean
age of 49.6 years (standard deviation 9). Mean number of years in practice as an endoscopist
was 20.9 (interquartile range 11). All participants completed the assignment and filled
out the questionnaire. Baseline characteristics can be found in [Table 1].
Table 1
Expert baseline characteristics.
|
Characteristic
|
|
|
Male, n (%)
|
40 (100 %)
|
|
Age, years[1]
|
49.6 (9)
|
|
Number of countries
|
16
|
|
Profession, n (%)
|
|
|
37 (92.5)
|
|
|
3 (7.5)
|
|
Endoscopic experience, years[2]
|
20.9 (11)
|
1 Data are expressed as mean and standard deviation.
2 Data are expressed as median and interquartile range.
Face validity
The experts rated the anatomical representation of the synthetic papilla 8 on a 10-point
Likert scale. Adequacy to position the endoscope in front of the papilla scored 9.
[Table 2] shows the experts’ ratings on the papilla and its performance. The realism of performing
a biliary sphincterotomy scored 7 on a 10-point Likert scale. Resemblance of maneuvers
compared to real life scored 8 by the experts and the associated tactile feedback
scored 7 on a 10-point scale. The experts scored the cutting as realistic with a 6
and the cutting result was rated 8 on a 10-point scale. The Intraclass Correlation
Coefficient demonstrated strong agreement between the experts (ICC = 0.917), with
a 95 % CI of 0.796 to 0.983.
Table 2
Expert opinion on novel synthetic papilla.
|
Expert opinion
N = 40
|
|
Resemblance to the real papilla
|
8 (4)
|
|
Position in front of the papilla
|
9 (1)
|
|
Realism of performing sphincterotomy
|
7 (1)
|
|
Making the exact maneuvers as in real life
|
8 (1)
|
|
Realism of haptic feedback
|
7 (3)
|
|
Cutting is perceived as expected
|
6 (3)
|
|
Cutting result
|
8 (1)
|
Data are expressed as median and interquartile range
Didactic/training value
Experts rated the papilla as a useful tool in basic training of novice endoscopists
(4 on a 4-point scale; interquartile range [IQR] 0) and they unanimously agreed that
the synthetic papilla should be incorporated in a training curriculum (4 on a 4-point
scale; IQR 0). The experts’ opinion was that the expertise gained with the synthetic
papilla is transferrable into the clinical setting (4 on a 4-point scale; IQR 1).
The role of the synthetic papilla in training more experienced ERCPist was rated to
be limited according to the experts (rated 2 on a 4-point scale; IQR 3). The ICC for
the average of the 40 experts was 0.983 with a 95 % CI of 0.951 to 0.998, indicating
an excellent level of inter-rater agreement and reliability.
Discussion
Performing a sphincterotomy is one of the key elements in ERCP and is considered a
challenging and high-risk procedure. Yet what that training of endoscopists should
look like and how ample it should be to ensure that sphincterotomies are performed
safely is a much-debated topic. The most obvious reason why current training practice
is considered suboptimal is lack of a suitable, representative, and safe simulator
training environment. Here we report the first results with and validation of a synthetic
papilla that can be used for training sphincterotomy in the Boškoski-Costamagna ERCP
Trainer. Data from the current study demonstrate good face validity and ERCP experts
from all over the world highly agree on the didactic value and added value of this
papilla in the training curriculum for novice endoscopists.
Recently, we presented the Boškoski-Costamagna ERCP Trainer, a mechanical simulator
for training ERCP [2]. Experts agreed on the didactic strength of the simulator and the added value of
this simulator in the training curriculum for novice endoscopists. An important limitation
of this model was inability to train on sphincterotomy. Currently, most endoscopists
are being trained in sphincterotomy – including their first attempts with the procedure
– on real patients. This is not a desirable situation because there is little to no
room for mistakes, potentially putting patients at risk. Furthermore, clinical training
opportunities are limited by the available patients that require a papillotomy and
the time and availability of an experienced endoscopist to train the novice ERCPist
appropriately. The optimal learning environment is a setting where the procedure can
be repeatedly simulated step by step in the most realistic way possible with room
for mistakes, thus enabling trainees to train inexhaustibly and gain technical skills
and confidence before being exposed to such a procedure in a real-life patient.
Despite the potential of currently available training models [6]
[7]
[8]
[9]
[10]
[11]
[12], all these simulators have certain limitations and an optimal model for training
sphincterotomy has not been developed yet. In terms of realism, biosimulation models
and live porcine models are superior [8]
[17]. Live anesthetized pig models have been shown to be adaptable to all procedural
aspects of ERCP, including sphincterotomy. In a study by Sedlack et al. 48 participants
followed a 2-day training course and showed an increase in confidence scores, especially
in complex procedures such as needle-knife pre-cut sphincterotomy [18]. The Erlangen ERCP model [7], an ex vivo tissue model, has been scored as one of the most realistic and useful
available training models [17]. Major drawbacks of both in vivo and ex vivo tissue models include important differences
between human and porcine anatomy (e. g. location of papilla) and, importantly for
training purpose of sphincterotomy, the papilla of the live porcine model can only
be used once. The complete set-up requires a lot of preparation and is therefore probably
only used in workshops and not in daily training. In addition, costs and organizational
difficulties due to the ethical considerations make this type of simulator setup difficult
to incorporate in a training curriculum. Known mechanical trainers for training ERCP
include the ERCP Mechanical Simulator (EMS) and X-Vision ERCP Training System [10]
[11]. Training sphincterotomy on the X-Vision ERCP Training System [11] was carried out using an organic papilla. No details have been provided on the biomaterials
that were used. The EMS [10] consists of a disposable papilla constructed of foam, held in place by electrical
contacts with conducting gel providing electrical conductivity. Studies validating
the use of the EMS for training sphincterotomy are lacking. Computer modules for training
endoscopic sphincterotomy are available on the Simbionix GI Mentor, with the possibility
to train on possible complications as well (e. g. bleeding, perforation). However,
the model has received low scores for realism because of a major lack of tactile feedback
and control of handling real equipment [13].
All experts in our study agreed that the novel synthetic papilla mimics the human
papilla well for training biliary sphincterotomy. They were satisfied with the realism
of performing a sphincterotomy, mainly with the opportunity to practice the exact
maneuvers needed to correctly perform the procedure. Tactile feedback fromf the synthetic
papilla was evaluated positively, despite the fact that the papilla is constructed
from rubber. This probably also explains why the cutting effect was rated only 6 as
it is not the same as cutting living tissue. The obvious advantage of the synthetic
papilla is that it is easily replaced by a new one after it has been cut, thereby
offering the possibility of repeatedly training on the procedure. Importantly, its
use is not impeded by ethical concerns, given the mechanical origin of the simulator
and papilla. The expert opinion on the possibility of using the synthetic papilla
as a training tool was considered of great value in our study and all agreed that
the synthetic papilla is a useful tool in training novice endoscopists to perform
sphincterotomy. Experts also agreed that the expertise gained on the papilla should
be directly transferrable to a clinical curriculum.
Despite the enthusiasm of experts for the synthetic papilla as a training tool for
biliary sphincterotomy, some limitations remain, including absence of simulation of
potential complications such as bleeding and perforation. Also, due to the mechanical
nature of the simulator, there is no peristalsis and therefore, endoscopic control
and positioning still differs from the real-life situation.
Notwithstanding these limitations, we believe that this novel synthetic papilla offers
added value over currently available simulator options for training sphincterotomy.
It has the advantage that a real endoscope with real accessories are used in a validated
mechanical ERCP trainer model, providing novice endoscopists with a safe opportunity
to learn how to execute the necessary movements and actions under the supervision
of an experienced endoscopists in order to perform a real sphincterotomy plus the
ability to train on the various steps in the procedure as many times as desired.
Conclusion
This novel synthetic papilla is a validated tool for training biliary sphincterotomy
on the Boškoski-Costamagna ERCP Trainer. We have demonstrated good face validity,
meaning that this papilla can be used to perform sphincterotomies that resemble the
real-life situation. ERCP experts highly agree on the didactic value and added value
of this papilla in the training curriculum for novice endoscopists.
