A simple model for a complex procedure: broadening access to endoscopic retrograde cholangiopancreatography simulation

Endoscopic retrograde cholangiopancreatography (ERCP) remains one of the most technically demanding procedures in gastrointestinal endoscopy. Its complexity, the need for coordinated endoscopic and fluoroscopic skills, and the potential for serious adverse events make supervised training essential. However, the number of clinical procedures required to achieve proficiency may be difficult to obtain during standard fellowship training, particularly in institutions with limited case volumes or educational resources.1,2 Simulation can help bridge this gap by enabling trainees to acquire basic psychomotor skills before performing ERCP in patients. Nevertheless, currently available options, including live animal models, ex vivo tissue platforms, virtual reality systems, and commercial mechanical simulators, are often constrained by cost, infrastructure requirements, accessibility, or incomplete tactile realism.3

In this issue of Clinical Endoscopy, Tiwari and Khanikar4 present a minimalistic ERCP simulator constructed from readily available materials at a reported materials cost of US $47.32. The model comprises a polyurethane foam base, cardboard tubes, a polyvinyl chloride bile duct and papillary orifice, and an onion bulb positioned over an electrosurgical grounding pad to enable needle-knife precut practice. The authors achieved selective biliary cannulation in 48 of 50 technical testing sessions and functional electrocautery in 24 of 25 precut attempts. They also demonstrated compatibility with fluoroscopic imaging and reported favorable assessments from eight experienced endoscopists. These results support the technical feasibility and preliminary face validity of the model.

The principal contribution of this study is not the development of a comprehensive replacement for existing ERCP simulators. Rather, it demonstrates how a focused and inexpensive design may address specific training needs in settings where access to sophisticated simulation systems is limited. Previous mechanical and three-dimensional printed simulators have shown that selective cannulation, scope positioning, and accessory manipulation can be practiced outside the clinical environment.5,6 However, specialized fabrication requirements and acquisition costs may restrict their widespread adoption. The addition of an inexpensive electrocautery-capable module is therefore particularly noteworthy. Needle-knife access techniques are usually performed during difficult biliary cannulation, when the clinical environment is least suitable for early-stage learning.7 A platform that enables repeated practice of scope stabilization, needle control, incision orientation, and electrosurgical activation without risk to patients may offer meaningful educational value.

However, accessibility should not be equated with educational validity. The reported 96% cannulation success rate primarily confirms that the device functions as intended; it does not demonstrate that simulator training improves trainee competence or clinical outcomes. The technical testing was conducted within the model’s development environment, and the expert evaluation included only eight participants. The simulator has not yet established construct validity by discriminating between novice and experienced operators, concurrent validity through correlation with accepted measures of ERCP competence, or predictive validity by demonstrating transfer of simulator performance to clinical practice.8 A device may appear realistic and receive favorable expert ratings while still failing to teach the components of performance that are most relevant to patient care.

The simplified anatomy also defines the appropriate role of this model. It may be suitable for repetitive practice of duodenoscope handling, en face papillary positioning, alignment of accessories with the bile duct axis, selective biliary cannulation, and basic needle-knife movements. However, it does not reproduce pancreatic duct cannulation, periampullary diverticula, variable papillary morphology, duodenal motility, respiratory movement, bleeding, or the consequences of excessive tissue injury. Additionally, it cannot currently provide comprehensive training in stone extraction, stricture management, or stent placement. These limitations do not diminish its potential value but indicate that the model should be regarded as an introductory or complementary simulator within a broader competency-based training curriculum rather than as a stand-alone tool for determining ERCP competence.

The next step should be formal educational validation. A multicenter study involving novice, intermediate, and expert endoscopists could evaluate whether standardized measures such as cannulation time, number of papillary contacts, loss of scope position, and precut trajectory differentiate levels of experience. Subsequent randomized studies should assess skill acquisition, retention, and transfer to supervised clinical ERCP. Independent video-based assessment and predefined procedural error criteria would help minimize evaluator bias. The low material costs of the model may facilitate such research by enabling repeated and distributed practice rather than occasional access to a centralized simulation facility.

The cost findings should also be interpreted carefully. The reported amount represents the material costs of the model and assumes access to a duodenoscope, electrosurgical generator, ERCP accessories, reprocessing facilities, and fluoroscopy.4 It therefore does not represent the total cost of establishing an ERCP simulation program. More broadly, the cost of simulation-based education should be evaluated comprehensively by considering the resources required to establish and maintain a training program.9 Nevertheless, the material costs remain substantially lower than those of most commercial simulation systems. This may be particularly relevant to institutions that already possess conventional ERCP equipment but lack a dedicated training platform. Its greatest potential may therefore lie in regional training centers, resource-limited environments, and programs seeking a practical bridge between didactic education and supervised patient-based training.

This proof-of-concept study reminds us that innovation in endoscopic education does not necessarily require highly complex technology. A simple simulator may be valuable when its educational purpose is clearly defined, its limitations are acknowledged, and its claims remain proportionate to the available evidence. The model developed by Tiwari and Khanikar4 should currently be viewed as a promising platform for deliberate practice and future validation rather than as a competency assessment tool or a substitute for supervised clinical training. If subsequent studies demonstrate meaningful transfer of acquired skills to clinical ERCP, this accessible approach may contribute to safer and more equitable endoscopy education.