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[16]. Specific chapters in this volume address training as it relates to quality in endoscopy and to specific standards for each of the major endoscopic procedures that are performed. Apart from the specific recommendations about learning particular procedures, a number of themes have emerged throughout all current guidelines, which reflect the evolution of the concepts of optimal training in endoscopy. Key principles include the following:

       Specificity of training and privileging: Individuals must be trained for each particular procedure they wish to perform.

       Threshold numbers for competency: Guidelines have steered away from earlier emphasis that trainees gain competence after independently performing a certain minimum number of procedures. It has been increasingly accepted that numbers do not guarantee competency; individuals develop proficiency at different rates; and accordingly, the best way to assess competency is to do so on the basis of some objective measures. Threshold numbers have been derived from evidence‐based studies in which objective competency for a particular procedure is achieved after a particular amount of training; however, these numbers are now viewed merely as a minimum amount of training that must be performed before competency can even be assessed. The end point of successful endoscopic training should be objective demonstration of competency.

Emergence of complementary teaching modalities

      Why use simulators?

Simulators have been proposed as a way to facilitate endoscopic training from the time of the earliest development of the field. In fact, Rudolf Schindler described using a model stomach for practice in orientation [17]. Many of the items in the “skill sets” listed above, and particularly those that involve dexterity, hand–eye coordination, and recognition of normal anatomy and abnormal pathology, can be addressed through the use of various endoscopic simulators.

      Endoscopy simulators, including ex vivo artificial tissue, animal tissue, and virtual reality computer‐based models, provide a unique method for endoscopic teaching. These devices allow for teaching which is free from the possibility of patient discomfort or injury. This factor alone confers several benefits to the learning process. First, the stress of the learning environment is reduced for the trainee and the trainer alike. There is more time for questions and feedback than available when an actual patient is involved. The issue of reduced trainee endoscope time due to critical clinical exigencies is eliminated, and there is ample opportunity for repetition. In fact, the sequence of demonstration of proper technique, repetitive practice of skills with expert feedback, and assessment of skill are all possible in this environment. Creative teaching exercises such as demonstrating common errors and what constitute poor technique are also uniquely possible using such alternative means of instruction to the traditional proctored human endoscopy setting for instruction (Video 1.1). In this way, simulators can confer excellent opportunities for “standard” techniques to be practiced by trainees and allow for new procedures to be taught to experienced clinicians [1]. To the extent that certain models might be used independently by trainees without real‐time instructor feedback, and to the extent that simulator work might hasten the time in which trainees can perform unsupervised procedures on their own, simulators also have the potential to address the time constraints facing endoscopy instructors with substantial nonteaching clinical responsibilities of their own to fulfill. However, as we will relate below, much of the actual effective learning using endoscopy simulators does require fairly labor‐intensive expert instruction, and to date, the potential for freeing up time spent mentoring trainees has not yet been realized.

      Evolution and types of endoscopy simulators

      Static models

      The initial attempts to complement endoscope training with simulators utilized static models. Such “phantoms” were intended to teach basic hand–eye coordination, the use of the endoscope dials, and even the recognition of basic pathology. In the 1970s, as upper endoscopy and colonoscopy were becoming established as important modalities, other models were developed. These included the Heinkel hemispheric anatomical model [18] and the upper GI plastic dummy introduced by Classen [19].

In the early 1970s, homemade demonstration models of the colon, featuring a mobile transverse colon and the ability to demonstrate an “N” or alpha loop, were devised (Figure 1.2). In 1972, a colonoscopy model fashioned from the spiral metal‐reinforced tubing of a hair dryer was introduced, with the ability to demonstrate corkscrewing movements (Figure 1.3). This early simulator featured the ability for the colonoscope to “become stuck” and then to be “straightened out.” Christopher Williams’ St. Marks/KeyMed colonoscopy model of 1975, shown in Figure 1.4, had an improved feeling of realism and was made commercially available. Twisting movements were required to negotiate the lumen, and endoscopists found it challenging [20].

Figure 1.2 Roller demonstration model (1971): Homemade model showing alpha loop and mobile transverse colon.

      (Courtesy: Dr. Christopher Williams.)

Figure 1.3 Hair dryer tube model (1972).

      (Courtesy: Dr. Christopher Williams.)

Simultaneously, hand–eye coordination models were developed. These included an electronic targeting model (Figure 1.5), which had a photocell at the center, tested two‐handed coordination, and allowed for “scoring” of results. An endoscopic version of the popular game “Pong” was even developed in 1977 (Figure 1.6), allowing for reinforcement of left/right coordination maneuvers in an enjoyable and motivating “game.”

Figure 1.4 St Mark’s/KeyMed model (1975): Commercially available with semirealistic feel.

      (Courtesy: Dr. Christopher Williams.)

Figure 1.5 Electronic targeting model (1975): Tested hand–eye coordination.

      (Courtesy: Dr. Christopher Williams.)

The Imperial College/St Mark’s College Simulator was introduced in 1980 (Figure 1.7) and allowed for insertion of a limited amount of the shaft of an endoscope into the computer model, with real‐time video feedback. This model demonstrated that such devices were feasible, although the particular model was limited by the fragility of the microswitches. Improvements were made over the ensuing 5 years, and by 1985, an updated and substantially more robust version of that simulator existed. The MK2 simulator allowed full “shaft” insertion, a sensation of resistance during looping, and audio tracks to simulate patient

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