have employed endoscopy performed on live anesthetized pigs and dogs [39–42]. Using live animals provides the best possible tactile “feel” of real tissue and endoscope movements with conditions most closely resembling those that occur during human endoscopy. Specifically, this includes the presence of luminal fluid, motility, and the ability to cause real bleeding and perforation (Video 1.5). Such courses have been conducted to teach therapeutic techniques, most notably ERCP and EUS [41]. At present, live animal courses are the only means of nonhuman simulation of sphincter of Oddi manometry [42].
Although clearly advantageous for the above reasons, live animal courses also present some substantial drawbacks. Among these are that animals are very expensive to maintain and there are significant ethical considerations in using animals for training. These ethical considerations are magnified by the fact that ex vivo alternatives now exist for teaching most techniques and do not require sacrificing any animals solely for this purpose. In contrast to the multiple uses possible on other simulator types, once certain procedures, such as sphincterotomy, are performed, it is difficult or impossible for others to practice the same techniques on the same animal.
For these and other reasons, training on live animals, while potentially more realistic than on inanimate simulators, appears now to be on the wane in the evolution of endoscopic training techniques. It appears likely that live animal courses will be limited to advanced procedures such as sphincter of Oddi manometry, for which no comparable inanimate model exists, and advanced training in ESD and NOTES®. For the latter techniques, many of the skill sets would still be best taught in inanimate tissue models, saving the live animal work for later training in which real physiological conditions and the potential for complication management is required. Live animal endoscopy laboratories remain well suited for clinical investigation. Finally, testing of new accessories and development of new techniques on live animals will likely continue, but much of the groundwork for these tests will have been already completed on inanimate simulators.
Computer simulation
Parallel to the introduction and adoption of ex vivo animal tissue models has been the development of increasingly sophisticated computer simulators. The technology has evolved to incorporate two main features, the ability to vary the pathology encountered and refinements of forced feedback or “haptics” to improve the realism of the earlier static models.
A number of investigators have pioneered efforts to produce computer models, which can allow a realistic experience of handling the endoscope, and are also able to incorporate broad exposure to pathologic images [20, 43–53]. Because so many diverse images can be stored, computer simulation offers the best opportunity to expose trainees to a wide range of pathology. Computer‐based learning can take place either independently or as part of larger training courses, and progressive tutorials of increasing difficulty can be constructed. Unlimited repetition and drilling in specific infrequently encountered procedures is possible. Moreover, progress during training can be recorded and opportunities for feedback exist.
Computer simulators typically utilize a “real” endoscope passed into a dummy mannequin. Tactile feedback capability, generated by sensors on the endoscope tip, is a key feature. The experience is enhanced by incorporation of real video images. Moreover, insufflation, suction, and bowel wall motility can be reproduced. An ASGE technology assessment statement on simulators describes in detail the innovative technological developments in this field [43]. The images on the display can be derived from interactive video stored on the computer or external storage devices, computer‐generated images, or a combination of both.
The AccuTouch® endoscopy simulator (Immersion Medical) system (Figure 1.12) (http://www.immersion.com/products/medical/endoscopy.html) allows training in a number of procedures, including flexible sigmoidoscopy and colonoscopy, as well as bronchoscopy. It is possible to practice mucosal biopsy on this model. The simulator provides direct performance feedback to the trainee. A number of validation studies have been conducted using this simulator [53–56], which will be covered in detail in Chapters 5 and 6 of this book.
The GI Mentor II (Simbionix) (Figure 1.13) (http://www.simbionix.com/GI_Mentor.html) offers several diagnostic and therapeutic modules [49]. Upper and lower endoscopy and ERCP are all performed on the same mannequin using a special endoscope for each procedure type. An accessory channel allows the endoscopist to perform a variety of therapeutic techniques, including biopsy, polypectomy, sclerotherapy, and electrocoagulation to control active bleeding, ERCP cannulation, and sphincterotomy. This simulator also includes some manual dexterity training exercises ideal for beginners to develop skills controlling the endoscope dials and using torque. The logical descendent of the Lucero model and progressive training program, the simulator incorporates a series of cases of varying pathology and technical difficulty. Instructors may delineate specific training programs. Trainees can get immediate feedback during and after completing each simulated procedure. In fact, the computer will even generate an expression of pain for overinsufflation or excessive looping of the instrument. Performance is recorded, including numbers and types of errors made. The instructor can review the progress of each trainee and the written procedure reports to determine whether abnormalities were correctly detected and identified; feedback messages may be sent back to the trainee.
Figure 1.12 Immersion AccuTouch® colonoscopy simulator.
Figure 1.13 GI Mentor II (Simbionix) colonoscopy virtual reality simulator.
The GI Mentor II computer simulator has been incorporated into a number of European endoscopy courses, most notably in Scandinavia [57–59]. Respondents to questionnaires have expressed great satisfaction with the limited experience on the GI Mentor II simulator. As with the AccuTouch® simulator, a number of objective validation studies have been carried out for the GI Mentor II, and these data are presented in detail elsewhere in this book in Chapters 5 and 6.
If computer simulators are to have a role in credentialing in addition to training, they must be able to distinguish between a novice and an accomplished endoscopist. A study from the Mayo Clinic demonstrated that performance parameters on the simulator vary according to real colonoscopy experience [56]. To date, however, no investigator has shown that a particular performance level measured on a computer or any other simulator is predictive of competent performance on subsequent real endoscopy.
The Olympus colonoscopy simulator was a colonoscopy‐specific simulator based on advanced mathematical models developed in the late 2000s. Among its features, this model attempted to better simulate more difficult colonoscope passage [60, 61]. While this model was discontinued and is not commercially available, the rationale and performance characteristics to which it aspired remain critical to current simulator development and needs. For, it is enhanced realism and simulated procedure challenge that will be